WorldWideScience
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 Phenol had been replaced by lignin [that was extracted from black liquor of oil palm empty fruit bunch (EFB)] in synthesizing resin with a ratio lignin to phenol 1:1.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)

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Study on binder system of CO2-cured phenol-formaldehyde resin used in phenol-formaldehyde resin used in foundry  

OpenAIRE

A new aqueous alkaline resol phenol-formaldehyde resin has been prepared from phenol and formaldehyde using NaOH as catalyst; the optimum synthetic process has been determined. With addition of some cross-linking agents, after passing carbon dioxide gas through the resin bonded sand, high as-gassed strength and 24 h strength are achieved. The bonding bridge of the resin bonded sand fracture has been analyzed by using SEM.

Liu Weihua; Li Yingmin; Qu Xueliang

2008-01-01

3

Study on binder system of CO2-cured phenol-formaldehyde resin used in phenol-formaldehyde resin used in foundry  

Directory of Open Access Journals (Sweden)

Full Text Available A new aqueous alkaline resol phenol-formaldehyde resin has been prepared from phenol and formaldehyde using NaOH as catalyst; the optimum synthetic process has been determined. With addition of some cross-linking agents, after passing carbon dioxide gas through the resin bonded sand, high as-gassed strength and 24 h strength are achieved. The bonding bridge of the resin bonded sand fracture has been analyzed by using SEM.

Liu Weihua

2008-05-01

4

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.)

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

OpenAIRE

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-NM...

Nour Eddine El Mansouri; Qiaolong Yuan Mail; Farong Huang

2011-01-01

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A novel thermal degradation mechanism of phenol-formaldehyde type resins  

International Nuclear Information System (INIS)

The thermal degradation of phenol-formaldehyde resins (PFR) was studied using thermogravimetry analysis (TG) technique. The structural changes of thermal degradation of synthetical and commercial PFR were investigated by Fourier-transform infrared rays (FTIR) and solid-state 13C nuclear magnetic resonance (13C NMR) spectroscopy. The experimental results show that the degradation of PFR can be divided into three stages. Additional cross-links are formed and small exposed groups of the cured resin are removed in the first stage. In the second stage, methylene bridges decompose into methyl groups then both phenol and cresol homolog appear. The degradation of phenol group occurs in the third stage. According to these results, a novel degradation mechanism of phenol-formaldehyde type resins is proposed: the mainly degradation process of PFR is the decomposition reaction of methylene bridges in this mechanism instead of auto-oxidation of the methylene bridges in the prevenient mechanism

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Modified phenol-formaldehyde resins and their application in bitumen-polymeric mixtures  

OpenAIRE

Phenol-formaldehyde resins (PhFR) with reactive methacrylate fragments or labile peroxy bonds in the side branches used as a polymeric component of bitumen-polymeric mixtures have been investigated.Taking into account that PhFR with peroxy fragments based on epoxy resin does not described in literature,its synthesis procedure has been developed. The kinetic regularities of the reaction between peroxy derivative of epoxy resin (PDER) and phenol group of PhFR were studied taking the re...

Strap, Galyna; Astakhova, Olena; Lazorko, Olexander; Shyshchak, Oleh; Bratychak, Michael

2013-01-01

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Tannin–Phenol Formaldehyde Resins As Binders for Cellulosic Fibers: Mechanical Properties  

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Full Text Available In this study Eucalyptus tannin (T was isolated from outer bark of Eucalyptus trees; as sodium phenoxide salt and used as extender or copolymer into phenol formaldehyde (PF resin at five percent (10, 20, 30, 40 and 50% W/W. Tan-nin-phenol formaldehyde (TPF and tannin formaldehyde-phenol formaldehyde (TFPF resins that synthesized in this study were evaluated as adhesive material for cellulosic fibers by study the mechanical properties of the composite sheets .The results show that the substituting of (PF with tannin at (10 –50% W/W give resins with mechanical properties comparable or near to those of pure (PF , where the tensile strength at break (Tb ranging from 15.15 Mpa to 22.27 Mpa as compared with 17.6 Mpa for pure (PF; while the impact strength properties (Im of composites sheets increased with increased the (T percents which were about 5.16 KJ/m2 for (TPF – 10% and 7.21 KJ/m2 for (TPF - 50% .On the other hand modification of (T to tannin formaldehyde resin (TF appear less performance at the results of this study , this effect probably to low penetration of (TFPF resins between the small voids of cellulose fibers when soaked it in resin solutions. In general the results of this study indicate that the Eucalyptus tannin can be used for par-tial substitution of (PF to produce resins with feasible mechanical properties and can be used in some applications of (PF resins.

A.S. Hussein

2011-06-01

9

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

Directory of Open Access Journals (Sweden)

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

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Effect of modification with phenol formaldehyde resin on the mechanical properties of wood from Chinese fir  

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Full Text Available Samples of Chinese fir were treated with either low-molecular-weight or commercial phenol-formaldehyde (PF resins. The macro- and micromechanical properties of the treated and untreated samples were determined. The average longitudinal tensile modulus of elasticity (MOE was 30.88% larger for the samples treated with the low-molecular-weight PF resin than it was for the untreated samples. The average MOE of the samples treated with the commercial PF resin was 29.84% less than that of the untreated samples. The micromechanical properties of the samples were investigated through nanoindentation studies. For the samples modified with low-molecular-weight PF resin, the values of average MOE and hardness were 32.94 and 32.93%, respectively, greater than those of the untreated samples. In contrast, the average MOE and hardness values were 11.99 and 18.14%, respectively, greater for the samples modified with commercial PF resin compared to the untreated samples. It could be inferred that the low-molecular-weight PF resin was able to diffuse into the nanopores in the S2 layer of the tracheid cell wall of the Chinese fir, thereby improving its macromechanical properties. Modification with low-molecular-weight PF resin was an effective way to enhance the longitudinal macromechanical properties of wood from the Chinese fir.

Yanhui Huang

2013-02-01

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

Energy Technology Data Exchange (ETDEWEB)

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.

Zhao Mu [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Chinergy CO. Ltd., Beijing 100084 (China); Song Huaihe, E-mail: songhh@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

2010-11-01

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

Energy Technology Data Exchange (ETDEWEB)

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 systems and at higher waste loadings failure results after only a few days. 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. Addition of BFS and sodium hydroxide prevent the formation of these salts by removal of calcium hydroxide from the system in other reactions. (author).

Constable, M.; Howard, C.G.; Johnson, M.A.; Jolliffe, C.B. (AEA Decommissioning and Waste Management, Winfrith (United Kingdom)); Sellers, R.M. (Nuclear Electric plc, Barnwood (United Kingdom))

1992-01-01

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USE OF LIGNIN SEPARATED FROM BIO-OIL IN ORIENTED STRAND BOARD BINDER PHENOL-FORMALDEHYDE RESINS  

Directory of Open Access Journals (Sweden)

Full Text Available Bio-oil produced from fast pyrolysis of biomass has been investigated as a renewable fuel and as a source of industrial chemicals. The lignin fraction of bio-oil produced from wood in our fast pyrolysis reactor was separated by using only water and methanol with a 25% yield based on bio-oil weight. This separation procedure appears to be of lower cost than the reported extraction procedure using ethyl acetate as solvent. The isolated pyrolytic lignin was smoothly incorporated into phenol-formaldehyde resins at 30%, 40%, and 50% phenol replacement levels, and the resultant resins were evaluated as oriented strand board core-layer binders. The evaluation results indicated that the pyrolytic lignin is effective for up to about 40% replacement of phenol in synthesizing wood adhesive type PF resins.

Badamkhand Sukhbaatar

2009-05-01

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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.

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

OpenAIRE

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...

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

2013-01-01

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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)

20

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

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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

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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)

23

Influence of Nanoclay/Phenol Formaldehyde Resin on Wood Polymer Nanocomposites  

OpenAIRE

Selected tropical wood specie was low dense soft wood and it is abundantly available in Borneo Island. This specie is not suitable for construction materials due to their law physical and mechanical properties. In order to overcome this problem the wood species were impregnate by Nanoclay/PF resin system. Raw wood specimens were then placed into an impregnation chamber, in which there was no contact between samples and they were covered completely by nanoclay/PF mixtures. The system was evacu...

Md Saiful Islam,; Sinin Hamdan; Md. Rezaur Rahman,; Abu Saleh Ahmed

2012-01-01

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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 SciELO Mexico | Language: Spanish Abstract in spanish 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

26

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

27

???????????????????? Fabrication of Phenolic Formaldehyde-Basedhollow Carbon Microspheres and Study of Their Pore Structure  

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Full Text Available ?????????????????????????????????460 nm????80 nm??????????????????????????????????????????492.89 m2/g????????4 nm????????In this study, hollow carbon microspheres with diameter about 460 nm and a shell of about 80 nm were fab- ricated using sulfonated polystyrene microspheres as templates and phenolic formaldehyde resins as carbon precursor. The pore structure of hollow carbon microspheres was characterized through nitrogen adsorption method, which showed that the specific area of hollow carbon microspheres was 492.89 m2/g and the pores were mainly composed of mesopores with diameter about 4 nm.

??

2012-07-01

28

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

29

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

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

Science.gov (United States)

...2010-07-01 2010-07-01 false Polymer of substituted phenol, formaldehyde...Specific Chemical Substances § 721.7220 Polymer of substituted phenol, formaldehyde...chemical substance identified generically as polymer of substituted phenol,...

2010-07-01

31

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 SciELO Brazil | Language: English Abstract in portuguese 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

32

Ordered mesoporous phenolic resins: highly versatile and ultra stable support materials.  

Science.gov (United States)

Ordered mesoporous phenolic resins and carbons - an advanced class of ultra-stable mesoporous materials - offer potential applications in the field of catalysis, electrodes and adsorbents. This review gives an extensive overview of the main principles and the recent progress made in the synthesis of these innovative materials using the soft-template method. Furthermore, the versatility towards functionalization and the incorporation of hetero-atoms in the organic framework of the mesoporous resins and carbons are considered. Finally, the broad range of potential applications is discussed and future perspectives in the field of mesoporous polymers and carbons are given. PMID:22525791

Muylaert, Ilke; Verberckmoes, An; De Decker, Jeroen; Van Der Voort, Pascal

2012-07-15

33

Thermal Properties of Capparis Decidua (ker) Fiber Reinforced Phenol Formaldehyde Composites  

International Nuclear Information System (INIS)

Simultaneous measurement of effective thermal conductivity (?), effective thermal diffusivity (?) and specific heat of Ker fiber reinforced phenol formaldehyde composites have been studied by transient plane source (TPS) technique. The samples of different weight percentage typically (5, 10, 15, 20 and 25%) have been taken. It is found that values of effective thermal conductivity and effective thermal diffusivity of the composites decrease, as compared to pure phenol formaldehyde, as the fraction of fiber loading increases. Experimental data is fitted on Y. Agari model. Values of thermal conductivity of composites are calculated with two models (Rayleigh, Maxwell and Meredith-Tobias model). Good agreement between theoretical and experimental result has been found.

34

21 CFR 177.2260 - Filters, resin-bonded.  

Science.gov (United States)

...chapter. Melamine-formaldehyde chemically modified with methyl alcohol. Melamine-formaldehyde chemically modified with urea; for use only as provided...this section. Phenol-formaldehyde resins. Polyvinyl...

2010-04-01

35

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

OpenAIRE

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 usin...

Lv, J.; Meng, L. T.; Wei, C.; Yu, C. B.; Liu, H. X.

2012-01-01

36

Adhesive bonding of beech wood modified with a phenol formaldehyde compound  

OpenAIRE

Untreated (controls) and phenol–formaldehyde (PF)-modified beech wood (10 and 25 % solid content) were glued with phenol resorcinol formaldehyde (PRF) and polyvinyl acetate (PVAc). Shear strength of PRF-bonded specimens was higher than that of PVAc-bonded ones under dry and wet conditions irrespective of the pre-treatment. Under dry conditions, only PVAc-bonded specimens exhibited reduction in shear strength due to PF-modification with 25 % PF concentration as compared to the controls. PF...

Adamopoulos, Stergios; Bastani, Alireza; Gasco?n-garrido, Patricia; Militz, Holger; Mai, Carsten

2012-01-01

37

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 0min. 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

38

Magnetic mesoporous Fe/carbon aerogel structures with enhanced arsenic removal efficiency.  

Science.gov (United States)

Wastewater treatment has drawn significant research attention due to its associated environmental issues. Adsorption is a promising method for treating wastewater. The development of an adsorbent with a high surface area is important. Therefore, we successfully developed mesoporous Fe/carbon aerogel (CA) structures with high specific surface areas of 48 7m(2)/g via the carbonization of composite Fe3O4/phenol-formaldehyde resin structures, which were prepared using a hydrothermal process with the addition of phenol. The mesoporous Fe/CA structures were further used for the adsorption of arsenic ions with a maximum arsenic-ion uptake of calculated 216.9 mg/g, which is higher than that observed for other arsenic adsorbents. Ferromagnetic behavior was observed for the as-prepared mesoporous Fe/CA structures with an excellent response to applied external magnetic fields. As a result, the adsorbent Fe/CA structures can be easily separated from the solution using an external magnetic field. This study develops the mesoporous Fe/CA structures with high specific surface areas and an excellent response to an applied external magnetic field to provide a feasible approach for wastewater treatment including the removal of arsenic ions. PMID:24559703

Lin, Yi-Feng; Chen, Jia-Ling

2014-04-15

39

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

40

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

41

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)

42

Effects of phenol-formaldehyde / isocyanate hybrid adhesives on properties of oriented strand lumber (OSL) from rubberwood waste  

OpenAIRE

The objective of this research project was to study the effects of hybrid adhesives of Phenol-Formaldehyde (PF) and Polymeric Diphenylmethane Diisocyanate (MDI) on the properties of Oriented Strand Lumber (OSL) to determine the optimal ratio of both adhesives. The results showed that OSL formed by pure adhesive or hybrid adhesives (3 blends: 25:75, 50:50 and 75:25) had properties that pass the CSA O437.1 standards, such as (1) modulus of rupture, (2) modulus of elasticity, and (3) internal bo...

Wanchart Preechatiwong; Wisanee Yingprasert; Buhnnum Kyokong

2007-01-01

43

Resole resin products derived from fractionated organic and aqueous condensates made by fast-pyrolysis of biomass materials  

Science.gov (United States)

A process for preparing phenol-formaldehyde resole resins by fractionating organic and aqueous condensates made by fast-pyrolysis of biomass materials while using a carrier gas to move feed into a reactor to produce phenolic-containing/neutrals in which portions of the phenol normally contained in said resins are replaced by a phenolic/neutral fractions extract obtained by fractionation.

Chum, Helena L. (8448 Allison Ct., Arvada, CO 80005); Black, Stuart K. (4976 Raleigh St., Denver, CO 80212); Diebold, James P. (57 N. Yank Way, Lakewood, CO 80228); Kreibich, Roland E. (4201 S. 344th, Auburn, WA 98001)

1993-01-01

44

Ultrafast hydrothermal synthesis of high quality magnetic core phenol-formaldehyde shell composite microspheres using the microwave method.  

Science.gov (United States)

An ultrafast, facile, and efficient microwave hydrothermal approach was designed to fabricate magnetic Fe(3)O(4)/phenol-formaldehyde (PF) core-shell microspheres for the first time. The structure of the Fe(3)O(4)/PF core-shell microspheres could be well controlled by the in situ polycondensation of phenol and formaldehyde with magnetic Fe(3)O(4) clusters as the seeds in an aqueous solution without any surfactants. The effect of synthetic parameters, such as the feeding amounts of phenol, the dosages of formaldehyde, the reaction temperatures, and the microwave heating time, on the morphologies and sizes of the Fe(3)O(4)/PF microspheres were investigated in details. The phenol-formaldehyde shell is found to be evenly coated on Fe(3)O(4) clusters within 10 min of the irradiation. The as-prepared microspheres were highly uniform in morphology, and the method was found to allow the shell thickness to be finely controlled in the range of 10-200 nm. The properties of the composite microspheres were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetic analysis (TGA), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The as-prepared Fe(3)O(4)/PF microspheres were monodisperse and highly dispersible in water, ethanol, N,N-dimethyformamide, and acetone, a beneficial quality for the further functionalization and applications of the Fe(3)O(4)/PF microspheres. PMID:22712558

You, Li-Jun; Xu, Shuai; Ma, Wan-Fu; Li, Dian; Zhang, Yu-Ting; Guo, Jia; Hu, Jack J; Wang, Chang-Chun

2012-07-17

45

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

2014-09-10

46

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

47

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

48

Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,  

OpenAIRE

First, phenol - formaldehyde (PF) and urea - formaldehyde (UFII) resins were separately conventionally prepared in our laboratory. Also, UF resin synthesized from the acid modified synthesis procedure was synthesized in a purely acid medium of pH 1.0, FU molar ratio of 1.0 and at 50oC (one-stage acid modified-synthesis procedure). Subsequently, the UF resin II was modified during synthesis by incorporating ethylated urea-ether (EUER) (i.e. UFIII) and glycerol (GLYC) (i.e. UFV) cured with and ...

Edoga, Mathew Obichukwu

2006-01-01

49

Interactive oxidation-reduction reaction for the in situ synthesis of graphene-phenol formaldehyde composites with enhanced properties.  

Science.gov (United States)

We report a facile in situ synthesis of reduced graphene oxide (RGO)-phenol formaldehyde (PF) composites with an interactive oxidation-reduction reaction. In this interactive chemical reaction, graphene oxide (GO) was reduced to RGO by phenol, and simultaneously phenol was oxidized to benzoquinone. The noncovalently adsorbed phenol on the RGO surface can not only serve as an effective reductant but also participate in the in situ polymerization and guide the formation of PF on the RGO surface. RGO-PF composites with different RGO contents were prepared successfully and further characterized with fluorescent spectroscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical strength, electrical conductivity, thermal conductivity, and thermal resistance of the created RGO-PF were investigated. The results indicated that the dispersity of RGO in the PF matrix and the interfacial interaction between RGO and PF were improved greatly because of formation of the RGO-PF hybrid in the in situ synthesis. The homogeneous dispersion and in situ polymerization of RGO sheets help to enhance the thermal conductivity of RGO-PF composites from 0.1477 to 0.3769 W m(-1) K(-1) and endow the composites with a good electrical conductivity. In addition, the well-dispersed RGO-PF composites are much more effective in improving their mechanical property and heat resistance. PMID:24588055

Zhao, Xiaojia; Li, Yang; Wang, Jinhui; Ouyang, Zhaofei; Li, Jingfeng; Wei, Gang; Su, Zhiqiang

2014-03-26

50

Characterization of alkaline lignins for use in penol-formaldehyde and epoxy resins  

OpenAIRE

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-NM...

El Mansouri, Nour-eddine; Yuan, Qiaolong; Huang, Farong

2011-01-01

51

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

52

Study of the mechanism of radiation-chemical transformations in rubber-resinous materials  

International Nuclear Information System (INIS)

Materials based on butadiene-nitrile rubbers reinforced by phenol-formaldehyde resins presently find wide application as reliable heat-insulating coatings for various metallic constructions and are utilized under exposure to ionizing radiation. In this connection, when estimating the assured lifetime of heat-insulating coatings, it is necessary to take into account the character and degree of their radiation-chemical transformations. The aim of the present work was to study the radiation-chemical transformations of materials based on a composite of butadiene-nitrile rubber and phenol-formaldehyde resin. The investigations were carried out on model materials S-O, S-25, S-100, S-130, and S-150 based on the SKN-40M rubber with a varied content of SF-010A brand phenol-formaldehyde resin, the content of which in parts by weight per 100 parts by weight of rubber is indicated in the specifications of the materials. The possible directions of the radiation-chemical transformations in the rubber-resinous vulcanizates were studied by the method of disrupted total internal reflection (MDTIR) IR spectroscopy

53

Lignocellulosic composites from brazilian giant bamboo (Guadua magna) Part 1: Properties of resin bonded particleboards  

OpenAIRE

This experiment evaluated the utilization of the recently identified Brazilian giant bamboo, Guadua magna (Londoño & Filg.) to manufacture medium density particleboard. Four board types were tested: two of them exclusively with particles of bamboo and two in a mixture of bamboo with Pinus taeda wood particles. The target density of the panels was 0.65 g/cm³ for all treatments. The particleboards were bonded using 8% content of urea-formaldehyde (UF) and phenol-formaldehyde (PF) resins, base...

Arruda, Larissa M.; Del Menezzi, Cla?udio H. S.; Teixeira, Divino E.; Arau?jo, Priscila C.

2011-01-01

54

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

55

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

56

Mechanical and Physical Properties of Low Density Kenaf Core Particleboards Bonded with Different Resins  

OpenAIRE

Single layer kenaf (Hibiscus cannabinus) core particleboards bonded with urea formaldehyde (UF), phenol formaldehyde (PF) and polymeric 4,4-methyl phenylmethane di-isocyanate (PMDI) resins were manufactured. The boards were fabricated with three different densities i.e 350 kg/m3, 450 kg/m3 and 550 kg/m3. Each type of the resin used was sprayed at three different resin loadings on the kenaf core particles. The boards produced was evaluated for its modulus of rupture (MOR), m...

Mohamad Jani Saad; Izran Kamal

2012-01-01

57

Fabrication of N-doped highly ordere mesoporous polymers and carbons.  

Science.gov (United States)

N-doped highly ordered mesoporous carbons are synthesized via a one-step organic-organic evaporation induced self-assembly method by using phenol, formaldehyde and m-aminophenol as carbon and nitrogen sources and triblock copolymer as a structure-directing agent. The frameworks are constituted by polymer and carbon upon calcination at 350 degrees C and 900 degrees C, respectively, and N incorporates into the frameworks (0.2-1.6% in molar ratio). N-doped mesoporous carbons have high surface areas (approximately 1200 m2/g) and large pore volumes (approximately 0.65 cm3/g). Various mesostructures (p6mm and Im3m) can be obtained by simply tuning the ratio of phenol to triblock copolymer in the synthesis. With the increase of the initial amount of m-aminophenol, the graphitizing degree of mesoporous carbon increases. PMID:19441570

Feng, Cuimiao; Li, Hexing; Wan, Ying

2009-02-01

58

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

OpenAIRE

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...

Crown, S. C.

2004-01-01

59

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

60

Radiation testing of organic ion exchange resins  

International Nuclear Information System (INIS)

A number of ion exchange materials are being evaluated as part of the Tank Waste Remediation System (TWRS) Pacific Northwest Laboratory (PNL) Pretreatment Project for the removal of 137Cs from aqueous tank wastes. Two of these materials are organic resins; a phenol-formaldehyde resin (Duolite CS-100) produced by Rohm and Haas Co. (Philadelphia, Pennsylvania) and a resorcinol-formaldehyde (RF) resin produced by Boulder Scientific Co. (Mead, Colorado). One of the key parameters in the assessment of the organic based ion exchange materials is its useful lifetime in the radioactive and chemical environment that will be encountered during waste processing. The focus of the work presented in this report is the radiation stability of the CS-100 and the RF resins. The scope of the testing included one test with a sample of the CS-100 resin and testing of two batches of the RF resin (BSC-187 and BSC-210). Samples of the exchangers were irradiated with a 60Co source to a total absorbed dose of 109 R over a period of 5 months in a static (no flow) and a flowing configuration with neutralized current acid waste (NCAW) simulant as a feed. Based on a maximum concentration of 137Cs on the resin that would result from processing NCAW, this dose represents an operational period of at least 150 days for the RF resin and at least 1260 days for the CS-100 resin. Gas generation in the static experiment was continuously monitored and G values (molecules of gas per 100 eV) were determined for each species. Resin samples were obtained periodically and the equilibrium behavior of the resins was assessed by determining the distribution coefficients (Kds). Structural information was also obtained by 13C cross polarization magic angle (CPMAS) nuclear magnetic resonance (NMR) spectrometry and Fourier Transform Infrared (FTIR) spectroscopy so that changes to the chemical structure could be correlated with changes in Kd

61

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)

62

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

63

Study the Effect Different Radioactive Dose on MechanicalProperties of Composite Material from Novolak ResinExposure to High ? Energy Radiation  

OpenAIRE

The research involves using phenol ? formaldehyde (Novolak) resin as matrix for making composite material, while glass fiber type (E) was used as reinforcing materials. The specimen of the composite material is reinforced with (60%) ratio of glass fiber.The impregnation method is used in test sample preparation, using molding by pressure presses.All samples were exposure to (Co60) gamma rays of an average energy (2.5)Mev. The total doses were (208, 312 and 728) KGy. The mechanical tests (ben...

Muhammad Slab Hamza; Muzher Ali Sahib; Rula Abdul Khider Abbas

2009-01-01

64

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

65

Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,  

Directory of Open Access Journals (Sweden)

Full Text Available First, phenol - formaldehyde (PF and urea - formaldehyde (UFII resins were separately conventionally prepared in our laboratory. Also, UF resin synthesized from the acid modified synthesis procedure was synthesized in a purely acid medium of pH 1.0, FU molar ratio of 1.0 and at 50oC (one-stage acid modified-synthesis procedure. Subsequently, the UF resin II was modified during synthesis by incorporating ethylated urea-ether (EUER (i.e. UFIII and glycerol (GLYC (i.e. UFV cured with and without acid curing agent. The structural and physicochemical analyses of the various resin samples were carried out.The results showed that the unmodified UF resin (UF II synthesized in acid medium of pH 1.0, F/U molar ratio 1.0, and at 50oC, cured in absence of acid curing catalyst, showed features in their spectra which are consistent with a tri-, and/or tetra-substituted urea in the reaction to give a 3 - dimensional network cured UF resin. Modification of the UF resin(UF II with ethylated urea-ether and glycerol to produce UF resins III and respectively V prominently increased the absorbance of methylene and ether groups in the spectra which are consistent with increased hydrophobicity and improved hydrolytic stability. For the conventional UF resin (UF I, the only clear distinction between spectra for the UF resin II and UF resins (III/V is the presence of diminished peaks for methylene groups at 2.2 ppm. The relationship between the logarithmic viscosity of cured PF resin with time showed continuos dependence of viscosity with time during cure up to 70 minutes. Similar trends were shown by UF resins (III/V, cured in absence of acid catalyst. In contrast, the conventional UF resins I and UF IV (i.e. UF II cured with NH4CL showed abrupt discontinuity in viscosity with time just after about 20 minutes of cure.

Mathew Obichukwu EDOGA

2006-07-01

66

Thermosetting Resins  

Science.gov (United States)

Thermosetting polymers are made from a mixture of monomers which react to form a large macromolecular network. They are used in diverse fields such as aerospace technology and wood composites, mostly as adhesives. The history of these products can be traced to ancient Egypt. The main thermosetting systems used nowadays are phenol-formaldehyde, urea-formaldehyde, polyurethanes polyesters and epoxydes. Each of these is reviewed briefly as to its chemistry and applications. The physical chemistry of these adhesives can be followed by differential scanning calorimetry and rheometry and examples are given.

Peng, W.; Riedl, B.

1995-07-01

67

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

68

Lignocellulosic composites from brazilian giant bamboo (Guadua magna Part 1: Properties of resin bonded particleboards  

Directory of Open Access Journals (Sweden)

Full Text Available This experiment evaluated the utilization of the recently identified Brazilian giant bamboo, Guadua magna (Londoño & Filg. to manufacture medium density particleboard. Four board types were tested: two of them exclusively with particles of bamboo and two in a mixture of bamboo with Pinus taeda wood particles. The target density of the panels was 0.65 g/cm³ for all treatments. The particleboards were bonded using 8% content of urea-formaldehyde (UF and phenol-formaldehyde (PF resins, based on dry weight mat. Mechanical, physical and nondestructive properties of the panels were assessed. The particleboards produced with PF showed better dimensional stability than UF particleboards. The addition of wood particles improved the mechanical properties of E M, fM and IB. The flexural properties of the panels (E M, fM could be modeled using either E Md or density and the models fitted presented high predictability (>66%.

Larissa M Arruda

2011-01-01

69

High capacity magnetic mesoporous carbon-cobalt composite adsorbents for removal of methylene green from aqueous solutions.  

Science.gov (United States)

Mesoporous carbons containing cobalt nanoparticles are synthesized by tri-or quad-constituent self assembly of Pluronic F127, phenol-formaldehyde oligomer (resol), cobalt acetylacetonate (acac), and optionally tetraethyl orthosilicate (TEOS, optional). Upon pyrolysis in N(2) atmosphere, the resol provides sufficient carbon yield to maintain the ordered structure, while decomposition of the Co(acac) yields cobalt nanoparticles. To provide increased surface area, the dispersed silicate from condensation of TEOS can be etched after carbonization to yield micropores, Without silica templated micropores, the surface area decreases as the cobalt content increases, but there is a concurrent increase in the volume-average pore diameter (BHJ) and a dramatic increase in the adsorption capacity of methylene green with the equilibrium adsorption capacity from 2 to 90 mg/g with increasing Co content. Moreover, the surface area and pore size of mesoporous composites can be dramatically increased by addition of TEOS and subsequent etching. These composites exhibit extremely high adsorption capacity up to 1151 mg/g, which also increases with increases in the Co content. Additionally, the inclusion of cobalt nanoparticles provides magnetic separation from aqueous suspension. The in situ synthesis of the Co nanoparticles yields to a carbon shell that can partially protect the Co from leaching in acidic media; after 96 h in 2 M HCl, the powders remain magnetic. PMID:22975394

Dai, Mingzhi; Vogt, Bryan D

2012-12-01

70

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

71

Mechanical and Physical Properties of Low Density Kenaf Core Particleboards Bonded with Different Resins  

Directory of Open Access Journals (Sweden)

Full Text Available Single layer kenaf (Hibiscus cannabinus core particleboards bonded with urea formaldehyde (UF, phenol formaldehyde (PF and polymeric 4,4-methyl phenylmethane di-isocyanate (PMDI resins were manufactured. The boards were fabricated with three different densities i.e 350 kg/m3, 450 kg/m3 and 550 kg/m3. Each type of the resin used was sprayed at three different resin loadings on the kenaf core particles. The boards produced was evaluated for its modulus of rupture (MOR, modulus of elasticity (MOE, internal bond (IB, screw withdrawal (SWD, water absorption (WA and thickness swelling (TS in accordance with the British Standards. The study revealed that boards with higher resin contents gave higher MOR, MOE, internal bond and screw withdrawal and also improved the water absorption and thickness swelling. Similar trend was also observed from boards with higher densities. It is concluded that the boards with the density of 550 kg/m3 were able to fulfill the British Standard specifications.

Mohamad Jani Saad

2012-07-01

72

Bonding exterior grade structural panels with copolymer resins of biomass residue components, phenol, and formaldehyde  

Energy Technology Data Exchange (ETDEWEB)

Components of various forest and agricultural residue biomass-including the polyphenolic compounds-were converted into aqueous solution and/or suspension by extraction and digestion. Some biomass components reacted vigorously under alkaline catalysis with formaldehyde and initially showed a high degree of exothermic reaction; however, other components did not react as vigorously under these conditions, indicating that different biomass materials require different methods to obtain optimum reactivity for the copolymerization with phenol. Our primary goal is to develop adhesives capable of producing acceptable bond quality, as determined by the wood products industries` standards, under a reasonable range of gluing conditions. Copolymer resins of phenol, formaldehyde, and biomass components were synthesized and evaluated for gluability of bonding exterior grade structural replaced with chemicals derived from peanut hulls, pecan shell flour, pecan pith, southern pine bark, and pine needle required shorter press times. These resins also tolerated a broader range of gluing conditions. In summary, it appears that the technology of the fast curing copolymer resins of biomass components as adhesives for wood products has been developed and is ready to be transferred to industrial practice.

Chen, C.M. [Univ. of Georgia, Athens, GA (United States)

1993-12-31

73

Preparation of free-standing high quality mesoporous carbon membranes  

Energy Technology Data Exchange (ETDEWEB)

Flat-sheet mesoporous carbon membranes with uniform pore size (e.g., 6.4 nm) and controllable thickness were prepared by pyrolysis of polymeric composite films, which were formed by self-assembly of phenolic resin and block copolymer under acidic conditions. Hexamethylenetetramine was selected as a solid cross-linker to control the rheology of polymeric carbon precursors so that the flat-sheet polymeric films could undergo carbonization without deformation, ensuring the preparation of mesoporous carbon membranes on a large scale with high quality. Gas transport properties through these mesoporous carbon membranes are also reported.

Wang, Xiqing [ORNL; Liang, Chengdu [ORNL; Dai, Sheng [ORNL; Mahurin, Shannon Mark [ORNL; Zhu, Qing [ORNL

2010-01-01

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

Responsive mesoporous photonic cellulose films by supramolecular cotemplating.  

Science.gov (United States)

Cellulose-based materials have been and continue to be exceptionally important for humankind. Considering the bioavailability and societal relevance of cellulose, turning this renewable resource into an active material is a vital step towards sustainability. Herein we report a new form of cellulose-derived material that combines tunable photonic properties with a unique mesoporous structure resulting from a new supramolecular cotemplating method. A composite of cellulose nanocrystals and a urea-formaldehyde resin organizes into a chiral nematic assembly, which yields a chiral nematic mesoporous continuum of desulfated cellulose nanocrystals after alkaline treatment. The mesoporous photonic cellulose (MPC) films undergo rapid and reversible changes in color upon swelling, and can be used for pressure sensing. These new active mesoporous cellulosic materials have potential applications in biosensing, optics, functional membranes, chiral separation, and tissue engineering. PMID:24981200

Giese, Michael; Blusch, Lina K; Khan, Mostofa K; Hamad, Wadood Y; MacLachlan, Mark J

2014-08-18

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

Lignocellulosic composites from brazilian giant bamboo (Guadua magna) Part 1: Properties of resin bonded particleboards  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english This experiment evaluated the utilization of the recently identified Brazilian giant bamboo, Guadua magna (Londoño & Filg.) to manufacture medium density particleboard. Four board types were tested: two of them exclusively with particles of bamboo and two in a mixture of bamboo with Pinus taeda wood [...] particles. The target density of the panels was 0.65 g/cm³ for all treatments. The particleboards were bonded using 8% content of urea-formaldehyde (UF) and phenol-formaldehyde (PF) resins, based on dry weight mat. Mechanical, physical and nondestructive properties of the panels were assessed. The particleboards produced with PF showed better dimensional stability than UF particleboards. The addition of wood particles improved the mechanical properties of E M, fM and IB. The flexural properties of the panels (E M, fM) could be modeled using either E Md or density and the models fitted presented high predictability (>66%).

Larissa M, Arruda; Cláudio H. S, Del Menezzi; Divino E, Teixeira; Priscila C, de Araújo.

79

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

80

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

81

Physico-mechanical properties of plywood bonded by nano cupric oxide (CuO) modified pf resins against subterranean termites  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Nano CuO and alkane surfactant modified phenol Formaldehyde (PF) resins were applied to manufacture plywood, and physical and mechanical properties, such as shear strength, tensile property, modulus of rupture (MOR), modulus of elasticity (MOE), as well as termite resistance were evaluated. The resu [...] lt showed that the combination of nano CuO and alkane surfactantplayed different effect on tensile strength, and especially on shear strength as evaluated at different test conditions. But it was confirmed to improve the water resistance of treated plywood specimens. The introduction of nano CuO and surfactant did not influence the flexural properties significantly by statistically. The result of termite tests indicated that the weight loss decreases gradually from 31,12% to less than 10,37%, and the mortality increases from 32,61% to higher than 86,35%. And the AWPA rating also rises from 4 (very severe attack) to 7 (moderate attack).

Wei, Gao; Guanben, Du.

82

Phenolic resin-grafted reduced graphene oxide as a highly stable anode material for lithium ion batteries.  

Science.gov (United States)

A novel and effective route for preparing phenol formaldehyde resin grafted reduced graphene oxide (rGO-g-PF) electrode materials with highly enhanced electrochemical properties is reported. In order to prepare rGO-g-PF, hydroxymethyl-terminated PF is initially grafted to graphene oxide (GO) via esterification reaction. Subsequently, the grafted GO is reduced by the carbonization process under an inert gas atmosphere. The covalent linkage, morphology, thermal stability and electrochemical properties of rGO-g-PF are systematically investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis, differential scanning calorimetry and a variety of electrochemical testing techniques. In the constructed architecture, the amorphous carbon shell can inhibit the co-intercalation of solvated lithium ion and avoid partial exfoliation of the graphene layers, thus effectively reducing the irreversible capacity and preserving the structural integrity. Meanwhile, the carbon coating layer leading to a decreased thickness of SEI film can improve the conductivity of electrode materials. As a result, the rGO-g-PF electrode exhibits impressive high cycling stability at various large current densities (376.5 mA h g(-1) at 50 mA g(-1) for 250 cycles, 337.8 mA h g(-1) at 200 mA g(-1) and 267.8 mA h g(-1) at 1 A g(-1) for 200 cycles), in combination with high rate capability. PMID:25521487

Li, Mochen; Song, Huaihe; Chen, Xiaohong; Zhou, Jisheng; Ma, Zhaokun

2015-02-01

83

Interactions of Plutonium and Lanthanides with Ordered Mesoporous Materials  

Science.gov (United States)

Ordered mesoporous materials are porous solids with a regular, patterned structure composed of pores between 2 and 50 nm wide. Such materials have attracted much attention in the past twenty years because the chemistry of their synthesis allows control of their unique physicochemical properties, which can be tuned for a variety of applications. Generally, ordered mesoporous materials have very high specific surface areas and pore volumes, and offer unique structures that are neither crystalline nor amorphous. The large tunable interface provided by ordered mesoporous solids may be advantageous in applications involving sequestration, separation, or detection of actinides and lanthanides in solution. However, the fundamental chemical interactions of actinides and lanthanides must be understood before applications can be implemented. This dissertation focuses primarily on the fundamental interactions of plutonium with organically modified mesoporous silica, as well as several different porous carbon materials, both untreated and chemically oxidized. A method for functionalizing mesoporous silica by self assembly and molecular grafting of functional organosilane ligands was optimized for the 2D-hexagonal ordered mesoporous silica known as SBA-15 (Santa Barbara amorphous silica). Four different organically-modified silica materials were synthesized and characterized with several techniques. To confirm that covalent bonds were formed between the silane anchor of the ligand and the silica substrate, functionalized silica samples were analyzed with 29Si nuclear magnetic resonance spectroscopy. Infrared spectroscopy was used in combination with 13C and 31P nuclear magnetic resonance spectroscopy to verify the molecular structures of the ligands after they were synthesized and grafted to the silica. The densities of the functional silane ligands on the silica surface were estimated using thermogravimetric analysis. Batch sorption experiments were conducted with solutions of Pu(IV), Pu(VI), Eu(III), Ce(III), and Zr(IV). The acetamide phosphonate functionalized silica called Ac-Phos-SBA-15 required more extensive synthesis than the other three functionalized silica materials. Development of functionalized mesoporous silica extractants for actinides is contingent on their synthesis and hydrolytic stability, and these two aspects of the Ac-Phos-SBA-15 material are discussed. This material showed the highest binding affinity for all of the target ions, and the sorption and desorption of Pu(VI) to Ac-Phos-SBA-15 was extensively investigated. Ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes, and could be suitable substrates for the development of actinide sensors based on their electrochemical properties. Three different mesoporous carbon materials were synthesized by collaborators to test their application as radionuclide sorbent materials. The first is called CMK (carbons mesostructured by Korea Advanced Institute of Science and Technology), and was synthesized using a hard silica template with 3D-bicontinuous ordered mesostructure. Highly ordered body-centered cubic mesoporous carbon was synthesized by self-assembly of a phenol resin around a soft polymer template, and this material is known as FDU-16 (Fudan University). Etching of the silica portion of mesoporous carbon-silica composites created the 2D-hexagonal mesoporous carbon called C-CS (carbon from carbon-silica nanocomposites) with a bimodal pore size distribution. The as-synthesized nanocast mesoporous carbon in this work is called UN CMK, and the same material after oxidation treatment with nitric acid is called OX CMK. A portion of both FDU-16-type and C-CS-type ordered mesoporous carbons were oxidized with acidic ammonium persulfate, which created the oxidized carbon materials called FDU-16-COOH and C-CS-COOH, respectively. The mesoporous carbons were characterized by scanning electron microscopy to view their particle sizes and morphologies. Their porosities and structures on the meso-scale were an

Parsons-Moss, Tashi

84

Nano Hibrid Resin Komposit  

OpenAIRE

Resin komposit adalah tambalan sewarna gigi yang merupakan material kompleks dan mengandung komponen resin organik yang membentuk matriks, inorganic filler, coupling (interfacial) agent untuk menyatukan resin dengan filler, initiator untuk mengaktifkan mekanisme setting komposit, stabilisers dan pigmen. Klasifikasi resin komposit berdasarkan ukuran partikel filler ada 4 yaitu Makrofill, Mikrofill, Hibrid dan Hibrid partikel kecil (Small-particle hybrid) resin komposit. Nano hibrid resin ...

Panto, Vincent

2011-01-01

85

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

86

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

87

Mesoporous aluminum phosphite  

International Nuclear Information System (INIS)

High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S+I- surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption-desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed. - Abstract: TEM image of the mesoporous aluminum phospTEM image of the mesoporous aluminum phosphite showing the hexagonal disordered pore array that is generated by using surfactant micelles as template. Also a scheme emphasizing the presence of an alumina-rich core and an ALPO-like pore surface is presented.

88

Review: Resin Composite Filling  

OpenAIRE

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 ...

Desmond Ng; Hsiao, Jimmy C. M.; Tong, Keith C. T.; Harry Kim; Yanjie Mai; Chan, Keith H. S.

2010-01-01

89

Mesoporous molecular sieve catalysts  

DEFF Research Database (Denmark)

This thesis deals with a very specific class of molecular sieves known as zeolites. Zeolites are a class of crystalline aluminosilicates characterised by pores or cavities of molecular dimensions as part of their crystal structure. In this work zeolites were modified for the use and understanding of different catalytic applications. Primarily the zeolites were modified regarding the porosity and the introduction of metals to the framework. The obtained materials were used as solid acid catalysts, as an inert matrix for stabilising metal nanoparticles and as an anchoring material for molecular metal oxide species. Nanosized and mesoporous zeolites were prepared to investigate the effect of inter- or intracrystalline mesopores on the catalytic lifetime in the conversion of methanol to hydrocarbons (MTH). It was found that the mesoporous zeolite with intracrystalline mesopores displayed the significantly longest catalytic lifetime compared to the nanosized zeolites and the conventional counterpart. Even though the introduction of mesopores improved the catalytic lifetime in the MTH reaction it was concluded that the normal benefits from desilication, e.g. mesoporosity and repairing of defects, became masked by the generation of extra-framework aluminum and that the catalytic lifetime was severely dependent on the amount of extra-framework aluminum. Conventional and mesoporous ZSM-5 zeolites were prepared together with the Ga-MFI zeotype analogues to investigate the differences in activity, selectivity and mode of deactivation. The differences in selectivity were primarily ascribed to the difference in the lower acidity of the individual active sites of the Ga-MFI zeotypes compared to the zeolites. In general, the Ga-MFI zeotypes deactivated faster than the ZSM-5 zeolites. Further investigations of the mode of deactivation revealed that the zeolites deactivated due to coke formation and that the Ga-MFI zeotypes deactivated due to loss of the catalytically active Brønsted acid sites caused by hydrolysis of Ga-O bonds leading to formation of inactive extra-framework gallium. Zeolites can not only be used as solid acid catalysts but can also be used as a size-selective matrix. It was shown that it is possible to encapsulate 1-2 nm sized gold nanoparticles by silicalite-1 or ZSM-5 zeolite crystals thereby forming a sintering-stable and substrate size-selective oxidation catalyst. After carrying out calcination experiments, both in situ and ex situ indicated that the gold nanoparticles embedded in the crystals were highly stable towards sintering. The catalytic tests proved that the embedded gold nanoparticles were active in selective aldehyde oxidation and were only accessible through the micropores. Furthermore, preliminary work was done using mesoporous ZSM-5 zeolites as support material for anchoring molecular CoMo6 species for the application as potential bi-functional catalyst in simultaneous hydrodesulfurisation (HDS) and hydrocracking. HDS activity tests revealed that the anchoring improved the activity compared to an impregnated counterpart.

HØjholt, Karen Thrane

2011-01-01

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

Phenolic resin syntactic foams  

Energy Technology Data Exchange (ETDEWEB)

Syntactic foams were prepared from blends of six phenolic resins and carbon microbubbles. The compressive strength of the phenolic resin foams is equivalent to the strength of foams made from a polyimide resin. Ammonia evolved during the cure diffuses rapidly and is not bound by the foam.

McIlroy, H.M.

1980-06-01

93

Resin Longevity Studies  

International Nuclear Information System (INIS)

Radioactive resin waste has been generated at the Savannah River Site as a result of water treatment at F- and H-Areas. Key factors in the risk assessment of disposing of these materials in trenches include resin retention of 129I, a long-lived isotope, and the degradation rate of the organic resin itself. In order to estimate the degradation of resin wastes during underground burial, simulated aging studies were carried out with Dowex 21K, CG-8, and GT-73 ion exchange resins. These resins have a polystyrene-base but bear different functional groups. The specific resins considered in this study include anion (Dowex 21K), cation (CG8), and neutral (GT73) resins with, respectively, quaternary ammonium, sulfonate, and thiol functionalities. The objective of this study is to carry out laboratory experiments to simulate aging of organic resin wastes in order to (1) determine the functional life span of CG8, GT73 and Dowex 21K resins under field (trench) conditions, and (2) determine the expected performance of these resins as they degrade

94

Removal of viruscide agents by using styrenic resins.  

Science.gov (United States)

Strong and weak anionic polystyrene/divinylbenzene ion exchange resins were investigated both as iodophores and as iodine/iodide ion removal agents in blood disinfection applications. Resin-iodine complexes were prepared, but there was no significant iodine release observed in either distilled water or isotonic saline solution. However, all ion-exchange resin were able to remove almost quantitatively both iodine and iodide ions from water solutions. Cross-linked styrene/divinylbenzene resins are excellent polyaromatic viruscide adsorbents, although their hydrophobicity is responsible for poor wettability in physiologi-cal fluids. Surface modification with hydrophilic reagents appeared a promising strategy to overcome this drawback. A Merrifield-type chloromethylated resin and a highly cross-linked mesoporous resin (Lewatit 1064) with a large surface area and content of unreacted vinyl groups were selected as starting materials. The Merrifield resin was modified by the reaction of the pendant chloromethyl groups with triethyleneglycol, tetraethyleneglycol and â -cyclodextrin. The conversion of Lewatit double bonds into hydrophilic moieties was attempted by the radical grafting of N-vinyl-2-pyrrolidinone (NVP), maleic anhydride (MAn), 2-hydroxyethyl methacrylate, acrylamide (AAm) and different poly(ethyleneglycol) (PEG) methacrylates. The addition of 2-mer-captoethanol (2ME) and epoxidation were also investigated. The modified Merrifield resins demonstrated very low efficiency in acridine viruscide uptake, in spite of the large increase in both wettability and water uptake. On the other hand, all modified Lewatit samples removed rapidly and almost quantitatively the viruscide from aqueous solutions, although only a few samples resulted in being very hydrophilic. In all cases, hydrophilicity and viruscide adsorbing capacity were maintained after heating at 180 degrees C to simulate pyrogen elimination. PMID:20803444

Bartolozzi, I; Solaro, R; Mari, G; Bonaguidi, P; Chiellini, E

2004-01-01

95

21 CFR 177.2600 - Rubber articles intended for repeated use.  

Science.gov (United States)

...distillates of cracked petroleum stocks). Petroleum oil, sulfonated. Phenol-formaldehyde resin. ...Propylene glycol. n -Propyl ester of tall oil fatty acids. Rapeseed oil vulcanized with rubber maker's sulfur....

2010-04-01

96

46 CFR Table I to Part 150 - Alphabetical List of Cargoes  

Science.gov (United States)

...AMN Ammonium nitrate, Urea solution (containing...UAS Ammonium nitrate, Urea solution (not containing...MBK Butyl phenol, Formaldehyde resin in Xylene32n-Butyl...benzenesUDB AKBUrea, Ammonium mono-...

2010-10-01

97

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

98

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

99

Ordered mesoporous silica: microwave synthesis  

Energy Technology Data Exchange (ETDEWEB)

Ordered mesoporous silicas, FDU-1, synthesized by using triblock copolymer, EO{sub 39}BO{sub 47}EO{sub 39}, as template were hydrothermally treated in a microwave oven at 373 K for different periods of time. The structural and morphological properties of these silicas were investigated by X-ray diffraction and nitrogen adsorption and compared with those for the FDU-1 samples prepared by conventional hydrothermal treatment at 373 K. All samples were calcined at 813 K in N{sub 2} and air. This procedure succeeded in producing ordered cage-like mesoporous structures even after 15 min of the microwave treatment. The best sample was obtained after 60 min of the microwave treatment, which is reflected by narrow pore size distribution, uniform pore size entrances and thick mesopore walls. Longer time of the microwave treatment increased nonuniformity of the pore entrance sizes as evidenced by changes in the hysteresis loops of nitrogen adsorption isotherms.

Fantini, M.C.A. [IF-USP, CP 66318, 05315-970, Sao Paulo, SP (Brazil)]. E-mail: mfantini@if.usp.br; Matos, J.R. [IQ-USP, CP 26077, 05599-970, Sao Paulo, SP (Brazil); Silva, L.C. Cides da [IQ-USP, CP 26077, 05599-970, Sao Paulo, SP (Brazil); Mercuri, L.P. [IQSC-USP, CP 780, 13560-970, Sao Carlos, SP (Brazil); Chiereci, G.O. [IQSC-USP, CP 780, 13560-970, Sao Carlos, SP (Brazil); Celer, E.B. [Department of Chemistry, Kent State University, Kent, OH 44240 (United States); Jaroniec, M. [Department of Chemistry, Kent State University, Kent, OH 44240 (United States)

2004-09-25

100

Single crystalline mesoporous silicon nanowires  

Energy Technology Data Exchange (ETDEWEB)

Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. The photoluminescence of these nanowires suggest they are composed of crystalline silicon with small enough dimensions such that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices. A better understanding of this electroless route to mesoporous silicon could lead to facile and general syntheses of different narrow bandgap semiconductor nanostructures for various applications.

Hochbaum, Allon; Dargas, Daniel; Hwang, Yun Jeong; Yang, Peidong

2009-08-18

101

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  

Directory of Open Access Journals (Sweden)

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 para 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.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 important 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

2008-08-01

102

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 SciELO Brazil | Language: Portuguese Abstract in portuguese 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

103

Magnetic mesoporous material for the sequestration of algae  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides a magnetic mesoporous nanoparticle that includes a mesoporous silicate nanoparticle and iron oxide. The present invention also provides a method of using magnetic mesoporous nanoparticles to sequester microorganisms from a media.

Trewyn, Brian G.; Kandel, Kapil; Slowing, Igor Ivan; Lee, Show-Ling

2014-09-09

104

Mesoporous Silica: A Suitable Adsorbent for Amines  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices.

Abdollahzadeh-Ghom Sara

2009-01-01

105

Mesoporous silica: a suitable adsorbent for amines.  

Science.gov (United States)

Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices. PMID:20628459

Zamani, Cyrus; Illa, Xavi; Abdollahzadeh-Ghom, Sara; Morante, J R; Romano Rodríguez, Albert

2009-01-01

106

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

Science.gov (United States)

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. PMID:22047720

Wan, Ying; Cui, Xiangting; Wen, Zhentao

2011-12-30

107

Synthesis of non-siliceous mesoporous oxides.  

Science.gov (United States)

Mesoporous non-siliceous oxides have attracted great interest due to their unique properties and potential applications. Since the discovery of mesoporous silicates in 1990s, organic-inorganic assembly processes by using surfactants or block copolymers as soft templates have been considered as a feasible path for creating mesopores in metal oxides. However, the harsh sol-gel conditions and low thermal stabilities have limited the expansion of this method to various metal oxide species. Nanocasting, using ordered mesoporous silica or carbon as a hard template, has provided possibilities for preparing novel mesoporous materials with new structures, compositions and high thermal stabilities. This review concerns the synthesis, composition, and parameter control of mesoporous non-siliceous oxides. Four synthesis routes, i.e. soft-templating (surfactants or block copolymers as templates), hard-templating (mesoporous silicas or carbons as sacrificial templates), colloidal crystal templating (3-D ordered colloidal particles as a template), and super lattice routes, are summarized in this review. Mesoporous metal oxides with different compositions have different properties. Non-siliceous mesoporous oxides are comprehensively described, including a discussion of constituting elements, synthesis, and structures. General aspects concerning pore size control, atomic scale crystallinity, and phase control are also reviewed. PMID:23942521

Gu, Dong; Schüth, Ferdi

2014-01-01

108

Cellular membrane trafficking of mesoporous silica nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine the specific organelle that mesoporous silica nanoparticles could approach via the identification of harvested proteins from exocytosis process. Based on the study of endo- and exocytosis behavior of mesoporous silica nanoparticle materials, we can design smarter drug delivery vehicles for cancer therapy that can be effectively controlled. The destination, uptake efficiency and the cellular distribution of mesoporous silica nanoparticle materials can be programmable. As a result, release mechanism and release rate of drug delivery systems can be a well-controlled process. The deep investigation of an endo- and exocytosis study of mesoporous silica nanoparticle materials promotes the development of drug delivery applications.

Fang, I-Ju

2012-06-21

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

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)

111

Optical transparency of mesoporous metals  

OpenAIRE

We examine the optical properties of metals containing a periodic arrangement of nonoverlapping spherical mesopores, empty or filled with a dielectric material. We show that a slab of such a porous metal transmits light over regions of frequency determined by the dielectric constant of the cavities and the fractional volume occupied by them, with an efficiency which is many orders of magnitude higher than predicted by standard aperture theory. Also, the system absorbs light ...

Stefanou, N.; Modinos, A.; Yannopapas, V.

2001-01-01

112

Mesoporous and microporous titania membranes  

OpenAIRE

The research described in this thesis deals with the synthesis and properties of ceramic oxide membrane materials. Since most of the currently available inorganic membranes with required separation properties have limited reliability and long-term stability, membranes made of new oxide materials that can improve their performance are developed. Anatase and amorphous titania were chosen as mesoporous and microporous material for membrane development, respectively. The relationship between synt...

Sekulic-kuzmanovic, Jelena

2004-01-01

113

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)

114

Phenolic Resin for Refractories  

Science.gov (United States)

Refractories are used in furnaces and boilers that process steel, cement, or glass as well as incinerators that operate at high temperatures. A variety of binders is used when refractories are manufactured. In this chapter, the use of phenolic resin as a binder for refractories is described. There are several factors that support the use of phenolic resins in comparison to other refractory binders. These include the following: 1. Both adhesion and green body strength are high.

Irie, Shunsuke; Rappolt, James

115

Preparation of nanosized micro/mesoporous composites  

International Nuclear Information System (INIS)

Micro/mesoporous composite material is prepared via reaction of zeolite Beta seeds solution and mesoporous precursor solution under hydrothermal conditions. The resulted micro/mesoporous composite contains nanoparticles with a mean radius of about 90 nm, while pure zeolite Beta and MCM-41 have particles with size of about 50 and 230 nm, respectively. The presence of highly cross-linked silicon framework walls and tetrahedrally coordinated aluminum in the framework structure are confirmed with solid-state 29Si and 27Al NMR investigations. Adsorption measurements show the presence of micropores, mesopores and high interparticle porosity due to the nanometer-sized particles in the micro/mesoporous composite. Various techniques such as dynamic light scattering, scanning electron microscopy, X-ray diffraction, FT-IR, NMR spectroscopy and nitrogen sorption measurements were carried out in order to investigate the properties of the prepared material

116

Cleanup of 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). It was also required to limit the maximum cesium activities in the resin eluates (SDSD feeds) so that the radiation field surrounding the pipelines would not be excessive. The process consisted of 17 stages of batch elution. In the initial stage, the resin was contacted with 0.18 M boric acid. Subsequent stages subjected the resin to increasing concentrations of sodium in NaH2BO3-H3BO3 solution (total boron= 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 with 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

117

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

118

Single crystalline mesoporous silicon nanowires  

Energy Technology Data Exchange (ETDEWEB)

Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. These porous nanowires also retain the crystallographic orientation of the wafer from which they are etched. Electron microscopy and diffraction confirm their single-crystallinity and reveal the silicon surrounding the pores is as thin as several nanometers. Confocal fluorescence microscopy showed that the photoluminescence (PL) of these arrays emanate from the nanowires themselves, and their PL spectrum suggests that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices.

Hochbaum, A.I.; Gargas, Daniel; Jeong Hwang, Yun; Yang, Peidong

2009-08-04

119

Synthesis and characterization of mesoporous zirconia and aluminated mesoporous zirconia  

Science.gov (United States)

Synthesis of mesoporous zirconia has been performed by slowly hydrolyzing zirconium propoxide in the presence of anionic surfactants: namely, dodecyl phosphate or sulfate (P12 and Sf12) and hexadecyl sulfonate (So16) The zirconia. outgassed at 140--150°C has T-plot surface areas higher than 400 M2/g. This outgassing does not remove the surfactant. After calcination in air at 500°C and combustion of the surfactant, the mesoporous volume is reduced by a factor of about 2, whereas the pore wall material crystallizes in the tetragonal phase. The high-resolution electron microscopic study reveals the presence of a disorganized network of polygonal pores structure. It is suggested that the chemistry of the hydrolysis solution is instrumental in determining the pore structure. A schematic model in which the surfactant is a scaffold component is suggested in order to explain these results and the fixation of PO4, or SO4 in the walls may help to preserve the porous structure. It is very different from the templating mechanism. From the density obtained from phase transition temperature, and from the mesoporous volume (N2 adsorption), the thickness of the wall can be calculated as well as the pseudo-length of the pores. From the thickness, the T-plot area can be recalculated and agrees well with the measured T-plot surface area for the sample calcined at 500°C. Around 900°C, the walls become thicker and crystallizes into monoclinic zirconia without pore structure. In order to try to modify, the acidity of the mesoporous sulfated and oxo-phosphated zirconia, they were doped with aluminum. The sulfated zirconia only has a coating layer of amorphous alumina, while the phosphated zirconia has aluminum in the lattice and the alumina coat. A maximum ratio of Al/Zr ˜ 0.04 can be reached in the lattice. The introduction of aluminum into the lattice prevents the crystallization of the oxo-phosphate at 900°C, and helps to preserve the surface area and porosity of the sulfated zirconia above 500°C. However the acidity was not modified by doping. The comparison of the effects of adsorbing water or ammonia on the infrared bands between 1400 and 1000 cm-1 suggests that, besides structural Lewis sites on the surface of ZrO2, the strong Lewis sites are made from chemisorbed SO3. Upon adsorption of water, SO3 is converted, probably, into HSO4 which may act as strong Bronsted sites. At moderate surface hydration, both SO 3 and HSO4, may coexist. The catalytic activity in the isomerization of isobutane is a function of the overall nominal surface density of SO 4. The acid sites on the surface of phosphated mesoporous zirconia are attributable to surface P-OH groups working, as weak Bronsted sites.

Zhao, Elizabeth Sun

120

Synthesis of mesoporous SAPO-34 zeolite from mesoporous silica materials for methanol to light olefins.  

Science.gov (United States)

Mesoporous SAPO-34 zeolites were synthesized by using as-prepared mesoporous silica material as both silica source and mesopore tailor. The mesoporous SAPO-34 zeolite materials thus obtained are characterized by a series of different techniques, including poweder X-ray diffraction pattern, nitrogen physisorption analysis, scanning electron micrograph, temperature programmed desorption of ammonia, and inductively coupled plasma atomic emission spectrometry. The resultant mesoporous SAPO-34 crystals exhibit sphere-like particle with zeolite layer units. The mesopore size distribution and particle size can be changed by amounts of silica source and water. The methanol-to-olefins (MTO) reactions using these mesoporous SAPO-34 zeolites are carried out with a fixed-bed reactor. Catalytic tests exhibit that the mesoporous SAPO-34 zeolite materials show high catalytic activity compared with the conventional SAPO-34 for MTO reaction. The better catalytic activity and longer life time of the mesoporous SAPO-34 catalysts in MTO are mainly due to the existence of the mesoporosity of SAPO-34 with small particle size. PMID:24245281

Kang, Eun A; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Min; Jeong, Kwang-Eun; Kim, Joo-Wan; Kim, Chul-Ung; Jeong, Soon-Yong

2013-11-01

121

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

122

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

International Nuclear Information System (INIS)

Highlight: ? Surfactant self-assembly of ordered mesoporous carbon coating on honeycomb cordierite. ? Carbon coating with opened, hexagonally ordered pore arrays. ? Honeycomb adsorbents for removal of p-chlorophenol. ? 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.

123

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

124

Synthesized mercaptopropyl nanoporous resins in DGT probes for determining dissolved mercury concentrations.  

Science.gov (United States)

3-Mercaptopropyl functionalized SBA-15 (SH-SBA) and 3-mercaptopropyl functionalized ethenylene bridged periodic mesoporous organosilica (SH-PMO) were included in a Diffusive Gradients in Thin film (DGT) probe and compared to similar commercially available resins also containing thiol functional groups, such as Sumichelate Q10R (SQR) and 3-mercaptopropyl functionalized silica gel (SH-KG), and also to the Chelex-100 resin for the determination of labile Hg concentrations. An agarose gel was used as the diffusive gel because the classic polyacrylamide gel shows more than 20% of Hg adsorption. According to our results, the Chelex-100 resin presents a much lower affinity for Hg than the thiol based resins. The non-linear accumulation profile of mercury with time for the Chelex-100 resin makes it in fact impossible to use Fick's law for estimating the diffusion coefficient of Hg. The 4 other resins all show a linear accumulation profile of Hg with time. Although the highest accumulation rate is observed for SH-PMO followed by SQR, SH-SBA and SH-KG, these values do not differ very much. PMID:22099677

Gao, Yue; De Canck, Els; Leermakers, Martine; Baeyens, Willy; Van Der Voort, Pascal

2011-12-15

125

Microwave absorption properties and infrared emissivities of ordered mesoporous C-TiO2 nanocomposites with crystalline framework  

International Nuclear Information System (INIS)

Ordered mesoporous C-TiO2 nanocomposites with crystalline framework were prepared by the evaporation-induced triconstituent co-assembly method. The products were characterized by XRD, TEM, N2 adsorption-desorption and TG. Their microwave absorption properties were investigated by mixing the product and epoxy resin. It is found that the peak with minimum reflection loss value moves to lower frequencies and the ordered mesoporous C-TiO2 nanocomposite possesses an excellent microwave absorbing property with the maximum reflection loss of -25.4 dB and the bandwidth lower than -10 dB is 6.6 GHz. The attenuation of microwave can be attributed to dielectric loss and their absorption mechanism is discussed in detail. The mesoporous C-TiO2 nanocomposites also exhibit a lower infrared emissivity in the wavelength from 8 to 14 ?m than that of TiO2-free powder. -- Graphical abstract: Ordered mesoporous C-TiO2 nanocomposite with crystalline framework possess excellent microwave absorbing properties with the maximum reflection loss of -25.4 dB and the bandwidth lower than -10 dB is 6.6 GHz. Display Omitted

126

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

127

Microleakage Pada Restorasi Resin Komposit  

OpenAIRE

Bisfenol A-glisidil metakrilat (bis-GMA) merupakan resin dimetakrilat dan penggunaan silane yang dapat berikatan kimia dengan resin untuk melapisi bahan pengisi. Penggunaan demetakrilat juga menyebabkan bertambahnya ikatan silang dan perbaikan sifat polimer. Polimerisasi pada resin komposit diawali dengan pembentukan radikal bebas sebagai awal proses aktivasinya. Resin komposit diaktivasi secara kimia dan sinar tampak. Sistem adhesive diperoleh melalui mekanisme mekanis dinamakan teknik etchi...

Sinulingga, Andri

2011-01-01

128

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

129

Progress in the Periodic Mesoporous Organosilicas  

OpenAIRE

The integration of organic and inorganic fragments within the pore wall of the periodic mesoporous organosilicas (PMOs) represents one of the recent breakthroughs in the fields of material science. The organic moieties distributed uniformly in the mesoporous framework will not block the pore, which is beneficial to the diffusion of guest molecule. The surface hydrophilicity/hydrophobicity, mechanical and hydrothermal stability of the PMOs could be easi...

Yang Qi-hua, Liu Jian

2009-01-01

130

Immobilization of Methyltrioxorhenium on Mesoporous Aluminosilicate Materials  

OpenAIRE

The presented report focuses on an in-depth detailed characterization of immobilized methyltrioxorhenium (MTO), giving catalysts with a wide spectra of utilization. The range of mesoporous materials with different SiO2/Al2O3 ratios, namely mesoporous alumina (MA), aluminosilicates type Siral (with Al content 60%–90%) and MCM-41, were used as supports for immobilization of MTO. The tested support materials (aluminous/siliceous) exhibited high surface area, well-defined regular structure and ...

Martina Stekrova; Radka Zdenkova; Martin Vesely; Eliska Vyskocilova; Libor Cerveny

2014-01-01

131

Radiation curable epoxy resin  

International Nuclear Information System (INIS)

A carboxyl containing polymer is either prepared in the presence of a polyepoxide or reacted with a polyepoxide. The polymer has sufficient acid groups to react with only about 1 to 10 percent of the epoxide (oxirane) groups. The remaining epoxide groups are reacted with an unsaturated monocarboxylic acid such as acrylic or methacrylic acid to form a radiation curable resin

132

Preparation and properties of mesoporous silica/bismaleimide/diallylbisphenol composites with improved thermal stability, mechanical and dielectric properties  

Directory of Open Access Journals (Sweden)

Full Text Available New composites with improved thermal stability, mechanical and dielectric properties were developed, which consist of 2,2'-diallylbisphenol A (DBA/4,4'-bismaleimidodiphenylmethane (BDM resin and a new kind of organic/inorganic mesoporous silica (MPSA. Typical properties (curing behavior and mechanism, thermal stability, mechanical and dielectric properties of the composites were systematically investigated, and their origins were discussed. Results show that MPSA/DBA/BDM composites have similar curing temperature as DBA/BDM resin does; however, they have different curing mechanisms, and thus different crosslinked networks. The content of MPSA has close relation with the integrated performance of cured composites. Compared with cured DBA/BDM resin, composites with suitable content of MPSA show obviously improved flexural strength and modulus as well as impact strength; in addition, all composites not only have lower dielectric constant and similar frequency dependence, more interestingly, they also exhibit better stability of frequency on dielectric loss. For thermal stability, the addition of MPSA to DBA/BDM resin significantly decreases the coefficient of thermal expansion, and improves the char yield at high temperature with a slightly reduced glass transition temperature. All these differences in macro-properties are attributed to the different crosslinked networks between MPSA/DBA/BDM composites and DBA/BDM resin.

2011-06-01

133

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

Science.gov (United States)

...Acid Polyesters *Furan Resins Glyoxal-Urea Formaldehyde Textile Resin *Ketone-Formaldehyde Resins *Melamine...Polyurethane Prepolymers *Polyurethane Resins *Urea Formaldehyde Resins *Urea Resins [52 FR 42568,...

2010-07-01

134

Mesoporous Fe2O3 microspheres: rapid and effective enrichment of phosphopeptides for MALDI-TOF MS analysis.  

Science.gov (United States)

Mesoporous Fe(2)O(3) microspheres have been successfully synthesized by the polymerization (urea and formaldehyde)-induced ferric hydroxide colloid aggregation. The urea-formaldehyde resin was removed by calcination in air. The obtained mesoporous Fe(2)O(3) materials have spherical morphology with uniform particle size of approximately 3.0 microm and porous surface with large inter-particle pores of approximately 48.0 nm. The surface area is as large as approximately 33.3 m(2)/g and the pore volume is 0.31 cm(3)/g. The mesoporous Fe(2)O(3) microspheres were used for the enrichment of phosphopeptides for the first time, in which high sensitivity, selectivity and capacity of specifically enriched phosphopeptides were achieved under a mild condition in a relative short time. After enriched from tryptic digest products of beta-casein by the novel mesoporous Fe(2)O(3) microspheres, phosphopeptides can be selectively detected with high intensity in MALDI-TOF mass spectrometry. Elimination of "shadow effect" was observed by using mesoporous Fe(2)O(3) microspheres, and the detectable limitation is 5x10(-10) M. This material is also effective for enrichment of phosphopeptides from the complex tryptic digests of commercial phosphoprotein casein, with much more phosphorylated sites (26 in 27 of total) and higher signal/noise ratio in the MALDI-TOF mass spectrometry, compared to commercial Fe(2)O(3) nanoparticles. It shows a great potential application in the field of rapid and effective isolation of phosphopeptides. PMID:18001758

Han, Lu; Shan, Zhe; Chen, Dehong; Yu, Xijuan; Yang, Pengyuan; Tu, Bo; Zhao, Dongyuan

2008-02-15

135

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

136

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

137

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

138

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

139

Adsorption of nitrosamines by mesoporous zeolite.  

Science.gov (United States)

On the basis of a study of the adsorption of zeolite and mesoporous silica, we attempted to create a hierarchical structure in the new nitrosamines trapper. Thus, mesoporous HZSM-5 zeolite was fabricated through impregnating a structure-directing agent into the as-synthesized MCM-41 followed by dry-gel conversion to transform amorphous silica to zeolite crystal. The texture of mesoporous ZSM-5 was tailored by adjusting the Si/Al ratio in the MCM-41 source and the thermal treatment time. The resulting samples were characterized by N(2) adsorption to evaluate their textural properties. One volatile nitrosamine, N-nitrosopyrrolidine (NPYR), was used as probe molecule in instantaneous adsorption to survey the function of the resulting composites. Adsorptions of N'-nitrosonornicotine (NNN) in dichloromethane solution and tobacco-specific nitrosamines (TSNA) in tobacco-extract solution were also utilized for the same purpose. As expected, mesoporous zeolite exhibits a good adsorption capacity in laboratory tests, superior to either microporous zeolite or mesoporous silica, providing a valuable candidate for controlling nitrosamines in the environment. PMID:20621826

Lin, Wei Gang; Wei, Feng; Gu, Fang Na; Dong, Xin; Gao, Ling; Zhuang, Ting Ting; Yue, Ming Bo; Zhu, Jian Hua

2010-08-15

140

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

141

Biokompatibilitas Gelas Ionomer Modifikasi Resin  

OpenAIRE

Saat ini banyak berkembang material baru dalam dunia kedokteran gigi diantaranya adalah Gelas ionomer modifikasi resin yang dikembangkan untuk mengatasi kekurangan-kekurangan dari gelas ionomer konvensional. Adanya penambahan monomer resin daIam bentuk 2-hydroxyethylmetacylate (HEMA) telah meningkatkan kekuatan dari bahan ini. Gelas ionomer modifikasi resin mempunyai sifat-sifat fisis dan mekanis yang lebih baik dibandingkan dengan gelas ionomer konvensional. Gelas ionomer modifikasi ...

Rotua Lestari M

2008-01-01

142

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

143

Dry PMR-15 Resin Powders  

Science.gov (United States)

Shelf lives of PMR-15 polymides lengthened. Procedure involves quenching of monomer reactions by vacuum drying of PRM-15 resin solutions at 70 to 90 degree F immediately after preparation of solutions. Absence of solvent eliminates formation of higher esters and reduces formation of imides to negligible level. Provides fully-formulated dry PMR-15 resin powder readily dissolvable in solvent at room temperature immediately before use. Resins used in variety of aerospace, aeronautical, and commercial applications.

Vannucci, Raymond D.; Roberts, Gary D.

1988-01-01

144

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

145

A new polyimide laminatine resin  

Science.gov (United States)

Addition polyimide for composite materials is based on liquid monomers and has significant advantages over most existing high-temperature resins. Essentially solventless prepreg has improved drape, tack.

Barrick, J. D. W.; Jewell, R. A.; Stclair, T. L.

1977-01-01

146

Synthesis of Polymer—Mesoporous Silica Nanocomposites  

Directory of Open Access Journals (Sweden)

Full Text Available Polymer nanocomposites show unique properties combining the advantages of the inorganic nanofillers and the organic polymers. The mesoporous silica nanofillers have received much attention due to their ordered structure, high surface area and ease for functionalization of the nanopores. To accommodate macromolecules, the nanopores lead to unusually intimate interactions between the polymer and the inorganic phase, and some unusual properties can be observed, when compared with nonporous fillers. Whereas many review articles have been devoted to polymer/nonporous nanofiller nanocomposites, few review articles focus on polymer/mesoporous silica nanocomposites. This review summarizes the recent development in the methods for synthesizing polymer/mesoporous silica nanocomposites based on the papers published from 1998 to 2009, and some unique properties of these composites are also described.

Yafei Zhang

2010-07-01

147

Templated mesoporous carbons for supercapacitor application  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous carbons prepared by an inverse replica technique have been used as electrodes for electrochemical capacitors. Such well-sized carbons were prepared from mesostructured SBA-16 silica materials that served as templates whereas polyfurfuryl alcohol was the carbon precursor. Two highly mesoporous carbons characterized by 3 and 8 nm average pore diameter were tested in various electrolytic solutions (acidic, alkaline and aprotic). It can be concluded that templated mesoporous carbons with tailored pore size distribution are very promising materials to be used as electrodes in supercapacitors. The design of their pore size allows suiting the dimensions of electrolyte ions and efficient charging of the electrical double layer is achieved especially at high current load. Definitively better capacitance performance has been found for carbon with 3 nm pores range, however, cycling performance depends not only on the pore size. (Author)

Fuertes, A.B.; Centeno, T.A. [Instituto Nacional del Carbon-C.S.I.C., Oviedo (Spain); Lota, G.; Frackowiak, E. [Poznan Univ. of Technology (Poland). Inst. of Chemistry and Technical Electrochemistry

2005-05-05

148

Pore Narrowing of Mesoporous Silica Materials  

Directory of Open Access Journals (Sweden)

Full Text Available 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 cyclic-bridged organosilane precursor on MCM-41 is presented. Secondly, it is demonstrated that pore narrowing can be obtained without losing porosity by removing the porogen template after grafting. The remaining silanols in the pores can then be end-capped with hexamethyl disilazane (HMDS to make the material completely hydrophobic. Finally, we applied the pore narrowing method on organosilica films to prove that this method is also successful on existing low-k materials.

Christophe Detavernier

2013-02-01

149

Dodecagonal tiling in mesoporous silica.  

Science.gov (United States)

Recent advances in the fabrication of quasicrystals in soft matter systems have increased the length scales for quasicrystals into the mesoscale range (20 to 500 ångströms). Thus far, dendritic liquid crystals, ABC-star polymers, colloids and inorganic nanoparticles have been reported to yield quasicrystals. These quasicrystals offer larger length scales than intermetallic quasicrystals (a few ångströms), thus potentially leading to optical applications through the realization of a complete photonic bandgap induced via multiple scattering of light waves in virtually all directions. However, the materials remain far from structurally ideal, in contrast to their intermetallic counterparts, and fine control over the structure through a self-organization process has yet to be attained. Here we use the well-established self-assembly of surfactant micelles to produce a new class of mesoporous silicas, which exhibit 12-fold (dodecagonal) symmetry in both electron diffraction and morphology. Each particle reveals, in the 12-fold cross-section, an analogue of dodecagonal quasicrystals in the centre surrounded by 12 fans of crystalline domains in the peripheral part. The quasicrystallinity has been verified by selected-area electron diffraction and quantitative phason strain analyses on transmission electron microscope images obtained from the central region. We argue that the structure forms through a non-equilibrium growth process, wherein the competition between different micellar configurations has a central role in tuning the structure. A simple theoretical model successfully reproduces the observed features and thus establishes a link between the formation process and the resulting structure. PMID:22810699

Xiao, Changhong; Fujita, Nobuhisa; Miyasaka, Keiichi; Sakamoto, Yasuhiro; Terasaki, Osamu

2012-07-19

150

21 CFR 872.3140 - Resin applicator.  

Science.gov (United States)

... 2010-04-01 2010-04-01 false Resin applicator. 872.3140 Section 872.3140...DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device intended...

2010-04-01

151

21 CFR 177.1595 - Polyetherimide resin.  

Science.gov (United States)

...2010-04-01 2009-04-01 true Polyetherimide resin. 177.1595 Section 177.1595 Food and Drugs...Contact Surfaces § 177.1595 Polyetherimide resin. The polyetherimide resin identified in this section may be safely...

2010-04-01

152

21 CFR 872.3140 - Resin applicator.  

Science.gov (United States)

...Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device...intended for use in spreading dental resin on a tooth during application of tooth shade material. (b)...

2010-04-01

153

21 CFR 178.3930 - Terpene resins.  

Science.gov (United States)

...Drugs 3 2010-04-01 2009-04-01 true Terpene resins. 178.3930 Section 178.3930 Food...Certain Adjuvants and Production Aids § 178.3930 Terpene resins. The terpene resins identified in paragraph (a) of...

2010-04-01

154

Storage process of contaminated ion exchange resin  

International Nuclear Information System (INIS)

Process for the efficient storage of contaminated ion exchange resins, whether anionic, cationic or mixed, and irrespective of their amount of use. The process in accordance with the invention brings the contaminated ion echange resin(s) into contact with a base compound in sufficient quantity to block the active sites of the cationic resin(s). The ion exchange resins processed in this manner are incorporated in a thermohardening resin at ambient temperature and this thermohardening resin is made to cross-link. The resins that can be stored by this process are polystyrene resins cross-linked with divinylbenzene, which include either sulphonic groupings SO3H (cationic resins) or OH functions taken up on a quaternary ammonium grouping (anionic resins)

155

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

156

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

157

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

158

Properties of the Carboxylate ion exchange resins  

International Nuclear Information System (INIS)

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)

159

Mesoporous Building Blocks : Synthesis and Characterization of Mesoporous Silica Particles and Films  

OpenAIRE

Catalyst supports, drug delivery systems, hosts for nanoparticles, and solar cells are just some examples of the wide range of exciting applications for mesoporous silica. In order to optimize the performance of a specific application, controlling the material’s morphology and pore size is crucial. For example, short and separated particles are beneficial for drug delivery systems, while for molecular sieves, the pore size is the key parameter. In this thesis, mesoporous silica building blo...

Bjo?rk, Emma M.

2013-01-01

160

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  

International Nuclear Information System (INIS)

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 m2/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 m2/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.

161

Unidirectional self-assembly of soft templated mesoporous carbons by zone annealing  

Science.gov (United States)

Surfactant or block copolymer-templated mesoporous films have been extensively explored, but achieving mesostructure coherence and unidirectional orientation over macroscopic dimensions has remained quite challenging for these self-assembled systems. Here, we extend the concepts associated with zone refinement of crystalline materials to soft templated mesoporous carbon films based on the cooperative assembly of commercial non-ionic surfactants (block copolymers) and phenolic resin oligomers (resol) to provide macroscopic alignment of both cubic (FDU-16) and hexagonal (FDU-15) mesostructures. The average orientation of these mesophases is determined from rotation grazing incidence small angle X-ray scattering (GISAXS) measurements. For FDU-15 templated by Pluronic P123, the orientation factor for the zone-annealed film is 0.98 based on the average of the second Legendre polynomial, but this orientation deteriorates significantly during carbonization. Notably, a thermal stabilization step following zone annealing preserves the orientation of the mesostructure during carbonization. The orientation factor for an isotropic cubic structure (FDU-16 templated by Pluronic F127) is only 0.48 (based on the 111 reflection with incident angle 0.15°) for the same zone annealing protocol, but this illustrates the versatility of zone annealing to different mesostructures. Unexpectedly, zone annealing of FDU-15 templated by Pluronic F127 leads to stabilization of the mesostructure through carbonization, whereas this structure collapses fully during carbonization even after extended oven annealing; despite no clear macroscopic orientation of the cylindrical mesostructure from zone annealing. Thermal zone annealing provides a simple methodology to produce highly ordered and macroscopically oriented stable mesoporous carbon films, but the efficacy is strongly tied to the mobility of the template during the zone annealing.Surfactant or block copolymer-templated mesoporous films have been extensively explored, but achieving mesostructure coherence and unidirectional orientation over macroscopic dimensions has remained quite challenging for these self-assembled systems. Here, we extend the concepts associated with zone refinement of crystalline materials to soft templated mesoporous carbon films based on the cooperative assembly of commercial non-ionic surfactants (block copolymers) and phenolic resin oligomers (resol) to provide macroscopic alignment of both cubic (FDU-16) and hexagonal (FDU-15) mesostructures. The average orientation of these mesophases is determined from rotation grazing incidence small angle X-ray scattering (GISAXS) measurements. For FDU-15 templated by Pluronic P123, the orientation factor for the zone-annealed film is 0.98 based on the average of the second Legendre polynomial, but this orientation deteriorates significantly during carbonization. Notably, a thermal stabilization step following zone annealing preserves the orientation of the mesostructure during carbonization. The orientation factor for an isotropic cubic structure (FDU-16 templated by Pluronic F127) is only 0.48 (based on the 111 reflection with incident angle 0.15°) for the same zone annealing protocol, but this illustrates the versatility of zone annealing to different mesostructures. Unexpectedly, zone annealing of FDU-15 templated by Pluronic F127 leads to stabilization of the mesostructure through carbonization, whereas this structure collapses fully during carbonization even after extended oven annealing; despite no clear macroscopic orientation of the cylindrical mesostructure from zone annealing. Thermal zone annealing provides a simple methodology to produce highly ordered and macroscopically oriented stable mesoporous carbon films, but the efficacy is strongly tied to the mobility of the template during the zone annealing. Electronic supplementary information (ESI) available: GISAXS profiles for the FDU-15-F127 at ? = 0° and ? = 90° is included along with 2D GISAXS data for all azimuthal data associated with FDU-15-P123 to illustrate th

Xue, Jiachen; Singh, Gurpreet; Qiang, Zhe; Karim, Alamgir; Vogt, Bryan D.

2013-08-01

162

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

163

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

164

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.

165

Advanced resin cleaning system (ARCS)  

International Nuclear Information System (INIS)

Ebara's novel and unprecedented ion exchange resin cleaning system, for use in BWR plants and featuring a vibration separator and basic design factors of Radiological Solutions, Inc., had been delivered to Tokai No.2 Power Station, Japan Atomic Power Company, in October 2005. This compactly-designed system effectively separates crud and resin fines from ion exchange resins, with no clogging of separation screens. It generates minimized waste liquid and has a specially designed over-pack cleaning tank. The system has been in operation for about a year now and favorable operational data and evaluation results are being reported from the owner-side. (author)

166

Formation of Mesopores in USY zeolites: a Case Revisited  

OpenAIRE

Abstract Steaming of NH4Y zeolite at 723 K and 873 K is accompanied by the formation of extra-framework amorphous aluminosilicate and silica gel in addition to earlier observed extra-framework aluminium species. Their occurrence is directly associated with the formation of mesopores. Bulk (intracrystalline) mesopores occur inside the crystallite nuclei and surface (intercrystalline) mesopores are located nearby the crystallite surface. Corrosion of the zeolite framework results in ...

Lutz, Wolfgang; Kurzhals, Rolf; Kryukova, Galina; Enke, Dirk; Weber, Manfred; Heidemann, Detlef

2010-01-01

167

46 CFR Table I to Part 150 - Alphabetical List of Cargoes  

Science.gov (United States)

...Butyl phenol, Formaldehyde resin in Xylene32n-Butyl...Calcium long chain alkyl phenolic amine (C8-C40) 9CPQ...C28-C250)34 POSPolyolefin phenolic amine (C28-C250)7 ...OTLTall oil fatty acid (Resin acids less than 20%)...

2010-10-01

168

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

Science.gov (United States)

... Polyethylene *Polyethylene—Ethyl Acrylate Resins *Polyethylene—Polyvinyl Acetate Copolymers Polyethylene Resin (HDPE) Polyethylene Resin (LPDE) Polyethylene Resin, Scrap Polyethylene Resin, Wax (Low M.W.) Polyethylene...

2010-07-01

169

Bending characteristics of resin concretes  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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

170

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

171

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

172

76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

...Third Review)] Granular Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade...antidumping duty order on granular polytetrafluoroethylene resin (``granular PTFE resin'') from...

2011-01-27

173

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

174

Aerosol-generated mesoporous silicon oxycarbide particles  

International Nuclear Information System (INIS)

Aerosol-generated mesoporous organosilica submicronic spheres have been converted into porous silicon oxycarbide (SiCO) glasses by pyrolysis at 1000 grad C in an inert atmosphere. Spherical mesoporous particles obtained from acidic solutions of 1,2-bis(triethoxysilyl) ethane and Pluronic F127 structuring agent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption/desorption, and multi nuclear solid-state magic-angle spinning (MAS) NMR. These particles were then pyrolyzed at 1000 grad C and transformed into a SiCO phase as evidenced by 29Si MAS NMR, while TEM shows preserved mesoporosity, unfortunately difficult to access owing to the presence of an outer layer of dense silica. (authors)

175

Diffraction analysis of mesostructured mesoporous materials.  

Science.gov (United States)

Ordered mesostructured mesoporous materials, combining nano-organization with atomic disorder, are both attractive and challenging objects of investigation by X-ray and neutron diffraction. The development of diffraction mesostructure analysis methods and their applications in studies on structural characterization, formation processes and physisorption phenomena in these advanced materials are summarized in this tutorial review. The focus here is on the techniques that allow extracting mesostructure parameters and peculiarities of density distribution in the materials from the Bragg reflection positions and intensities. The investigations of mesoporous silicates, their nonsilica replicas and composites are discussed including the combined use of diffraction with electron microscopy and physisorption. The small-angle scattering curve analysis, which is also an important methodology in the field, is out of the scope of this review. PMID:23038418

Solovyov, Leonid A

2013-05-01

176

Towards understanding morphogenesis of mesoporous silica shapes  

Science.gov (United States)

A creative combination of self-assembly and microfabrication may provide the way to future nanotechnology because of its inherent simplicity, high reliability and low cost of production. Recently the biomimetic synthesis of extraordinary curved mesoporous silica shapes has been reported, such as rods, discoids, spheres, tubes and hollow helicoids, obtained through the nucleation, growth and polymerization of silicate liquid crystals. Potential ability to control curved shapes portends a variety of applications and new technologies where mesostructure and form determine function. In this talk I shall focus on the problem of morphogenesis of mesoporous silica shapes and surface patterns. An outline of possible theoretical model will be presented to describe the variety of forms and surface designs that result from the liquid crystal stage, silicification and rigidification of silicate liquid crystals. A few examples of numerical 3-D simulation will be discussed to compare theory with experiment and to project beyond the experimental results.

Sokolov, Igor Yu.

2002-03-01

177

Oil absorption in mesoporous silica particles  

OpenAIRE

Mesoporous silica particles were prepared from highly basic sodium silicate solutions, having different silica modulus and SiO2 concentrations, by adding sulphuric acid at different temperatures. Pore structure of prepared silica particles (aggregates) is strongly influenced by processing conditions and easy controllable in broad range of the specific surface area, pore size, pore volume and size distribution. It is shown that there is a clear correlation between volume of absorbed oil and pr...

Radislav Filipovi?; Dragica Lazi?; Mitar Peruši?; Ivan Stijepovi?

2010-01-01

178

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.

179

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 temperatu...

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

2010-01-01

180

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 temperatu...

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

2011-01-01

181

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

182

Mesoporous silica nanoparticles for active corrosion protection.  

Science.gov (United States)

This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (?1000 m2·g(-1)), narrow pore size distribution (d?3 nm), and large pore volume (?1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect. PMID:21344888

Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

2011-03-22

183

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

184

Facile synthesis of gradient mesoporous carbon monolith based on polymerization-induced phase separation  

Science.gov (United States)

In this paper, a gradient mesoporous carbon (GMC) monolith derived from the mixtures of phenolic resin (PF) and ethylene glycol (EG) was prepared by a facile route based on polymerization-induced phase separation under temperature gradient (TG). A graded biphasic structure of PF-rich and EG-rich phases was first formed in preform under a TG, and then the preform was pyrolyzed to obtain the GMC monolith. The TG is mainly induced by the thermal resistance of the preferential phase separation layer at high temperature region. The pore structure of the monolith changes gradually along the TG direction. When the TG varies from 58°C to 29°C, the pore size, apparent porosity and specific surface area of the monolith range respectively from 18 nm to 83 nm, from 32% to 39% and from 140.5 m2/g to 515.3 m2/g. The gradient porous structure of the monolith is inherited from that of the preform, which depends on phase separation under TG in the resin mixtures. The pyrolysis mainly brings about the contraction of the pore size and wall thickness as well as the transformation of polymerized PF into glassy carbon.

Xu, Shunjian; Luo, Yufeng; Zhong, Wei; Xiao, Zonghu; Luo, Yongping; Ou, Hui; Zhao, Xing-Zhong

2014-06-01

185

Crystalline three-dimensional cubic mesoporous niobium oxide  

OpenAIRE

A well-ordered three-dimensional (3D) cubic Ia3d mesoporous niobium oxide with amorphous wall is prepared under controlled humidity by a sol-gel method and further converted to crystalline 3D niobium oxide with the retention of its original mesoporous system. © The Royal Society of Chemistry.

Ye, L.; Xie, S.; Yue, B.; Qian, L.; Feng, S.; Tsang, Sc; Li, Y.; He, H.

2010-01-01

186

Synthesis and Catalytic Performance of Mesoporous Material by Twostep Crystallization  

Directory of Open Access Journals (Sweden)

Full Text Available A mesoporous material was synthesized by using the precursor of MCM22 zeolite through a twostep synthesis route, and characterized by XRD, N2 physical adsorptiondesorption, TEM, 27Al MAS NMR, IR spectra of pyridine adsorbed methods and so on. It was found that the synthesized sample was not a mixture of microporous zeolite and mesoporous material but a new mesoporous molecular sieve with strong acid sites and good thermal stability. The acid catalytic activity for macromolecules was evaluated and compared with conventional mesoporous material MCM-41 through the cracking reaction of cumene and alkylation reaction of benzene with 1dodecen. The results show that the conversions of cumene cracking at 350? over the new mesoporous material and MCM-41 are 68.98% and 48.80%, respectively. For the alkylation reaction of benzene with 1dodecen at 210?, the conversions of 1dodecen over the new mesoporous materials and MCM-41 are around 95.20% and 86.89%, respectively. The selectivities of linear alkylbenzene over the new mesoporous materials and MCM-41 are around 88.11% and 90.06%, respectively. The results show that the catalytic property of the new mesoporous materials for macromolecules is superior to that of MCM-41.

LIU Wei-Qiao,SHANG Tong-Ming,LI Gong,WU Fei-Ke,TONG Hui-Juan,SUN Yu-Han

2010-07-01

187

Mesoporous zeolite and zeotype single crystals synthesized in fluoride media  

DEFF Research Database (Denmark)

We report the synthesis and characterization of a series of new mesoporous zeolite and zeotype materials made available by combining new and improved procedures for directly introducing carbon into reaction mixtures with the fluoride route for conventional zeolite synthesis. The mesoporous materials were all prepared by hydrothermal crystallization of gels adsorbed on carbon matrices which were subsequently removed by combustion. The procedures presented here resulted in mesoporous zeolite and zeotypes materials with MFI, MEL, BEA, AFI and CHA framework structures. All samples were characterized by XRPD, SEM, TEM and N-2 physisorption measurements. For the zeolite materials it A as found that mesoporous MFI and MEL structured single crystals could indeed be crystallized from fluoride media using an improved carbon-templating approach. More importantly, it was found that mesoporous BEA-type single crystals could be crystallized from fluoride media by a newly developed procedure presented here. Thus, we here present the only known route to mesoporous BEA-type single crystals, since crystallization of this framework structure from basic media is known to give only nanosized crystals as opposed to mesoporous single crystals. For the zeotype materials it was found that highly crystalline mesoporous materials of AFI and CHA structure types could be synthesized using a newly developed procedure. (c) 2006 Elsevier Inc. All rights reserved.

Egeblad, Kresten; Kustova, Marina

2007-01-01

188

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

189

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

190

Resin composition for coatings  

International Nuclear Information System (INIS)

A radiation curable surface coating composition for the production of coated steel sheets is given comprising a copolymerizable monomer with unsaturated bonds on the side chain, and a resin obtained by reacting a polymer or copolymer of vinyl containing a hydroxyl group on its side chain with an unsaturated isocyanate mixture. The isocyanate reacts with the hydroxyl group at low temperature in a short time. The amount of the isocyanate mixture may be 0.1-0.4 gram equivalent weight per 1,000 g of the hydroxyl polymer. The isocyanate mixture is obtained by reacting one mol of diisocyanates with 1.4-0.6 mol (meth)acrylic acid esters having one hydroxyl group. For industrial purposes, an electron beam accelerator of 0.1-2 MeV is advantageously used for curing. In one example, 50 parts of methyl methacrylate, 30 parts of butyl methacrylate, 20 parts of 2-hydroxyl ethyl methacrylate and 1 part of azobis butyl nitrile were blended and polymerized by dropping into 50 parts of boiled butyl acetate. After polymerization, 50 parts of methyl methacrylate were added to produce a hydroxy polymer solution. Separately, 168 parts of hexamethylene diisocyanate and 100 parts of 2-hydroxy ethyl acrylate were reacted at 500C for 3 hours and then diluted with 170 parts of methyl methacrylate to obtain unsaturated isocyanate mixture having a 400 isocyanate equivalent. Thereafter, 135 parts of the hydroxy polymer and 10 parts of the isocyanate mixture underwent a urethane reaction at 600C for 5 hours. (Iwakiri, K.)

191

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

192

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

193

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

194

21 CFR 175.300 - Resinous and polymeric coatings.  

Science.gov (United States)

... Zinc resinate. (vi) Phenolic resins as the basic polymer formed by...with formaldehyde: (a ) Phenolic resins formed by reaction of formaldehyde...Xylenol. (b ) Adjunct for phenolic resins: Aluminum butylate....

2010-04-01

195

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

196

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...polymerization of Nylon 66 salts and epsilon -caprolactam. (5) Nylon 11 resins are manufactured...by the polymerization of epsilon- caprolactam. (7) Nylon 66T resins are manufactured...to 1 ratio by weight of epsilon -caprolactam and omega -laurolactam....

2010-04-01

197

Method for loading resin beds  

International Nuclear Information System (INIS)

An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145 to 2000C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 1450C with a second aqueous component to provide a gaseous phase containing HNO3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate

198

Anionic resin by radiation grafting  

International Nuclear Information System (INIS)

Anion-exchange resin has been prepared by grafting of 4-Vinyl Pyridine on PVC by simultaneous irradiation in the presence of air in multipurpose gamma irradiator (RAVI). Grafting was studied at two different dose rate, cumulative dose up to 26 kGy and by pre-irradiation of the Trunk polymer. A marked increase in the grafting percentage from 98 to 145 was observed when the trunk polymer was pre-irradiated and an ion-exchange capacity of 7.3 m eq/gm (dry) resin was achieved. Other properties like bulk density, particle size etc. has also been studied. (author)

199

Radiation hardening of carbamide resins  

International Nuclear Information System (INIS)

The process of hardening of carbamide resins of commercial grade under the action of fast electrons has been studied. Composition based on the carbamide resin with addition of chlorinated hydrocarbons, namely, tetrachlorethane and carbon tetrachloride, exerting catalitic action upon irradiation, have been irradiated in air at room temperature. The hardening of the compositions has been studied by determining pH of the solution, content of gel-fraction in the films being formed, a change of physical state of the composition for a certain period of time after irradiation. Integral dose of hardening the carbamide compositions increases with a dose rate

200

21 CFR 172.280 - Terpene resin.  

Science.gov (United States)

...2010-04-01 2009-04-01 true Terpene resin. 172.280 Section 172.280 Food and Drugs...and Related Substances § 172.280 Terpene resin. The food additive terpene resin may be safely used in accordance with the...

2010-04-01

201

21 CFR 172.280 - Terpene resin.  

Science.gov (United States)

... 3 2010-04-01 2009-04-01 true Terpene resin. 172.280 Section 172.280 Food...Films and Related Substances § 172.280 Terpene resin. The food additive terpene resin may be safely used in accordance...

2010-04-01

202

21 CFR 172.280 - Terpene resin.  

Science.gov (United States)

...2009-04-01 true Terpene resin. 172.280 Section 172...Substances § 172.280 Terpene resin. The food additive terpene resin may be safely used in accordance...barrier on powders of ascorbic acid or its salts in an amount...

2010-04-01

203

21 CFR 177.1555 - Polyarylate resins.  

Science.gov (United States)

...000. (3) Polyarylate resins may be identified by their characteristic... The finished polyarylate resins in sheet form at least 0.5...extractives not to exceed 2.33 micrograms per square centimeter...square inch) of the exposed resin surface. (d)...

2010-04-01

204

Method for removing contaminants from plastic resin  

Energy Technology Data Exchange (ETDEWEB)

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

205

Method of removing contaminants from plastic resins  

Energy Technology Data Exchange (ETDEWEB)

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)

2007-08-07

206

Method of removing contaminants from plastic resins  

Energy Technology Data Exchange (ETDEWEB)

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

207

Improved Fire-Resistant Resins for Laminates  

Science.gov (United States)

Fire-resistant resins for fabricating laminates with inorganic fibers, especially graphite fibers, are formed from bisimides containing main-chain phosphorus and olefinic end groups. Bisimides are thermally polymerized to form resins and laminates virtually imcombustible in pure oxygen at 300 degrees C. New resins are suitable for many applications requiring good adhesion and excellent resistance to heat, fire, solvents and chemicals.

Fohlen, G. M.; Parker, J. A.; Varma, I. K.

1982-01-01

208

Controlling polymerization initiator concentration in mesoporous silica thin films.  

Science.gov (United States)

We present a strategy toward controlled polymer density in mesopores by specifically adjusting the local amount of polymerization initiator at the pore wall. The polymerization initiator concentration as well as the polymer functionalization has a direct impact on mesoporous membrane properties such as ionic permselectivity. Mesoporous silica-based thin films were prepared with specifically adjusted amount of polymerization initiator (4-(3-triethoxysilyl)propoxybenzophenone (BPSilane)) or initiator binding functions ((3-aminopropyl)triethoxysilane (APTES)), directly and homogeneously incorporated into the silica wall pursuing a sol-gel-based co-condensation approach. The amount of polymerization initiator was adjusted by varying its concentration in the sol-gel precursor solution. The surface chemistry, porosity, pore accessibility, and reactivity of the surface functional groups were investigated by using infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray reflectometry, ellipsometry, atomic force microscopy, and transmission electron microscopy. We could gradually modify the amount of reactive polymerization initiators in these mesoporous membranes. Mesopores were maintained for APTES containing films for all tested ratios up to 25 mol % and for BPSilane containing films up to 15 mol %. These films showed accessible and charge-dependent ionic permselectivity and an increasing degree of functionalization with increasing precursor ratio. This approach can directly result in control of polymer grafting density in mesoporous films and thus has a direct impact on applications such as the control of ionic transport through mesoporous silica membranes. PMID:24364647

Krohm, Fabio; Didzoleit, Haiko; Schulze, Marcus; Dietz, Christian; Stark, Robert W; Hess, Christian; Stühn, Bernd; Brunsen, Annette

2014-01-14

209

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.

210

Ultrastable, redispersible, small, and highly organomodified mesoporous silica nanotherapeutics.  

Science.gov (United States)

Practical biomedical application of mesoporous silica nanoparticles is limited by poor particle dispersity and stability due to serious irreversible aggregation in biological media. To solve this problem, hydrothermally treated mesoporous silica nanoparticles of small size with dual-organosilane (hydrophilic and hydrophobic silane) surface modification have been synthesized. These highly organomodified mesoporous silica nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, N(2) adsorption-desorption, dynamic light scattering, zeta potential, and solid-state (29)Si NMR, and they prove to be very stable in simulated body fluid at physiological temperature. Additionally, they can be dried to a powdered solid and easily redispersed in biological media, maintaining their small size for a period of at least 15 days. Furthermore, this preparation method can be expanded to synthesize redispersible fluorescent and magnetic mesoporous silica nanoparticles. The highly stable and redispersible mesoporous silica NPs show minimal toxicity during in vitro cellular assays. Most importantly, two types of doxorubicin, water-soluble doxorubicin and poorly water-soluble doxorubicin, can be loaded into these highly stable mesoporous silica nanoparticles, and these drug-loaded nanoparticles can also be well-redispersed in aqueous solution. Enhanced cytotoxicity to cervical cancer (HeLa) cells was found upon treatment with water-soluble doxorubicin-loaded nanoparticles compared to free water-soluble doxorubicin. These results suggest that highly stable, redispersible, and small mesoporous silica nanoparticles are promising agents for in vivo biomedical applications. PMID:22050408

Lin, Yu-Shen; Abadeer, Nardine; Hurley, Katie R; Haynes, Christy L

2011-12-21

211

Oil absorption in mesoporous silica particles  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous silica particles were prepared from highly basic sodium silicate solutions, having different silica modulus and SiO2 concentrations, by adding sulphuric acid at different temperatures. Pore structure of prepared silica particles (aggregates is strongly influenced by processing conditions and easy controllable in broad range of the specific surface area, pore size, pore volume and size distribution. It is shown that there is a clear correlation between volume of absorbed oil and processing parameters used in preparation of silica aggregates. Thus, oil absorption is higher in the samples prepared from sodium silicate solution with higher SiO2 concentration and at higher synthesis temperature.

Radislav Filipovi?

2010-12-01

212

Construction of mesoporous frameworks with vanadoborate clusters.  

Science.gov (United States)

A new porous vanadoborate was synthesized by employing the scale chemistry theory with the vanadoborate cluster V10B28. The twofold interpenetrated lvt network was assembled with zinc-containing elliptical vanadoborate clusters and Zn polyhedra. The single lvt framework contains a three-dimensional 38×38×20 ring channel system with the pore size (24.7×12.7?Å) reaching the mesoscale, thus indicating the possibility of constructing 3D ordered mesopores with vanadoborate clusters. The porosity of the SUT-7 structure was confirmed by CO2 adsorption of the as-synthesized materials. PMID:24590597

Chen, Hong; Yu, Zheng-Bao; Bacsik, Zoltán; Zhao, Huishuang; Yao, Qingxia; Sun, Junliang

2014-04-01

213

Synthesis and Functionalization of Periodic Mesoporous Silica  

OpenAIRE

Different periodic mesoporous silica materials have been synthesized in order to investigate the topic of size-selective heterogeneous catalysis. SBA-1, SBA-2, SBA-16, and MCM-41 were synthesized. The cagelike SBA-1 and the channel-like MCM-41 have been modified by post-synthesis methods involving grafting of HN(SiHMe)2, HN(SiMe2Ph)2, and HN(SiMePh2)2 to tailor the surface for subsequent metalation reactions. The three disilazanes showed different reactivity to the two differen...

Lønstad, Bjørn Tore

2008-01-01

214

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

215

Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure  

Science.gov (United States)

Methods are disclosed for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physical sorption 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. 17 figs.

Sachtler, W.M.H.; Huang, Y.Y.

1998-07-28

216

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

217

Commercial Ion Exchange Resin Vitrification Studies  

International Nuclear Information System (INIS)

In the nuclear industry, ion exchange resins are used for purification of aqueous streams. The major contaminants of the resins are usually the radioactive materials that are removed from the aqueous streams. The use of the ion exchange resins creates a waste stream that can be very high in both organic and radioactive constituents. Therefore, disposal of the spent resin often becomes an economic problem because of the large volumes of resin produced and the relatively few technologies that are capable of economically stabilizing this waste. Vitrification of this waste stream presents a reasonable disposal alternative because of its inherent destruction capabilities, the volume reductions obtainable, and the durable product that it produces

218

A Method for Characterizing PMR-15 Resin  

Science.gov (United States)

Quantitative analysis technique based on reverse-phase, highperformance liquid chromatography (HPLC) and paired-ion chromatography (PIC) developed for PMR-15 resins. In reverse-phase HPLC experiment, polar solvent containing material to be analyzed passed through column packed with nonpolar substrate. Composition of PMR-15 Resin of 50 weight percent changes as resin ages at room temperature. Verification of proper resin formulation and analysis of changes in resin composition during storage important to manufacturers of PMR-15 polymer matrix composite parts. Technique especially suitable for commercial use by manufacturers of high-performance composite components.

Roberts, G. D.; Lauver, R. W.

1986-01-01

219

Recovery of platinum, tin and indium from spent catalysts in chloride medium using strong basic anion exchange resins  

International Nuclear Information System (INIS)

Highlights: ? Platinum, tin and indium recoveries from spent reforming catalysts. ? Adsorption of metal chlorocomplexes on strongly basic anion-exchange resins. ? Sequential desorption via elution with reducing (Pt, Sn) or complexing (In) agents. ? The elements were recovered in very high yields. ? The anion-exchange resins can be reused. - Abstract: This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al2O3 catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl- form). The catalysts were leached with aqua regia (75 oC, 20-25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L-1 HCl. Platinum was desorbed passing 1 mol L-1 Na2S2O3 (pH 9). Tin was removed by elution with 0.1 mol L-1 ascorbic acid. Indium was removed using 0.1 mol L-1 EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).

220

Occupational eczema from para-tertiary-butylphenol formaldehyde resins: a review of the sensitizing resins.  

Science.gov (United States)

The first case of allergy due to para-tertiary-butylphenol formaldehyde resins (PTBP resins) were found in 1958 in the shoe-making industry. These resins are found in certain neoprene adhesives. PTBP resin hypersensitivity may be due either to the para-tertiary-butylphenol, to the resin itself or less frequently to the formaldehyde. These resins may cause occupational allergy (in the automobile industry and chiefly in the shoe-making industry) and non-occupational allergy (footwear and clothing hypersensitivity). Patients allergic to PTBP resins have been found to show a cross-reaction to other resins such as Alresen PA 103, Schenectady SP 126 and Schenectady SP 154. The authors give a reference list of sensitizing neoprene adhesives and PTBP resins so that manufacturers can limit the use of these products as far as possible. PMID:138517

Foussereau, J; Cavelier, C; Selig, D

1976-10-01

221

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

222

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

Science.gov (United States)

...Exchange) *Styrene-Methacrylate Terpolymer Resins *Styrene-Methyl Methacrylate Copolymers...Terpolymers *Sulfonated Styrene-Maleic Anhydride Resins *Unsaturated Polyester Resins *Vinyl Toluene Resins *Vinyl...

2010-07-01

223

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

Science.gov (United States)

... *Styrene Maleic Anhydride Resins Styrene Polymeric Residue *Styrene-Acrylic Copolymer Resins *Styrene-Acrylonitrile-Acrylates Copolymers *Styrene-Butadiene Resins *Styrene-Butadiene Resins (Butadiene)...

2010-07-01

224

Synthesis of mesoporous nano-hydroxyapatite by using zwitterions surfactant  

Science.gov (United States)

Mesoporous nano-hydroxyapatite (mn-HAP) was successfully synthesized via a novel micelle-templating method using lauryl dimethylaminoacetic acid as zwitterionic surfactant. The systematic use of such a surfactant in combination with microwave energy inputenables the precise contr...

225

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

226

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

227

Mesoporous carbon incorporated metal oxide nanomaterials as supercapacitor electrodes  

Energy Technology Data Exchange (ETDEWEB)

Supercapacitors have attracted huge attention in recent years as they have the potential to satisfy the demand of both huge energy and power density in many advanced technologies. However, poor conductivity and cycling stability remains to be the major challenge for its widespread application. Various strategies have been developed for meeting the ever-increasing energy and power demands in supercapacitors. This Research News article aims to review recent progress in the development of mesoporous carbon incorporated metal oxide nanomaterials, especially metal oxide nanoparticles confined in ordered mesoporous carbon and 1D metal oxides coated with a layer of mesoporous carbon for high-performance supercapacitor applications. In addition, a recent trend in supercapacitor development - hierarchical porous graphitic carbons (HPGC) combining macroporous cores, mesoporous walls, and micropores as an excellent support for metal oxides - is also discussed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Jiang, Hao [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Ma, Jan [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Li, Chunzhong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2012-08-08

228

Mesoporous carbons as low temperature fuel cell platinum catalyst supports  

OpenAIRE

Platinum catalysts supported on ordered mesoporous carbons (OMC) are described. The mesoporous carbon support, CMK3 type, was synthesised as an inverse replica of a SBA-15 silica template. The platinum catalysts (i.e. Pt 20 wt% and Pt 10 wt%, respectively), obtained through a conventional wet impregnation method, have been investigated to determine their structural characteristics and electrochemical behaviour. The electro-catalytic performance towards the oxygen reduc...

Ghiotti, Giovanna; Manzoli, Maela

2008-01-01

229

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

230

In-situ immobilization of enzymes in mesoporous silicas  

Science.gov (United States)

Lipase from Candida antarctica B, horseradish peroxidase and laccase have been entrapped in silica cages rising mesoporous structures. Lipase and laccase yielded the highest structured mesoporous material whereas horseradish peroxidase may have altered the symmetry giving as a result mesocelullar foam (MCF) type of cages. The possible effect in the final structure of the material of the nature, size and surface structure of the proteins as well as the presence of various additives in the enzyme extracts is currently under investigations.

Santalla, Esther; Serra, Elías; Mayoral, Alvaro; Losada, José; Blanco, Rosa M.; Díaz, Isabel

2011-04-01

231

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

232

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

233

Novel Syntheses, Structures and Functions of Mesoporous Silica Materials  

OpenAIRE

The field of mesoporous silica has been studied for about 20 years but it is still an area attracting a lot of attention. The use of novel templating molecules and several issues related to the synthesis and fine structural details are still poorly understood. These aspects are of special relevance to the theme of this thesis, which includes novel work on three fronts; the synthesis, characterization and applications of mesoporous materials. The work described in this thesis aims to contribut...

Atluri, Rambabu

2010-01-01

234

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.

235

Advanced thermoplastic resins, phase 2  

Science.gov (United States)

High temperature structural resins are required for use on advanced aerospace vehicles as adhesives and composite matrices. NASA-Langley developed polyimide resins were evaluated as high temperature structural adhesives for metal to metal bonding and as composite matrices. Adhesive tapes were prepared on glass scrim fabric from solutions of polyamide acids of the semicrystalline polyimide LARC-CPI, developed at the NASA-Langley Research Center. Using 6Al-4V titanium adherends, high lap shear bond strengths were obtained at ambient temperature (45.2 MPa, 6550 psi) and acceptable strengths were obtained at elevated temperature (14.0 MPa, 2030 psi) using the Pasa-Jell 107 conversion coating on the titanium and a bonding pressure of 1.38 MPa (200 psi). Average zero degree composite tensile and compressive strengths of 1290 MPa (187 ksi) and 883 MPa (128 ksi) respectively were obtained at ambient temperature with unsized AS-4 carbon fiber reinforcement.

Brown, A. M.; Hill, S. G.; Falcone, A.

1991-01-01

236

Progress on the Multifunctional Mesoporous Silica-based Nanotheranostics  

Directory of Open Access Journals (Sweden)

Full Text Available Inorganic mesoporous nano-biomaterials have broad application potentials in molecular imaging, targeted drug delivery, tissue engineering, gene therapy, and non-invasive surgical therapy, etc., which are of great significance in the early diagnosis and efficient therapy of serious diseases such as cancer. This article reviews the most recent research advances and outlooks future development trends of mesoporous nanotheranostics based on clinical requirements, the principle of nano-synthetic chemistry and the design strategy of multifunctional mesoporous nano-biomaterials, by combining the recent achievements of our group. By integrating various functions into mesoporous silica nanoparticles to endow them with special capabilities, the mesoporous nanotheranostics could act as the contrast agents for clinical molecular imaging (magnetic resonance imaging, fluorescent imaging and the combinations of various imaging modalities, as well as the carriers for the encapsulation and delivery of drugs for the therapy of diseases (chemotherapy, gene therapy, photodynamic therapy and non-invasive surgical therapy. With the development of bio-nanotechnology and nano-synthetic chemistry, mesoporous nanotheranostics are expected to satisfy the clinical requirements following the systematic investigation of their biological effects and bio-safety, and finally find their applications in clinical practices to benefit human beings.

SHI Jian-Lin, CHEN Yu, CHEN Hang-Rong

2013-01-01

237

Reinforcement of Denture Base Resins  

OpenAIRE

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 flexura...

Nejatiant, T.; Noortr, J.

2005-01-01

238

Bending characteristics of resin concretes  

OpenAIRE

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 methodolog...

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

2003-01-01

239

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.

240

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

Directory of Open Access Journals (Sweden)

Full Text Available 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

2012-01-01

241

Synthesis of improved polyester resins  

Science.gov (United States)

Eighteen aromatic unsaturated polyester prepolymers prepared by a modified interfacial condensation technique were investigated for their solubility in vinyl monomers and ability to provide high char yield forming unsaturated polyester resins. The best resin system contained a polyester prepolymer of phthalic, fumaric and diphenic acids reacted with 2,7-naphthalene diol and 9,9-bis(4-hydroxyphenyl)fluorene. This prepolymer is very soluble in styrene, divinyl benzene, triallyl cyanurate, diallyl isophthalate and methylvinylpyridine. It provided anaerobic char yields as high as 41 percent at 800 C. The combination of good solubility and char yield represents a significant improvement over state-of-the-art unsaturated polyester resins. The majority of the other prepolymers had only low or no solubility in vinyl monomers. Graphite composites from this prepolymer with styrene were investigated. The cause for the observed low shear strengths of the composites was not determined, however 12-week aging of the composites at 82 C showed that essentially no changes in the composites had occurred.

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

1979-01-01

242

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

243

Synthesis of Vanadium-mesoporous Hollow Spheres  

Directory of Open Access Journals (Sweden)

Full Text Available Vanadium-containing mesoporous silica with hollow spherical morphology was successfully synthesized by using CTAB, SDS and P123 as co-template. The influences of vanadium content and reaction conditions on the formation of the materials were also studied. Results indicated that the hollow spheres could not be shaped as molar ratio of V to Si was lower than 0.05 while excess vanadium content led large amount of vanadium oxides existed in the materials. The adequate molar ratio of V to Si was 0.1. The optimal synthesis conditions were reacted at 45¡?or 2 h under pH value of 5. The products with regular structure and morphology exhibited high catalytic activity on the selective oxidation of styrene by hydrogen peroxide.

SHI Xiao-Bo, CHEN Yu, KONG Yan, WU Cheng, WANG Jun

2012-07-01

244

Photocarrier grating technique in mesoporous silicon  

Energy Technology Data Exchange (ETDEWEB)

We present the first measurement of the ambipolar diffusion length in mesoporous silicon using the steady state photocarrier grating technique. Taking also response time measurements into account, we can deduce a typical value of the ambipolar diffusion coefficient of about 1.8x10{sup -6}cm{sup 2}s{sup -1}. The mobility-lifetime products of majority and minority carriers are found to be ({mu}{tau}){sub maj}=10{sup -8}cm{sup 2}V{sup -1} and ({mu}{tau}){sub min}=7x10{sup -10}cm{sup 2}V{sup -1} respectively. Together with temperature-dependent dark conductivity and intensity-dependent secondary photocurrent measurements we argue that a high density of trap states with a broad energetic distribution is responsible for such a small diffusion coefficient. ((orig.))

Schwarz, R. [Physics Department E16, Technical University of Munich, D-85747 Garching (Germany); Wang, F. [Physics Department E16, Technical University of Munich, D-85747 Garching (Germany); Ben-Chorin, M. [Physics Department E16, Technical University of Munich, D-85747 Garching (Germany); Grebner, S. [Physics Department E16, Technical University of Munich, D-85747 Garching (Germany); Nikolov, A. [Physics Department E16, Technical University of Munich, D-85747 Garching (Germany); Koch, F. [Physics Department E16, Technical University of Munich, D-85747 Garching (Germany)

1995-01-15

245

Adsorption of octadecyltrichlorosilane on mesoporous SBA-15  

International Nuclear Information System (INIS)

Adsorption of octadecyltrichlorosilane (OTS) on mesoporous SBA-15 has been studied by using Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermo-gravimetric analysis (TGA) techniques. BET surface area analysis shows decrease of surface area from 930 to 416 m2/g after OTS adsorption. SEM pictures show close attachment of SBA-15 particles. EDAX measurements show increase of carbon weight percentage and decrease of oxygen and silicon weight percentage. XPS results closely support EDAX analysis. FTIR spectra shows presence of methyl (-CH3) and methylene (-CH2) bands and oriented OTS monolayer on SBA-15. Thermo-gravimetric analysis shows that the OTS adsorbed on SBA-15 are stable up to a temperature of 230 deg. C and that the OTS monolayers decompose between 230 and 400 deg. C

246

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.)

247

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

248

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

249

Decomposition of ion exchange resins by pyrolysis  

International Nuclear Information System (INIS)

Pyrolysis of spent ion exchange resins is one of the most effective methods for reducing radioactive waster volume and for making the final waste form more stable. Fundamental experiments were performed to clarify the pyrolysis characteristics of anion and cation exchange resins. Residual elemental analyses and off-gas analyses showed that the decomposition ratio of cation resins was only 50 wt% at 6000C, while that of anion resins was 90 wt% at 4000C. Infrared spectroscopy for cation resins attributed its low decomposition ratio to formation of a highly heat-resistant polymer (sulfur bridged) during pyrolysis. Measurements of residual hygroscopicity and cement package strength indicated that the optimum pyrolysis temperatures for preventing resins swelling and package expansion were between 300 and 5000C

250

Low chloride content anion exchange resins  

International Nuclear Information System (INIS)

A process is described for the preparation of a strong base anion exchange resin in the hydroxy form and substantially free from chloride functionality which comprises (a) exchanging chloride functional groups in a strong base anion exchange resin with functional groups of selectivity intermediate between chloride and hydroxy and (b) exchanging intermediate selectivity groups with hydroxy groups by contacting the resin with aqueous inorganic or organic base. The strong base anion exchange resin is subjected, before step (a), to solvolytic displacement of non-ionic chlorine to convert it to ionic chloride functionality by contact with an aqueous medium at a pH of at least 7; and the aqueous base for use in step (b) is treated to reduce or remove chloride impurities by contact with an ion exchange resin highly selective for chloride ions before being contacted with the resin in step (b). (author)

251

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

252

Drying of ion-exchange resins for resin-based preparation of nuclear reactor fuels  

International Nuclear Information System (INIS)

The reference fuel kernel for recycle of 233U to HTGRs (High Temperature Gas-Cooled Reactors) is prepared by loading carboxylic acid cation-exchange resins with uranium and carbonizing at controlled conditions. The loaded, dried resin must meet specifications for sphericity, composition, and other properties. Microwave heating is used to give controlled and reproducible drying of 11-liter batches of uranium-loaded (4 kg of uranium) resin in a vessel of safe dimensions for nuclear criticality (12.7 cm ID). The dried resin must have a water content of 9 to 16 wt percent to minimize handling problems. The microwave heating evaporates water throughout the resin bed, with preferential heating of the wettest resin, and allows short drying cycles. As part of the resin feed preparation before uranium loading, the sodium-form resin is dried to allow separation of spheres from irregularly shaped material. A commercial, packaged fluidized bed dryer gives acceptable control and uniformity of drying

253

Performance of templated mesoporous carbons in supercapacitors  

Energy Technology Data Exchange (ETDEWEB)

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{sup -2} in aqueous electrolytes such as H{sub 2}SO{sub 4} and KOH and 0.06 F m{sup -2} for the aprotic medium (C{sub 2}H{sub 5}){sub 4}NBF{sub 4} in CH{sub 3}CN. 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 m{sup 2} g{sup -1}, and therefore exceeds the value obtained for many activated carbons (typically 900-1300 m{sup 2} g{sup -1}). On the other hand, the relatively low amount of surface oxygen in the present TMCs, as opposed to activated carbons, reduces the contribution of pseudo-capacitance effects and limits the gravimetric capacitance to 200-220 F g{sup -1} for aqueous electrolytes. In the case of non-aqueous electrolyte, it rarely exceeds 100 F g{sup -1}. It is also shown that the average mesopore diameter of these TMCs does not improve significantly the ionic mobility compared with typical activated carbons of pore-widths above 1.0-1.3 nm. This study suggests that activated carbons remain the more promising candidates for supercapacitors with high performances. (author)

Sevilla, M.; Alvarez, S.; Centeno, T.A.; Fuertes, A.B. [Instituto Nacional del Carbon-C.S.I.C., Apartado 73, 33080 Oviedo (Spain); Stoeckli, F. [IMT-Chimie des Surfaces, Universite de Neuchatel, Rue Emile Argand 11, CH-2009 Neuchatel (Switzerland)

2007-02-15

254

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

255

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

256

Electrosynthesis of Epoxy Resins via Superoxide Anion  

OpenAIRE

Epoxy resins are a class of reactive pre polymers and polymers which contain epoxide groups. Inspite of their high costs the epoxy resins find many important applications. The resins are used in both molding and laminating technique for making glass fiber-reinforced articles which are having better mechanical strength chemical resistance and electrical insulating properties. They also use in casting, potting encapsulating and embedment in the electrical and tooling industries. The general imp...

Rajni Mathur; Meeta Trivedi

2013-01-01

257

Release and toxicity of dental resin composite  

OpenAIRE

Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies h...

Gupta, Saurabh K.; Saxena, Payal; Pant, Vandana A.; Pant, Aditya B.

2012-01-01

258

Stabilitas Warna Resin Komposit Sebagai Bahan Tambalan  

OpenAIRE

(G) Resin komposit merupakan resin akrilik yang telah ditambah dengan bahan lain seperti bubuk quartz untuk membentuk struktur komposit. Untuk mendapatkan warna seperti warna gigi geligi asli, pigmen warna ditambahkan seperti ferric oxide, cadmium black, mercuric sulfide dan lain-lain. Bahan resin komposit ini biasanya digunakan untuk menumpat gigi anterior, memperbaiki gigi patah, melapisi permukaan gigi yang rusak, atau menutup warna gigi yang berubah karena obat-obatan antibiotik terten...

Soraya, Siti Sarah

2010-01-01

259

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

260

Recent progress in mesoporous titania materials: adjusting morphology for innovative applications  

OpenAIRE

This review article summarizes recent developments in mesoporous titania materials, particularly in the fields of morphology control and applications. We first briefly introduce the history of mesoporous titania materials and then review several synthesis approaches. Currently, mesoporous titania nanoparticles (MTNs) have attracted much attention in various fields, such as medicine, catalysis, separation and optics. Compared with bulk mesoporous titania materials, which are above a micrometer...

Juan L Vivero-escoto, Ya-dong Chiang

2012-01-01

261

The absorption of plutonium by anion resins  

Energy Technology Data Exchange (ETDEWEB)

Equilibrium experiments have shown Pu{sup +4} to be absorbed from nitric acid onto an anion resin as a complex anion Pu(NO{sub 3}){sub 6}{sup -2}. The amount of absorption is dependent on the plutonium and nitric acid concentrations in the equilibrium solution with a maximum at 7N to 8N HNO{sub 3}. A low cross-linked resin has a higher capacity and reaches equilibrium more rapidly than the normally supplied resin. Saturation capacity of one per cent cross-linked Nalcite SBR (Dowex 1), 50 -- 100 mesh, is 385 mg Pu/gram dry resin. (author)

Durham, R.W.; Mills, R.

1961-10-15

262

Microbiological Study of Water-Softener Resins  

Science.gov (United States)

Microbial identification using effluents backflushed from exhausted urban and rural tank resins and cleaned resins containing the sulfonated copolymer of styrene and divinylbenzene (SDB) were completed, along with microbial assessment of the concentrated stock salt brine. Forty-four different bacterial and fungal genera were identified. Extensive biochemical and animal virulence tests completed on one of the six bacterial salt brine isolates indicated a pathogenic staphylococcal strain. The retention of Staphylococcus aureus, a Flavobacterium sp, and Escherichia coli B bacteriophage was demonstrated both by using the nonexhausted sodium-regenerated resin and by using the same resin exchanged with different mono-, di-, and trivalent cations. Effluent counts completed after bacterial seepage through the resins indicated the Pb++ exchanged resin removed 55% of the bacteria; Na+, Fe++, and Al+++ removed 31 to 36% and Ca++ and Cu++ removed about 10 to 15%. Seventy per cent or more of the bacteriophage was removed by Fe++, Cu++, and Al+++, whereas the Ca++ and Na++ cations removed 25 to 31%. Over a 77-day period, nonsterile tap water was passed through bacterial seeded and uninoculated SDB (Na) resin columns. Effluent and resin elution counts demonstrated the growth and survival of 2 different bacteria per column. Increased bacterial retention, survival, and multiplication occurred concomitantly with accumulation of organic and inorganic materials and the Ca++ and Mg++ cations from the tap water. Furthermore, microbial elution from resin particles taken from column depths of 1, 8, and 16 cm indicated a bacterial diminution with increasing depths. PMID:5373675

Stamm, John M.; Engelhard, Warren E.; Parsons, James E.

1969-01-01

263

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

264

Kinetic Study of Resin-Curing on Carbon Fiber/Epoxy Resin Composites by Microwave Irradiation  

OpenAIRE

Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin-curing of carbon fiber/epoxy resin composite that was composed of discontinuous carbon fibers of 130 ?m or 3 mm were investigated. The mechanical properties of carbon fiber/epoxy resin comp...

Daisuke Shimamoto; Yusuke Imai, Yuji Hotta

2014-01-01

265

PHENOL - WHEAT PROTEIN - FORMALDEHYDE ADHESIVES FOR WOOD - BASED PANELS  

OpenAIRE

Phenol-formaldehyde (PF) resins were prepared with a level of 10%, 20% and 30% substitution of the phenol in the resin by three types of wheat gluten protein hydrolysates having different characteristics, namely (i) an enzymatic hydrolysate, (ii) a lower molecular weight enzymatic hydrolysate, and (iii) a middle sized molecular weight acid hydrolysate. The mixed protein-phenolic oligomer species distribution formed in the preparation of these resins were identified by matrix assisted laser de...

Lagel, Marie-christine; Pizzi, Antonio; Redl, Andreas

2014-01-01

266

21 CFR 872.3820 - Root canal filling resin.  

Science.gov (United States)

... 2010-04-01 2010-04-01 false Root canal filling resin. 872.3820 Section...DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device...

2010-04-01

267

21 CFR 172.215 - Coumarone-indene resin.  

Science.gov (United States)

... 2009-04-01 true Coumarone-indene resin. 172.215 Section 172.215 Food and...Substances § 172.215 Coumarone-indene resin. The food additive coumarone-indene resin may be safely used on grapefruit,...

2010-04-01

268

75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan  

Science.gov (United States)

...Review)] Granular Polytetrafluoroethylene Resin From Italy and Japan AGENCY: United States...orders on granular polytetrafluoroethylene resin from Italy and Japan...orders on granular polytetrafluoroethylene resin from Italy and Japan would be likely...

2010-11-01

269

21 CFR 872.3310 - Coating material for resin fillings.  

Science.gov (United States)

...2010-04-01 false Coating material for resin fillings. 872.3310 Section 872...Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be...

2010-04-01

270

40 CFR 721.2673 - Aromatic epoxide resin (generic).  

Science.gov (United States)

...2010-07-01 false Aromatic epoxide resin (generic). 721.2673 Section 721...Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance...identified generically as aromatic epoxide resin (PMN P-99-1399) is subject to...

2010-07-01

271

21 CFR 872.3690 - Tooth shade resin material.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section 872.3690...Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of...

2010-04-01

272

21 CFR 173.10 - Modified polyacrylamide resin.  

Science.gov (United States)

...2009-04-01 true Modified polyacrylamide resin. 173.10 Section 173.10 Food and Drugs...Treatment § 173.10 Modified polyacrylamide resin. Modified polyacrylamide resin may be safely used in food in accordance...

2010-04-01

273

21 CFR 872.3670 - Resin impression tray material.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Resin impression tray material. 872.3670...DEVICES Prosthetic Devices § 872.3670 Resin impression tray material. (a) Identification. Resin impression tray material is a device...

2010-04-01

274

21 CFR 573.120 - Acrylamide-acrylic acid resin.  

Science.gov (United States)

...2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food and Drugs...Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin (hydrolized polyacrylamide), only for...

2010-04-01

275

40 CFR 721.5908 - Modified phenolic resin (generic).  

Science.gov (United States)

...2010-07-01 false Modified phenolic resin (generic). 721.5908 Section 721...Substances § 721.5908 Modified phenolic resin (generic). (a) Chemical substance...identified generically as modified phenolic resin (PMN P-01-561) is subject to...

2010-07-01

276

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). 721...Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). ...substance identified generically as an epoxy resin containing phosphorus (PMN...

2010-07-01

277

76 FR 39896 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

...Review)] Granular Polytetrafluoroethylene Resin From Italy Determination On the basis of...order on granular polytetrafluoroethylene resin from Italy would be likely to lead to continuation...entitled Granular Polytetrafluoroethylene Resin from Italy: Investigation No....

2011-07-07

278

40 CFR 721.2755 - Cycloaliphatic epoxy resin (generic).  

Science.gov (United States)

...2010-07-01 false Cycloaliphatic epoxy resin (generic). 721.2755 Section 721...Substances § 721.2755 Cycloaliphatic epoxy resin (generic). (a) Chemical substance...identified generically as cycloaliphatic epoxy resin (PMN P-98-105) is subject to...

2010-07-01

279

21 CFR 872.3820 - Root canal filling resin.  

Science.gov (United States)

...2010-04-01 false Root canal filling resin. 872.3820 Section 872.3820 Food...Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material,...

2010-04-01

280

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

Science.gov (United States)

...2010-07-01 false Phosphorous modified epoxy resin (generic). 721.3135 Section 721...721.3135 Phosphorous modified epoxy resin (generic). (a) Chemical substance...generically as a phosphorous modified epoxy resin (PMNs P-00-992 and...

2010-07-01

281

21 CFR 872.3200 - Resin tooth bonding agent.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Resin tooth bonding agent. 872.3200 Section...DEVICES Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a device...

2010-04-01

282

21 CFR 872.3300 - Hydrophilic resin coating for dentures.  

Science.gov (United States)

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

2010-04-01

283

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 Food...872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2010-04-01

284

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

Science.gov (United States)

...2010-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

2010-07-01

285

21 CFR 177.2410 - Phenolic resins in molded articles.  

Science.gov (United States)

...2010-04-01 2009-04-01 true Phenolic resins in molded articles. 177.2410 Section...Intended for Repeated Use § 177.2410 Phenolic resins in molded articles. Phenolic resins identified in this section may be...

2010-04-01

286

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

287

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

288

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

289

21 CFR 872.3310 - Coating material for resin fillings.  

Science.gov (United States)

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

2010-04-01

290

21 CFR 872.3670 - Resin impression tray material.  

Science.gov (United States)

... 2010-04-01 false Resin impression tray material. 872.3670 Section...Devices § 872.3670 Resin impression tray material. (a) Identification...The device consists of a resin material, such as methyl...

2010-04-01

291

21 CFR 175.300 - Resinous and polymeric coatings.  

Science.gov (United States)

...175.300 Resinous and polymeric coatings. Resinous and polymeric coatings may be safely...production of resinous and polymeric coatings that is the subject...obtained from cashew nut shell liquid. Phenol. Phenyl...

2010-04-01

292

21 CFR 573.120 - Acrylamide-acrylic acid resin.  

Science.gov (United States)

...2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food and...Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin (hydrolized polyacrylamide), only for...

2010-04-01

293

21 CFR 175.300 - Resinous and polymeric coatings.  

Science.gov (United States)

...employed in the production of resinous...Drying oils, including...tung). Coconut. Corn... Tall oil. Walnut...Natural fossil resins, as the...including alkyd-type...reactants in oil-based or...acid-based alkyd resins. (c...

2010-04-01

294

21 CFR 573.120 - Acrylamide-acrylic acid resin.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food...Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin (hydrolized polyacrylamide),...

2010-04-01

295

21 CFR 872.3690 - Tooth shade resin material.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section 872... Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed...

2010-04-01

296

Curing kinetics of alkyd/melamine resin mixtures  

OpenAIRE

Alkyd resins are the most popular and useful synthetic resins applied as the binder in protective coatings. Frequently they are not used alone but are modified with other synthetic resins in the manufacture of the coatings. An alkyd/melamine resin mixture is the usual composition for the preparation of coating called 'baking enamel' and it is cured through functional groups of resins at high temperatures. In this paper, curing kinetics of alkyd resins based on castor oil and dehydrated castor...

Jovi?i? Mirjana C.; Z?, Radic?evic? Radmila

2009-01-01

297

EFFECTS OF ETHANOL, PHENOL, FORMALDEHYDE, AND SELECTED METABOLITES ON METABOLIC COOPERATION BETWEEN CHINESE HAMSTER V79 LUNG FIBROBLASTS  

Science.gov (United States)

The discovery that phorbol ester tumor promoters inhibit metabolic cooperation between cultured cells in proportion to their promoting activity in vivo suggests that such inhibition may be a mechanism in tumor promotion. Because metabolic cooperation appears to be essential for n...

298

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

299

Wear rates of resin composites.  

Science.gov (United States)

SUMMARY A laboratory study was conducted to examine the wear of resin composite materials using a generalized wear simulation model. Ten specimens each of five resin composites (Esthet•X [EX], Filtek Supreme Plus [SP], Filtek Z250 [Z2], Tetric EvoCeram [EC], and Z100 Restorative [Z1]) were subjected to wear challenges of 100,000, 400,000, 800,000, and 1,200,000 cycles. The materials were placed in cylinder-shaped stainless-steel fixtures, and wear was generated using a flat stainless-steel antagonist in a slurry of polymethylmethacrylate beads. Wear (mean facet depth [?m] and volume loss [mm(3)]) was determined using a noncontact profilometer (Proscan 2000) with Proscan and ProForm software. Statistical analysis of the laboratory data using analysis of variance and Tukey's post hoc test showed a significant difference (p1200K cycles were as follows: Z1 13.9 (2.0), Z2 26.7 (2.7), SP 30.1 (4.1), EC 31.8 (2.3), and EX 67.5 (8.2). Volume loss (mm(3)) and SDs for 1200K cycles were as follows: Z1 0.248 (0.036), Z2 0.477 (0.044), SP 0.541 (0.072), EC 0.584 (0.037), and EX 1.162 (0.139). The wear rate (?m) and volume loss rate (mm(3)) per 100,000 cycles for the five resin composites were as follows: wear rate Z1 0.58, EC 1.27, Z2 1.49, SP 1.62, and EX 4.35, and volume loss rate Z1 0.009, EC 0.024, Z2 0.028, SP 0.029, and EX 0.075. The generalized wear model appears to be an excellent method for measuring relative wear of resin composite materials. PMID:22856679

Barkmeier, W W; Erickson, R I; Latta, M A; Wilwerding, T M

2013-01-01

300

Input to Resin Column Structural Analysis if Autocatalytic Resin Reaction Occurs in HB-Line Phase II  

Energy Technology Data Exchange (ETDEWEB)

Solutions of plutonium in nitric acid are purified and concentrated using anion resin prior to precipitation. There have been instances of resin column explosions caused by autocatalytic reactions of anion resins in nitric acid within the DOE complex

Hallman, D.F.

2001-07-10

301

Input to Resin Column Structural Analysis if Autocatalytic Resin Reaction Occurs in HB-Line Phase II  

International Nuclear Information System (INIS)

Solutions of plutonium in nitric acid are purified and concentrated using anion resin prior to precipitation. There have been instances of resin column explosions caused by autocatalytic reactions of anion resins in nitric acid within the DOE complex

302

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

303

Hydrogen sorption in transition metal modified mesoporous materials  

Energy Technology Data Exchange (ETDEWEB)

Ni, Rh and Pd incorporated mesoporous MCM-41, MCM-48, HMS and SBA-15 samples were synthesized and were characterized using XRD, ICP/EDX and N{sub 2} adsorption-desorption at 77.4 K. The hydrogen adsorption studies in the synthesized materials were performed at 77.4 K (up to 112 kPa) and 303 K (up to 4000 kPa). The hydrogen adsorption isotherms of pristine and transition metals incorporated mesoporous materials at 77.4 K were completely reversible reflecting physisorption of hydrogen in these materials. The hydrogen adsorption isotherms at 303 K were not reversible showing the chemisorption of hydrogen in these materials at 303 K. Hydrogen sorption studies showed that transition metal modification improved the hydrogen storage capacity of mesoporous materials at 303 K. The desorption of the adsorbed hydrogen by heating up to 500 K from the mesoporous materials were also carried out for studying the recovery of adsorbed hydrogen from transition metal incorporated mesoporous materials. (author)

Prasanth, K.P.; Raj, Manoj C.; Bajaj, H.C. [Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (CSMCRI), Council of Scientific and Industrial Research (CSIR), G.B.Marg, Bhavnagar, Gujarat-364 002 (India); Kim, T.H. [Advanced Process Research Center, KIER, Daejeon (Korea); Jasra, R.V. [R and D Centre, Reliance Industries Limited, Manufacturing Division, Vadodara, 391 346, Gujarat (India)

2010-03-15

304

DEVELOPMENT OF MESOPOROUS MEMBRANE MATERIALS FOR CO2 SEPARATION; SEMIANNUAL  

International Nuclear Information System (INIS)

Mesoporous and precipitated alumina were synthesized as the base material for CO(sub 2) adsorbent. The porous alumina is doped with Ba to enhance it CO(sub 2) affinity due to the basicity of Ba. it is shown by gas chromatograph (GC) that the addition of Ba enhances the separation CO(sub 2) from N(sub 2). It was found that mesoporous alumina has larger specific surface area and better selectivity of CO(sub 2) than precipitated alumina. Ba improves the affinity of mesoporous alumina with CO(sub 2). Phase may play an important role in selective adsorption of CO(sub 2). It is speculated that mesoporous alumina is more reactive than precipitated alumina creating the xBaO(centerdot) Al(sub 2)O(sub 3) phase that may be more affinity to CO(sub 2) than N(sub 2). On the other hand, the barium aluminate phase (Ba(sub 3)Al(sub 2)O(sub 6)) in the mesoporous sample does not help the adsorption of CO(sub 2)

305

Organized thiol functional groups in mesoporous core shell colloids  

Energy Technology Data Exchange (ETDEWEB)

The co-condensation in situ of tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS) using cetyltrimethylammonium bromide (CTAB) as a template results in the synthesis of multilayered mesoporous structured SiO{sub 2} colloids with 'onion-like' chemical environments. Thiol groups were anchored to an inner selected SiO{sub 2} porous layer in a bilayered core shell particle producing different chemical regions inside the colloidal layered structure. X-Ray Photoelectron Spectroscopy (XPS) shows a preferential anchoring of the -SH groups in the double layer shell system, while porosimetry and simple chemical modifications confirm that pores are accessible. We can envision the synthesis of interesting colloidal objects with defined chemical environments with highly controlled properties. - Graphical abstract: Mesoporous core shell SiO{sub 2} colloids with organized thiol groups. Highlights: Black-Right-Pointing-Pointer Double shell mesoporous silica colloids templated with CTAB. Black-Right-Pointing-Pointer Sequential deposition of mesoporous SiO{sub 2} layers with different chemistries. Black-Right-Pointing-Pointer XPS shows the selective functionalization of mesoporous layers with thiol groups.

Marchena, Martin H. [Gerencia Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Avda. Gral. Paz 1499, B1650KNA Buenos Aires (Argentina); Granada, Mara [Centro Atomico Bariloche-CNEA, 8400 San Carlos de Bariloche (Argentina); Instituto Balseiro-Centro Atomico Bariloche-CNEA, San Carlos de Bariloche 8400 (Argentina); Bordoni, Andrea V. [Gerencia Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Avda. Gral. Paz 1499, B1650KNA Buenos Aires (Argentina); Joselevich, Maria [Asociacion Civil Expedicion Ciencia, Cabrera 4948, C1414BGP Buenos Aires (Argentina); Troiani, Horacio [Centro Atomico Bariloche-CNEA, 8400 San Carlos de Bariloche (Argentina); Instituto Balseiro-Centro Atomico Bariloche-CNEA, San Carlos de Bariloche 8400 (Argentina); Williams, Federico J. [DQIAQyF-INQUIMAE FCEN, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon II, C1428EHA Buenos Aires (Argentina); Wolosiuk, Alejandro, E-mail: wolosiuk@cnea.gov.ar [Gerencia Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Avda. Gral. Paz 1499, B1650KNA Buenos Aires (Argentina)

2012-03-15

306

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

307

Photocatalytic activity of a hierarchically macro/mesoporous titania.  

Science.gov (United States)

Light-harvesting macroporous channels have been successfully incorporated into a mesoporous TiO(2) framework to increase its photocatalytic activity. This bimodal porous material was characterized by X-ray diffractometry in both low-angle and wide-angle ranges, N(2) adsorption-desorption analysis, scanning and transmission electron microscopy, FT-IR, and diffuse reflectance spectroscopy. Ethylene photodegradation in gas-phase medium was employed as a probe reaction to evaluate the photocatalytic reactivity of the catalysts. The results reveal that sintering temperature significantly affects the structural stability and photocatalytic activity of titania. The catalyst which calcined at 350 degrees C possessed an intact macro/mesoporous structure and showed photocatalytic reactivity about 60% higher than that of commercial P25 titania. When the sample was calcined at 500 degrees C, the macroporous structure was retained but the mesoporous structure was partly destroyed. Further heating at temperatures above 600 degrees C destroyed both macro- and mesoporous structures, accompanied by a loss in photocatalytic activity. The high photocatalytic performance of the intact macro/mesoporous TiO(2) may be explained by the existence of macrochannels that increase photoabsorption efficiency and allow efficient diffusion of gaseous molecules. PMID:15752052

Wang, Xinchen; Yu, Jimmy C; Ho, Chunman; Hou, Yidong; Fu, Xianzhi

2005-03-15

308

Bond strength of resin-resin interfaces contaminated with saliva and submitted to different surface treatments  

DEFF Research Database (Denmark)

The purpose of this study was to investigate the effect of different surface treatments on shear bond strength of saliva-contaminated resin-resin interfaces. Flat resin surfaces were fabricated. In the control group, no contamination or surface treatment was performed. The resin surfaces of the experimental groups were contaminated with saliva and air-dried, and then submitted to: (G1) rinsing with water and drying; (G2) application of an adhesive system; (G3) rinsing and drying, abrasion with finishing disks, etching and application of adhesive system; (G4) rinsing and drying, etching, application of silane and adhesive system. Resin cylinders were placed over the treated surfaces. The specimens were stored in water or ethanol. Shear bond strength tests were performed and the mode of failure was evaluated. Data were submitted to two-way ANOVA and Dunnett T3 test. Contamination of resin-resin interfaces with saliva significantly reduced shear strength, especially after prolonged storage (p

Furuse, Adilson Yoshio; da Cunha, Leonardo Fernandes

2007-01-01

309

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

310

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%

311

Volumetric polymerization shrinkage of contemporary composite resins  

Directory of Open Access Journals (Sweden)

Full Text Available 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 (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

2007-10-01

312

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

Science.gov (United States)

...an asterisk (*). *Abietic Acid—Derivatives *ABS Resins *ABS-SAN Resins...Ethylene-Vinyl Chloride *Rosin Derivative Resins *Rosin Modified Resins ...Silicone Resins *Silicones: Silicone Rubbers *Styrene Maleic Anhydride...

2010-07-01

313

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

314

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.

315

Physical Properties of Synthetic Resin Materials  

Science.gov (United States)

A study was made to determine the physical properties of synthetic resins having paper, canvas, and linen reinforcements, and of laminated wood impregnated with a resin varnish. The results show that commercial resins have moduli of elasticity that are too low for structural considerations. Nevertheless, there do exist plastics that have favorable mechanical properties and, with further development, it should be possible to produce resin products that compare favorably with the light-metal alloys. The results obtained from tests on Compound 1840, resin-impregnated wood, show that this material can stand on its own merit by virtue of a compressive strength four times that of the natural wood. This increase in compressive strength was accomplished with an increase of density to a value slightly below three times the normal value and corrected one of the most serious defects of the natural product.

Fishbein, Meyer

1939-01-01

316

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

317

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

318

Adsorption of vitamin E on mesoporous titania nanocrystals  

International Nuclear Information System (INIS)

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 oC, 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 oC to 500 oC. The N2 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.

319

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

320

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

321

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

322

Plutonium complexation by phosphonate-functionalized mesoporous silica  

International Nuclear Information System (INIS)

MCM-41-type mesoporous silica functionalized with the CMPO-based 'Ac-Phos' silane has been reported in the literature (1) to show good capacity as an acftinide sorbent material, with potential applications in environmental sequestration, aqueous waste separation and/or vitrification, and chemical sensing of actinides in solution. The study explores the complexation of Pu(IV and VI) and other selected actinides and lanthanides by SBA-15 type mesoporous silica functionalized with Ac-Phos. The Pu binding kinetics and binding capacity were determined for both the Ac-Phos functionalized and unmodified SBA-15. They analyzed the binding geometry and redox behavior of Pu(VI) by X-ray absorption spectroscopy (XAS). They discuss the synthesis and characterization of the functionalized mesoporous material, batch sorption experiments, and the detailed analyses of the actinide complexes that are formed. Structural measurements are paired with high-level quantum mechanical modeling to elucidate the binding mechanisms.

323

Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2).  

Science.gov (United States)

Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed. PMID:20060956

Chew, Thiam-Leng; Ahmad, Abdul L; Bhatia, Subhash

2010-01-15

324

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

325

A facile soft-template synthesis of mesoporous polymeric and carbonaceous nanospheres  

Science.gov (United States)

Owing to the weak self-assembly ability of precursor components and the serious crosslinking of neighbouring nanospheres during a hydrothermal process, the synthesis of monodisperse mesoporous polymer nanospheres with diameters below 500?nm remains a great challenge. Here we extend the synthesis method of mesoporous silica nanospheres to enable the preparation of ordered mesoporous resorcinol formaldehyde nanospheres with particle size from 80 to 400?nm and mesopores of ~3.5?nm in diameter. By finely tuning the synthesis parameters, multi-layered mesoporous resorcinol formaldehyde hollow nanospheres can be successfully synthesized. Mesoporous carbon nanospheres and hollow nanospheres with high surface area are further obtained through carbonization of the polymer spheres. The resulting mesoporous carbon nanospheres are demonstrated as the host cathode material for lithium-sulphur batteries. The synthesis strategy provides a benchmark for fabricating well-defined porous carbonaceous nanospheres with potential for energy storage and conversion applications.

Liu, Jian; Yang, Tianyu; Wang, Da-Wei; Lu, Gao Qing (Max); Zhao, Dongyuan; Qiao, Shi Zhang

2013-12-01

326

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

327

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

328

Controlled drug release from bifunctionalized mesoporous silica  

International Nuclear Information System (INIS)

Serial of trimethylsilyl-carboxyl bifunctionalized SBA-15 (TMS/COOH/SBA-15) have been studied as carriers for controlled release of drug famotidine (Famo). To load Famo with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized by one-pot synthesis under the assistance of KCl. The mesostructure of carboxyl functionalized SBA-15 (COOH/SBA-15) could still be kept even though the content of carboxyl groups was up to 57.2%. Increasing carboxyl content could effectively enhance the loading capacity of Famo. Compared with pure SBA-15, into which Famo could be hardly adsorbed, the largest drug loading capacity of COOH/SBA-15 could achieve 396.9 mg/g. The release of Famo from mesoporous silica was studied in simulated intestine fluid (SIF, pH=7.4). For COOH/SBA-15, the release rate of Famo decreased with narrowing pore size. After grafting TMS groups on the surface of COOH/SBA-15 with hexamethyldisilazane, the release of Famo was greatly delayed with the increasing content of TMS groups. - Graphical abstract: Trimethylsilyl-carboxyl bifunctionalized SBA-15 has been studied as carrier for controlled release of drug famotidine. To load drug with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized. After grafting trimethylsilyl groups on the surface of carboxyl functionalized SBA-15, the release of Famo was greatly delayed with the increasing content of TMS groups

329

Monolithic gyroidal mesoporous mixed titanium-niobium nitrides.  

Science.gov (United States)

Mesoporous transition metal nitrides are interesting materials for energy conversion and storage applications due to their conductivity and durability. We present ordered mixed titanium-niobium (8:2, 1:1) nitrides with gyroidal network structures synthesized from triblock terpolymer structure-directed mixed oxides. The materials retain both macroscopic integrity and mesoscale ordering despite heat treatment up to 600 °C, without a rigid carbon framework as a support. Furthermore, the gyroidal lattice parameters were varied by changing polymer molar mass. This synthesis strategy may prove useful in generating a variety of monolithic ordered mesoporous mixed oxides and nitrides for electrode and catalyst materials. PMID:25122534

Robbins, Spencer W; Sai, Hiroaki; DiSalvo, Francis J; Gruner, Sol M; Wiesner, Ulrich

2014-08-26

330

Mesoporous alumina from colloidal biotemplating of Al clusters.  

Science.gov (United States)

A simple and green synthesis route was disclosed for the achievement of mesoporous alumina microparticles employing polysaccharide nanoparticles (?-chitin nanorods) as templates. Pore textures can be tuned by the cationic alumina precursor. Compared to small cations, the use of Al13 and Al30 oxo-hydroxo clusters leads to better defined and elongated mesopores. Electron microscopy and spectroscopic ((13) C, (27) Al NMR, XPS) measurements demonstrated that this is related to the effective coating of ?-chitin nanorods by these pre-condensed colloids. PMID:25588647

Sachse, Alexander; Cardoso, Laura; Kostov, Krassimir L; Gérardin, Corine; Belamie, Emmanuel; Alonso, Bruno

2015-02-16

331

Synthesis and characterization of mesoporous semiconductors and their energy applications  

Science.gov (United States)

In this dissertation, we examine the structure and physical properties of mesoporous group IV materials. Two different synthetic routes were developed to synthesize mesoporous germanium powder and thin film mesoporous silicon. The structural of these materials was confirmed by various analytical techniques. The electrochemical behavior of mesoporous silicon was further explored for applications as anodes in lithium ion batteries. The thermal conductivity was also measured and the electrical conductivity was tuned for potential applications as thermoelectrics. Ordered nanostructured germanium composite materials were produced using solution-phase surfactant templating methods. Anionic germanium/surfactand frameworks with a 2-D hexagonal structure were prepared and then condensed to form zero-valent porous germanium using oxidative coupling. The majority of the cationic surfactant inside the pores can be removed, resulting in mesoporous germanium with surface areas up to 500 m2/g. Thin film of mesoporous silicon was produced from polymer template porous silica films at relatively low temperature (directly on a metal current collector showed stable cycling with excellent coulomb efficiency over 3000 cycles with capacities up to 3000 mAh/g at cycling rates between 1C to 20C. The results indicate porous silicon material in this size scale can accommodate the volume expansion associated with Li alloying without cracking or loosing contact with the current collector. The thermal conductivity of mesoporous silicon was also measured using the 3 omega method. Periodic pores and grain boundaries enhance phonon scattering to dissipate thermal energy throughout the material, resulting in a decrease in the thermal conductivity by 3-5 orders of magnitude (as low as 0.01 W/m*K) from the bulk value (150 W/m*K). As thermal conductivity of mesostructured silicon decreased, its electrical conductivity decreased as well. To overcome the high overall resistance, several dopoing methods were developed to decrease the internal resistance of silicon grains. The internal resistivity decreased from 25ohm?cm for as-prepared mesoporous silicon to as low as 0.16 ohm?cm for samples optimally doped with boron.

Kang, Chris Byung-hwa

332

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

333

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

334

Hybrid non-silica meso-porous thin films  

Energy Technology Data Exchange (ETDEWEB)

Large-pore TiO{sub 2} and ZrO{sub 2} meso-porous films with 2D-Hex or cubic meso-structures were prepared by dip-coating. Organic bifunctional molecules presenting an organic function and a complexing grafting group (phosphate, carboxylate) were explored as surface modifiers. The incorporation of these functions into the meso-porous network was monitored by crossed FT-IR and EDS techniques. Leaching experiments in different conditions were performed to assess the anchoring of the grafted groups. While phosphate or phosphonate groups are strongly grafted, carboxylate functions can be released in a pH-dependent way. (authors)

Angelome, P.C.; Soler-Illia, G.J.A.A. [Comision Nacional de Energia Atomica, Unidad de Actividad Quimica, Centro Atomico Constituyentes, Buenos Aires (Argentina); Aldabe-Bilmes, S.; Calvo, M.E. [Buenos Aires Univ. Nacional, Inquimae-DQIAQF, (Argentina). Facultad de Ciencias Exactas y Naturales; Crepaldi, E.L.; Grosso, D.; Sanchez, C.; Soler-Illia, G.J.A.A. [Universite Pierre et Marie Curie, Lab. de Chimie de la Matiere Condensee (CNRS UMR 7574), 75 - Paris (France)

2005-01-01

335

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

336

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.)

337

Mineralogy of fossil resins in Northern Eurasia  

Science.gov (United States)

The investigation is focused on identification and origin of fossil resins from the Cretaceous, Tertiary, and Quaternary sediments of Northern Eurasia on the basis of detailed study of their physical and chemical characteristics: morphology; size; mass; density; optical, mechanical, and thermal properties; chemical composition; etc. The composition of amorphous organic minerals with polymeric structure, fossil resins included, is studied with IR spectrometry, the EPR method, derivatography at low heating rates, XRD, chemical analysis, emission spectrometry, etc. The results of investigation summarized for the Baltic-Dnieper, North Siberian, and Far East amber-bearing provinces show some similarity of fossil resins in combination with specific features inherent to each province. Resins from the Baltic-Dnieper province should be termed as amber (succinite). Their variety is the most characteristic of Northern and Eastern Europe. Amber-like fossil resins from the North Siberian and Far East provinces are irrelevant to succinite. They usually occur as brittle resins, namely, retinite and gedanite, without jewelry value. Viscous fossil resin rumänite with an expected high economic value occurs in the Far East, on the shore of Sakhalin Island.

Bogdasarov, M. A.

2007-12-01

338

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

339

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

340

Epoxide resins for use at low temperatures  

International Nuclear Information System (INIS)

A simple screening test is presented which permits the rapid evaluation of many epoxide resin systems, with a subsequent more detailed evaluation of those which performed well in the test. Several hundred resin systems were investigated including such variables as hardened ratios and blends, diluents, flexibilisers and modifiers, but considering only one expoxide resin, namely diglycidyl ether of Bisphenol A. The materials and results are detailed and conclusions formulated. Polymers used in low temperature applications should contain, wherever possible, reinforcement in the form of glass fabrics, rovings or chopped strands. Further work is planned to assess the performance of these materials when used with fillers and in laminates in fatigue situations

341

SEM and elemental analysis of composite resins  

International Nuclear Information System (INIS)

Twenty-four chemically cured, 21 light-cured anterior, three light-cured anterior/posterior, and 18 light-cured posterior composite resins were examined using scanning electron microscopy, and the elemental composition of their filler particles was analyzed with an energy dispersive electron probe microanalyzer. According to the results obtained, the composite resins were divided into five groups (traditional, microfilled type, submicrofilled type, hybrid type, and semihybrid), with two additional hypothetical categories (microfilled and hybrid). Characteristics of each type were described with clinical indications for selective guidance of respective composite resins for clinical use

342

Immobilisation of ion exchange resins in cement  

International Nuclear Information System (INIS)

The removal of activity from spent decontaminating solutions eg LOMI can be achieved using organic ion exchange resins. These resins can be successfully immobilised in cement based matrices. The optimum cement system contained 10% ordinary Portland cement, 84% gg blast furnace slag, 6% microsilica with a water cement ratio of 0.5 and a dry resin loading of 36% with respect to total weight. This formulation was successfully scaled up to 200 litres giving a product with acceptable compressive strength, dimensional stability and elastic modulus. Storage of samples under water appears to have no detrimental effects on the products' properties. (author)

343

Immobilisation of ion exchange resins in cement  

International Nuclear Information System (INIS)

The removal of activity from spent decontaminating solutions eg LOMI can be achieved using organic ion exchange resins. These resins can be successfully immobilised in cement based matrices. The optimum cement system contained 10% ordinary Portland cement 84% gg blast furnace slag, 6% microsilica with a water cement ratio of 0.5 and a dry resin loading of 36% with respect to total weight. This formulation was successfully scaled up to 200 litres giving a product with acceptable compressive strength, dimensional stability and elastic modulus. Storage of samples under water appears to have no detrimental effects on the product's properties. (author)

344

In vivo wear pattern of experimental composite resins based on different resin monomers.  

Science.gov (United States)

This study investigated the effects of various monomer systems on composite resin wear in vivo. Experimental light-cured composite resins were prepared employing four different monomer systems: (1) Bis-GMA type, (2) D-2. 6E type, (3) UDMA type, (4) UTMA type. The resin monomers consisted of 70wt% main monomer and 30wt% TEGDMA. These composites contained 80wt% fine quartz. The resins were placed in 2 mm diameter cylindrical cavities located in the occlusal contact area or the contact free area in cast crowns, temporarily set in a mouth. The crowns were removed at monthly intervals, for longitudinal SEM observation. Two months after setting, wear was analyzed, using an electron probe surface roughness analyzer. Microabrasion of the resin matrix and loss of filler particles were observed for all types of monomer systems. The effect of matrix resin systems on occlusal wear was smaller than that of filler systems. PMID:8004909

Sekiya, K; Okamoto, A; Fukushima, M; Iwaku, M

1993-12-01

345

The mechanism of uranium adsorption on Resin 508 and isoelectric point of the resin  

International Nuclear Information System (INIS)

The adsorption process of uranium by Resin 508 at the solid-liquid interface was investigated and the mechanism of uranium adsorption including adsorption dynamics, adsorption thermodynamics and isoelectric point of resin was studied. The results are as follows: The maximum of uranium adsorption is attained at pH5-7; Uranium adsorption isotherm by Resin 508 in experimental conditions agrees with Langmuir's adsorption isotherm, the maximum of uranium adsorbed (Vm) is 716 mg U/g-dried resin; The adsorption of uranium by Resin 508 is an endothermic reaction and ?H = 16.87 kJ/mol; The exchange-adsorption rate is mainly controlled by liquid film diffusion; The isoelectric points of Resin 508 before and after uranium adsorption are found to be pH7.5 and pH5.7 respectively. It is a specific adsorption for uranium

346

Study on the Thermal Degradation Properties of Epoxy Resin for the Cast Resin Transformer  

Energy Technology Data Exchange (ETDEWEB)

In this paper, study on the properties of the thermal degradated epoxy resin which is used in cast resin transformer is performed to investigate the problems of the decreasing insulation characteristics and crack in the cast resin transformer. In the test, contact angle, weight loss, surface resistivity and relative dielectric constant are measured. As the results of the above measurements, the epoxy resin has increased to 150 degree C in the contact angle and surface resistivity but at the above 150 degree C in the contact angle and surface resistivity but at the above 150 degree C the values have decreased. The relative dielectric constants have increased in the thermal treated samples with the degradation temperature. Consequently, the insulation properties of the epoxy resin which is used in cast resin transformer have increased by the 150 degree C but decreased in the above 150 degree C. (author). 4 refs., 5 figs.

Nam, K. D.; Jung, J. I.; Huh, C. S. [Inha University (Korea)

2000-07-01

347

Condensate-polisher resin-leakage quantification and resin-transport studies  

International Nuclear Information System (INIS)

The objectives of this program were to: (1) determine the extent of resin leakage from current generation condensate polisher systems, both deep bed and powdered resin design, during cut-in, steady-state and flow transient operation, (2) analyze moisture separator drains and other secondary system samples for resin fragments and (3) document the level of organics in the secondary system. Resin leakage samples were obtained from nine-power stations that have either recirculating steam generators or once through steam generators. Secondary system samples were obtained from steam generator feedwater, recirculating steam generator blowdown and moisture separator drains. Analysis included ultraviolet light examination, SEM/EDX, resin quantification and infrared analysis. Data obtained from the various plants were compared and factors affecting resin leakage were summarized

348

TERPOLYMER RESIN-II -THERMAL AND METAL ION BINDING PROPERTIES OF RESORCINOLTHIOUREA- FORMALDEHYDE TERPOLYMER RESIN  

OpenAIRE

Terpolymer resin RTF-1 is prepared by the condensation of resorcinol (R), thiourea (T) and formaldehyde (F) in the presence of 2M HCl as catalyst at 140?2?C. The synthesised terpolymer resin is characterized by FTIR, 1HNMR and gel permeation chromatographic techniques. To establish the thermal stability of the resin, TGAanalysis is performed. The Doyle, Horowitz & Metzger, Broido and Dharwadkar & Kharkhanavala methods are used to calculate the thermodynamic parameters, which include entha...

Karunakaran, M.; Vijayakumar, C. T.; Magesh, C.; Amudha, T.

2011-01-01

349

Magnetic ion-exchange resin treatment: Impact of water type and resin use  

OpenAIRE

Three raw waters of fundamentally different natural organic matter (NOM) character were treated by magnetic resin using a bench-scale method designed to mimic how the resin is used in continuous operation. Increasing water hydrophobicity resulted in reduced dissolved organic carbon (DOC) removal with removal of 56%, 33% and 25% for waters containing 21%, 50% and 75% hydrophobic NOM, respectively. Study of consecutive resin uses showed that the NOM in the hydrophobic water ha...

Mergen, Maxime Rodolphe Denis; Jefferson, Bruce; Parsons, Simon A.; Jarvis, Peter

2008-01-01

350

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)

351

Pengaruh Sifat-Sifat Fisik Resin Akrilik Terhadap Basis Protesa  

OpenAIRE

Saat ini resin akrilik banyak digunakan secara umum untuk konstruksi gigi tiruan. Sebagai bahan basis prothesa, penggunaan resin akrilik terutama resin heat cured adalah yang paling sering digunakan selain bernilai estetis, juga lebih ekonomis. Pada prothesa yang ideal memerlukan suatu basis yang kuat, Syarat- syarat basis protesa tidak semuanya dapat dipenuhi oleh basis resin akrilik. Sifat-sifat fisik resin akrilik mempunyai pengaruh terhadap basis protesa. Untuk menghindari k...

Amriani Syahfitri

2008-01-01

352

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

353

Selection of Unsaturated Polyester Resins for Closed Resin Transfer Moulding Processes  

OpenAIRE

In this paper three commercial unsaturated polyester resins of wide use in Colombia are analyzed and it is evaluated the convenience of their use in resin transfer molding processes according to viscosity and reactivity criteria. The resin viscosities are compared between 15 and 50°C, in the same way as the reactivity by mean of the curing curves at room temperature, using catalyst at 1, 1.5 and 2%. In agreement with the results, it was determined that some resins are suitable for RTM proces...

Jaramillo-zapata, Leyla Y.; Patin?o-arcila, Iva?n D.

2012-01-01

354

Ordered mesoporous cobalt oxide as highly efficient oxygen evolution catalyst.  

Science.gov (United States)

Oxygen evolution from water by use of earth-abundant element-based catalysts is crucial for mass solar fuel production. In this report, a mesoporous cobalt oxide with an ultrahigh surface area (up to 250 m(2)·g(-1)) has been fabricated through Mg substitution in the mesoporous Co3O4 spinel, followed by a Mg-selective leaching process. Approximately a third of Mg cations were removed in the leaching process, resulting in a highly porous cobalt oxide with a significant amount of defects in the spinel structure. The activated mesoporous cobalt oxide exhibited high oxygen evolution activities in both the visible-light-driven [Ru(bpy)3](2+)-persulfate system and the Ce(4+)/Ce(3+) chemical water oxidation system. Under a strong acidic environment, a high turnover frequency (TOF) of ~2.2 × 10(-3) s(-1) per Co atom was achieved, which is more than twice the TOF of traditional hard-templated, mesoporous Co3O4. PMID:23448405

Rosen, Jonathan; Hutchings, Gregory S; Jiao, Feng

2013-03-20

355

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

356

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

357

Mesoporous hybrid thin films: the physics and chemistry beneath  

OpenAIRE

Mesoporous films containing organic or biological functions within an organised array of cavities are produced by combining sol-gel, self-assembly of supramolecular templates and surface chemistry. This paper reviews the essential physics and chemical concepts behind the synthesis of these complex multifunctional materials.

Soler-illia, Galo J. A. A.; Innocenzi, Plinio

2006-01-01

358

Antibacterial performance of nanocrystallined titania confined in mesoporous silica nanotubes.  

Science.gov (United States)

In this paper, we study synthesis and characteristics of mesoporous silica nanotubes modified by titanium dioxide, as well as their antimicrobial properties and influence on mitochondrial activity of mouse fibroblast L929. Nanocrystalized titania is confined in mesopores of silica nanotubes and its light activated antibacterial response is revealed. The analysis of the antibacterial effect on Escherichia coli. (ATCC 25922) shows strong enhancement during irradiation with the artificial visible and ultraviolet light in respect to the commercial catalyst and control sample free from the nanomaterials. In darkness, the mesoporous silica/titania nanostructures exhibited antibacterial activity dependent on the stirring speed of the suspension containing nanomaterials. Obtained micrograph proved internalization of the sample into the microorganism trough the cell membrane. The analysis of the mitochondrial activity and amount of lactate dehydrogenase released from mouse fibroblast cells L929 in the presence of the sample were determined with LDH and WST1 assays, respectively. The synthesized silica/titania antibacterial agent also exhibits pronounced photoinduced inactivation of the bacterial growth under the artificial visible and UV light irritation in respect to the commercial catalyst. Additionally, mesoporous silica/titania nanotubes were characterized in details by means of high resolution transmission electron microscopy (HR-TEM), XRD and BET Isotherm. PMID:24676537

Cendrowski, Krzysztof; Peruzynska, Magdalena; Markowska-Szczupak, Agata; Chen, Xuecheng; Wajda, Anna; Lapczuk, Joanna; Kurzawski, Mateusz; Kalenczuk, Ryszard J; Drozdzik, Marek; Mijowska, Ewa

2014-06-01

359

Crystalline vanadium pentoxide with hierarchical mesopores and its capacitive behavior.  

Science.gov (United States)

Crystalline vanadium pentoxide with hierarchical mesopores was synthesized by using a CTAB/BMIC cotemplate (CTAB = cetyltrimethylammonium bromide, BMIC = 1-butyl-3-methylimidazolium chloride). The material was fully characterized by SEM, TEM, N2 adsorption-desorption, XRD, XPS, and CV methods. By elaborate adjustment of the template proportions, the distribution and size of the hierarchical pores were tuned successfully. CTAB cationic surfactant contributed more to the larger mesopores, whereas BMIC ionic liquid was beneficial in forming the smaller nanopores. The vanadium-containing anions combined with CTA+ micelles and BMI+ rings through electrostatic interactions. The CTA(+)-O(VO)O(-)-BMI(+) entities built up an orderly array, which finally formed the hierarchical mesoporous framework during thermal treatment. The mesoporous vanadium pentoxide directed by the cotemplate of CTAB/BMIC = 1:1 showed many orderly crystalline structures and demonstrated a large capacitance (225 F g(-1)); it is thus a promising material for electrochemical capacitors. Two alternative solutions to the disappearance of capacitance due to insertion of K+ are proposed in view of possible future applications. PMID:17441111

Liu, Hongtao; He, Ping; Li, Zhiying; Sun, Danzi; Huang, Haiping; Li, Jinghong; Zhu, Guoyi

2006-11-20

360

Adsorption of mycotoxins in beverages onto functionalized mesoporous silicas  

Science.gov (United States)

Mycotoxins, natural toxins produced by fungi, are a global concern as contaminates of agricultural commodities. Exposure to these toxins can be reduced by the use of binding materials. Templated mesoporous silicas are promising materials with favorable adsorptive properties for dyes, ions, and toxin...

361

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

362

The bond strength of a visible light-cured reline resin to acrylic resin denture base material.  

Science.gov (United States)

The introduction of Triad visible light-cured denture resin has led to several applications. Among them is direct intraoral relining of complete and partial dentures. This study investigated the bonding characteristics of Triad reline resin to four commonly used heat-cured denture base resins. The shear and tensile bond strengths of Triad resin and four denture base resins were determined and compared with intact tensile strengths. The findings of this study indicate that the bond strength of Triad resin to denture base resin is sufficiently high to suggest its clinical applicability. PMID:2184235

Razavi, R; Khan, Z; von Fraunhofer, J A

1990-04-01

363

Formation of carbon nanosheets via simultaneous activation and catalytic carbonization of macroporous anion-exchange resin for supercapacitors application.  

Science.gov (United States)

Two-dimensional mesoporous carbon nanosheets (CNSs) have been prepared via simultaneous activation and catalytic carbonization route using macroporous anion-exchange resin (AER) as carbon precursor and ZnCl2 and FeCl3 as activating agent and catalyst, respectively. The iron catalyst in the skeleton of the AER may lead to carburization to form a sheetlike structure during the carbonization process. The obtained CNSs have a large number of mesopores, a maximum specific surface area of 1764.9 m(2) g(-1), and large pore volume of 1.38 cm(3) g(-1). As an electrode material for supercapacitors application, the CNSs electrode possesses a large specific capacitance of 283 F g(-1) at 0.5 A g(-1) and excellent rate capability (64% retention ratio even at 50 A g(-1)) in 6 mol L(-1) KOH. Furthermore, CNSs symmetric supercapacitor exhibits specific energies of 17.2 W h kg(-1) at a power density of 224 W kg(-1) operated in the voltage range of 0-1.8 V in 0.5 mol L(-1) Na2SO4 aqueous electrolyte, and outstanding cyclability (retains about 96% initial capacitance after 5000 cycles). PMID:25372656

Peng, Hui; Ma, Guofu; Sun, Kanjun; Mu, Jingjing; Zhang, Zhe; Lei, Ziqiang

2014-12-10

364

Silicone modified resins for graphite fiber laminates  

Science.gov (United States)

The development of silicon modified resins for graphite fiber laminates which will prevent the dispersal of graphite fibers when the composites are burned is discussed. Eighty-five silicone modified resins were synthesized and evaluated including unsaturated polyesters, thermosetting methacrylates, epoxies, polyimides, and phenolics. Neat resins were judged in terms of Si content, homogeneity, hardness, Char formation, and thermal stability. Char formation was estimated by thermogravimetry to 1,000 C in air and in N2. Thermal stability was evaluated by isothermal weight loss measurements for 200 hrs in air at three temperatures. Four silicone modified epoxies were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 25 to 50%. The highest flexural values measured for the laminates were a strength of 140 kpsi and a modulus of 10 Mpsi. The highest interlaminar shear strength was 5.3 kpsi.

Frost, L. W.; Bower, G. M.

1979-01-01

365

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

366

XAD2 resin in phenolics separation.  

OpenAIRE

Hydroxy cinnamoyl tartaric acids, free phenolic acids, catechins, proanthoacyanidins and both free and polymeric pigments of wines were separated by adsorbtions on XAD2 resin and by subsequent elution with organic inert solvents. The obtained fractions were analyzed by HPLC.

Guidoni, Silvia

1990-01-01

367

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...and polymerization of Nylon 66 salts and epsilon -caprolactam. (5) Nylon 11 resins...manufactured by the polymerization of epsilon- caprolactam. (7) Nylon 66T...copolymerization of a 1 to 1 ratio by weight of epsilon -caprolactam and omega...

2010-04-01

368

21 CFR 177.1550 - Perfluorocarbon resins.  

Science.gov (United States)

...tetrafluoroethylene resins may be irradiated by either a cobalt-60 sealed source, at a maximum dose of gamma radiation not to exceed 7.5 megarads...Determination of Melt Viscosity, Molecular Weight Distribution Index and Viscosity Stability,”...

2010-04-01

369

A magnetic mesoporous silica nanoparticle-based drug delivery system for photosensitive cooperative treatment of cancer with a mesopore-capping agent and mesopore-loaded drug  

Science.gov (United States)

Lately, there has been a growing interest in anticancer therapy with a combination of different drugs that work by different mechanisms of action, which decreases the possibility that resistant cancer cells will develop. Herein we report on the development of a drug delivery system for photosensitive delivery of a known anticancer drug camptothecin along with cytotoxic cadmium sulfide nanoparticles from a magnetic drug nanocarrier. Core-shell nanoparticles consisting of magnetic iron-oxide-cores and mesoporous silica shells are synthesized with a high surface area (859 m2 g-1) and hexagonal packing of mesopores, which are 2.6 nm in diameter. The mesopores are loaded with anticancer drug camptothecin while entrances of the mesopores are blocked with 2-nitro-5-mercaptobenzyl alcohol functionalized CdS nanoparticles through a photocleavable carbamate linkage. Camptothecin release from this magnetic drug delivery system is successfully triggered upon irradiation with UV light, as measured by fluorescence spectroscopy. Photosensitive anticancer activity of the drug delivery system is monitored by viability studies on Chinese hamster ovarian cells. The treatment of cancer cells with drug loaded magnetic material leads to a decrease in viability of the cells due to the activity of capping CdS nanoparticles. Upon exposure to low power UV light (365 nm) the loaded camptothecin is released which induces additional decrease in viability of CHO cells. Hence, the capping CdS nanoparticles and loaded camptothecin exert a cooperative anticancer activity. Responsiveness to light irradiation and magnetic activity of the nanocarrier enable its potential application for selective targeted treatment of cancer.

Kneževi?, Nikola Ž.; Lin, Victor S.-Y.

2013-01-01

370

Biocompatibility of Resin-based Dental Materials  

OpenAIRE

Oral and mucosal adverse reactions to resin-based dental materials have been reported. Numerous studies have examined thebiocompatibility of restorative dental materials and their components, and a wide range of test systems for the evaluation of the biological effects of these materials have been developed. This article reviews the biological aspects of resin-based dental materials and discusses the conventional as well as the new techniques used for biocompatibility assessment of dental mat...

Keyvan Moharamzadeh; Brook, Ian M.; Richard van Noort

2009-01-01

371

Fluoride and Chlorhexidine Release from Filled Resins  

OpenAIRE

Resin-based materials that release either fluoride or chlorhexidine have been formulated for inhibiting caries activity. It is not known if the two agents, when incorporated into one material, would interact and affect their release potential. We hypothesized that the ratio of fluoride to chlorhexidine incorporated into a resin, and the pH of the storage medium, will affect their releases from the material. The material investigated contained 23 wt% of filler, and the ratios of calcium fluori...

Shen, C.; Zhang, N. -z; Anusavice, K. J.

2010-01-01

372

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. 2 figs.

Bibler, J.P.; Wallace, R.M.

1995-08-15

373

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.

374

Resin composites : Sandwich restorations and curing techniques  

OpenAIRE

Since the mid-1990s resin composite has been used for Class II restorations in stress-bearing areas as an alternative to amalgam. Reasons for this were the patients’ fear of mercury in dental amalgam and a growing demand for aesthetic restorations. During the last decades, the use of new resin composites with more optimized filler loading have resulted in reduced clinical wear. Improved and simplified amphiphilic bonding systems have been introduced. However, one of the main problems with r...

Lindberg, Anders

2005-01-01

375

Synthesis of a boron modified phenolic resin  

OpenAIRE

Phenolic resin has long been used as matrix for composites mainly because of its flame retardant behavior and high char yield after pyrolysis, which results in a self supporting structure. The addition of ceramic powders, such as SiC and B4C, as fillers to the phenolic resin, results in better thermo-oxidative stability, but as drawbacks, it has poor homogeneity, adhesion and processing difficulties during molding of the composites. The addition of single elements, such as boron, silicon and ...

Kawamoto, Aparecida M.; Luiz Cláudio Pardini; Milton Faria Diniz; Vera Lúcia Lourenço; Takahashi, Marta Ferreira K.

2010-01-01

376

Shock behaviour of a phenolic resin  

OpenAIRE

Phenolic resins are used in many aspects of everyday life, e.g. as the matrix material for carbon fibre laminates used in the aerospace industry. Consequently detailed knowledge of this material, especially while under shock loading, is extremely useful for the design of components that could be subjected to impact during their lifespan. The shock Hugoniot equation of state for phenolic resin (Durite SC-1008), with initial density of 1.18 gcm ?3 have been determined using ...

Wood, D. C.; Hazell, P. J.; Appleby-thomas, G. J.; Barnes, N. R.

2011-01-01

377

Cycloaliphatic epoxide resins for cationic UV - cure  

International Nuclear Information System (INIS)

This paper introduces the cyclo - aliphatic epoxide resins used for the various applications of radiation curing and their comparison with acrylate chemistry. Radiation curable coatings and inks are pre - dominantly based on acrylate chemistry but over the last few years, cationic chemistry has emerged successfully with the unique properties inherent with cyclo - aliphatic epoxide ring structures. Wide variety of cationic resins and diluents, the formulation techniques to achieve the desired properties greatly contributes to the advancement of UV - curing technology

378

Adsorption of plant phenols by polystyrene resins  

OpenAIRE

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 ...

Akiyoshi Fukushima; Hioaki Hase; Koshi Saito

1987-01-01

379

Microleakage of Nanofilled Composite Resin Restorative Material  

OpenAIRE

The role of nanofillers in reducing the microleakage of dental composite resins has not been previously investigated. So this study was designed to evaluate microleakage of nanofilled composite resin in comparison to the conventional hybrid composite. Twenty extracted sound molars were selected. Class II cavities were prepared. All cavities were etched (enamel and dentin) with 37% phosphoric acid. Dentin bonding agents were applied to etched tooth surfaces and restored with nanofilled and hyb...

Ibrahim Hamouda; Hagag abd Elkader; Badawi, Manal F.

2011-01-01

380

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

381

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

382

Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties  

Directory of Open Access Journals (Sweden)

Full Text Available 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 explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS, nanobeam electron diffraction (NBED, and high-angle annular dark field (HAADF scanning transmission electron microscopy (STEM imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting.Keywords: mesoporosity, surface characterization, microorganisms, adhesion

Variola F

2014-05-01

383

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

384

Electrosynthesis of Epoxy Resins via Superoxide Anion  

Directory of Open Access Journals (Sweden)

Full Text Available Epoxy resins are a class of reactive pre polymers and polymers which contain epoxide groups. Inspite of their high costs the epoxy resins find many important applications. The resins are used in both molding and laminating technique for making glass fiber-reinforced articles which are having better mechanical strength chemical resistance and electrical insulating properties. They also use in casting, potting encapsulating and embedment in the electrical and tooling industries. The general important uses are industrial flooring adhesive foams, highway surfacing patching material and stabilizers for vinyl resins. Epoxy resins may be reacted either with them- selves through catalytic homo polymerization or with a wide range of co-reactant like amino acid ,phenol, alcohols and thiols. These co-reactants are referred to as curatives. When linear epoxy resins react with suitable curative to form three dimensional cross linked thermo state structure. Epoxidation of unsaturated alcohol is carried out with the help of superoxide. The electrochemical generation of super-oxide anion and subsequent electro oxidation in situ is found to be advantageous and easy over the conventional technique. The work extended further in persuasive oxygen reduction studies on non-metallic surface such as different types of carbon and graphite with a view to understand the reaction mechanism and possible application to fuel cell technology.

Rajni Mathur

2013-04-01

385

[Resin-bonded fixed partial dentures].  

Science.gov (United States)

A resin-bonded fixed partial denture is a prosthetic construction which can replace I or several teeth in an occlusal system and which comprises a pontic element which is adhesively attached to 1 or more abutment teeth. To compensate for the limited shear strength of the adhesive layer, the Jixed partial denture is occlusally supported by the abutment(s). A direct resin-bonded fixed partial denture is made of composite, reinforced or not by a frame of flexible metal or fiber material. For an indirect resin-bonded fixed partial denture, a metal, fibre-reinforced composite or ceramic substructure is fabricated in a dental laboratory. The basic principle of a resin-bonded fixed partial denture is minimal invasiveness. However, a restoration in an abutment tooth requires a certain occlusal space which is realized by tooth preparation. Resistance preparations may be performed to improve the longevity of resin-bonded fixed partial dentures. Both financially and biologically, a resin-bonded bridge is a cost-effective prosthetic construction. The longevity is limited, but when the construction fails the negative consequences for the abutments are generally limited, which leaves open several types of other treatments. PMID:23495569

Kreulen, C M; Creugers, N H J

2013-02-01

386

Investigation of TOC Removal from IndustrialWastewaters using Electrocoagulation Process  

OpenAIRE

"n "nBackgrounds and Objectives: Formaldehyde and phenol are key precursors in the industrial manufacture of resins. Toxicity of these compounds prevents function of microbial populations, so they affect the biological treatments. The aim of this study was investigation of TOC removal from phenol-formaldehyde resin manufacturing wastewater by electrocoagulation using Al- electrodes."nMaterials and Methods: This study is the laboratory scale experiment was conducted as a pilot. Wastewater samp...

Ahmadimoghadam, M.; Amiri, H.

2010-01-01

387

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

388

Kinetic features of foaming thermosetting polymers in the preparation of thermal insulation materials in the presence of a mineral filler  

OpenAIRE

This article presents the research of dependencies with a filler in the form of fly ash, the mixture temperature and other factors influencing the kinetic characteristics of composite foaming based on the mixture of thermosetting resin (phenol-formaldehyde resins of different brands), fly ash and special modifiers. The article shows the duration and multiplicity of foaming, as well as the induction period of the composition depending on the amount of the filler used and other process para...

Burdonov, A. E.

2014-01-01

389

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

390

Preparation and in vitro evaluation of mesoporous hydroxyapatite coated ?-TCP porous scaffolds.  

Science.gov (United States)

A mesoporous hydroxyapatite (HA) coating was prepared on a ?-tricalcium phosphate (?-TCP) porous scaffold by a sol-gel dip-coating method using the block copolymer Pluronic F127 (EO106PO70EO106) as the template. For application as a bone graft, in vitro cell response and bone-related protein expression of mesoporous HA coated ?-TCP scaffold were investigated, using the non-mesoporous HA coated scaffold as the control group, to evaluate the influence of the mesoporous structure on the biological properties of HA coating. It was found that the increased surface area of the mesoporous HA coating greatly affected the response of MC3T3-E1 osteoblasts and the expression of proteins. An enzyme-linked immunosorbent assay recorded a significantly higher expression of alkaline phosphatase (ALP) and bone sialoprotein (BSP) in the mesoporous group than those in the control group (*pmaterial for the surface modification of the tissue engineering scaffolds. PMID:24094217

Ye, Xinyu; Cai, Shu; Xu, Guohua; Dou, Ying; Hu, Hongtao; Ye, Xiaojian

2013-12-01

391

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

392

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

International Nuclear Information System (INIS)

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. 27Al-MAS-NMR and NH3-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

393

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

394

Multitasking mesoporous nanomaterials for biorefinery applications  

Science.gov (United States)

Mesoporous silica nanoparticles (MSNs) have attracted great interest for last two decades due to their unique and advantageous structural properties, such as high surface area, pore volume, stable mesostructure, tunable pore size and controllable particle morphology. The robust silica framework provides sites for organic modifications, making MSNs ideal platforms for adsorbents and supported organocatalysts. In addition, the pores of MSNs provide cavities/ channels for incorporation of metal and metal oxide nanoparticle catalysts. These supported metal nanoparticle catalysts benefit from confined local environments to enhance their activity and selectivity for various reactions. Biomass is considered as a sustainable feedstock with potential to replace diminishing fossil fuels for the production of biofuels. Among several strategies, one of the promising methods of biofuel production from biomass is to reduce the oxygen content of the feedstock in order to improve the energy density. This can be achieved by creating C-C bonds between biomass derived intermediates to increase the molecular weight of the final hydrocarbon molecules. In this context, pore size and organic functionality of MSNs are varied to obtain the ideal catalyst for a C-C bond forming reaction: the aldol condensation. The mechanistic aspects of this reaction in supported heterogeneous catalysts are explored. The modification of supported organocatalyst and the effect of solvent on the reaction are rationalized. The significance of two functional surfaces of MSNs is exploited by enzyme immobilization on the external surface and organo catalyst functionalization on the internal surface. Using this bifunctional catalyst, the tandem conversion of small chain alcohols into longer chain hydrocarbon molecules is demonstrated. The ability to incorporate metal and metal oxide nanoparticles in the pores and subsequent functionalization led to develop organic modified magnetic MSNs (OM-MSNs) for applications in microalgae biorefinery. Two different integrated biorefinery systems are highlighted. (i) OM-MSNs are used to harvest microalgae and selectively sequester free fatty acids (FFAs). (ii) OM-MSNs are shown to selectively sequester FFAs and convert them into diesel-range liquid hydrocarbon fuels. A similar MSN supported metal nanoparticle catalyst is demonstrated to transform FFAs into green diesel with even greater activity and selectivity. The incorporation of a different organic functional group into MSN provides a selective adsorbent for separation and purification of alpha-tocopherol from microalgae oil. The functional group with electron deficient aromatic rings demonstrated high sequestration capacity and selectivity of alpha-tocopherol.

Kandel, Kapil

395

Volume reduction of spent radioactive ion exchange resin  

International Nuclear Information System (INIS)

A process is described for reducing the volume of spent radioactive ion exchange resins which have been used for conditioning water circulated through a nuclear reactor. The spent resins are discharged from the reactor system as radioactive wastes to a spent resin storage tank in the form of a slurry. The slurry is first vacuum dewatered to remove the free water and then the intrinsic water in the wet resin beads is removed by drying in a vacuum fluidized bed chamber utilizing superheated steam which also acts to fluidize the bed. Further drying is accomplished by spraying the partially dried resin and superheated steam through a steam injected two-fluid nozzle for further extraction of intrinsic water from the resins. The steam is discharged to a condenser and the dried resins to an evacuated disposal drum. Approximate 4:1 volume reductions from the resin-water slurry to the dried resin is obtainable by practicing the process. 5 claims, 2 figures

396

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

397

Fluorescent mesoporous hybrid materials based on GFP adsorbed into SBA-15  

OpenAIRE

Green Fluorescent Protein (GFP) has been confined within the pores and channels of inorganic mesoporous materials belonging to SBA-n family. The confinement of GFP into the pores/channels of mesoporous systems has some important advantages such as the protection of the bio-molecule against chemical attack, photo-bleaching and thermal decomposition. In addition, the structure of mesoporous silica offers the possibility of coupling fluorescence detection with drug delivery. An exhaustive physic...

Coluccia, Salvatore

2008-01-01

398

Preparation of Fe-substituted Mesoporous Silicas with Highly Isolated Iron Species in Buffer Solution  

OpenAIRE

The iron-substituted mesoporous silicas were synthesized under mild acidic conditions (pH = 4.4, HOAc-NaOAc buffer solution) using tetramethoxysilane (TMOS), tetraethoxysilane (TEOS) or sodium silicate solution as silica source in the presence of block copolymer Pluronic P123 as the mesoporous template. TMOS and sodium silicate led to iron-containing silicas with ordered two-dimensional hexagonal mesoporous structure, and vesicle mesostructure was obtained using TEOS as silica precursor. UV-V...

Xin Hong-chuan, Tang Jian-ting

2010-01-01

399

Photon-Manipulated Drug Release from Mesoporous Nanocontainer Controlled by Azobenzene-Modified Nucleic Acid  

OpenAIRE

Herein a photon manipulated mesoporous release system was constructed based on azobenzene-modified nucleic acids. In this system, the azobenzene-incorporated DNA double strands were immobilized at the pore mouth of meso-porous silica nanoparticles. The photo-isomerization of azobenzene induced dehybridization/hybridization switch of complementary DNA, causing uncapping/capping of pore gates of mesoporous silica. This nanoplatform permits holding of guest molecules within the nanopores under v...

Yuan, Quan; Zhang, Yunfei; Chen, Tao; Lu, Danqing; Zhao, Zilong; Zhang, Xiaobing; Li, Zhenxing; Yan, Chun-hua; Tan, Weihong

2012-01-01

400

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

401

Bond strength of resin-resin interfaces contaminated with saliva and submitted to different surface treatments  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this study was to investigate the effect of different surface treatments on shear bond strength of saliva-contaminated resin-resin interfaces. Flat resin surfaces were fabricated. In the control group, no contamination or surface treatment was performed. The resin surfaces of the experimental groups were contaminated with saliva and air-dried, and then submitted to: (G1 rinsing with water and drying; (G2 application of an adhesive system; (G3 rinsing and drying, abrasion with finishing disks, etching and application of adhesive system; (G4 rinsing and drying, etching, application of silane and adhesive system. Resin cylinders were placed over the treated surfaces. The specimens were stored in water or ethanol. Shear bond strength tests were performed and the mode of failure was evaluated. Data were submitted to two-way ANOVA and Dunnett T3 test. Contamination of resin-resin interfaces with saliva significantly reduced shear strength, especially after prolonged storage (p<0.05. Similar values to the original bond strength were obtained after abrasion and application of adhesive (G3 or etching and application of silane and adhesive (G4. If contamination occurs, a surface treatment is required to guarantee an adequate interaction between the resin increments.

Adilson Yoshio Furuse

2007-12-01

402

Bitumenization process for radioactive wastes constituted of cation exchange resins or/and anion exchange resins  

International Nuclear Information System (INIS)

In a pretreatment H+ ions are replaced by Ca, Sr or Ba ions in cationic resins and OH- or Cl- ions are replaced by NO3, HCO2 and CH3COO ions in anionic resins. This pretreatment increases the capacity of the encapsulation facility and limits the swelling in water of encapsulated wastes

403

Selection of Unsaturated Polyester Resins for Closed Resin Transfer Moulding Processes  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper three commercial unsaturated polyester resins of wide use in Colombia are analyzed and it is evaluated the convenience of their use in resin transfer molding processes according to viscosity and reactivity criteria. The resin viscosities are compared between 15 and 50°C, in the same way as the reactivity by mean of the curing curves at room temperature, using catalyst at 1, 1.5 and 2%. In agreement with the results, it was determined that some resins are suitable for RTM process, because of their appropriate viscosity, consistent reactivity and curing velocity. These features are of great importance in the unsaturated polyester resin selection, according to conditions of closed mold processes.

Leyla Y. Jaramillo-Zapata

2012-06-01

404

Dual-pore mesoporous carbon@silica composite core-shell nanospheres for multidrug delivery.  

Science.gov (United States)

Monodispersed mesoporous phenolic polymer nanospheres with uniform diameters were prepared and used as the core for the further growth of core-shell mesoporous nanorattles. The hierarchical mesoporous nanospheres have a uniform diameter of 200?nm and dual-ordered mesopores of 3.1 and 5.8?nm. The hierarchical mesostructure and amphiphilicity of the hydrophobic carbon cores and hydrophilic silica shells lead to distinct benefits in multidrug combination therapy with cisplatin and paclitaxel for the treatment of human ovarian cancer, even drug-resistant strains. PMID:24764082

Fang, Yin; Zheng, Gengfeng; Yang, Jianping; Tang, Haosha; Zhang, Yafeng; Kong, Biao; Lv, Yingying; Xu, Congjian; Asiri, Abdullah M; Zi, Jian; Zhang, Fan; Zhao, Dongyuan

2014-05-19

405

Self-assembly of ordered mesoporous platinum from nanoparticle-block copolymer mixtures  

Science.gov (United States)

Discovery of novel catalyst architectures with enhanced stability and high platinum utilization is essential to progress in fuel cell materials. I present results from the first synthesis and characterization of an ordered, mesoporous metal produced from co-assembly of metal nanoparticles with block copolymers. This process leads to an ordered, inverse hexagonal hybrid mesostructure; pyrolysis converts this to an ordered mesoporous platinum-carbon nanocomposite. Removal of the carbon yields hexagonally ordered, mesoporous platinum. These materials exhibit the highest electrical conductivity yet measured for ordered mesoporous materials fabricated from block copolymer self-assembly. The use of these materials as a fuel cell electrocatalyst is demonstrated.

Warren, Scott; Disalvo, Frank; Wiesner, Ulrich

2010-03-01

406

Morphological control of multifunctionalized mesoporous silica nanomaterials for catalysis applications  

Science.gov (United States)

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 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 Cu2+ 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 varied the amount of two organic groups and performed the three model reactions to compare rate enhancements.

Huh, Seong

407

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

408

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)

409

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)

410

Color stability of composite resin cements.  

Science.gov (United States)

This study sought to determine the difference in color stability of resin cements after one year of storage in water. Three commercial resin cements (Nexus 3, Calibra, Variolink 2) were evaluated under three different curing conditions (photo-, dual-, and self-cure) over three storage time periods (3, 6, and 12 months). A plastic mold was used to prepare cylindrical specimens of each of the three resin cements. For the phototcured specimens, only the base component of the resin cement was cured. For the dual- and self-cure specimens, the base and catalyst of the cements were mixed according to the manufacturer's instructions, syringed into the mold, and either photocured as before (dual-cure) or allowed to chemically set (self-cure). The total amount of color change (delta E) was calculated using a spectrophotometer after 24 hours (baseline) and after 3, 6, and 12 months of storage in distilled water. Data were analyzed using a repeated measures ANOVA and a Tukey test. After one year of storage, Nexus 3 demonstated the lowest color change values (delta E) under all curing conditions, although it was not significantly different from Variolink 2 when photocured or Calibra when self-cured. New resin cements without a traditional benzoyl peroxide/amine redox initiator system, such as Nexus 3, could be more color-stable over time. PMID:22313825

Smith, Darrell S; Vandewalle, Kraig S; Whisler, Gerry

2011-01-01

411

40 CFR 63.5728 - What standards must I meet for closed molding resin operations?  

Science.gov (United States)

...standards must I meet for closed molding resin operations? 63.5728 Section 63...Manufacturing Standards for Closed Molding Resin Operations § 63.5728 What standards must I meet for closed molding resin operations? (a) If a resin...

2010-07-01

412

40 CFR 63.5714 - How do I demonstrate compliance if I use filled resins?  

Science.gov (United States)

...resin or filled tooling resin, you must demonstrate compliance for the filled material on an as-applied basis...for a filled production resin or tooling resin, kilograms organic HAP per megagram of filled material. PVu = The...

2010-07-01

413

21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films.  

Science.gov (United States)

...Limitations (i) Resins and polymers: Acrylic acid polymer and its ethyl...resin Polyamide resins, derived from dimerized vegetable oil acids (containing not...temperature. Polyamide resins having a maximum acid value of 5 and...

2010-04-01

414

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

415

Mesoporous silica nanoparticles for bioadsorption, enzyme immobilisation, and delivery carriers  

Science.gov (United States)

Mesoporous silica nanoparticles (MSNs) provide a non-invasive and biocompatible delivery platform for a broad range of applications in therapeutics, pharmaceuticals and diagnosis. The creation of smart, stimuli-responsive systems that respond to subtle changes in the local cellular environment are likely to yield long term solutions to many of the current drug/gene/DNA/RNA delivery problems. In addition, MSNs have proven to be promising supports for enzyme immobilisation, enabling the enzymes to retain their activity, affording them greater potential for wide applications in biocatalysis and energy. This review provides a comprehensive summary of the advances made in the last decade and a future outlook on possible applications of MSNs as nanocontainers for storage and delivery of biomolecules. We discuss some of the important factors affecting the adsorption and release of biomolecules in MSNs and review of the cytotoxicity aspects of such nanomaterials. The review also highlights some promising work on enzyme immobilisation using mesoporous silica nanoparticles.

Popat, Amirali; Hartono, Sandy Budi; Stahr, Frances; Liu, Jian; Qiao, Shi Zhang; Qing (Max) Lu, Gao

2011-07-01

416

Mesoporous Silica Nanoparticles and Films for Cargo Delivery  

Science.gov (United States)

Mesoporous silica materials are well known materials that can range from films to nanoparticles. Mesoporous silica nanoparticles (MSNs) and mesoporous silica films have been of increasing interest among the scientific community for its use in cargo delivery. Silica provides ease of functionalization, a robust support and biocompatibility. Several methods have been used in order to give the mesoporous silica nanomaterials different qualities that render them a useful material with different characteristics. Among these methods is surface modification by taking advantage of the OH groups on the surface. When a molecule attached to the surface can act as a molecular machine it transforms the nanomaterial to act as delivery system that can be activated upon command. The work covered in this thesis focuses on the development and synthesis of different mesoporous silica materials for the purpose of trapping and releasing cargo molecules. Chapter 2 focuses in the photoactivation of "snap-top" stoppers over the pore openings of mesoporous silica nanoparticles that releases intact cargo molecules from the pores. The on-command release can be stimulated by either one UV photon or two coherent near-IR photons. Two-photon activation is particularly desirable for use in biological systems because it enables good tissue penetration and precise spatial control. Chapter 3 focuses on the design and synthesis of a nano-container consisting of mesoporous silica nanoparticles with the pore openings covered by "snap-top" caps that are opened by near-IR light. A photo transducer molecule that is a reducing agent in an excited electronic state is covalently attached to the system. Near IR two-photon excitation causes intermolecular electron transfer that reduces a disulfide bond holding the cap in place, thus allowing the cargo molecules to escape. The operation of the "snap-top" release mechanism by both one- and two photon is described. This system presents a proof of concept of a near-IR photoredox-induced nanoparticle delivery system that may lead to a new type of photodynamic drug release therapy. Chapter 4 focuses on the attachment of a photoacid molecule on the surface of silica nanoparticles. Upon light irradiation the pKa of the photoacid molecules decreases causing the dissociation of the proton and the acidification of the nanoparticle surface. The local nanoparticle surface acidification was probed using a pH sensitive nanovalve that was attached to MSNs next to a photoacid. The particles were loaded with a fluorescent dye that was contained by the naovalve and released upon acidification of the surrounding environment. The amount of the dye release was measure continuously by detecting its fluorescence. Chapter 5 focuses on the synthesis of materials that utilize the micropatterned structure of a mesoporous silica film to successfully load and release cargo using a thermal sensitive polymer. Films with pore sizes of ˜2 and ˜5 nm aligned in the pulling direction were synthesized using evaporation induced self-assembly techniques. The pores are exposed using a new method of stamping micropatterns without the use hydrofluoric acid. A well-studied temperature dependent polymer [poly(N-isopropylacrylamide-co-acrylamide)] was grafted onto the surface of these films to act as a temperature activated gatekeeper. Below the lower critical solution temperature (LCST) the polymer is erect and can block the pore openings, trapping cargo inside the pores. When the temperature is above the LCST the polymer collapses and unblocks the pores, allowing cargo to escape. The loading capacities as well as the reusability of these films were studied.

Guardado Alvarez, Tania Maria

417

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

418

Surface properties of mesoporous carbon-silica gel adsorbents  

Energy Technology Data Exchange (ETDEWEB)

Carbon/silica (carbosil) samples prepared utilizing mesoporous silica gel (Si-60) modified by methylene chloride pyrolysis were studied by nitrogen adsorption, quasi-isothermal thermogravimetry, p-nitrophenol adsorption from aqueous solution, and {sup 1}H NMR methods. The structural characteristics and other properties of carbosils depend markedly on the synthetic conditions and the amount of carbon deposited. The changes in the pore size distribution with increasing carbon concentration suggest grafting of carbon mainly in pores, leading to diminution of the mesopore radii. However, heating pure silica gel at the pyrolysis temperature of 550 C leads to an increase in the pore radii. The quasi-isothermal thermogravimetry and {sup 1}H NMR spectroscopy methods used to investigate the water layers on carbosils showed a significant capability of carbosils to adsorb water despite a relatively large content of the hydrophobic carbon deposit, which represents a nonuniform layer incompletely covering the oxide surface.

Leboda, R.; Turov, V.V.; Charmas, B.; Skubiszewska-Zieba, J.; Gun' ko, V.M.

2000-03-01

419

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

420

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

421

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

422

Preparation and photoluminescence study of mesoporous indium hydroxide nanorods  

International Nuclear Information System (INIS)

Mesoporous indium hydroxide nanorods were successfully synthesized by a mild one-step one-pot method. The obtained samples were characterized by X-ray diffraction, transmission electron microscopy with selected area electron diffraction, N2 adsorption, ultraviolet-visible absorption and photoluminescence, respectively. Transmission electron microscopy showed that there were some pores in the samples, which were mainly composed of rod-like shapes with length of 300 nm and diameter of 90 nm. N2 adsorption/desorption measurements confirmed that the prepared powder was mesoporous with average pore diameter of 3.1 nm. The ultraviolet-visible absorption spectroscopy analysis indicated that the band gap energy of the samples was 5.15 eV. Photoluminescence spectrum showed that there were two strong emissions under ultraviolet light irradiation. The growth mechanism of indium hydroxide nanorods and the role of cetyltrimethyl ammonium bromide were also discussed.

423

In Mesopore Protein Digestion: A New Forthcoming Strategy in Proteomics  

Directory of Open Access Journals (Sweden)

Full Text Available 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 complexity of proteomics workflows. An overview of the procedures for in situ proteolysis of single proteins or complex protein mixtures is reported, with a special focus on porous materials used as catalysts. The challenging efforts for designing such systems aimed at mimicking the biochemistry of living cells are reviewed. Potentials, limitations and challenges of this branch of enzyme catalysis, which we indicate as in mesopore digestion, are discussed, in relation to its suitability for high-speed and high-throughput proteomics.

Rosa Terracciano

2011-07-01

424

Preparation of mesoporous silica films SBA-15 over different substrates  

International Nuclear Information System (INIS)

Mesoporous materials have been target of frequent interest due to its wide application possibilities, for example development of gas sensors, catalysis, molecules transportation, pharmaceuticals release, synthesis of auto-organized nanostructures, among others. The possibilities of application are enhanced when such materials are disposed in the form of thin and ultrathin films. In this work the preparation of mesoporous SBA-15 silica films is explored by means of the dipcoating technique of a sol-gel on different substrates (glass slides, stainless steel, copper), using the surfactant poly(ethylene glycol)-block-poly(propylene glycol)- block-poly(ethylene glycol), known as P123, a block copolymer. Synthesis parameters surfactant concentration, aging time and temperature were investigated. In this work we present the morphological and structural characterization of the prepared films, which were obtained using atomic force microscopy and x-ray fluorescence and diffraction. (author)

425

Mesoporous multilayer thin films: environment-sensitive photonic crystals  

Energy Technology Data Exchange (ETDEWEB)

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)

Soler Illia, Galo; Fuertes, Maria Cecilia; Angelome, Paula Cecilia [Comision Nacional de Energia Atomica, San Martin, Buenos Aires (Argentina). Centro Atomico Constituyentes. Gerencia de Quimica; Marchi, Maria Claudia [Universidad de Buenos Aires (Argentina). Facultad de Ciencias Exactas y Naturales. INQUIMAE; Troiani, Horacio [Comision Nacional de Energia Atomica (CNEA), San Carlos de Bariloche (Argentina). Centro Atomico Bariloche and Instituto Balseiro; Luca, Vittorio [Australian Nuclear Science and Technology Organization, Lucas Heights (Australia). Inst. of Materials and Engineering Sciences; Miguez, Hernan [Consejo Superior de Investigaciones Cientificas, Isla de La Cartuja, Sevilla (Spain). Inst. de Ciencia de Materiales

2008-11-15

426

Novel nanofluids based on mesoporous silica for enhanced heat transfer  

International Nuclear Information System (INIS)

Nanofluids, which are liquids with engineered nanometer-sized particles suspensions, have drawn remarkable attraction from the researchers because of their enormous potential to enhance the efficiency in heat-transfer fluids. In the present study, water-based calcined mesoporous silica nanofluids were prepared and characterized. The commercial mesoporous silica (MPSiO2) nanoparticles were dispersed in deionized water by means of pH adjustment and ultrasonic agitation. MPSiO2 nanoparticles were observed to have an average particle size of 350 ± 100 nm by SEM analysis. The concentration of MPSiO2 was varied between 1 and 6 wt%. The physicochemical properties of nanofluids were characterized using various techniques, such as particle size analyzer, zeta-potential meter, TEM, and FT-IR. The thermal conductivity was measured by Transient Plane Source (TPS) method, and nanofluids showed a higher thermal conductivity than the base liquid for all the tested concentrations.

427

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

428

Synthesis of Mesoporous Carbon Using Halloyiste As Template  

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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

429

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

430

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

431

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)

432

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

433

Synthesis of mesoporous birnessite-MnO2 composite as a cathode electrode for lithium battery  

International Nuclear Information System (INIS)

Highlights: •Mesoporous b-MnO2 was successfully synthesized by using a modified interfacial method. •Mesoporous b-MnO2 has a BET specific surface area of 226 m2 g?1 with pore diameter of 5. 2 nm. •Mesoporous b-MnO2 shows an initial discharge capacity of 305 mAh g?1 at current density of 10 mA g?1. •Mesoporous nanostructure with high crystallinity can improve electrochemical performance. -- Abstract: Mesoporous polythiophene birnessite (b)-MnO2 has been synthesized by a modified interfacial method to develop cathode electrode materials for lithium batteries. The N2 adsorption/desorption isotherm test of mesoporous polythiophene MnO2 shows a type IV hysteresis loop, which is characteristic of a mesoporous structure. Mesoporous polythiophene MnO2 has a high surface area of 226 m2 g?1 with a pore diameter of 5.2 nm The mesoporous polythiophene b-MnO2 cathode electrode for Li-ion battery exhibited an initial discharge capacity of 305 mAh g?1 at a current density of 10 mA g?1, which is almost equal to its theoretical capacity. When applying a current of 300 mA g?1, mesoporous polythiophene MnO2 electrode shows the initial discharge capacity of 211 mAh g?1, which is 69% of its theoretical capacity. Mesoporous polythiophene MnO2 shows high capacity and good cycle stability even at high current densities due to its high surface area and fast Li-ion diffusion path

434

Structural Characterisation and Mechanical Stability of Titanium Substituted Mesoporous Materials  

OpenAIRE

Mesoporous silica and titanium SBA-15 samples with different Si/Ti molar ratio were prepared by direct one-step synthesis under strongly acidic hydrothermal conditions. The materials were characterised by X-ray diffraction, nitrogen adsorption at 77K. The Si/Ti values of the final calcined materials were determined by ICP analysis. It was found that all samples presented 2-D hexagonal structures with high degree of ordering. However, the metal content incorporated in all titani...

Galacho, Cristina; Ribeiro Carrott, M. M. L.; Vale?rio, J.; Carrott, P. J. M.; Valente Nabais, J. M.

2010-01-01

435

Synthesis and characterization of hydrophobic mesoporous silicas with controlled porosity  

OpenAIRE

The influence of synthesis parameters and post-synthesis treatments on the hydrophobic/hydrophilic character of SBA-15 type ordered mesoporous silicas (OMS) was studied. It was found that the duration of ripening can be reduced to the precipitation time. Temperature, stirring and duration of synthesis steps can modulate the morphology of particles and aggregates. Heating process, presence of an inorganic salt and silica/surfactant ratio are also parameters that affect the structure and textur...

Benamor, Taissire

2011-01-01

436

Gated Silica Mesoporous Supports for Controlled Release and Signaling Applications  

OpenAIRE

Blending molecular and supramolecular advances with materials science has resulted in recent years in the development of new organic-inorganic hybrid materials displaying innovative functionalities. One appealing concept in this field is the development of gated nanodevices. These materials are prepared by grafting molecular or supramolecular caps onto the external surface of mesoporous inorganic scaffolds loaded with a particular cargo. The caps or "gates" can then be opened and the cargo de...

Coll Merino, Mª Carmen; Bernardos Bau, Andrea; Marti?nez Man?ez, Ramo?n; Sanceno?n Galarza, Fe?lix

2013-01-01

437

Intrusion and extrusion of water in hydrophobic mesopores  

OpenAIRE

We present experimental and theoretical results on intrusion-extrusion cycles of water in hydrophobic mesoporous materials, characterized by independent cylindrical pores. The intrusion, which takes place above the bulk saturation pressure, can be well described using a macroscopic capillary model. Once the material is saturated with water, extrusion takes place upon reduction of the externally applied pressure; Our results for the extrusion pressure can only be understood b...

Barrat, Jean-louis; Lefevre, Benoit; Bocquet, Lyderic; Saugey, Anthony; Vigier, Ge?rard; Gobin, Pierre-franc?ois; Charlaix, Elisabeth

2003-01-01

438

Sulfonated ordered mesoporous materials : Synthesis, Charcacterization, Catalytic properties  

OpenAIRE

Catalysis with solid acids has been for a long time the subject of intense research activities, especially for the petrochemical industry. Nowadays, solid acid catalysts are more and more studied in other areas and particularly in those related to "green chemistry" and bioresources valorization such as biodiesel synthesis and now polysaccharides transformations. The present work aimed to investigate the potential of acidic ordered mesoporous materials with a controlled local environment of th...

Karaki, Mariam

2013-01-01

439

Synthesis of Mesoporous Carbon Using Halloyiste As Template  

OpenAIRE

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 carbo...

Zhou Shu-hui, Chuan Xiu-yun

2014-01-01

440

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

441

Development of Polymer Resins using Neural Networks  

Directory of Open Access Journals (Sweden)

Full Text Available The development of polymer resins can benefit from the application of neural networks, using its great ability to correlate inputs and outputs. In this work we have developed a procedure that uses neural networks to correlate the end-user properties of a polymer with the polymerization reactor's operational condition that will produce that desired polymer. This procedure is aimed at speeding up the development of new resins and help finding the appropriate operational conditions to produce a given polymer resin; reducing experimentation, pilot plant tests and therefore time and money spent on development. The procedure shown in this paper can predict the reactor's operational condition with an error lower than 5%.

Fabiano A. N. Fernandes

2002-01-01

442

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)

443

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)

444

Jetted mixtures of particle suspensions and resins  

Science.gov (United States)

Drop-on-demand (DoD) ink-jetting of hard particle suspensions with volume fraction ? ˜ 0.25 has been surveyed using 1000 ultra-high speed videos as a function of particle size (d90 = 0.8—3.6 ?m), with added 2 wt. % acrylic (250 kDa) or 0.5 wt. % cellulose (370 kDa) resin, and also compared with Newtonian analogues. Jet break-off times from 80 ?m diameter nozzles were insensitive (120 ± 10 ?s) to particle size, and resin jet break-off times were not significantly altered by >30 wt. % added particles. Different particle size grades can be jetted equally well in practice, while resin content effectively controls DoD break-off times.

Hoath, S. D.; Hsiao, W.-K.; Hutchings, I. M.; Tuladhar, T. R.

2014-10-01

445

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

446

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 improve