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1

Chemical Characterization of Phenol/Formaldehyde Resins  

Science.gov (United States)

Report discusses tests of commercial phenol/formaldehyde resins to establish relationships among composition before use, behavior during curing, and strength after curing. Resin used in carbon/carbon laminates. In curing process, two molecules of phenol joined together in sequence of reactions involving molecule of formaldehyde. Last step of sequence, molecule of water released. Sequence repeats until one of ingredients used up, leaving solidified thermoset plastic. Issues to be resolved: number and relative abundances of ingredients, presence of certain chemical groups, heat-producing ability of resin, and range of molecular weights present.

Brayden, T. H.

1986-01-01

2

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 Phenol had been replaced by lignin [that was extracted from black liquor of oil palm empty fruit bunch (EFB)] in synthesizing resin with a ratio lignin to phenol 1:1.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

2007-01-01

3

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

Directory of Open Access Journals (Sweden)

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

MONIKA ŠUPOVÁ

2012-03-01

4

Thermal and mechanical behavior of modified phenol formaldehyde resin  

International Nuclear Information System (INIS)

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

2004-01-01

5

Thermokinetic behavior of powdered phenol-formaldehyde (PPF) resins  

International Nuclear Information System (INIS)

This study was conducted to investigate thermokinetic behavior of powdered phenol-formaldehyde (PPF) resins used for the production of wood-based panel products. Both fusion diameter and stroke cure time of the PPF resins were measured to characterize flow properties and reactivity of PPF resins. In addition, differential scanning calorimetry (DSC) was also used to obtain apparent glass transition temperature (T g) and activation energy (E a) of the PPF resins. The results showed that the stroke cure time of PPF resins was positively related with fusion diameter of the PPF resins. The T g of PPF resins depended on the heating rate with a linear relationship established between heating rate and the T g. The E a of PPF resins depended on types of PPF resin and spray-drying temperatures

2005-08-01

6

Thermokinetic behavior of powdered phenol-formaldehyde (PPF) resins  

Energy Technology Data Exchange (ETDEWEB)

This study was conducted to investigate thermokinetic behavior of powdered phenol-formaldehyde (PPF) resins used for the production of wood-based panel products. Both fusion diameter and stroke cure time of the PPF resins were measured to characterize flow properties and reactivity of PPF resins. In addition, differential scanning calorimetry (DSC) was also used to obtain apparent glass transition temperature (T {sub g}) and activation energy (E {sub a}) of the PPF resins. The results showed that the stroke cure time of PPF resins was positively related with fusion diameter of the PPF resins. The T {sub g} of PPF resins depended on the heating rate with a linear relationship established between heating rate and the T {sub g}. The E {sub a} of PPF resins depended on types of PPF resin and spray-drying temperatures.

Park, Byung-Dae [Department of Forest Products, Korea Forest Research Institute (KFRI), Seoul 130-712 (Korea, Republic of)]. E-mail: byungdae@foa.go.kr; Wang Xiangming [Forintek Canada Corp., 314 rue Franquet, Ste-Foy, G1P 4R4 (Canada)

2005-08-01

7

Electron beam curable phenol-formaldehyde resin  

International Nuclear Information System (INIS)

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

1979-01-01

8

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 sub...

2011-01-01

9

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-01-01

10

Phenol-formaldehyde resin substitutes from biomass tars  

Energy Technology Data Exchange (ETDEWEB)

Approximately 320,000 tonnes of phenol and formaldehyde are currently used annually in North America to make adhesive resins that are used to make exterior-grade structural panels. The demand for phenol-formaldehyde (PF) resins is growing faster than the demand for panels, because more adhesive is required to join/coat the surface of wood flakes (for oriented strand board - OSB) than is required to join veneer; OSB is replacing plywood as logs large enough for veneer become scarcer. Also, competitive uses for phenol and methanol (for making formaldehyde) have increased raw materials cost and threatened availability. Production of adhesive resins from biomass to reduce reliance on raw materials derived from commodity petrochemicals and to lower resin cost looks attractive. A simple fluidized-bed reactor system can be used to produce tars that can substitute for a major portion of the phenol and formaldehyde in PF resin adhesives. This can be done in an air-fluidized, single-bed reactor; no inert gas or dual-bed system is required. The key is recognizing that optimum phenolic character in the tar is not produced at the maximum tar yield, but at reactor temperatures around 600{degrees}C and short gas-phase residence times that produce a yield of about 25 to 30 weight percent. A wide range of phenols, aldehydes and other compounds capable of polymerization are produced. Feedstock can be any wood waste larger than sander dust; low cost agricultural wastes such as bagasse are also suitable. Adhesive resin is produced from the entire tar product by shifting the pH from acidic to basic with NaOH, and combining and heating the resulting resole with phenol and formaldehyde, similarly to conventional resins. Approximately half of the phenol and formaldehyde by weight can be replaced with tar. A plant producing 13,865,000 kg (30,566,000 lb) annually from 308 tonnes (340 tons) per day of green wood chips would cost approximately $8,400,000.

Himmelblau, D.A. [Biocarbons Corporation, Woburn, MA (United States)

1995-11-01

11

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

12

Reactivity of pyrolysis oils and model compounds under phenol formaldehyde resin synthesis conditions  

Energy Technology Data Exchange (ETDEWEB)

Fast pyrolysis of biomass produces an oil, that can be upgraded to a phenolic and neutrals (PN) fraction suitable for incorporation into phenol formaldehyde resins. The formaldehyde reactivity of several phenolic model compounds commonly found in the PN fraction of pyrolysis oils was studied under a variety of reaction conditions, including temperature, pH, and formaldehyde ratio. The formaldehyde reactivity of the PN model compounds appears to be greater than that of phenol. The PN fraction of pyrolysis oils was also incorporated into phenol formaldehyde (PF) resins and cured. The chemical structure PN-PF resins synthesized and cured under different conditions was monitored with solid state nuclear magnetic resonance spectroscopy. These studies indicate that the PN fraction of pyrolysis oils are highly reactive under commercial resin synthesis conditions and are chemically incorporated into the cured PF resin network.

Wang, Xiangming; Davis, M.F.; Myers, M.D.; Kelley, S.S. [National Renewable Energy Lab., Golden, CO (United States)

1996-10-01

13

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.)

1986-01-01

14

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

2008-09-30

15

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Yung-Sheng Lin; Chih-Hui Yang; Chin-Tung Wu; Alexandru Mihai Grumezescu; Chih-Yu Wang; Wan-Chen Hsieh; Szu-Yu Chen; Keng-Shiang Huang

2013-01-01

16

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

Science.gov (United States)

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

Young, Philip R.

1999-01-01

17

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

International Nuclear Information System (INIS)

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

2009-12-10

18

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

Energy Technology Data Exchange (ETDEWEB)

The pyrolysis of pure phenol-formaldehyde (PF) resin and boron carbide (B{sub 4}C) modified PF resin was investigated by using thermogravimetry (TG) and pyrolysis gas-chromatography-mass-spectrometry (PY-GC/MS). Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy were also employed to investigate the micro-structural evolution. It was shown from the TG analysis that the char residues of pure PF resin were 62.9 and 60.5% after being pyrolyzed at 700 and 1000 {sup o}C, respectively. The degradation and failure of the resin matrix were mainly resulted from the release of volatiles. The phenol and its methyl derivates took a large proportion in the amount of volatiles. In comparison with the pure PF resin, the char residues of B{sub 4}C modified PF resin were obviously higher, with the values of 71.9 and 68.4% at 700 and 1000 {sup o}C, respectively. Due to the oxidation-reduction reactions between B{sub 4}C additive and oxygen-containing volatiles including CO and H{sub 2}O, partial carbon and oxygen elements in the volatiles remained in the resin matrix in the forms of amorphous carbon and B{sub 2}O{sub 3}, respectively. The results of SEM and FT-IR characterization demonstrated the occurrence of the modification, and the amorphous carbon existed in the form of reticular substance. In addition, the amount of the released phenol and its methyl derivates was also decreased drastically due to the formation of borate.

Wang, Jigang, E-mail: wangjigang@seu.edu.cn [Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiang, Haiyun [Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); School of Materials Science and Engineering, Southeast University, Nanjing Institute of Technology, Nanjing 210013 (China); Jiang, Nan [Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210093 (China)

2009-12-10

19

Micro-structural evolution of phenol-formaldehyde resin modified by boron carbide at elevated temperatures  

International Nuclear Information System (INIS)

The phenol-formaldehyde (PF) resin was modified by boron carbide (B4C). In order to investigate the modification effect of B4C, the residue values of pure PF resin and B4C modified PF resin were measured using thermal gravity. It was shown that the residue values of B4C modified PF resin are 71.9% and 68.4% after being pyrolyzed at 700 and 1000 deg. C, respectively, which are obviously higher than those of the pure PF resin (62.9% and 60.5% at 700 and 1000 deg. C, respectively). The microstructure evolution of the modified resin at high temperatures was also investigated by scanning electron microscopy and energy dispersive analysis of X-rays. By means of the microstructure characterization, the modification reactions between the B4C additives and the oxygen-containing volatiles, such as CO and H2O, are demonstrated. The carbon and oxygen elements remained in the resin matrix in the forms of amorphous carbon and B2O3, respectively, resulting in the improvement of residue values and stability of the PF resin at high temperatures. The distribution of modification particles became well-proportioned gradually at the elevated temperatures, and the shape of ceramic additives changed into white spherules due to the surface tension.

2010-03-15

20

Micro-structural evolution of phenol-formaldehyde resin modified by boron carbide at elevated temperatures  

Energy Technology Data Exchange (ETDEWEB)

The phenol-formaldehyde (PF) resin was modified by boron carbide (B{sub 4}C). In order to investigate the modification effect of B{sub 4}C, the residue values of pure PF resin and B{sub 4}C modified PF resin were measured using thermal gravity. It was shown that the residue values of B{sub 4}C modified PF resin are 71.9% and 68.4% after being pyrolyzed at 700 and 1000 deg. C, respectively, which are obviously higher than those of the pure PF resin (62.9% and 60.5% at 700 and 1000 deg. C, respectively). The microstructure evolution of the modified resin at high temperatures was also investigated by scanning electron microscopy and energy dispersive analysis of X-rays. By means of the microstructure characterization, the modification reactions between the B{sub 4}C additives and the oxygen-containing volatiles, such as CO and H{sub 2}O, are demonstrated. The carbon and oxygen elements remained in the resin matrix in the forms of amorphous carbon and B{sub 2}O{sub 3}, respectively, resulting in the improvement of residue values and stability of the PF resin at high temperatures. The distribution of modification particles became well-proportioned gradually at the elevated temperatures, and the shape of ceramic additives changed into white spherules due to the surface tension.

Wang Jigang, E-mail: wangjigang@seu.edu.cn [Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, Jiangsu 211189 (China); Jiang Nan [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093 (China); Jiang Haiyun [Jiangsu Key Laboratory of Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, Jiangsu 211189 (China); Department of Materials Engineering, Nanjing Institute of Technology, Nanjing 211167 (China)

2010-03-15

 
 
 
 
21

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

Directory of Open Access Journals (Sweden)

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

22

Phenol-formaldehyde resins: A quantitative NMR study of molecular structure and molecular dynamics  

Science.gov (United States)

Phenol-formaldehyde (PF) resins have been the subject of this work. 13C liquid-state and solid-state NMR has been used to investigate the molecular structure of mainly novolak and partially of resole resins. 1H wideline in combination with 13C solid-state NMR relaxometry has been applied to study the curing and the molecular dynamics of phenolic resins. It was the intention to provide an insight in the relationship between resin composition, resin structure and subsequent resin properties (by means of the molecular dynamics). An improved 13C liquid-state NMR quantification technique of novolaks in THF-CDCl3 solutions is demonstrated. Full quantitative 13C liquid-state spectra of phenol-formaldehyde resins with high signal- to-noise ratio were obtained by using chromium acetylacetonate under optimized spectral conditions within a few hours spectrometer time. Attached proton test (APT) spectra enabled proper peak assignments in the region with significant overlap. For several novolaks, prepared under different catalytic conditions, the degree of polymerization, degree of branching, number average molecular weight, isomeric distribution, and the number of unreacted ortho and para phenol ring positions was determined with a reduced margin of error, by analyzing and integrating the 13C spectra. The power of 13C solid-state NMR in the analysis of cured PF resins is shown. Particular importance was ascribed to the question of the quantifiability of the experiments when it was desired to measure the degree of conversion by means of a 13C CP/MAS contact time study. The network structure present, and thus also the mechanical properties, is critically dependent upon the final degree of conversion obtained after curing. The degree of conversion, which depended on the cure conditions (cure temperature, cure pressure and cure time), was limited by vitrification as was demonstrated by DSC experiments. Changes in the spin-lattice relaxation time T 1H were observed, providing criteria to follow the curing evolution. FT-Raman spectroscopy showed to be complementary to 13C NMR for the determination of the degree of polymerization and of conversion in PF prepolymers or in cured PF resins. In the last part of this work it was shown that 1H wideline and 13C CP/MAS solid-state NMR relaxometry provides interesting information concerning the molecular dynamics of cured novolak resins and resole/novolak copolymers. The relaxation times investigated were the spin-lattice relaxation time (T 1H), the spin-lattice relaxation time in the rotating frame (T 1pH), and the spin-spin relaxation time (T 2H). It was noticed that these relaxation times of the PF resins, at temperatures below the glass transition temperature, were ascertained not only by dynamic phenomena, but also a contribution from the spin diffusion mechanism should be implemented. Measurements as a function of the temperature indicated for a reversible hydrogen bond deformation, confirmed by FT-IR measurements. 13C CP/MAS and 1H wideline NMR can be applied as complementary techniques in order to investigate phenol-formaldehyde resins in the solid state. The chemical structure and the molecular dynamics of these resins can be studied in an adequate manner. Correlations can be made between their relaxation times, their chemical structure and their macroscopic properties.

Ottenbourgs, Benjamin Tony

23

Proton conducting polymer electrolytes based on phosphorylated phenol-formaldehyde resins  

Energy Technology Data Exchange (ETDEWEB)

Phosphorylated phenol-formaldehyde (PPF) resins were synthesized and investigated as the acidic components of proton conducting polymer electrolytes. The synthesis of PPF resins was carried out by melt polycondensation of monophenyl phosphate and formaldehyde (in the form of trioxane). The structure and molecular weight characterization of PPF resins were performed employing {sup 1}H-, {sup 13}C- and {sup 31}P-NMR spectroscopy, Fast Atom Bombardment mass spectrometry and elemental analysis. PPF resins may be cured with an excess of formaldehyde. Depending on the curing conditions, products of different crosslinking density (expressed by equilibrium swelling ratio) and total ion-exchange capacity up to 9mequiv.g{sup -1} may be obtained. The soluble and crosslinked PPF resins were examined from the viewpoint of conducting properties and hydrolytical stability. Crosslinked PPF resins embedded in poly(vinylidene fluoride) binder form ion-exchange membranes of ambient conductivities above 0.05Scm{sup -1}. These composite membranes have been investigated in a methanol fuel cell and showed stable performance during several hours of cell operation. (author)

Kedzierski, Michal [Industrial Chemistry Research Institute, ul.Rydygiera 8, 01-793 Warsaw (Poland); Florjanczyk, Zbigniew [Department of Chemistry, Warsaw University of Technology, ul.Noakowskiego 3, 00-664 Warsaw (Poland)

2006-09-13

24

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

Directory of Open Access Journals (Sweden)

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

25

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

Science.gov (United States)

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

Zhang, Xu; Ma, Qing-Zhi; Zhang, Zhong-Feng; Peng, Wan-Xi; Zhang, Ming-Long

2009-07-01

26

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.

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

2014-03-19

27

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.

28

Intrinsic fluorescence studies of compatibility in thermoplastic phenol formaldehyde resin / poly(?-caprolactone blends  

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Full Text Available Intrinsic fluorescence method was applied to study the miscibility and interactions of thermoplastic phenol formaldehyde resin (TPF / poly(?-caprolactone (PCL blends. The characteristic intrinsic fluorescence emission of TPF at 313 nm showed the very good sensitivity to monitor the macromolecular chain motion in the TPF/PCL blends. The glass transition (Tg, crystallization (Tc, and melting transition point (Tm of TPF/PCL blends were measured by the temperature dependence of intrinsic fluorescence intensities upon heating or cooling process. Interestingly, when TPF/PCL ? 5/5, besides a Tg for the amorphous phase of blend, another transition at temperature a little higher than Tg of PCL can be observed by intrinsic fluorescence method. This microheterogeneity can be explained by the so-called ‘rigid amorphous phase’ (RAP due to the good flexibility and the strong self-association of PCL chains in amorphous phase. Besides, the analysis of the dependence of Tg on the content of PCL suggests that this microheterogeneity can attenuate the interactions between TPF and PCL chains and result in a lowering of Tgs of blends. In view of the simplicity and sensitivity of measurement as well as affordability of instrument, intrinsic fluorescence proved to be an effective means for characterization of microstructural variation in polymer blends.

2011-08-01

29

Study on carbon nanotube reinforced phenol formaldehyde resin/graphite composite for bipolar plate  

Energy Technology Data Exchange (ETDEWEB)

Using carbon nanotubes (CNTs) after different Fenton treatments as a reinforcement and a phenol formaldehyde resin/graphite (PF/G) composite as matrix, a new composite for bipolar plate was formed by hot-pressing. The effects of Fenton, Fenton/ultrasonic and Fenton/ultraviolet treatments on the surface of the CNTs, and the bend strength and conductivity of bipolar plate composite produced using them were investigated. It was found that Fenton/UV treatment was an effective and advanced oxidation process, which could generate a large quantity of hydroxyl groups and few carboxyl groups on the sidewalls of the CNTs, but without severe damage. The functional groups on CNTs after Fenton/ultraviolet treatment can improve the interfacial adhesion between CNTs and matrix, which can improve the bend strength, but does not play an important role in the improvement of the conductivity. The bend strength and conductivity of the composite with 3% CNTs after Fenton/ultraviolet treatment are 68.6 MPa and 145.2 s cm{sup -1}, respectively, when pressed at 240 C for 60 min. (author)

Yin, Qiang; Sun, Kang-ning; Li, Ai-ju; Shao, Lei; Liu, Song-ming; Sun, Chang [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong Key Laboratory of Engineering Ceramics, Shandong University, 73 Jing Shi Road, Jinan 250061 (China)

2008-01-10

30

Study on the electrical and mechanical properties of phenol formaldehyde resin/graphite composite for bipolar plate  

Energy Technology Data Exchange (ETDEWEB)

With phenol formaldehyde resin (PF) powder and graphite powder as raw materials, a kind of conductive composite for bipolar plate is obtained by hot-pressure molding. The effects of PF resin content, molding temperature and time on conductivity and bending strength of the composite were investigated in this paper; and the optimum PF resin content, molding temperature and time were obtained. The results show that: the conductivity decreases and bending strength increases with the increasing of PF resin content; the conductivity varies wave-like and bending strength increases firstly and then decreases with the increasing of molding temperature; the effects of molding time on properties of the composite are similar to that of molding temperature; and the best conductivity and bending strength of the composite are 142 s cm{sup -1} and 61.6 MPa, respectively, when its PF resin content is 15% molded at 240 C for 60 min. (author)

Yin, Qiang; Li, Ai-ju [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Shandong Key Laboratory of Engineering Ceramics, Shandong University, Jinan 250061 (China); Wang, Wei-qiang; Xia, Li-gang [School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Wang, Yan-ming [School of Civil Engineering, Shandong University, Jinan 250061 (China)

2007-03-20

31

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 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)

1992-03-01

32

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

33

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

34

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

International Nuclear Information System (INIS)

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

2006-01-01

35

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)

1992-03-01

36

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.

2010-12-10

37

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

Directory of Open Access Journals (Sweden)

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

38

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)

2006-04-01

39

Structure/function studies of resorcinol-formaldehyde (R-F) and phenol-formaldehyde (P-F) copolymer ion-exchange resins  

Energy Technology Data Exchange (ETDEWEB)

he U.S. Department of Energy`s (DOE) Hanford Site was established to produce plutonium for the U.S. defense mission. Over the course of decades, hazardous, toxic, and radioactive chemical wastes were generated and disposed of in a variety of ways including storage in underground tanks. An estimated 180 million tons of high-level radioactive wastes are stored in 177 underground storage tanks. During production of fissile plutonium, large quantities of 90Sr and 137CS were produced. The high abundance and intermediate length half- lives of these fission products are the reason that effort is directed toward selective removal of these radionuclides from the bulk waste stream before final tank waste disposal is effected. Economically, it is desirable to remove the highly radioactive fraction of the tank waste for vitrification. Ion-exchange technology is being evaluated for removing cesium from Hanford Site waste tanks. This report summarizes data and analysis performed by Pacific Northwest National Laboratory (PNNL)for both resorcinol-formaldehyde (R-F) and phenol-formaldehyde (P-F) resins and relates their observed differences in performance and chemical stability to their structure. The experimental approach used to characterize the resins was conducted using primarily two types of data: batch distribution coefficients (Kds) and solid-state 13C NMR. Comparison of these data for a particular resin allowed correlation of resin performance to resin structure. Additional characterization techniques included solid-state 19F NMR, and elemental analyses.

Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Hogan, M.O.; Hallen, R.T.; Brown, G.N.; Linehan, J.C.

1996-09-01

40

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

Directory of Open Access Journals (Sweden)

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

 
 
 
 
41

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-15

42

Thermogravimetry of Phenol-Formaldehyde Polycondensates.  

Science.gov (United States)

For constant heating rate thermogravimetry of phenol-formaldehyde polycondensates, it proved necessary to first reduce procedural bias of kinetics. The ensuing method, limited largely by instrument accuracy and practical sample form, gave empirical kineti...

R. W. Farmer

1966-01-01

43

Structure-function investigations of modified phenol-formaldehyde and resorcinol-formaldehyde ion-exchange resins that are selective for cesium  

International Nuclear Information System (INIS)

Resorcinol-Formaldehyde (R-F) resin is a candidate regenerable ion-exchange material for removal of radioactive cesium from alkaline waste tank supernates at both the Hanford and Savannah River sites. The chemical stability of the R-F resin is a primary issue under the typical process conditions encountered for cesium removal, especially during the acid elution step. Part of our examination into this issue has been directed toward preparation of resins that contain fluorine to examine the effect on chemical stability of resorcinol and phenol based resins and to explore the effect of structural modification of the polymer on its cesium selectivity. Polymer modifiers included 2-, 3-, and 4-fluorophenol as well as 2,5-, 3,4-, and 3,5-difluorophenol. The resins were characterized using spectroscopic techniques (IR, 13C CP-MAS NMR) and by determination of cesium-specific distribution coefficients (Kd's)

1995-01-01

44

Structure-function investigations of modified phenol-formaldehyde and resorcinol-formaldehyde ion-exchange resins that are selective for cesium  

Energy Technology Data Exchange (ETDEWEB)

Resorcinol-Formaldehyde (R-F) resin is a candidate regenerable ion-exchange material for removal of radioactive cesium from alkaline waste tank supernates at both the Hanford and Savannah River sites. The chemical stability of the R-F resin is a primary issue under the typical process conditions encountered for cesium removal, especially during the acid elution step. Part of our examination into this issue has been directed toward preparation of resins that contain fluorine to examine the effect on chemical stability of resorcinol and phenol based resins and to explore the effect of structural modification of the polymer on its cesium selectivity. Polymer modifiers included 2-, 3-, and 4-fluorophenol as well as 2,5-, 3,4-, and 3,5-difluorophenol. The resins were characterized using spectroscopic techniques (IR, {sup 13}C CP-MAS NMR) and by determination of cesium-specific distribution coefficients (K{sub d}`s).

Hubler, T.L.; Hallen, R.T. [Pacific Northwest Lab., Richland, WA (United States)

1995-12-31

45

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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; Popova Marina Nikolayevna

2011-01-01

46

Development and Characterization of Phenol - Formaldehyde Molding Powder  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis of phenol-formaldehyde resin was carried out at pH 4.0-4.3, formaldehyde to phenol (F/P of 0.881 in the presence of acid catalyst (hydrochloric acid and oxalic acid, at operating temperature and pressure of 115°C and 1 atmospheric pressure respectively. Forty-six grams of the resin produced was formulated into molding powder by incorporating the following: 44.6 grams of water-free- wood-floor, 6.7 g of hexamethylene-tetramine, 2.0 g of magnesium oxide and 1.0 g of magnesium stearate. The determination of pH, viscosity, specific gravity, refractive index, molecular weight and total solid content were carried out at 25°C for both the neat/ conventional P-F resin and the molding powder, while infrared spectrum was performed only on the neat P-F resin. The result obtained showed the sample with water-free-floor (sample y has better mechanochemical properties than the neat sample (simple x. The results for both sample X and Y are: pH valve of 4.11 and 4.5, viscosity of 173.72 and 243.12 poise, refractive index for sample X was 1.67, molecular weight 16967.63 and 25234.54 respectively. The analysis of infrared spectroscopy of sample X showed that at region 3650-3590 cm-1, ­­­there was an absorption whose peak was between sharp and weak and is also O-H stretch-free indicating presence of phenol. The intensity of absorption at region 2800-2700cm-1 is medium indicating C-H stretching vibration of -CHO presence confirming aldelydes. Hence the physiochemical properties and the intra-red spectrum compared well with literature values.

M .O. Edoga

2006-01-01

47

Synthesis of white light emitting mesoporous carbon-silica nanocomposite  

International Nuclear Information System (INIS)

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

2011-05-01

48

Synthesis of white light emitting mesoporous carbon-silica nanocomposite  

Science.gov (United States)

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

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

2011-05-01

49

Synthesis of white light emitting mesoporous carbon-silica nanocomposite  

Energy Technology Data Exchange (ETDEWEB)

White light emitting mesoporous carbon-silica (MPCS) was synthesized by serially adding triblock copolymer (Pluronic, F127), ethanol (EtOH), tetraethoxysilane (TEOS), hydrochloric acid aqueous (HCl) and phenol-formaldehyde resin (resol) followed by the heat treatments of carbonization and oxidation. The PL intensity of MPCS showed a tendency to be strong with increasing of HCl concentration in {>=} 0.2 M. The pore size of MPCS that emits white light was 8 {approx} 9 nm and the specific surface area was 320 {approx} 418 m{sup 2} / g.

Sato, Koji; Ishikawa, Yukari [Japan Fine Ceramics Center, Atsuta-ku Nagoya 456-8587 (Japan); Matsumura, Akihiro [Department of Frontier Materials, Showa-ku Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Ishii, Yosuke; Kawasaki, Shinji, E-mail: kosato@jfcc.or.jp, E-mail: yukari@jfcc.or.jp [Department of Materials Science and Engineering, Showa-ku Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

2011-05-15

50

Stability of phenol-formaldehyde ion-exchange sorbents in aqueous solutions  

Science.gov (United States)

It is shown that ion-exchange sorbents based on phenol-formaldehyde resins can be used for a long time for isolating and separating rare alkali metals without any significant changes in the ion-exchange selectivity and capacity. When the phenol sorbents were used in alkaline solutions at elevated temperatures, carboxyl groups gradually accumulated in them as a result of the oxidation of methylol groups with oxygen dissolved in the solution. This led to a considerable increase in the ion-exchange capacity of the sorbents and a simultaneous decrease in the selectivity with respect to Cs+-Rb+ and Rb+-K+ ions (it is desirable to avoid the drying of phenol ionites in air by storing them in a swelled state in closed vessels).

Shelkovnikova, L. A.; Gavlina, O. T.; Ivanov, V. A.

2011-09-01

51

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.

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

52

Investigation of radiation curing of phenol-formaldehyde oligomers  

International Nuclear Information System (INIS)

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

1978-02-01

53

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.

2010-06-29

54

21 CFR 177.2260 - Filters, resin-bonded.  

Science.gov (United States)

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

2009-04-01

55

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2012-01-01

56

Reactive synthetic resins in mining  

Energy Technology Data Exchange (ETDEWEB)

Polyurethane resins are used for consolidating coal and rock and for sealing against water. Heavily-filled unsaturated polyester resins are used for resin bolts. Urea-formaldehyde resins are used, in the form of Isoschaum to fill roof voids and other cavities, to prevent methane accumulation in the crowns, and to seal ribsides. Epoxy resins, melamine-formaldehyde, and phenol-formaldehyde resins are also suitable for underground use. (In German)

Meyer, F.

1981-07-23

57

Phenol-formaldehyde intumescent coating composition and coating prepared therefrom  

Science.gov (United States)

Intumescent coatings which form a thick, uniform, fine celled, low density foam upon exposure to a high intensity heat flux or flame are disclosed, the invention coatings comprise phenolic resin prepolymer containing a blowing agent and a nucleating agent; in the preferred embodiments the coatings also contains a silicone surfactant, the coatings are useful in thermal and fire protection systems.

Salyer, Ival O. (Inventor); Fox, Bernard L. (Inventor)

1986-01-01

58

Extraction properties of nitrogen-containing phenol-formaldehyde oligomer in hydrochloric acid media  

International Nuclear Information System (INIS)

Distribution of molybdenum(6) and tellurium(4) between aqueous solutions of HCl and solutions of nitrogen-containing phenol-formaldehyde oligomer (Yarrezin B) in organic solvents during extraction of the elements chloride complexes from hydrochloric solutions is studied. Influence of composition of the organic and aqueous phases on interphase distribution is considered. It is ascertained that Yarrezin B extracts the complexes studied according to anion exchange mechanism

2000-05-01

59

Synthesis and Characterization of Periodic Mesoporous Organosilicas as Anion-Exchance Resins for Perrhenate Adsorption.  

Energy Technology Data Exchange (ETDEWEB)

A new methodology to immobilize ionic liquids through the use of a bridged silsesquioxane N-(3-triethoxysilylpropyl), N(3)-3-trimethoxysilylpropyl-4,5-dihydroimidazolium iodide that incorporates an ionic functionality for the assembly of novel periodic mesoporous organosilica (PMO) materials has been developed. The resulting PMO materials were investigated for use as novel anion exchange resins for the separation of perrhenate anions in aqueous solution. As compared with cetyltrimethylammonium chloride, 1-hexadecane-3-methylimidazolium bromide has been demonstrated to be a more efficient surfactant template for the generation of mesopores and surface areas for such PMO materials.

Lee, Byunghwan [Korea Institute of Industrial Technology, ChonAn, Korea; Im, Hee-Jung [ORNL; Luo, Huimin [ORNL; Hagaman, Edward {Ed} W [ORNL; Dai, Sheng [ORNL

2005-01-01

60

Structural transformations in phenol-formaldehyde-pitch dispersions in the course of their curing and coking  

Energy Technology Data Exchange (ETDEWEB)

A dynamic mechanical method was used to study the parameters of curing kinetics and the relaxation transitions during the cure and in the cured state of a phenol-formaldehyde-coal-tar-pitch (PF-CTP) dispersion, obtained by dispersing a quinoline-soluble fraction of a coal-tar pitch in melted phenol, followed by condensation with formaldehyde. Electron microscopy and X-ray diffraction showed a heterophase structure of the PF-CTP dispersion. This structure provides the formation, upon thermolysis, of a dispersion of ordered graphitized coke in a less ordered non-graphitized medium. 14 refs., 4 figs., 2 tabs.

Babaevskii, P.G.; Siplivyi, I.V. [Tsiolokovsky State Aviation Technology University, Moscow (Russian Federation)

1996-06-01

 
 
 
 
61

Studies on phenol-formaldehyde crosslinked polymer gels in bulk and in porous media  

Energy Technology Data Exchange (ETDEWEB)

The general conditions for gel formation by phenol-formaldehyde polymer solutions have been examined in studies with three acrylamide polymers. Contrary to an earlier report, polymer crosslinking is found to take place over a wide interval of pH. While the gelation time is relatively insensitive to the concentrations of phenol and formaldehyde or pH, it is strongly influenced by the temperature and the nature of the polymer. These gelants display good infectivity in corefloods and slim-tube experiments at temperatures up to 140 C. On the other hand, the partitioning of phenol into crude oil is found to be a significant issue for the propagation of these gelants. The use of a phenol pre-flush of the formation is shown by numerical modeling to be a potentially viable solution for this problem.

Albonico, P.; Bartosek, M.; Malandrino, A.; Bryant, S.; Lockhart, T.P.

1995-11-01

62

Challenges in Fabrication of Mesoporous Carbon Films with Ordered Cylindrical Pores via Phenolic Oligomer Self-Assembly with Triblock Copolymers  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous phenol formaldehyde (PF) polymer resin and carbon films are prepared by a solution self-assembly of PF oligomers with amphiphilic triblock copolymers. After thermopolymerization of the PF to cross-link the network, the films show an ordered morphology as determined by X-ray diffraction and grazing incidence small-angle X-ray scattering (GISAXS). Our results show that the amphiphilic triblock copolymer template greatly influences the stability of the final porous mesostructures. The pyrolysis of the two-dimensional (2-D) hexagonal films with p6mm symmetry templated by Pluronic F127 yields a disordered porous structure following the template removal. Conversely, films templated by Pluronic P123 can exhibit well-ordered cylindrical pores after the template removal, but the solution composition range to yield ordered cylindrical mesopores is significantly reduced (nearly 70%) for thin films in comparison to bulk powders. We propose two dominant difficulties in fabricating well-ordered cylindrical mesopores in films: first, the stress from contraction during the pyrolysis can lead to a collapse of the mesostructure if the wall thickness is insufficient, and second, the surface wetting behavior in thin films leads to a small compositional range.

Song, Lingyan; Feng, Dan; Fredin, Nathaniel J.; Yager, Kevin G.; Jones, Ronald L.; Wu, Quanyan; Zhao, Dongyuan; Vogt, Bryan D. (On Semi); (AZU); (NIST); (Fudan)

2010-06-22

63

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

International Nuclear Information System (INIS)

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

1996-08-01

64

Nitrogen-containing mesoporous carbons prepared from melamine formaldehyde resins with CaCl2 as a template.  

Science.gov (United States)

Melamine formaldehyde resins were synthesized with encapsulated CaCl(2) as a template. Carbonization at high temperatures led to the formation of carbon materials containing N atoms. Washing with de-ionized water removed encapsulated CaCl(2), resulting in the formation of mesopores (3-30 nm) with the high surface areas (770-1300 m(2)/g). The template can be recycled and the method is simple and cost effective as compared to the hard template techniques. The mesoporous carbons containing nitrogen (NMC) thus prepared exhibited the amphipathic surfaces (both hydrophilic and lipophilic) and adsorbed great amount of water and benzene. In addition, the incorporated N atoms exhibited quite strong basicity for the adsorption of great amount of SO(2). PMID:21840533

Huang, Yu'an; Yang, Feng; Xu, Zheng; Shen, Jianyi

2011-11-01

65

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

2007-05-01

66

Thermal rearrangement of novolak resins used in microlithography  

Science.gov (United States)

Changes in phenolic-formaldehyde resin properties are described in terms of thermal exposure. At high temperature, resin molecular weight, dissolution properties and chemical composition change depending on the presence or absence of monomers. Without monomer in the resin melt at 220 degree(s)C, resin molecular weight increases with a corresponding decrease in dissolution rate. In the presence of monomer, molecular weight generally decreases. Dissolution rate may fluctuate depending on the monomer mixture. Three,five- Xylenol and 2,3,5-trimethylphenol co-monomers induced the most extreme changes in resin properties with thermal treatment. Resin degradation-recombination processes suggest a classical Friedel-Craft rearrangement mechanism.

Hardy, Ricky; Zampini, Anthony; Monaghan, Michael J.; O'Leary, Michael J.; Cardin, William J.; Eugster, Timothy J.

1995-06-01

67

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-for...

2009-01-01

68

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 bond strength. However, the thickness swelling and bond durability of OSL formed by pure MDI failed to pass the standards, while those formed by pure PF or hybrid adhesives passed. Among the three blends of adhesives, the blend 75:25 (PF: MDI gave the best properties while ratio of 50:50 gave the worst properties, especially internal bond strength due to the phase separation of both adhesives. In addition, the modulus of rupture and modulus of elasticity in the "edgewise" direction were higher than those in the "flatwise" direction. In the edgewise direction, load is transferred in the direction of width of strand that is large while in the flatwise direction, load is transferred in the direction of thickness of strand which is small.

Wanchart Preechatiwong

2007-09-01

69

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

70

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

71

Chemical derivatization of Resorcinol-Formaldehyde resin leading to enhanced chemical/oxidative stability of the resin  

Energy Technology Data Exchange (ETDEWEB)

Resorcinol-Formaldehyde (R-F) resin is a candidate regenerable ion-exchange resin for removal of radioactive cesium from highly alkaline waste tank supernates at both the Hanford and Savannah River sites. Our previous investigations into the structure/function relationships of R-F resin have shown that the R-F resin undergoes facile oxidation to produce, para-bisquinones, with loss of ion-exchange sites, hence lowered performance of the resin for cesium ion-exchange. Our studies have also shown that Phenol-Formaldehyde (P-F) resin has a substantially lower capacity compared to R-F resin, based on predicted values, because over half the ion-exchange sites of the P-F resin undergo etherification during the standard synthetic procedures used for preparation of these resins. In this report, we present our studies into rational synthetic solutions to enhance the chemical/oxidative stability of R-F resin.

Hubler, T.L.; Franz, J.A. [Pacific Northwest Lab., Richland, WA (United States)

1996-10-01

72

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2011-01-01

73

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

Energy Technology Data Exchange (ETDEWEB)

Tank wastes at Hanford and SRS contain highly alkaline supernate solutions of conc. Na, K nitrates with large amounts of {sup 137}Cs. 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.

Hubler, T.L.; Shaw, W.J.; Brown, G.N.; Linehan, J.C.; Franz, J.A.; Hart, T.R.; Hogan, M.O.

1996-09-01

74

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

1996-01-01

75

Preparation of coal tar-modified phenolic resin  

Energy Technology Data Exchange (ETDEWEB)

Reaction of prescribed amount of phenol, formaldehyde, sodium hydroxide with coal tar were conducted. The reaction mixture was dehydrated under a reduced pressure of 0.08 MPa until to an appropriate viscosity to get coal tar-modified phenolic resin. TG and DSC analyses show that compared to unmodified phenolic resin, solid and carbon residue contents in the modified phenolic resin by adding 15% of coal tar are increased to 98.1% and 38.9% from 83.1% and 32.9%, respectively. The initial decomposing temperature of modified phenolic resin is up to 536{sup o}C from 372{sup o}C. This technique can greatly reduce the cost of phenolic resin and increase the application fields of coal tar. 7 refs., 2 figs., 1 tab.

L. Wu; Z.-H. Ouyang; D.-L. Yi; X.-R. Qin; S.-C. Cao; Y. Wang; X.-Y. Wei [Wuhan University of Science & Technology, Wuhan (China). Hubei Province Key Laboratory of Ceramics & Refractories

2005-07-01

76

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

Science.gov (United States)

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

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

2014-01-01

77

Formaldehyde resins in building materials. December 1973-October 1989 (Citations from the Rubber and Plastics Research Association data base). Report for December 1973-October 1989  

Energy Technology Data Exchange (ETDEWEB)

This bibliography contains citations concerning regulations, standards, safety, and applications of formaldehyde-resin compositions in the building industry. Urea formaldehyde is emphasized; however, phenol formaldehyde and melamine formaldehyde are also considered for such applications as thermal insulation, bonding agents, and composite construction materials. Ramifications of state and federal legislation, substitute materials, and toxicology studies are included. (This updated bibliography contains 376 citations, 46 of which are new entries to the previous edition.)

1989-12-01

78

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

Energy Technology Data Exchange (ETDEWEB)

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

Chi Yue; Li Nan; Tu Jinchun; Zhang Yujie [School of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, Changchun 130012 (China); Li Xiaotian, E-mail: xiaotianli@jlu.edu.c [School of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, Changchun 130012 (China); Shao Changlu, E-mail: clshao@nenu.edu.c [Center for Advanced Optoelectronic Functional Materials Research, Northeast Normal University, Changchun 130024 (China)

2010-03-15

79

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

International Nuclear Information System (INIS)

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

2010-03-01

80

Urea/phenol/melamine formaldehyde polymeric resins. (Latest citations from the NTIS data base). Published Search  

Energy Technology Data Exchange (ETDEWEB)

The bibliography contains citations concerning characteristics, safe use regulations and standards, and applications of formaldehyde polymeric resins. Modelling, test procedures, and test results for identifying the hazards of formaldehyde resin system emissions are presented. Methods of preparation and modification of formaldehyde foams for use in the building industry are included. Corrosion of formaldehyde polymeric foam thermal insulation, crosslinking and catalysis of phenol-formaldehyde polymer concrete, and disposal of urea-formaldehyde waste are considered. (Contains a minimum of 103 citations and includes a subject term index and title list.)

1992-04-01

 
 
 
 
81

Mesoporous Carbon-based Materials for Alternative Energy Applications  

Science.gov (United States)

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

Cross, Kimberly Michelle

82

Urea/phenol/melamine formaldehyde polymeric resins. January 1970-February 1990 (A Bibliography from the NTIS data base). Report for January 1970-February 1990  

Energy Technology Data Exchange (ETDEWEB)

This bibliography contains citations concerning characteristics, safe use regulations and standards, and applications of formaldehyde polymeric resins. Modelling, test procedures, and test results for identifying the hazards of formaldehyde resin system emissions are presented. Methods of preparation and modification of formaldehyde foams for use in the building industry are included. Corrosion of formaldehyde polymeric foam thermal insulation, crosslinking and catalysis of phenol-formaldehyde polymer concrete, and urea-formaldehyde waste disposal are considered. (This updated bibliography contains 238 citations, 17 of which are new entries to the previous edition.)

1990-02-01

83

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

International Nuclear Information System (INIS)

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

1979-03-28

84

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

1995-01-01

85

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)

1997-01-01

86

Monitoring resin cure of medium density fiberboard using dielectric sensors  

Energy Technology Data Exchange (ETDEWEB)

Flush mounted, in-press microwave (600--800 MHz) sensors have been developed for monitoring the complex permittivity in real time during the cure of medium density fiberboard. The measured dielectric constant ({var_epsilon}{prime}) and loss factor ({var_epsilon}{double_prime}) are independent diagnostic indicators of dynamic cure events that are catalyzed by heat, pressure and moisture. In particular, with this technique the instantaneous effects of resin viscosity, rate and degree of adhesive cure, the wood density, the changes in phase of the moisture and the rate of moisture depletion can be monitored during the entire curing process. The comparative roles of moisture and adhesive content are discussed, along with the comparative modulus of rupture with cure duration. Results are presented comparing the dynamics of phenol-formaldehyde and isocyanate resins.

King, R.J. [KDC Technology Corp., Livermore, CA (United States); Rice, R.W. [Univ. of Maine, Orono, ME (United States). Wood Science and Technology Dept.

1996-12-31

87

Qualidade de compensados fabricados com adesivos à base de Tanino-Formaldeído de Pinus oocarpa e Fenol-Formaldeído / Quality of plywood manufactured with Tannin-formaldehyde from Pinus oocarpa plus Phenol-Formaldehyde-based adhesive  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho teve por objetivo avaliar a qualidade de compensados fabricados com adesivos à base de taninos da casca de Pinus oocarpa e Fenol-Formaldeído (FF). O plano experimental foi composto de quatro tratamentos: Tanino-Formaldeído (TF); Fenol-Formaldeído (FF); FF + 10%TF (90:10), e FF + 20% TF [...] (80:20). Os painéis foram avaliados nos seguintes aspectos: resistência à flexão estática (MOR); ensaio de cisalhamento na linha de cola; densidade e recuperação em espessura (RE); inchamento mais recuperação em espessura (IR), e absorção em água (AA). Os resultados mostraram que é possível substituir o adesivo FF por tanino em até 20% sem alterar os valores de MOR paralelo e perpendicular à grã das lâminas externas dos compensados. Para obtenção de maior estabilidade dimensional dos compensados fabricados com adesivo à base de tanino, torna-se necessária a adição de parafina. Os resultados mostraram também que não houve diferença significativa nos valores de resistência ao cisalhamento dos compensados para os diferentes tratamentos. Abstract in english The aim of this paper was to evaluate the quality of plywood panels manufactured with tannin-based adhesives extracted from the bark of Pinus oocarpa and Phenol-Formaldehyde. The experimental plan was composed of four treatments: Tannin-formaldehyde (TF), Phenol-formaldehyde (FF), FF + 10%TF (90:10) [...] and FF + 20%TF (80:20). The quality of plywood panels was evaluated by the static bending (MOR), bonding line shear test of the adhesive, and dimensional stability: thickness swelling, recovery of thickness and water absorption. Results showed that it is possible to substitute Phenol-Formaldehyde adhesive by tannin up to 20% without changing MOR parallel and MOR perpendicular to the grain of the the panels. In order to obtain higher values of physical properties of plywood made with tannin from bark of Pinus oocarpa, it is necessary to add paraffin. Results showed that there was no significant difference in values of shear strength for the different treatments.

Silva, Bruno Couto da; Vieira, Michel Cardoso; Oliveira, Gisely de Lima; Gonçalves, Fabricio Gomes; Rodrigues, Nayara Dorigon; Lelis, Roberto Carlos Costa; Iwakiri, Setsuo.

88

Influence of structure of a crosslinked epoxy resin on its properties studied by positron annihilation and other methods  

International Nuclear Information System (INIS)

Positron annihilation has been applied to study samples of two crosslinked epoxy resins: diglycidyl ether of bisphenol A (Epikote 828) and polyglycidyl-ether of phenol-formaldehyde novolac (Epikote 155) cured with 4,4'-diamino-diphenylo-methane (MDA), phenol-formaldehyde novolac resin (Novolac Z) and bisphenol A (formaldehyde resin). Results of measurements of positron lifetime spectra were compared with the ones coming from DMTA, flexural strength testing and density measurements. The most important features of samples (glass transition temperature, storage modulus, flexural strength, crosslinking density and tan ?) proved to be correlated with the product ?3 x v-bar, proportional to the fractional free volume in samples. Values of v-bar have been estimated from the values of ?3, the longest lifetime in positron lifetime spectra. ?3 corresponds to the intensity of the longest-lived component in them. Distributions of free volume radii reconstructed in the basis of PAL measurements are given for all samples. The influences of structure of both cured resin and the curing agent on the properties of the crosslinked products is clearly seen from the presented results. (author)

1996-06-09

89

Solid-state /sup 13/C NMR study of cured resorcinol-formaldehyde resins  

Energy Technology Data Exchange (ETDEWEB)

The curing process generally follows the pattern observed in the stage of prepolymer formation. Catalysts (NaOH, hexa, Mg(OCOCH/sub 3/)/sub 2/) that have no substantial influence on the isomeric composition of the resorcinol-formaldehyde prepolymers, do not affect the isomeric composition of the cured resins to any significant extent either. Isomeric composition of the cured resins depends mostly on the presence of water during the curing process, necessary for depolymerisation of the added paraformaldehyde. Curing in the melt leads to enhanced 2-substitution in the 1,3-dihydroxybenzene rings. In the /sup 13/C NMR spectra of cured powdered samples, the tendency of 5-methylresorcinol to form oligomers with a higher degree of 2-substitution than resorcinol is clearly apparent. Polycondensation process continues in the powdered resins after initial curing until complete consumption of all formaldehyde. Curing of phenol-formaldehyde resols proceeds through intermediate dimethylene ether formation.

Lippmaa, H.; Samoson, A.

1988-08-01

90

Solid-state 13C NMR study of cured resorcinol-formaldehyde resins  

International Nuclear Information System (INIS)

The curing process generally follows the pattern observed in the stage of prepolymer formation. Catalysts (NaOH, hexa, Mg(OCOCH3)2) that have no substantial influence on the isomeric composition of the resorcinol-formaldehyde prepolymers, do not affect the isomeric composition of the cured resins to any significant extent either. Isomeric composition of the cured resins depends mostly on the presence of water during the curing process, necessary for depolymerisation of the added paraformaldehyde. Curing in the melt leads to enhanced 2-substitution in the 1,3-dihydroxybenzene rings. In the 13C NMR spectra of cured powdered samples, the tendency of 5-methylresorcinol to form oligomers with a higher degree of 2-substitution than resorcinol is clearly apparent. Polycondensation process continues in the powdered resins after initial curing until complete consumption of all formaldehyde. Curing of phenol-formaldehyde resols proceeds through intermediate dimethylene ether formation. (author)

1988-01-01

91

Synthesis of a boron modified phenolic resin  

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Full Text Available 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 phosphorus in the main backbone of the thermo-set resin is a new strategy to obtain special high performance resins, which results in higher mechanical properties, avoiding the drawbacks of simply adding fillers, which results in enhanced thermo-oxidative stability compared to conventional phenol-formaldehyde resins. Therefore, the product can have several applications, including the use as ablative thermal protection for thermo-structural composites. This work describes the preparation of a boron-modified phenolic resin (BPR using salicyl alcohol and boric acid. The reaction was performed in refluxing toluene for a period of four hours, which produced a very high viscosity amber resin in 90% yield.The final structure of the compound, the boric acid double, substituted at the hydroxyl group of the aromatic ring, was determined with the help of the Infrared Spectroscopy, ¹H-NMR, TGA-DSC and boron elemental analysis. The absorption band of the group B-O at 1349 cm ?¹ can be visualized at the FT-IR spectrum. ¹H-NMR spectra showed peaks at 4.97-5.04 ppm and 3.60-3.90 ppm assigned to belong to CH2OH groups from the alcohol. The elemental analysis was also performed for boron determination.The product has also been tested in carbon and silicon fibers composite for the use in thermal structure. The results of the tests showed composites with superior mechanical properties when compared with the conventional phenolic resin.

Aparecida M. Kawamoto

2010-08-01

92

Characterization and utilization in phenolic resins of lignin from wood saccharification by mineral acids. Annual report, October 1, 1984-September 30, 1985  

Energy Technology Data Exchange (ETDEWEB)

This research is to explore conditions under which the lignin-rich residue from TVA's two stage hardwood based wood saccharification pilot plant can be used as a prepolymer for phenol-formaldehyde resin products and other thermosetting plastics. Six specific tasks studied were to isolate a uniform polymer fraction from the lignin-rich pilot plant residue; to characterize the chemical and molecular structure of the useful lignin fraction; to test the reactivity of this fraction with phenol, with formaldehyde and phenol in sequence, and with propylene oxide, and to analyze the reaction products; to synthesize phenolic resins with substitution levels in excess of 50% of phenol, and to evaluate these resins by thermal analysis; to test selected resins by shear block testing and to prepare polyurethane thermosets by crosslinking with diisocyanates; and to compare the performance of the phenolic resins and polyurethanes with those obtained with other lignins. 4 figs., 3 tabs.

Glasser, W.G.

1985-01-01

93

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2011-01-01

94

Use of gold and silver standards based on phenol-formalde-hyde resin in assay-activation analysis of geological samples  

International Nuclear Information System (INIS)

Using standards on phenol-formaldehyde resin base for assaying-activation analysis of geological specimens for gold and silver has bee the advantage of uniformly distributing Au and Ag in spesimens and possible preparing tablets of practically any form or size. The validity and accuracy of these standards have been studied for the cases of short irradiation. Conventional point standards were used as reference standards. The experiments carried out have shown that tablet resol standards are suitable for a mass assaying-activation analysis for gold and silver at practically any concentrations

1976-01-01

95

Synthesis and characterization of gyroidal mesoporous carbons and carbon monoliths with tunable ultralarge pore size.  

Science.gov (United States)

Ordered mesoporous carbons with high pore accessibility are of great interest as electrodes in energy conversion and storage applications due to their high electric and thermal conductivity, chemical inertness, and low density. The metal- and halogen-free synthesis of gyroidal bicontinuous mesoporous carbon materials with uniform and tunable pore sizes through bottom-up self-assembly of block copolymers thus poses an interesting challenge. Four double gyroidal mesoporous carbons with pore sizes of 12, 15, 20, and 39 nm were synthesized using poly(isoprene)-block-poly(styrene)-block-poly(ethylene oxide) (ISO) as structure-directing triblock terpolymer and phenol-formaldehyde resols as carbon precursors. The highly ordered materials were thermally stable to at least 1600 °C with pore volumes of up to 1.56 cm(3) g(-1). Treatment at this temperature induced a high degree of sp(2)-hybridization and low microporosity. Increasing the resols/ISO ratio led to hexagonally packed cylinders with lower porosity. A single gyroid carbon network with high porosity of 80 vol % was obtained using a similar synthesis strategy. Furthermore, we present a method to fabricate monolithic materials of the gyroidal carbons with macroscopic shape and thickness control that exhibit an open and structured surface with gyroidal features. The gyroidal materials are ideally suited as electrode materials in fuel cells, batteries, and supercapacitors as their high, three-dimensionally connected porosity is expected to allow for good fuel or electrolyte accessibility and to prevent total pore blockage. PMID:24328285

Werner, Jörg G; Hoheisel, Tobias N; Wiesner, Ulrich

2014-01-28

96

Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,  

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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

97

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

98

Radiation testing of organic ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

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 {sup 137}Cs 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 {sup 60}Co source to a total absorbed dose of 10{sup 9} 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 {sup 137}Cs 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 (K{sub d}s). Structural information was also obtained by {sup 13}C 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 K{sub d}.

Carlson, C.D.; Bray, L.A.; Bryan, S.A. [and others

1995-09-01

99

Production of renewable phenolic resins by thermochemical conversion of biomass: A review  

Energy Technology Data Exchange (ETDEWEB)

This review covers the production and utilisation of liquids from the thermal processing of biomass and related materials to substitute for synthetic phenol and formaldehyde in phenol formaldehyde resins. These resins are primarily employed in the manufacture of wood panels such as plywood, MDF, particle-board and OSB. The most important thermal conversion methods for this purpose are fast pyrolysis and vacuum pyrolysis, pressure liquefaction and phenolysis. Many feedstocks have been tested for their suitability as sources of phenolics including hard and softwoods, bark and residual lignins. Resins have been prepared utilising either the whole liquid product, or a phenolics enriched fraction obtained after fractional condensation or further processing, such as solvent extraction. None of the phenolics production and fractionation techniques covered in this review are believed to allow substitution of 100% of the phenol content of the resin without impacting its effectiveness compared to commercial formulations based on petroleum derived phenol. This survey shows that considerable progress has been made towards reaching the goal of a price competitive renewable resin, but that further research is required to meet the twin challenges of low renewable resin cost and satisfactory quality requirements. Particular areas of concern are wood panel press times, variability of renewable resin properties, odour, lack of reactive sites compared to phenol and potential for increased emissions of volatile organic compounds. (author)

Effendi, A.; Gerhauser, H.; Bridgwater, A.V. [Bio-Energy Research Group, Aston University, Birmingham B4 7ET (United Kingdom)

2008-10-15

100

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

 
 
 
 
101

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

International Nuclear Information System (INIS)

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

1995-01-01

102

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

Energy Technology Data Exchange (ETDEWEB)

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

Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Bryan, S.A.; Hallen, R.T.; Brown, G.N.; Bray, L.A.; Linehan, J.C.

1995-08-01

103

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

104

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

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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

105

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

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Full Text Available 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 (2.5Mev. The total doses were (208, 312 and 728 KGy. The mechanical tests (bending, bending strength, shear force, impact strength and surface indentation were performed on un irradiated and irradiate samples.All of the mechanical properties were improved with an increase in radioactive dose of up to (312 KGy to be decreased afterwards.The topography of some physically tested specimens was studied using optical microscopy.

Muhammad Slab Hamza

2009-01-01

106

Phosphonate-functionalized large pore 3-D cubic mesoporous (KIT-6) hybrid as highly efficient actinide extracting agent.  

Science.gov (United States)

A new type of radionuclide extraction material is reported based on phosphonate functionalities covalently anchored on the mesopore surface of 3-D cubic mesoporous silica (KIT-6). The easily prepared nanoporous hybrid shows largely superior performance in selective sorption of uranium and thorium as compared to the U/TEVA commercial resin and 2-D hexagonal SBA-15 equivalent. PMID:21946830

Lebed, Pablo J; de Souza, Kellen; Bilodeau, François; Larivière, Dominic; Kleitz, Freddy

2011-11-01

107

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

108

Composite material based on an ablative phenolic resin and carbon fibers  

Directory of Open Access Journals (Sweden)

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

DIMKO DIMESKI

2009-04-01

109

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.

110

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

111

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

112

Periodic Mesoporous Organosilica Nanorice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A periodic mesoporous organosilica (PMO) with nanorice morphology was successfully synthesized by a template assisted sol–gel method using a chain-type precursor. The PMO is composed of D and T sites in the ratio 1:2. The obtained mesoporous nanorice has a surface area of 753 m2 g?1, one-dimensional channels, and a narrow pore size distribution centered at 4.3 nm. The nanorice particles have a length of ca. 600 nm and width of ca. 200 nm.

Mohanty, Paritosh; Landskron, Kai

2008-01-01

113

Mesoporous carbons and polymers  

Energy Technology Data Exchange (ETDEWEB)

A mesoporous material prepared by polymerizing a resorcinol/formaldehyde system from an aqueous solution containing resorcinol, formaldehyde and a surfactant and optionally pyrolyzing the polymer to form a primarily carbonaceous solid. The material has an average pore size between 4 and 75 nm and is suitable for use in liquid-phase surface limited applications, including sorbent, catalytic, and electrical applications.

Bell, William (Boulder, CO); Dietz, Steven (Denver, CO)

2001-01-01

114

Mesoporous aluminum phosphite  

Science.gov (United States)

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 N 2 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.

El Haskouri, Jamal; Pérez-Cabero, Mónica; Guillem, Carmen; Latorre, Julio; Beltrán, Aurelio; Beltrán, Daniel; Amorós, Pedro

2009-08-01

115

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

116

Synthesis of extremely large mesoporous activated carbon and its unique adsorption for giant molecules  

Energy Technology Data Exchange (ETDEWEB)

The steam invigoration of pitches (softening points 85 and 280{degrees}C) homogenized with 1-3 wt% of organo rare0earth metal complexes such as Ln(C{sub 5}H{sub 5}){sub 3} or Ln(acac) (Ln=Y, Yb) at 930{degrees}C provided activated carbons with an extremely high mesopore ration, >70%. The resulted activated carbon selectively adsorbs giant molecules such as Vitamin B{sub 12}, blue acid 90 dye, dextran, nystatin, and humic acid, reflecting their large mesopore volumes. To understand what kind of carbon skeleton in pitch is suited for generation of high mesopore ration, the steam invigoration of a series of condensed polynuclear aromatics (COPNA) resins prepared from naphthlene, anthracene, phenanthrene, pyrene, or perylene and p-xylene-{alpha},{alpha}{prime}-diol were conducted in the presence of rare-earth metal complexes. As a result, COPNA resins containing phenanthrene, perylene, and pyrene generated large mesopore volume. 35 refs., 16 figs., 11 tabs.

Tamai, Hisashi; Kakii, Takuhiro; Hirota, Yoshifumi [Hiroshima Univ. (Japan)] [and others

1996-02-01

117

Adsorption and structural properties of soft-templated mesoporous carbons obtained by carbonization at different temperatures and KOH activation  

Science.gov (United States)

Two series of phenolic resin-based mesoporous carbons were prepared by soft-templating strategy, which involves the formation of thermosetting carbon precursor by polymerization of phloroglucinol and formaldehyde in hydrophilic mesodomains of a thermally decomposable triblock copolymer used as a soft-template. It was shown that the volumes of mesopores and micropores in the resulting carbons can be tuned by varying carbonization temperature of phenolic resins in the range from 400 to 1000 °C followed by the post-synthesis KOH activation at 700 °C. The highly microporous carbons were obtained by KOH activation of phenolic resins pyrolyzed at lower temperature (˜500 °C), while high temperature KOH activation (˜800 °C) afforded microporous carbons with preserved mesoporosity.

Górka, Joanna; Zawislak, Aleksandra; Choma, Jerzy; Jaroniec, Mietek

2010-06-01

118

Periodic mesoporous silica gels  

Energy Technology Data Exchange (ETDEWEB)

We have synthesized monolithic particulate gels of periodic mesoporous silica by adding tetramethoxysilane to a homogeneous alkaline micellar precursor solution. The gels exhibit 5 characteristic length scales over 4 orders of magnitude: fractal domains larger than the particle size (>500 nm), particles that are {approximately}150 to 500 nm in diameter, interparticle pores that are on the order of the particle size, a feature in the gas adsorption measurements that indicates pores {approximately}10-50 nm, and periodic hexagonal arrays of {approximately}3 nm channels within each particle. The wet gel monoliths exhibit calculated densities as low as {approximately}0.02 g/cc; the dried and calcined gels have bulk densities that range from {approximately}0.3-0.5 g/cc. The materials possess large interparticle ({approximately}1.0-2.3 cc/g) and intraparticle ({approximately}0.6 cc/g) porosities.

Anderson, M.T.; Martin, J.E.; Odinek, J.G. [and others

1996-06-01

119

Hydrophilic and mesoporous SiO2-TiO2-SO3H system for fuel cell membrane applications  

International Nuclear Information System (INIS)

Graphical abstract: The composite films containing SiO2-TiO2-SO3H resin additives, with strong water retention capabilities, showed superior proton conductivity, even at 120 oC and 25% RH, as well as a slightly improved current density at 30% RH and 70 oC, when compared to costly Nafion film. Display Omitted Research highlights: ? The hydrophilic and mesoporous SiO2-TiO2-SO3H resins have a potential to be used as alternative membrane source materials in PEFCs. ? The sulfonation for hydrophilicity is conducted via simple chelating chemistry between catecholic groups and surface Ti ions. ? The proton conductivity of SiO2-TiO2-SO3H composite films is superior to the commercial Nafion film. - Abstract: Hydrophilic and mesoporous sulfonated SiO2-TiO2-SO3H systems as new additives for fuel cell electrolyte membranes are directly synthesized by the binary sol-gel reaction of TEOS-TiCl4 and consecutive sulfonation with a hydrophilic generator, dihydroxy-m-benzenedisulfonic acid disodium salt. The sulfonation approach makes use of the simple chelating chemistry between the catecholic groups (dihydroxy benzene) and surface Ti ions of the inorganic ordered mesoporous SBA-15 structure. The system is successfully employed in fuel cell membrane applications with a composite Nafion membrane mixed with a mesoporous hydrophilic resin additive, and reveals an obvious enhancement of the proton conductivity at low humidity and elevated temperatures. This improvement was attributed to the excellent water retention capability of the hydrophilic mesoporous resin.

2011-03-30

120

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

 
 
 
 
121

Research Update: Mesoporous sensor nanoarchitectonics  

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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

122

Ordered mesoporous silica: microwave synthesis  

International Nuclear Information System (INIS)

Ordered mesoporous silicas, FDU-1, synthesized by using triblock copolymer, EO39BO47EO39, 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 N2 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

2004-09-25

123

Aligned mesoporous architectures and devices.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-03-01

124

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

125

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

126

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

127

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

128

A simple method to ordered mesoporous carbons containing nickel nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

A series of ordered mesoporous carbons containing magnetic Ni nanoparticles (Ni-OMCs) with a variety of Ni loadings was made by a simple one-pot synthetic procedure through carbonization of phenolic resin-Pluronic block copolymer composites containing various amount of nickel nitrate. Such composite materials were characterized by N{sub 2} sorption, XRD, and STEM. Ni-OMCs exhibited high BET surface area, uniform pore size, and large pore volume without obvious pore blockage with a Ni loading as high as 15 wt%. Ni nanoparticles were crystalline with a face-center-cubic phase and observed mainly in the carbon matrix and on the outer surface as well. The average particle size of Ni nanoparticles was dependent on the preparation (carbonization) temperature and Ni loading; the higher the temperature was used and the more the Ni was incorporated, the larger the Ni nanoparticles were observed. One of the applications of Ni-OMCs was demonstrated as magnetically separable adsorbents.

Dai, Sheng [ORNL; Wang, Xiqing [ORNL

2009-01-01

129

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

130

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

131

ZSM-5 monolith of uniform mesoporous channels.  

Science.gov (United States)

A ZSM-5 monolith of uniform mesopores(meso-ZSM-5) was synthesized with the template method using carbon aerogel of uniform mesopores of great pore volume. The pore size distribution determined by N2 adsorption showed the presence of mesopores with an average pore width of 11 nm and micropores with an average pore width of 0.51 nm. Field emission scanning electron micrograph observation revealed the presence of uniform mesopores. X-ray diffraction and FT-IR provided evidence that the synthesized meso-ZSM-5 monolith has a highly crystalline ZSM-5 structure. PMID:12785820

Tao, Yousheng; Kanoh, Hirofumi; Kaneko, Katsumi

2003-05-21

132

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-01-01

133

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

134

Mesoporous Silicate Materials in Sensing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 e...

Melde, Brian J.; Johnson, Brandy J.; Charles, Paul T.

2008-01-01

135

Activation of polymer blend carbon nanofibres by alkaline hydroxides and their hydrogen storage performances  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present work we study the hydroxide activation (NaOH and KOH) of phenol-formaldehyde resin derived CNFs prepared by a polymer blend technique to prepare highly porous activated carbon nanofibres (ACNFs). Morphology and textural characteristics of these ACNFs were studied and their hydrogen storage capacities at 77 K (at 0.1 MPa and at high pressures up to 4 MPa) were assessed, and compared, with reported capacities of other porous carbon materials. Phenol-formaldehyde resin derived car...

2009-01-01

136

Hydrophilic and mesoporous SiO{sub 2}-TiO{sub 2}-SO{sub 3}H system for fuel cell membrane applications  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: The composite films containing SiO{sub 2}-TiO{sub 2}-SO{sub 3}H resin additives, with strong water retention capabilities, showed superior proton conductivity, even at 120 {sup o}C and 25% RH, as well as a slightly improved current density at 30% RH and 70 {sup o}C, when compared to costly Nafion film. Display Omitted Research highlights: The hydrophilic and mesoporous SiO{sub 2}-TiO{sub 2}-SO{sub 3}H resins have a potential to be used as alternative membrane source materials in PEFCs. The sulfonation for hydrophilicity is conducted via simple chelating chemistry between catecholic groups and surface Ti ions. The proton conductivity of SiO{sub 2}-TiO{sub 2}-SO{sub 3}H composite films is superior to the commercial Nafion film. - Abstract: Hydrophilic and mesoporous sulfonated SiO{sub 2}-TiO{sub 2}-SO{sub 3}H systems as new additives for fuel cell electrolyte membranes are directly synthesized by the binary sol-gel reaction of TEOS-TiCl{sub 4} and consecutive sulfonation with a hydrophilic generator, dihydroxy-m-benzenedisulfonic acid disodium salt. The sulfonation approach makes use of the simple chelating chemistry between the catecholic groups (dihydroxy benzene) and surface Ti ions of the inorganic ordered mesoporous SBA-15 structure. The system is successfully employed in fuel cell membrane applications with a composite Nafion membrane mixed with a mesoporous hydrophilic resin additive, and reveals an obvious enhancement of the proton conductivity at low humidity and elevated temperatures. This improvement was attributed to the excellent water retention capability of the hydrophilic mesoporous resin.

Hong, Lan-Young [Department of Fine Chemical Engineering and Chemistry, Chungnam National University, 220 Kung-dong, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Oh, Song-Yul [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@ee.tut.ac.j [Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Lee, Chang-Soo [Department of Chemical Engineering, Chungnam National University, 220 Kung-dong, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Kim, Dong-Pyo, E-mail: dpkim@cnu.ac.k [Department of Fine Chemical Engineering and Chemistry, Chungnam National University, 220 Kung-dong, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Graduate School of Analytical Science and Technology, Chungnam National University, 220 Kung-dong, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

2011-03-30

137

Mesoporous mordenite, preparation and use thereof:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The invention is directed to a process for the preparation of a mesoporous mordenite, which process comprises subjecting a non-dealuminated mordenite having an atomic ratio of framework Si-to-Al of least, to an alkaline treatment in order to create mesoporosity by removal of silicon, to various mesoporous mordenites and to their use.

Groen, J. C.; Moulijn, J. A.; Perez-ramirez, J.

2008-01-01

138

Non-destructively shattered mesoporous silica for protein drug delivery  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous silicas have been extensively used for entrapping small chemical molecules and biomacromolecules. We hypothesize that the loading density of biomacromlecules such as proteins in mesoporous silicas could be limited due to mesopore disorderness and depth because of some pore volume inaccessible. We innovatively shattered mesoporous silicas resulting in reduced particle sizes and improved intramesoporous structures in aqueous solution by a powerful sonication, where the mesoporous structures were still well maintained. The sonication-shattered mesoporous silicas can allow protein loading densities to be increased by more than 170%, demonstrating that significantly more mesoporous room of the silicas could become accessible for biomacromolecule loading after the sonication-shattering.

Lei, Chenghong; Chen, Baowei; Li, Xiaolin; Qi, Wen N.; Liu, Jun

2013-07-15

139

Synthesis and catalytic applications of mesoporous metal oxides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis, the synthesis of mesoporous titanium oxide and its derivatives, mesoporous aluminia, and porous zirconium oxide is described. Of these, mesoporous titania and alumina were examined as catalysts or catalyst supports in DeNOx and dehydrogenation of benzyl alcohol. The Mesoporous molecular sieves were synthesized by a ligand-assisted templating method. Surfactant was removed by a combination of acid/base washing and calcination. Mesoporous alumina and titania indeed show promisin...

Li, Quanchang

2007-01-01

140

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

 
 
 
 
141

Catalyst-free synthesis of transparent, mesoporous diamond monoliths from periodic mesoporous carbon CMK-8  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report on the synthesis of optically transparent, mesoporous, monolithic diamond from periodic mesoporous carbon CMK-8 at a pressure of 21 GPa. The phase transformation is already complete at a mild synthesis temperature of 1,300?°C without the need of a catalyst. Surprisingly, the diamond is obtained as a mesoporous material despite the extreme pressure. X-ray diffraction, SEM, transmission electron microscopy, selected area electron diffraction, high-resolution transmission electron ...

2010-01-01

142

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

143

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

144

Surfactant-Templated Mesoporous Metal Oxide Nanowires  

Directory of Open Access Journals (Sweden)

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

Stacy Baber

2010-01-01

145

Dilatometry on Thermoset Resins.  

Science.gov (United States)

A simple capillary and bulb mercury dilatometer designed for making specific volume measurements on thermoset resin systems during the curing reaction and as a function of temperature is described. The design, calibration, operation, data treatment and er...

A. W. Snow J. P. Armistead

1991-01-01

146

Preparation of irregular mesoporous hydroxyapatite  

International Nuclear Information System (INIS)

An irregular mesoporous hydroxyapatite (meso-HA), Ca10(PO4)6(OH)2, is successfully prepared from Ca(NO3)2.4H2O and NH4H2PO4 using surfactant cetyltrimethyl ammonium bromide (CTAB) as template. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) results reveal that the positive head of CTAB is assembled on the surface precipitated HA and much NH4+ is enclosed in precipitated HA before calcination. Field scanning electron microscope (FSEM) reveals that there exist many interconnected pores throughout the HA reticular skeleton. Nitrogen adsorption-desorption experiment exhibits a mesoporous material type IV curve, and pore size distribution calculated from the desorption branch of the isotherms based on Barrett-Joyner-Halenda (BJH) model shows that most pores throughout the HA reticular skeleton are sized at about 40 nm, but the pores are not uniform on the whole, owning to decomposition of the 'organic' CTAB templating structures and ammonium salt enclosed in the precipitated HA. The specific surface area of irregular meso-HA is calculated to be 37.6 m2/g according to the Brunauer-Emmett-Teller (BET) equation. Moreover, after polylactic acid/meso-HA (PLA/meso-HA) composites degraded 12 weeks in normal saline at 37 deg. C, the interconnected pores throughout the HA skeleton were enlarged and sized in micron degree, which resemble trabecular bone structure very much

2008-06-03

147

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

148

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

149

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.

2011-12-30

150

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...

K. Kandel

2013-01-01

151

Pluronic polymer capped biocompatible mesoporous silica nanocarriers.  

Science.gov (United States)

A facile self-assembly method is described to prepare PEGylated silica nanocarriers using hydrophobic mesoporous silica nanoparticles and a pluronic F127 polymer. Pluronic capped nanocarriers revealed excellent dispersibility in biological media with cyto- and blood compatibilities. PMID:24026175

Yildirim, Adem; Demirel, Gokcen Birlik; Erdem, Rengin; Senturk, Berna; Tekinay, Turgay; Bayindir, Mehmet

2013-10-28

152

Mesoporous Carbon Produced from Tri-constituent Mesoporous Carbon-silica Composite for Water Purification  

Highly ordered mesoporous carbon-silica nanocomposites with interpenetrating carbon and silica networks were synthesized by the evaporation-induced tri-constituent co- assembly approach. The removal of silica by concentrated NaOH solution produced mesoporous carbons, which contained not only the primary large pores, but also the secondary mesopores in the carbon walls. The thus synthesized mesoporous carbon was further activated by using ZnCl2. The activated mesoporous carbon showed an improved surface area and pore volume. The synthesized mesoporous carbon was tested for diuron removal from water and the results showed that the carbon gave a fast diuron adsorption kinetics and a high diuron removal capacity, which was attributable to the primary mesopore channels being the highway for mass transfer, which led to short diffusion path length and easy accessibility of the interpenetrated secondary mesopores. The optimal adsorption capacity of the porous carbon was determined to be 390 mg/g, the highest values ever reported for diuron adsorption on carbon-based materials.

Yu, Yanjie

2012-05-01

153

Graphite fiber reinforced thermoplastic resins  

Science.gov (United States)

Mechanical properties of neat resin samples and graphite fiber reinforced samples of thermoplastic resins were characterized with particular emphasis directed to the effects of environmental exposure (humidity, temperature and ultraviolet radiation). Tensile, flexural, interlaminar shear, creep and impact strengths were measured for polysulfone, polyarylsulfone and a state-of-the-art epoxy resin samples. In general, the thermoplastic resins exhibited environmental degradation resistance equal to or superior to the reference epoxy resin. Demonstration of the utility and quality of a graphite/thermoplastic resin system was accomplished by successfully thermoforming a simulated compressor blade and a fan exit guide vane.

Novak, R. C.

1975-01-01

154

Thermally conductive polymers  

Science.gov (United States)

A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (inventors)

1971-01-01

155

Spent ion exchange resins  

International Nuclear Information System (INIS)

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

1991-01-01

156

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

157

Carbon Nanotube Synthesis Using Mesoporous Silica Templates  

Energy Technology Data Exchange (ETDEWEB)

Well-aligned carbon nanotubes (CNTs) were grown on mesoporous silica films by chemical vapor deposition (CVD). Ethylene was used as the carbon source and CVD was performed at 1023 K and atmospheric pressure. The films were doped with Fe during gelation, and three different structure directing agents were used for mesoporous silica synthesis: polyoxyethylene (10) cetyl ether (C16EO10), Pluronic tri-block copolymer (P123), and cetyltriethylammonium chloride (CTAC). A high degree of CNT alignment on C16EO10-mesoporous silica films was produced at Fe:Si molar ratio of 1.80. Similar alignment of CNTs was achieved on the other two types of films but on CTAC-mesoporous silica films, CNTs only grew parallel to the substrate surface from the cracks in the films because of the in-plane arrangement of the mesopores in such films. Considerable progress has been made in producing multi-walled carbon nanotubes (CNTs) by catalytic CVD techniques. If CNTs are to be integrated into certain useful devices, it is critical to be able to grow highly aligned arrays of CNTs with narrow size distribution and at specific locations on a substrate. Long-range alignment normal to the substrate results from steric crowding if the initial catalyst sites are sufficiently dense. Alignment may be improved with better control of the density of catalytic sites by means of a template of appropriate pore structure. The confinement of CNTs by the pores during the initial growth may also help align CNTs.

Zheng, Feng; Liang, Liang; Gao, Yufei; Sukamto, Johanes H.; Aardahl, Chris L.

2002-07-01

158

Mesoporous Carbon for Capacitive Deionization of Saline Water  

Energy Technology Data Exchange (ETDEWEB)

Self-assembled mesoporous carbon (MC) materials have been synthesized and tested for application in capacitive deionization (CDI) of saline water. MC was prepared by self-assembly of a triblock copolymer with hydrogen-bonded chains via a phenolic resin, such as resorcinol or phloroglucinol in acidic conditions, followed by carbonization and, in some cases, activation by KOH. Carbon synthesized in this way was ground into powder, from which activated MC sheets were produced. In a variation of this process, after the reaction of triblock copolymer with resorcinol or phloroglucinol, the gel that was formed was used to coat a graphite plate and then carbonized. The coated graphite plate in this case was not activated and was tested to serve as current collector during the CDI process. The performance of these MC materials was compared to that of carbon aerogel for salt concentrations ranging between 1000 ppm and 35,000 ppm. Resorcinol-based MC removed up to 15.2 mg salt per gram of carbon, while carbon aerogel removed 5.8 mg salt per gram of carbon. Phloroglucinol-based MC-coated graphite exhibited the highest ion removal capacity at 21 mg of salt per gram of carbon for 35,000 ppm salt concentration.

Tsouris, Costas [ORNL; Mayes, Richard T [ORNL; Kiggans, Jim [ORNL; Sharma, Ms. Ketki [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; DePaoli, David W [ORNL; Dai, Sheng [ORNL

2011-01-01

159

Thermosetting resin compositions  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a curable thermosetting resin composition. It comprises: an epoxyalkyl ether of a 1,6-diaza(4.4)spirodilactam having a hydroxyaryl-containing substituents on each spiro ring nitrogen atom and a diamine compound having at least two amino hydrogen substituents.

Wang, P.C.

1990-06-12

160

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

 
 
 
 
161

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

162

Synthesis and Characterization of Mesoporous Semiconductors  

Science.gov (United States)

Widely studied mesoporous oxide materials have a range of potential applications, such as catalysis, absorption and separation. However, they are not generally considered for their optical and electronic properties. Elemental semiconductors with nano-sized pores running through them represent a different form of framework material with physical characteristics contrasting with those of the more conventional bulk, thin film and nanocrystalline forms. This thesis describes two different routes to synthesize thin film mesoporous silicon and powder mesoporous germanium. Thin film of mesoporous silicon was produced from thin film of mesoporous silica at low temperature (silica. Top-view SEM and low angle X-ray diffraction also proves retain in order and cross-section SEM shows retention of the surface features and pores in the bulk of the film. Nanoscale ordered germanium composite materials were produced from solution phase using surfactant as structural directing agents. Non-classic anionic germanium Zintl clusters, discrete Ge94- or polymeric (Ge92-)n, co-assemble with cationic surfactant molecules via electrostatic interactions. Depending upon size and overall charge of polymerized Zintl clusters, shape of the inorganic/organic hybrid micelle can be varied, and the periodical nano-structures of composites can be hexagonal, lamellar, or worm-like, as determined by low angle X-ray diffraction (XRD). The anionic germanium framework of the 2-D hexagonally ordered germanium cluster/surfactant composite is condensed via oxidative coupling between the germanium Zintl clusters. EXAFS (Extended X-ray Absorption Fine Structure) study indicates that the germanium clusters were destroyed upon oxidation and tetrahedrally coordinated germanium was produced afterwards. IR absorption shows that the surface of this material is mostly hydrogen terminated. Majority of the cationic surfactant molecules inside the pores can be removed. The resulting dark brown mesoporous germanium exhibits surface area up to 500 m2/g.

Kang, Chris Byung-hwa

163

Ion exchange resin and desalter device filled with the resin  

International Nuclear Information System (INIS)

A crud capturing performance of an ion exchange resin is dominated by the size of a crud adsorption region on the surface of the ion exchange resin and a diffusion rate thereof from the surface of the ion exchange resin to the inside of grains. The ion exchange resin of the present invention is synthesized using a cross-linking agent having a longer chain than that of divinylbenzene, for example, diallyl benzene without changing the degree of cross-linking of a cation exchange resin and an anion exchange resin. Further, a resin floor is formed by using a cross-linking agent having at least one methyl group between a benzene ring and a vinyl group of divinylbenzene and by filling an ion exchange resin having a content of a cross-linking agent of at least 8%. Since an ion exchange resin having longer molecular chains than those of an existent cross-linking agent is used, fine pores in the ion exchange resin layer is increased in size and thereby increased in strength, then capturing performance of the crud is enhanced, and loss of cross-linking due to oxidation is suppressed thereby capable of reducing leaching of impurities. (T.M.)

1994-05-31

164

Mesoporous Silica and Composite Nanostructures for Theranostics  

Directory of Open Access Journals (Sweden)

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

Khlebtsov B.N.

2013-09-01

165

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

166

Carbon and SiC macroscopic beads from ion-exchange resin templates.  

Science.gov (United States)

A method for preparing carbon and SiC macroscopic beads using ion-exchange resins as a macrotemplate that determines the macroshape and the pore structure of the product materials is reported. First, silicates are ion-exchanged into the resins to prevent the resin from collapsing during subsequent carbonization and allow them to be used as precursors for SiC formation. SiC is prepared via carbothermal reduction of carbon/silica composite beads obtained upon carbonization of the resin/silicate in an inert atmosphere. Finally, silica is removed by HF etching. Very high-surface area (1670-2026 m2 g-1) micro- or micro-/mesoporous carbon beads and relatively high-surface area (35-63 m2 g-1) macro- and meso-/macroporous SiC beads were prepared by the described method. The pore structure and the macroshape of the particles were controlled by the type of ion-exchange resins employed, gel or macroreticular. PMID:15493913

Tosheva, Lubomira; Parmentier, Julien; Saadallah, Seifedine; Vix-Guterl, Cathie; Valtchev, Valentin; Patarin, Joël

2004-10-27

167

High strength cementized dried resins  

International Nuclear Information System (INIS)

One common method for disposal of radioactive resins is to mix them with cement and cast them into monolithic blocks in rigid liners (containers). In some cases, cementized resin samples have reabsorbed water and swelled until the cement crumbled. Therefore, the NRC Branch Technical Position on waste forms requires cementized bead resin to undergo a 0.34 MPa (50 psi) compressive strength test after immersion in water for 90 days in order to qualify as an acceptable radioactive waste disposal form. Many cementized resin waste forms cannot achieve high radioactive waste loading and still qualify as a waste form after the 90-day immersion strength test. It was found that chemically spent resins pretreated in a high efficiency dryer are nearly impermeable to water and will not reabsorb and swell when immersed. The chemical form of the resins was found to be an important factor in water reabsorption. Fresh resins in the H/sup +/ or OH/sup -/ form were susceptible to water reabsorption after high-efficiency drying. However, depleted resins were found to be well-suited for cement solidification and high-strength waste forms were produced with loadings as high as nearly 28 wt.% dried resins (equivalent to 70 wt.% dewatered resins). These waste forms easily withstood the compressive strength test after initial curing and after 90 days of immersion in water

1986-01-01

169

Stepwise adsorption in a mesoporous metal-organic framework: experimental and computational analysis.  

Science.gov (United States)

Stepwise adsorption in a metal-organic framework with both micro- and meso-pores is caused by adsorbates first filling the micropores, then adsorbing along the mesopore walls, and finally filling the mesopores. PMID:22358259

Yuan, Daqiang; Getman, Rachel B; Wei, Zhangwen; Snurr, Randall Q; Zhou, Hong-Cai

2012-04-01

170

Stepwise adsorption in a mesoporous metal?organic framework: experimental and computational analysis  

Energy Technology Data Exchange (ETDEWEB)

Stepwise adsorption in a metal-organic framework with both micro- and meso-pores is caused by adsorbates first filling the micropores, then adsorbing along the mesopore walls, and finally filling the mesopores.

Yuan, Daqiang; Getman, Rachel B.; Wei, Zhangwen; Snurr, Randall Q.; Zhou, Hong-Cai (TAM)

2012-04-02

171

Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials  

International Nuclear Information System (INIS)

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

2013-10-01

172

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

173

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2012-01-01

174

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

175

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-15

176

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

177

Optimization of mesoporous carbons for efficient adsorption of berberine hydrochloride from aqueous solutions.  

Science.gov (United States)

Sixteen mesoporous carbon adsorbents were synthesized by varying the ratio of soft to hard templates in order to optimize the pore textural properties of these adsorbents. The mesoporous carbon adsorbents have a high BET specific surface area (1590.3-2193.5 m(2)/g), large pore volume (1.72-2.56 cm(3)/g), and uniform pore size distribution with a median pore diameter ranging from 3.51 nm to 4.52 nm. It was observed that pore textural properties of the carbon adsorbents critically depend on the molar ratio of carbon sources to templates, and the hard template plays a more important role than the soft template in manipulating the pore textures. Adsorption isotherms of berberine hydrochloride at 303 K were measured to evaluate the adsorption efficacy of these adsorbents. The adsorption of berberine hydrochloride from aqueous solutions on the sixteen mesoporous carbon adsorbents synthesized in this work is very efficient, and the adsorption equilibrium capacities on all samples are more than double the adsorption capacities of berberine hydrochloride of the benchmark adsorbents (polymer resins and spherical activated carbons) at similar conditions. It was observed from the adsorption experiments that the equilibrium adsorption amounts of berberine hydrochloride are strongly correlated with the BET specific surface area and pore volume of the adsorbents. The adsorbent with the highest BET of 2193.5 m(2)/g displayed the largest adsorption capacity of 574 mg/g at an equilibrium concentration of 0.10mg/mL of berberine hydrochloride in an aqueous solution. PMID:24767505

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

2014-06-15

178

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

179

Transition metal ion capture using functional mesoporous carbon made with 1,10-phenanthroline  

Energy Technology Data Exchange (ETDEWEB)

Functional mesoporous carbon has been built using 1,10-phenanthroline as the fundamental building block, resulting in a nanoporous, high surface area sorbent capable of selectively binding transition metal ions. This material had a specific surface area of 870 m2/g, an average pore size of about 30Å, and contained as much as 8.2 weight percent N. Under acidic conditions, where the 1,10-phenanthroline ligand is protonated, this material was found to be an effective anion exchange material for transition metal anions like PdCl4-2 and H2VO4-1. 1,10-phenanthroline functionalized mesoporous carbon (“Phen-FMC”) was found to have a high affinity for Cu(II), even down to a pH of 1. At pHs above 5, Phen-FMC was found to bind a variety of transition metal cations (e.g. Co(II), Ni(II), Zn(II), etc.) from filtered ground water, river water and seawater. Phen-FMC displayed rapid sorption kinetics with Co(II) in filtered river water, reaching equilibrium in less than an hour, and easily lowering the [Co(II)] to sub-ppb levels. Phen-FMC was found to be more effective for transition metal ion capture than ion exchange resin or activated carbon.

Chouyyok, Wilaiwan; Yantasee, Wassana; Shin, Yongsoon; Grudzien, Rafal M.; Fryxell, Glen E.

2009-11-01

180

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...hexamethylene-diamine and adipic acid. (2) Nylon 610 resins are manufactured...condensation of hexamethylene-diamine and sebacic acid. (3) Nylon 66/610 resins are...condensation of 11-aminoundecanoic acid. (6) Nylon 6 resins are...

2009-04-01

 
 
 
 
181

Synthesis and Catalytic Performance of Mesoporous Material by Twostep Crystallization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Liu Wei-qiao, Shang Tong-ming

2010-01-01

182

Preparation and Characterization of Mesoporous Iron-Oxide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transition metal oxides are easy to form insoluble oligomer in reaction because of complicated oxidation states, so it is difficult to obtain the desired mesoporous structure. To resolve the problem, mesoporous iron oxide was synthesized by reacting a micellar phase of sodium dodecyl sulfate (SDS) with iron polymer solution which was prepared by controlling the proportion of sodium hydroxide and ferric chloride. Crystal structure and surface structure of the mesoporous iron oxide was characte...

Xue Hong-tao, Shen Shui-fa

2009-01-01

183

Self-standing mesoporous membranes toward highly selective molecular transportation.  

Science.gov (United States)

Self-standing mesoporous membranes are prepared by full infiltration of ordered mesoporous silica precursors into textural macrospaces of frequently used cellulose membrane filters. We succeed in fabricating composite membranes that hardly contained large cracks/voids under the optimized conditions, realizing highly size-selective rapid transportation of biomolecules by their uniformity. Biomolecules with different sizes are precisely separated at the nanometer-level by using the mesoporous membranes. PMID:24171191

Yamauchi, Yusuke; Kimura, Tatsuo

2013-12-18

184

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

International Nuclear Information System (INIS)

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

2010-10-15

185

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

Energy Technology Data Exchange (ETDEWEB)

Mesoporous silicas carrying di-, tri-, or penta-amine functional groups were prepared by prior functionalization of a mesoporous silica with bromopropyl-functional groups followed by nucleophilic displacement of the bromine atoms by ethylenediamine, diethylenetriamine, or tetraethylenepentamine, respectively. A synthetic method was developed that gave a starting material with very high surface coverage by the 3-brompropyl groups. Batch tests were conducted to investigate the capabilities of the prepared adsorbents for the removal of copper, zinc, and cadmium from aqueous solutions. The metal adsorption capacities for these metals were determined as a function of the polyamine group used and the total nitrogen content. The tendency to chemisorb divalent metal ions was found to follow the order: Cu{sup 2+} > Zn{sup 2+} > Cd{sup 2+}. It was found that the ethylenediamine derivative unexpectedly exhibited the highest capacities. The metal sorption by the ethylenediamine functionalized silica was found to follow first order kinetics with rate constants for Cu{sup 2+}, Zn{sup 2+} and Cd{sup 2+} uptake of 0.028, 0.019, and 0.014 min{sup -1}, respectively. The substituted mesoporous silicas showed high resistance to leaching of the grafted polyamine groups. Copper ions that were adsorbed at the surface of the mesoporous silicas can be recovered by washing with an aqueous solution of 1.0 M HNO{sub 3}. The activities of the recovered mesoporous silicas were between 80 and 90% of the original materials.

Alothman, Zeid A., E-mail: zaothman@ksu.edu.sa [Department of Chemistry, College of Science Building 5, P.O. Box 2455, King Saud University, Riyadh 11451 (Saudi Arabia); Apblett, Allen W. [Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, OK (United States)

2010-10-15

186

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)

2002-01-01

187

Imide modified epoxy matrix resins  

Science.gov (United States)

High char yield epoxy using novel bisimide amines (BIA's) as curing agents with a state of the art epoxy resin was developed. Stoichiometric quantities of the epoxy resin and the BIA's were studied to determine the cure cycle required for preparation of resin specimens. The bisimide cured epoxies were designated IME's (imide modified epoxy). The physical, thermal and mechanical properties of these novel resins were determined. The levels of moisture absorption exhibited by the bisimide amine cured expoxies (IME's) were considerably lower than the state of the art epoxies. The strain-to-failure of the control resin system was improved 25% by replacement of DDS with 6F-DDS. Each BIA containing resin exhibited twice the char yield of the control resin MY 720/DDS. Graphite fiber reinforced control (C) and IME resins were fabricated and characterized. Two of the composite systems showed superior properties compared to the other Celion 6000/IME composite systems and state of the art graphite epoxy systems. The two systems exhibited excellent wet shear and flexural strengths and moduli at 300 and 350 F.

Scola, D. A.; Pater, R. H.

1981-01-01

188

Experience on resin pyrolysis  

International Nuclear Information System (INIS)

The Swedish State Power Board has together with Nukem, Hanau, West-Germany carried out pyrolysis o powder resins in a pilot plant with a capacity of about 30 kg/hr. The pyrolysis reactor with its afterburner and offgas scrubber system has been operated under steady state condition. About 2200 kg resins have been pyrolysed under November-December 1983 and the decontamination factor for Cs has been measured. Solidification of the residues from the pyrolysis reactor and scrubber water solutions has been carried out and various recipes with cement have been tested. The pyrolysis process has high decontamination factors and no offgas problems as the operating temperature of the reactor is Low. The residues from the reactor are chemically dead and can not cause swelling problems. Compared with a normal cementation process the final waste volume will be reduced with a factor of 4 if also the scrubber water after neutralization is solidified. The reduction factor will be 5 if the scrubber water after neutralization is evaporated to a dry salt

1984-01-01

189

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)

2009-07-20

190

Biocompatibility and biofunctionalization of mesoporous silicon particles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several of the newly developed drug molecules experience poor biopharmaceutical behavior, which hinders their effective delivery at the proper site of action. Among the several strategies employed in order to overcome this obstacle, mesoporous silicon-based materials have emerged as promising drug carriers due to their ability to improve the dissolution behavior of several poorly water-soluble drugs compounds confined within their pores. In addition to improve the dissolution behavior of the ...

Bimbo, Luis

2012-01-01

191

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.

2011-07-07

192

Mesoporous carbon nanomaterials as environmental adsorbents.  

Science.gov (United States)

The transportation and diffusion of the guest objects or molecules in the porous carbon nanomaterials can be facilitated by reducing the pathway and resistance. The reduced pathway depends on the porous nature of carbon nanomaterials. Classification of porous carbon materials by the International Union of Pure and Applied Chemistry (IUPAC) has given a new opportunity to design the pores as per their applicability and to understand the mobility of ions, atoms, and molecules in the porous network of carbon materials and also advanced their countless applicability. However, synthesis of carbon nanomaterials with a desired porous network is still a great challenge. Although, remarkable developments have taken place in the recent years, control over the pores size and/or hierarchical porous architectures, especially in the synthesis of carbon nanospheres (CNSs) and ordered mesoporous carbon (OMCs) is still intriguing. The micro and mesoporous CNSs and OMCs have been prepared by a variety of procedures and over a wide range of compositions using various different surfactant templates and carbon precursors etc. The mechanisms of formation of micromesopore in the CNSs and OMCs are still evolving. On the other hand, the urge for adsorbents with very high adsorption capacities for removing contaminants from water is growing steadily. In this review, we address the state-of-the-art synthesis of micro and mesoporous CNSs and OMCs, giving examples of their applications for adsorptive removals of contaminants including our own research studies. PMID:24749459

Tripathi, Pranav K; Gan, Lihua; Liu, Mingxian; Rao, Nageswara N

2014-02-01

193

Preparation of Mesoporous Ceramics from Polymer Nanotubes  

Science.gov (United States)

Poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) nanotubes were prepared by placing polymer solution into the cylindrical nanopores of an anodic aluminum oxide (AAO) membrane. The PS-b-P4VP nanotubes within the AAO membranes were exposed to tetrahydrofuran vapor to produce uniform spherical micelles along the tube. The tubes were removed from the membranes, then suspended in ethylene glycol, a preferential solvent for P4VP. At 95^ oC, near the glass transition temperature (Tg) of PS, nanotubes with uniform nanopores were obtained by a reconstruction of the nanotubes. As the temperature was increased, mesoporous polymer structures were obtained. Tetraethyl orthosilicate or titanium tetraethoxide, ceramic precursors, were introduced into the 4VP microdomains. After exposure to an oxygen plasma or high temperature, the copolymer was removed and the precursor converted to a mesoporous ceramic. This process offers a simple route for the fabrication of tunable mesoporous ceramic or metallic structures by changing molecular weight of copolymers.

Chen, Dian; Park, Soojin; Chen, Jiun-Tai; Redston, Emily; Russell, Thomas

2009-03-01

194

Functionalized ordered mesoporous materials for environmental remediation  

Energy Technology Data Exchange (ETDEWEB)

Mesostructures, or molecular sieves, are high surface area inorganic matrices which typically consist of metal oxides and silica. They contain nanometer-scale uniform-diameter pore channels arranged in a periodic manner. The inclusion of functional groups within the mesostructure pore channel is necessary to make the material useful for environmental remediation. For example, mesostructure-based heavy metal ion adsorbents can be designed by grafting ligand groups within the pore channels of mesostructured silica. In this study, mesoporous silicas functionalized with thiol and amino metal ion complex groups were prepared by stirring tetraethylorthosilicate and functionalized organosilane. The uptake of various metal ions including mercury, lead, cadmium, zinc, iron, cobalt, nickel, copper, silver and gold, by these thiol- and amino-functionalized mesoporous materials was examined by batch adsorption studies using nitrate solutions of the various metals. The mesoporous materials were found to be highly effective as remediation agents for the selective removal and trapping of targeted metal ions from aqueous systems. Future research will focus on the removal of anionic pollutants, toxic organic molecules and noxious gas-phase species. 9 refs., 3 figs.

Mercier, L.; Bell, V. [Laurentian Univ., Sudbury, ON (Canada). Dept. of Chemistry and Biochemistry

2000-07-01

195

Immobilization of Methyltrioxorhenium on Mesoporous Aluminosilicate Materials  

Directory of Open Access Journals (Sweden)

Full Text Available 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 narrow pore size distribution of mesopores, and therefore represent excellent supports for the active components. Some of the supports were modified by zinc chloride in order to obtain catalysts with higher activities for instance in metathesis reactions. The immobilization of MTO was optimized using these supports and it was successful using all supports. The success of the immobilization of MTO and the properties of the prepared heterogeneous catalysts were characterized using X-ray Fluorescence (XRF, atomic absorption spectroscopy (AAS, X-ray powder diffraction (XRD, scanning electron microscopy (SEM, physical adsorption of N2, ultraviolet-visible spectroscopy (UV-Vis, infrared spectroscopy (FTIR, Fourier Transform Infrared Spectroscopy (FTIR using pyridine as a probe molecule and X-ray photoelectron spectroscopy (XPS. Furthermore, the catalytic activity of the immobilized MTO on the tested supports was demonstrated on metathesis reactions of various substrates.

Martina Stekrova

2014-03-01

196

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

197

Chromatography resin support  

Energy Technology Data Exchange (ETDEWEB)

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

Dobos, James G. (North Augusta, SC)

2002-01-01

198

Paper strength resins; Shiryoku zokyozai  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the trend of polycrylamide (PAM) based dry paper strength resins, the property improvement of which is demanded strongly by papermaking industry, is investigated. Further, wet paper strength resin of polyamide epichlorohydrin having few absorbent organic halogens is also introduced. Firstly, the history of development of PAM based paper strength resins, the moving of the amount of uses corresponding to the classification of PAM based strength resins of today, and the properties of copolymerized PAM based strength resins developed recently are described. Next, after the description on technical trends of paper strength resins for plate paper, the effects of changes of sulfuric acid band amount and paper pH on paper strength are described. Further, the level of the bad influence of the mixing of calcium carbonate on paper strength resins is evaluated. As an example of the increase of paper pH in plate paper represented by core, improved copolymerized PAM developed by Nippon PMC Co., Ltd. is introduced. 16 refs., 6 figs., 10 tabs.

Hirasawa, T. [Japan PMC Co. Ltd., (Japan)

1997-09-01

199

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

200

Zeolite Nanoclusters Coated onto the Mesopore Walls of SBA-15  

Energy Technology Data Exchange (ETDEWEB)

Hydrothermal stability and acidity are both essential for the application of mesoporous materials in catalysis.1,2 Several approaches have been aimed at improving these properties;3-8 for example, hydrothermally stable and strongly acidic mesoporous aluminosilicates have been assembled using protozeolitic seeds.

Do, Trong-On; Nossov, Andrei; Springuel-Huet, Marie-Anne; Schneider, Celine M.; Bretherton, Jeremy L.; Fyfe, Colin A.; Kaliaguine, Serge

2004-11-10

 
 
 
 
201

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

202

Aluminum-rich mesoporous MFI - type zeolite single crystals  

DEFF Research Database (Denmark)

Zeolitcs are crystalline materials, which are widely used as solid acid catalysts and supports in many industrial processes. Recently, mesoporous MFI-type zeolite single crystals were synthesized by use of carbon particles as a mesopore template and sodium aluminate as the aluminum Source. With this technique, only zeolites with relatively low Al contents were reported (Si/Al ratio about 100). In this work, the preparation of aluminum-rich mesoporous MFI-type zeolite single crystals (Si/Al similar to 16-50) using aluminum isopropoxide as the aluminum Source is reported for the first time. All samples are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature programmed desorption (NH3-TPD), and N-2 adsorption measurements. The obtained zeolites combine the high crystallinity and the characteristic micropores of zeolites with an intracrystalline mesopore system having mesopore volumes varying between 0.37-0.40 cm(3)/g.

Kustova, Marina; Kustov, Arkadii

2005-01-01

203

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

204

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

205

Comparison of mesoporous silicon and non-ordered mesoporous silica materials as drug carriers for itraconazole.  

Science.gov (United States)

Mesoporous materials have an ability to enhance dissolution properties of poorly soluble drugs. In this study, different mesoporous silicon (thermally oxidized and thermally carbonized) and non-ordered mesoporous silica (Syloid AL-1 and 244) microparticles were compared as drug carriers for a hydrophobic drug, itraconazole (ITZ). Different surface chemistries pore volumes, surface areas, and particle sizes were selected to evaluate the structural effect of the particles on the drug loading degree and on the dissolution behavior of the drug at pH 1.2. The results showed that the loaded ITZ was apparently in amorphous form, and that the loading process did not change the chemical structure/morphology of the particles' surface. Incorporation of ITZ in both microparticles enhanced the solubility and dissolution rate of the drug, compared to the pure crystalline drug. Importantly, the physicochemical properties of the particles and the loading procedure were shown to have an effect on the drug loading efficiency and drug release kinetics. After storage under stressed conditions (3 months at 40 °C and 70% RH), the loaded silica gel particles showed practically similar dissolution profiles as before the storage. This was not the case with the loaded mesoporous silicon particles due to the almost complete chemical degradation of ITZ after storage. PMID:21601623

Kinnari, Päivi; Mäkilä, Ermei; Heikkilä, Teemu; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2011-07-29

206

Regenerating Water-Sterilizing Resins  

Science.gov (United States)

Iodine-dispensing resin can be regenerated after iodine content has been depleted, without being removed from water system. Resin is used to make water potable by killing bacteria, fungi, and viruses. Regeneration technique may be come basis of water purifier for very long space missions. Enough crystalline iodine for multiple regenerations during mission can be stored in one small cartridge. Cartridge could be inserted in waterline as necessary on signal from iodine monitor or timer.

Colombo, G. V.; Putnam, D. F.

1982-01-01

207

Concrete rehabilitation using epoxy resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of polymeric materials in civil construction makes possible original bonding processes because they have good adhesion. In this paper the bond between fresh/hardened concrete was made using epoxy resins in aqueous solution. Also the incorporation of one filler in the epoxy resins was analyzed. This study had two phases. n the first were conducted two shear tests - slant and direct. In the second phase were produced concrete with different strength classes by varying the ratio W/C - 0....

Silva, Lui?s; Aguiar, J. L. Barroso

2010-01-01

208

The development of chiral nematic mesoporous materials.  

Science.gov (United States)

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

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

2014-04-15

209

Maleimide Functionalized Siloxane Resins  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-04-01

210

Performance of templated mesoporous carbons in supercapacitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

211

Optical bistability in mesoporous silicon microcavity resonators  

Science.gov (United States)

We report on the observation of significant optical bistability in the transmission and reflection properties of mesoporous silicon microcavities when illuminated with a 150 ns pulsed laser at 532 nm. The observed optical hysteresis is shown to be transient in nature and the properties are strongly dependent on the porosity of the cavity layer. The onset and damage threshold intensity are also shown to be porosity dependent. Our modeling suggests that the observed effects are due to changes in the nonlinear refractive index where the transient lifetime increases with increasing porosity. We investigate the role of surface states on influencing the bistable process by passivating the internal porous surface with hydrosilylation chemistry.

Pham, Anh; Qiao, Hong; Guan, Bin; Gal, Michael; Gooding, J. Justin; Reece, Peter J.

2011-05-01

212

Nanomaterials | Special Issue : Ordered Mesoporous Nanomaterials  

... Type of Paper: ArticleTitle: Mesoporous Materials Enhance the Solubility of Anti-tuberculosis Pharmaceutical CompoundsAuthors: Xin Xia 1, 2, Lluis Ballell 3, Jonathan Cechetto 4, Kevin Pethe 4 and Alfonso Garcia-Bennett 2,* Affiliations: 1 Nanologica AB, Drottning Kristinas Väg 61, 11428 Stockholm, Sweden2 Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden3 Diseases of the Developing World, GlaxoSmithKline, Severo Ochoa 2, 28769 Tres Cantos, Madrid, Spain4 Antibacterial Drug Discovery, Institute Pasteur Korea, Gyeonggi-do, Republic of Korea KoreaAbstract: Over ...

213

Mesoporous gold sponge as a prototype 'metamaterial'  

International Nuclear Information System (INIS)

Mesoporous gold sponge has optical properties that can be intermediate between those of metals and insulators, with a flat spectral response that is unlike that of bulk gold. Films of different thicknesses were produced and an extension of the Lorentz-Drude (LD) model used to model their spectral behavior. We found that it was necessary to include an additional special oscillator centered at 1.4 eV in order to model the unusual spectral response. This is quite unlike bulk gold, which can be modeled using a standard two-oscillator LD model

2007-05-15

214

Synthesis and Functionalization of Periodic Mesoporous Silica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

215

Method of solidifying radioactive ion exchange resin  

International Nuclear Information System (INIS)

Spent anion exchange resin formed in nuclear power plants, etc. generally catch only a portion of anions in view of the ion exchange resins capacity and most of the anions are sent while possessing activities to radioactive waste processing systems. Then, the anion exchange resins increase the specific gravity by the capture of the anions. Accordingly, anions are caused to be captured on the anion exchange resin wastes such that the specific gravity of the anion exchange resin wastes is greater than that of the thermosetting resins to be mixed. This enables satisfactory mixing with the thermosetting resins and, in addition, enables to form integral solidification products in which anion exchange resins and cation exchange resins are not locallized separately and which are homogenous and free from cracks. (T.M.)

1988-02-16

216

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

217

Purification of rare alkaline element compounds using phenol ionites  

International Nuclear Information System (INIS)

The equilibrium properties of monofunctional macroporous ionite based on phenol-formaldehyde resins PFR have been studied during the exchange of the ions of alkaline metals. It is shown that the PFR-based ionites manifest the highest selectivity to the ions of cesium and rubidium compared with the other types of the ion-exchange resins. An efficient technique for the ion-exchange separation of rubidium and cesium from their binary mixtures or from the mixtures with other alkaline metals has been proposed using the columns with immovable layer and in counterflow columns using phenol-formaldehyde ionites. Refs. 16, figs. 11

1995-01-01

218

Curing of phenylethynl terminated resins  

Energy Technology Data Exchange (ETDEWEB)

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

Hill, D.J.T.; Pomery, P.J.; Preston, C.M.L.; Wittaker, A.K. [Queensland Univ., St. Lucia, QLD (Australia)

1996-12-31

219

The surface acidity of mesoporous silicoaluminophosphates: A FTIR study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermally stable mesoporous ALPO and SAPO (Si/Al = 0.6) were synthesised using aluminum sulphate as aluminum source and without the need of HF as mineralizing agent. The mesophases prepared by this procedure were stable to calcination at 773K and presented a structure of non-parallel mesopores in the calcined form. FT-IR spectroscopy supplemented by the use of CO and NH3 as probe molecules was used to monitor the surface acidity of these new mesoporous materials and indicated that Al-OH, P-OH...

Coluccia, Salvatore; Gianotti, Enrica

2004-01-01

220

BETA zeolite made from mesoporous material and its hydrocracking performance  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a kind of BETA zeolite that was made out of mesoporous material. With MCM-41 mesoporous material being used as silicon source, this BETA zeolite shows improved physical and chemical properties. It not only keeps acidity advantage of microporous zeolite but also inherits some pore structure quality of mesoporous zeolite. Moreover, it also displays very small crystal granule close to the range of nanometer. Owing to these new characteristics, such BETA zeolite provides hydrocracking catalyst with enhanced activity and improved middle distillate selectivity when it is applied in hydrocracking catalyst for treating large molecule heavy hydrocarbon feed oil to produce middle distillates (jet fuel+diesel oil). (author)

Chen, Song; Yang, Yongrun; Wang, Jindai [Institute of Material and Chemical Engineering, Zhejiang University, Hangzhou 310027 (China); Zhang, Kuixi [Fu Shun Research Institute of Petroleum and Petrochemical Engineering, Fushun 113001 (China)

2006-07-30

 
 
 
 
221

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

1985-01-01

222

New ion exchange resins for condensate polishing  

Energy Technology Data Exchange (ETDEWEB)

Resins used for condensate polishing, particularly those operating in mixed bed units at high pH values, must have a high cation exchange capacity and very good physical stability. This paper describes two new monodisperse resins, a highly cross-linked gel-type cation exchanger and a macroporous anion exchanger. The properties and performance of the resins are illustrated. Particular emphasis is put on the ability of the resins to withstand a moderate oxidative attack, which could result in sulfonated TOC leachables from the cation resin and kinetic impairment of the anion resin. (orig.)

Dardel, F. de; Hoffman, B.J. [Rohm and Haas France S.A.S., Paris (France)

2001-09-01

223

Low Melt Viscosity Resins for Resin Transfer Molding  

Science.gov (United States)

In recent years, resin transfer molding (RTM) has become one of the methods of choice for high performance composites. Its cost effectiveness and ease of fabrication are major advantages of RTM. RTM process usually requires resins with very low melt viscosity (less than 10 Poise). The optimum RTM resins also need to display high thennal-oxidative stability, high glass transition temperature (T(sub g)), and good toughness. The traditional PMR-type polyimides (e.g. PMR-15) do not fit this requirement, because the viscosities are too high and the nadic endcap cures too fast. High T(sub g), low-melt viscosity resins are highly desirable for aerospace applications and NASA s Reusable Launch Vehicle (RLV) program. The objective of this work is to prepare low-melt viscosity polyimide resins for RTM or resin film infusion (RFI) processes. The approach involves the synthesis of phenylethynyl-terminated imide oligomers. These materials have been designed to minimize their melt viscosity so that they can be readily processed. During the cure, the oligomers undergo both chain extension and crosslinking via the thermal polymerization of the phenylethynyl groups. The Phenylethynyl endcap is preferred over the nadic group due to its high curing temperature, which provides broader processing windows. This work involved the synthesis and polymerization of oligomers containing zig-zag backbones and twisted biphenyl structures. Some A-B type precursors which possessed both nitro and anhydride functionality, or both nitro and amine functionality, were also synthesized in order to obtain the well defined oligomers. The resulting zig-zag structured oligomers were then end-capped with 4-phenylethynylphthalic anhydride (PEPA) for further cure. The properties of these novel imide oligomers are evaluated.

Harris, Frank W.

2002-01-01

224

Colloidal suspensions of functionalized mesoporous silica nanoparticles.  

Science.gov (United States)

The synthesis and characterization of colloidal mesoporous silica (CMS) functionalized with vinyl-, benzyl-, phenyl-, cyano-, mercapto-, aminopropyl- or dihydroimidazole moieties is reported. Uniform mesoporous particles ranging in size from 40 to 150 nm are generated in a co-condensation process of tetraethylorthosilicate (TEOS) and organotriethoxysilanes (RTES) in alkaline aqueous media containing triethanolamine (TEA) in combination with cetyltrimethylammonium chloride (CTACl) serving as a structure-directing agent. The materials are obtained as colloidal suspensions featuring long-term stability after template removal by ion exchange with an ethanolic solution of ammonium nitrate or HCl. The spherical particles exhibit a wormlike pore system with defined pore sizes and high surface areas. Samples are analyzed by a number of techniques including TEM, SEM, DLS, TGA, Raman, and cross-polarized (29)Si-MAS NMR spectroscopy, as well as nitrogen sorption measurements. We demonstrate that co-condensation and grafting methods result in similar changes in the nitrogen adsorption behavior, indicating a successful internal lining of the pores with functional groups through both procedures. PMID:19206612

Kobler, Johannes; Möller, Karin; Bein, Thomas

2008-04-01

225

Corrosion behavior of mesoporous transition metal nitrides  

Science.gov (United States)

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.

Yang, Minghui; Allen, Amy J.; Nguyen, Minh T.; Ralston, Walter T.; MacLeod, Michelle J.; DiSalvo, Francis J.

2013-09-01

226

21 CFR 177.2490 - Polyphenylene sulfide resins.  

Science.gov (United States)

...resins (poly(1,4-phenylene sulfide) resins) may be safely used...conditions. (a) Polyphenylene sulfide resins consist of basic resins...parts of p- dichlorobenzene and sodium sulfide, such that the finished...

2010-01-01

227

76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

...polytetrafluoroethylene resin (``granular PTFE resin'') from Italy...the antidumping duty orders on granular PTFE resin from Italy and Japan (75 FR 67082-67083...the initiation of the review on granular PTFE resin from Italy was incorrectly...

2011-01-27

228

An alternative method to remove PEO-PPO-PEO template in organic-inorganic mesoporous nanocomposites by sulfuric acid extraction  

Science.gov (United States)

Sulfuric acid is used as an extraction agent to remove PEO-PPO-PEO templates in the organic-inorganic mesoporous nanocomposites from the triconstituent co-assembly which includes the low-polymerized phenolic resins, TEOS and triblock copolymer F127. The XRD and TEM results show well ordered mesostructure after extraction with sulfuric acid. As followed from the N 2 sorption isotherms the extracted composites possess high surface areas (332-367 m 2/g), large pore volumes (0.66-0.78 cm 3/g), and large pore sizes (about 10.7 nm). The FT-IR analysis reveals almost complete elimination of triblock copolymer F127, and the maintenance of organic groups. This method shows potentials in removing templates from nanocomposites containing functional moieties.

Zhuang, Xin; Qian, Xufang; Lv, Jiahui; Wan, Ying

2010-06-01

229

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

230

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

231

Synthesis of Mesoporous Material from Chrysotile-Derived Silica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mesoporous MCM-41-type molecular sieves were synthesized using calcined and leached chrysotile and cetyltrimethylammonium bromide as the silica source and structure directing agent, respectively. Powder X-ray diffraction (XRD), N2 isothermal adsorption...

Anderson Joel Schwanke; Christian Wittee Lopes; Sibele Berenice Castellã Pergher

2013-01-01

232

Mesoporous Silicas with Tunable Morphology for the Immobilization of Laccase  

Directory of Open Access Journals (Sweden)

Full Text Available Siliceous ordered mesoporous materials (OMM are gaining interest as supports for enzyme immobilization due to their uniform pore size, large surface area, tunable pore network and the introduction of organic components to mesoporous structure. We used SBA-15 type silica materials, which exhibit a regular 2D hexagonal packing of cylindrical mesopores of uniform size, for non-covalent immobilization of laccase. Synthesis conditions were adjusted in order to obtain supports with different particle shape, where those with shorter channels had higher loading capacity. Despite the similar isoelectric points of silica and laccase and the close match between the size of laccase and the pore dimensions of these SBA-15 materials, immobilization was achieved with very low leaching. Surface modification of macro-/mesoporous amorphous silica by grafting of amine moieties was proved to significantly increase the isoelectric point of this support and improve the immobilization yield.

Victoria Gascón

2014-05-01

233

Mesoporous silicas with tunable morphology for the immobilization of laccase.  

Science.gov (United States)

Siliceous ordered mesoporous materials (OMM) are gaining interest as supports for enzyme immobilization due to their uniform pore size, large surface area, tunable pore network and the introduction of organic components to mesoporous structure. We used SBA-15 type silica materials, which exhibit a regular 2D hexagonal packing of cylindrical mesopores of uniform size, for non-covalent immobilization of laccase. Synthesis conditions were adjusted in order to obtain supports with different particle shape, where those with shorter channels had higher loading capacity. Despite the similar isoelectric points of silica and laccase and the close match between the size of laccase and the pore dimensions of these SBA-15 materials, immobilization was achieved with very low leaching. Surface modification of macro-/mesoporous amorphous silica by grafting of amine moieties was proved to significantly increase the isoelectric point of this support and improve the immobilization yield. PMID:24886935

Gascón, Victoria; Díaz, Isabel; Márquez-Álvarez, Carlos; Blanco, Rosa M

2014-01-01

234

Resins immobilization of ion exchange in cement  

International Nuclear Information System (INIS)

Ion exchange resins which arise from decontamination practices of cooling water in water cooled reactors can be successfully immobilized in cement matrices. This work presents some characteristics of products made of resins-cement mixtures. (author). 3 refs., 2 tabs

1995-07-02

235

Ion exchange resins embedding in cement  

International Nuclear Information System (INIS)

A slag cement is used to avoid water-resin interaction problems and resins are pretreated to avoid ion exchange with cement (especially calcium and sulfate). No degradation is observed (cracking, swelling ...) on samples tested

1987-01-01

236

Hyperbranched Polymers for Resin Transfer Molding.  

Science.gov (United States)

The purpose of this proposal study new low viscosity thermoset additives - hyperbranched polymers (HBPs) - as processing aids and toughening additives for high performance resin transfer molding (RTM) resins. The proposed research project will culminate w...

P. T. Mather

2005-01-01

237

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....

2010-01-01

238

Rapid Curing Epoxy Resins Derived from Resorcinol.  

Science.gov (United States)

Epoxy resins that can be cured rapidly at room temperature are highly desirable from the production standpoint. A new epoxy resin, diglycidyl ether of 4-methylol resorcinol was synthesized. In the molecule, the hydroxyl from the methylol substituent is pr...

J. J. Schmid W. McCarvill

1974-01-01

239

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 200"0C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145"0C with a second aqueous component to provide a gaseous phase containing HNO_3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate

1978-01-01

240

Uranium sorption by tannin resins  

International Nuclear Information System (INIS)

The sorption of uranium by immobilised Eucalyptus Saligna Sm. and Lysiloma latisiliqua L tannins was investigated. Immobilization condition were analyzed. These resins resulted suitable adsorbent for the concentration of uranium from aqueous systems. The sorption of uranium is pH dependent. At pH 5.5 maximum in sorption capacity is registered. The presence of appreciable amount of sodium chloride do not have any effect on uranium removal. Carbonate and calcium ions in concentrations similar to these that could be found in sea water and other natural water do not decrease the uranium uptake. Tannin resins can be used several times without an appreciable decay of their sorption capacity

1998-01-01

 
 
 
 
241

Progress on the Multifunctional Mesoporous Silica-based Nanotheranostics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 c...

Shi Jian-lin, Chen Yu

2013-01-01

242

On the compatibility criteria for protein encapsulation inside mesoporous materials.  

Science.gov (United States)

The properties of the enzyme pepsin, relevant to its incorporation inside the channels of mesoporous silica materials in the preparation of bioinorganic hybrids, are highlighted by molecular dynamics simulations of aqueous solutions of the protein under conditions optimal for encapsulation in SBA-15. The protein size, shape, flexibility and surface properties are calculated with the aim of deriving general accessibility/compatibility criteria favouring encapsulation inside mesoporous systems. PMID:20349495

Giussani, Lara; Fois, Ettore; Gianotti, Enrica; Tabacchi, Gloria; Gamba, Aldo; Coluccia, Salvatore

2010-06-01

243

Benzylation of Toluene over Iron Modified Mesoporous Ceria  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Green chemistry has been looked upon as a sustainable science which accomplishes both economical and environmental goals, simultaneously.With this objective, we developed an alternative process to obtain the industrially important benzyl aromatics by benzylation of aromatics using benzyl chloride, catalysed by mesoporous solid acid catalysts. In this work mesoporous ceria is prepared using neutral surfactant which helped the calcination possible at a lower temperature enabling a higher sur...

Rose Philo, K. J.; Sugunan, S.

2012-01-01

244

Low temperature crystallisation of mesoporous TiO2  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Conducting mesoporous TiO2 is rapidly gaining importance for green energy applications. To optimise performance, its porosity and crystallinity must be carefully fine-tuned. To this end, we have performed a detailed study on the temperature dependence of TiO2 crystallisation in mesoporous films. Crystal nucleation and growth of initially amorphous TiO2 derived by hydrolytic sol-gel chemistry is compared to the evolution of crystallinity from nanocrystalline building blocks obtained from non-h...

2013-01-01

245

Hollow mesoporous silica nanoparticles for intracellular delivery of fluorescent dye  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

246

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 (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

247

Synthesis of Mesoporous Material from Chrysotile-Derived Silica  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous MCM-41-type molecular sieves were synthesized using calcined and leached chrysotile and cetyltrimethylammonium bromide as the silica source and structure directing agent, respectively. Powder X-ray diffraction (XRD, N2 isothermal adsorption-desorption, scanning electron microscopy (SEM and thermogravimetric analysis (TGA were used to characterize the samples. The calcined and leached chrysotile can be employed as an inexpensive silica source for the formation of low-order MCM-41 mesoporous materials.

Anderson Joel Schwanke

2013-08-01

248

Effects of Acid on Synthesis of Mesoporous Titania  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mesoporous titania was prepared via Sol-Gel process from Ti(n-C4H9O)4(TBOT) without surfactant templates. Using sulfuric acid or acetic acid as acidity regulator, the TBOT was hydrolyzed in an acidic system, and then its hydrolysate was treated by hydrothermal method. The products were characterized by XRD, N2 adsorption-desorption isotherm and TG-DSC. The results indicate that mesoporous TiO2 can be synthesized thro...

He Jing-ping, Zhang Zhao

2009-01-01

249

Adsorption of acetone on nonporous and mesoporous silica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

250

Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

251

Synthesis of mesoporous silica microsphere from dual surfactant  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new procedure is reported to synthesis mesoporous silica micro sphere for the first time. In these method two surfactants namely Span 80 and Tween 80 were used. Small angle X ray diffraction and N2 adsorption analysis shows the synthesized material has mesoporous property. The material has spherical morphology with 1-10 µm particle size. Beside the material found to have microcapsule property as observed from the Transmission electron microscopy. The Fourier transform Infrared spectroscopi...

2008-01-01

252

Biomolecules Loading and Mesoporous SBA-15 Pore Sizes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The encapsulation and immobilization of biomolecules on solid materials, mesoporous SBA-15, have been studied. Highly ordered hexagonal mesoporous silicates (MPS) with different mean pore sizes have been synthesized using two kinds of triblock copolymers (P123 or L123) as a template. The mixture of tetraethyl orthosilicate (TEOS) and the triblock copolymer (poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol)) was stirred and hydrothermally treated at various temperatures to for...

Yokogawa, Y.; Toma, T.; Saito, A.; Nakamura, A.; Kishida, I.

2011-01-01

253

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.

2012-10-01

254

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...5 0.5 5.1 Nylon 11 resins for use in articles intended...25 .3 5.2 Nylon 11 resins for use only: 1.04...with food b. In side-seam cements for articles intended for...this chapter 6.1 Nylon 6 resins 1.15±.015...

2010-01-01

255

Method of removing contaminants from plastic resins  

Science.gov (United States)

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

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

2008-11-18

256

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

257

SRM filament wound case resin characterization studies  

Science.gov (United States)

The amine cured epoxy wet winding resin used in fabrication of the SRM filament wound case is analyzed. High pressure liquid chromatography (HPSC) is utilized extensively to study lot-to-lot variation in both resin and curing agent. The validity of quantitative hplc methodology currently under development in-process resin/catalyst assay is assessed.

Chou, L. W.

1985-01-01

258

Fluid Resin Technic of Processing Denture Bases.  

Science.gov (United States)

The fluid resin technic of processing acrylic resin denture bases was recently adopted for use in the dental module of the Air Transportable Hospital. The new technic, described in detail in this review, utilizes a pourable auto-curing acrylic resin for t...

C. D. Miller G. L. Hall

1968-01-01

259

Dielectric properties of dianic resin after ?-irradiation  

International Nuclear Information System (INIS)

Dielectric characteristics of resin after ?-irradiation of Eh-41 epoxide hardened with various qualities of hardener (methaphenylendiamine) are described. Films of resin with hardener content of 7, 8 and 9% from the resin mass have been stui brcause linking density depends on hardener quantity. Dependences of dielectric loss angle tangent and of dielectric constant on temperature (-100-140 deg) are presented

1980-01-01

260

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

 
 
 
 
261

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

2006-04-15

262

Enantioselective recognition at mesoporous chiral metal surfaces  

Science.gov (United States)

Chirality is widespread in natural systems, and artificial reproduction of chiral recognition is a major scientific challenge, especially owing to various potential applications ranging from catalysis to sensing and separation science. In this context, molecular imprinting is a well-known approach for generating materials with enantioselective properties, and it has been successfully employed using polymers. However, it is particularly difficult to synthesize chiral metal matrices by this method. Here we report the fabrication of a chirally imprinted mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and chiral template molecules. The porous platinum retains a chiral character after removal of the template molecules. A matrix obtained in this way exhibits a large active surface area due to its mesoporosity, and also shows a significant discrimination between two enantiomers, when they are probed using such materials as electrodes.

Wattanakit, Chularat; Côme, Yémima Bon Saint; Lapeyre, Veronique; Bopp, Philippe A.; Heim, Matthias; Yadnum, Sudarat; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander

2014-02-01

263

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

264

Vinylstyrylpyridine-modified bismaleimide composite resins  

Science.gov (United States)

Vinylstilbazole (vinylstyrylpyridine) and vinylpolystyrylpyridine was prepared for the purpose of modifying bismaleimide composite resins. Cure studies of resin systems were investigated by differential scanning calorimetry. The vinylstyrylpyridine-modified bismaleimide composite resins were found to have lower cure and gel temperatures, and shorter cure times than the corresponding unmodified composite resins. The resin systems were reinforced with commercially available satin-weave carbon cloth fabricated by hot melt (or solvent) techniques. Thermal stability, flammability, moisture absorption, and mechanical properties of the composites (such as flexural strength, modulus, tensile and short beam shear strength) were determined. Composite laminates showed substantial improvements in both processability and mechanical properties compared to the bismaleimide control systems.

Hsu, M.-T. S.; Chen, T. S.; Parker, J. A.; Heimbuch, A. H.

1984-01-01

265

Template method synthesis of mesoporous carbon spheres and its applications as supercapacitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mesoporous carbon spheres (MCS) have been fabricated from structured mesoporous silica sphere using chemical vapor deposition (CVD) with ethylene as a carbon feedstock. The mesoporous carbon spheres have a high specific surface area of 666.8?m2/g and good electrochemical properties. The mechanism of formation mesoporous carbon spheres (carbon spheres) is investigated. The important thing is a surfactant hexadecyl trimethyl ammonium bromide (CTAB), which accelerates the process of carbon dep...

Wilgosz, Karolina; Chen, Xuecheng; Kierzek, Krzysztof; Machnikowski, Jacek; Kalenczuk, Ryszard J.; Mijowska, Ewa

2012-01-01

266

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

267

Solvent refining of coal resin concentrates  

Energy Technology Data Exchange (ETDEWEB)

Certain bituminous coals of the western United States are known to contain appreciable quantities of macroscopic resinite (fossil resin). Such resinous coals are found in the states of Arizona, Colorado, New Mexico, Utah, Washington, Wyoming, etc. Among these, the Wasatch Plateau coal field in central Utah has a particularly high content of fossil resin. It has been reported that some seams in this field average as much as 5% resin. Fossil resins have been recovered intermittently from the Utah coal field since 1929 by gravity and/or flotation processes. Recently selective flotation procedures have been developed to produce high-grade fossil resin concentrates, and the flotation concentrates thus produced can be refined by solvent extraction. Such solvent-refined resin, at the present time, has a market value of about 0.50% per lb as a chemical commodity and can be used in the ink, adhesive, rubber, varnish, paints, coatings, and thermoplastics industries. A detailed study of batch solvent refining of resin concentrates from the Wasatch Plateau coal is in progress at the University of Utah to evaluate the effect of refining conditions on the extraction yield and product quality during various solvent extraction processes. These solvent-refined products are being characterized with respect to their physical/chemical properties. Important extraction variables for differential refining of fossil resin concentrates are examined in order to maximize the commercial value of this unique fossil resin resource.

Miller, J.D.; Yu, Q.; Li, L.L. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Metallurgical Engineering

1994-12-31

268

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. PMID:24950610

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

2014-07-10

269

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

270

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

271

DEVELOPMENT OF MESOPOROUS MEMBRANE MATERIALS FOR CO2 SEPARATION  

Energy Technology Data Exchange (ETDEWEB)

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 {center_dot} 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}.

Wei-Heng Shih; Qiang Zhao; Nanlin Wang

2002-05-01

272

Design and Functionalization of Photocatalytic Systems within Mesoporous Silica.  

Science.gov (United States)

In the past decades, various photocatalysts such as TiO2 , transition-metal-oxide moieties within cavities and frameworks, or metal complexes have attracted considerable attention in light-excited catalytic processes. Owing to high surface areas, transparency to UV and visible light as well as easily modified surfaces, mesoporous silica-based materials have been widely used as excellent hosts for designing efficient photocatalytic systems under the background of environmental remediation and solar-energy utilization. This Minireview mainly focuses on the surface-chemistry engineering of TiO2 /mesoporous silica photocatalytic systems and fabrication of binary oxides and nanocatalysts in mesoporous single-site-photocatalyst frameworks. Recently, metallic nanostructures with localized surface plasmon resonance (LSPR) have been widely studied in catalytic applications harvesting light irradiation. Accordingly, silver and gold nanostructures confined in mesoporous silica and their corresponding catalytic activity enhanced by the LSPR effect will be introduced. In addition, the integration of metal complexes within mesoporous silica materials for the construction of functional inorganic-organic supramolecular photocatalysts will be briefly described. PMID:24828540

Qian, Xufang; Fuku, Kojirou; Kuwahara, Yasutaka; Kamegawa, Takashi; Mori, Kohsuke; Yamashita, Hiromi

2014-06-01

273

Stabilizing Surfactant Templated Cylindrical Mesopores in Polymer and Carbon Films through Composite Formation with Silica Reinforcement  

Energy Technology Data Exchange (ETDEWEB)

A facile approach to maintain the periodic mesostructure of cylindrical pores in polymer-resin and carbon films after thermal template removal is explored through the reactive coassembly of resol (carbon precursor) and tetraethylorthosilicate (silica precursor) with triblock copolymer Pluronic F127. Without silica, a low porosity, disordered film is formed after pyrolysis despite the presence of an ordered mesostructure prior to template removal. However for silica concentration greater than 25 wt %, pyrolysis at 350 C yields a mesoporous silica-polymer film with well-defined pore mesostructure. These films remain well ordered upon carbonization at 800 C. In addition to the mesostructural stability, the addition of silica to the matrix impacts other morphological characteristics. For example, the average pore size and porosity of the films increase from 3.2 to 7.5 nm and 12 to 45%, respectively, as the concentration of silica in the wall matrix increases from 0 to 32 wt %. The improved thermal stability of the ordered mesostructure with the addition of silica to the matrix is attributed to the reinforcement of the mechanical properties leading to resistance to stress induced collapse of the mesostructure during template removal.

Song, Lingyan; Feng, Dan; Lee, Hae-Jeong; Wang, Chengqing; Wu, Quanyan; Zhao, Dongyuan; Vogt, Bryan D. (On Semi); (NIST); (AZU); (Fudan)

2010-10-22

274

Resin Diterpenes from Austrocedrus chilensis  

Directory of Open Access Journals (Sweden)

Full Text Available Seventeen diterpenes belonging to the labdane, abietane and isopimarane skeleton classes were isolated from the resin of the Chilean gymnosperm Austrocedrus chilensis and identified by spectroscopic and spectrometric methods. The diterpene 12-oxo-labda-8(17,13E-dien-19 oic acid is reported for the first time as a natural product and 14 diterpenes are reported for the first time for the species.

Verónica Rachel Olate

2011-12-01

275

Boron sorption characteristics in resins  

International Nuclear Information System (INIS)

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

1988-01-01

276

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.

277

Study of Novel Oligomeric Azo Dyes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Diazotization of p-anisidine and coupling with 3-amino-phenol-Formaldehyde (APF) resin give oligomaric azo dye TAPF, based on 3-amino-phenol-Formaldehyde (APF) polymer. The TAPF was then treated with 5-chloro methyl-8-quinolinol hydrochloride in the presence of a THF in alkaline medium (pH 9-10) at room temperature for 7 hrs. The resultant oligomaric ligand designated as azo polyphenol-formaldehyde-5-chloromethyl-8-quinolinol (AAPFQ) was characterized by elemental analysis, IR spectral studie...

2012-01-01

278

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

279

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

280

Treatment of spent ion-exchange resins  

International Nuclear Information System (INIS)

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

1983-05-16

 
 
 
 
281

FB-Line resin testing final report  

Energy Technology Data Exchange (ETDEWEB)

The Dowex 50W-X8 and 50W-Xl2 resin samples are both strong acid cation materials in the hydrogen form. Each material has a water retention capacity characteristic of its respective marketed degree of cross-linking. Dowex 21K gives confirmatory responses to tests for a strong anion exchange resin in the nitrate form. All three resins have the manufacturer's specified ionic type and form, and the Dowex 50W resins have characteristic water retention capacities. These tests conclude that the ion exchange resins in use in FB-Line meet the approved safety document criteria for cross-linking, ionic form, and resin type.

Bannochie, C.J.

1992-01-23

282

Development of tough, moisture resistant laminating resins  

Science.gov (United States)

Tough, moisture resistant laminating resins for employment with graphite fibers were developed. The new laminating resins exhibited cost, handleability and processing characteristics equivalent to 394K (250 F) curing epoxies. The laminating resins were based on bisphenol A dicyanate and monofunctional cyanates with hydrophobic substituents. These resins sorb only small quantities of moisture at equilibrium (0.5% or less) with minimal glass transition temperature depression and represent an improvement over epoxies which sorb around 2% moisture at equilibrium. Toughening was accomplished by the precipitation of small diameter particles of butadiene nitrile rubber throughout the resin matrix. The rubber domains act as microcrack termini and energy dissipation sites, allowing increased stress accommodation prior to catastrophic failure. A unique blend of amine terminated butadiene nitrile elastomer (MW 2,000) and a high nitrile content butadiene nitrile rubber yielded the desired resin morphology.

Brand, R. A.; Harrison, E. S.

1982-01-01

283

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 600"0C, while that of anion resins was 90 wt% at 400"0C. 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 500"0C

1986-01-01

284

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)

1979-01-01

285

Plutonium complexation by phosphonate-functionalized mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

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.

Parsons-Moss, T; Schwaiger, L K; Hubaud, A; Hu, Y J; Tuysuz, H; Yang, P; Balasubramanian, K; Nitsche, H

2010-10-27

286

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.

2010-07-01

287

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

288

Ultrahigh porosity in mesoporous MOFs: promises and limitations.  

Science.gov (United States)

Mesoporous MOFs are currently record holders in terms of the specific surface area with values exceeding 7000 m(2) g(-1), a textural feature unattained by traditional porous solids such as zeolites, carbons and even by graphene. They are promising candidates for high pressure gas storage and also for conversion or separation of larger molecules, whose size exceeds the pore size of zeolites. The rational strategies for synthesis of mesoporous MOF are outlined and the unambiguous consistent assessment of the surface area of such ultrahighly porous materials, as well as present challenges in the exciting research field, of mesoporous MOFs are discussed. The crystallinity, dynamic properties, functional groups, and wide range tunability render these materials as exceptional solids, but for the implementation in functional devices and even in industrial processes several aspects and effective characteristics (such as volumetric storage capacities, recyclability, mechanical and chemical stability, activation) should be addressed. PMID:24722662

Senkovska, Irena; Kaskel, Stefan

2014-06-10

289

Electrochromic and optical properties of mesoporous tungsten oxide films  

Energy Technology Data Exchange (ETDEWEB)

Standard and mesoporous sol-gel tungsten oxide thin films were prepared by a spin-coating technique from an ethanolic solution of tungsten hexachloride. A block copolymer (BASF Pluronic p{sub 123}) was employed as a template to generate the mesoporous structure. An ultraviolet (UV) illumination method was employed to remove the polymer templates at room temperature. The electrochromic and optical properties of the mesoporous films are described and compared to standard sol-gel tungsten oxide films. Results are also presented on the samples prepared by thermal treatment. We demonstrate that the UV illumination/ozone treatment is a superior method to remove templates which enables us to more effectively investigate the effect of mesoporosity on the electrokinetics of ion insertion into tungsten oxide films.

Ozkan, Esra; Lee, Se-Hee; Liu, Ping; Tracy, C. Edwin; Pitts, J. Roland; Deb, Satyen K. [National Renewable Energy Laboratory, 1617 Cole Boulevard, 80401 Golden, CO (United States); Tepehan, Fatma Z. [Department of Physics, Faculty of Science and Letters, Istanbul Technical University, Maslak, 80626 Istanbul (Turkey)

2002-07-01

290

Actinide Sequestration Using Self-Assembled Monolayers on Mesoporous Supports  

International Nuclear Information System (INIS)

Surfactant templated synthesis of mesoporous ceramics provides a versatile foundation upon which to create high efficiency environmental sorbents. These nanoporous ceramic oxides condense a huge amount of surface area into a very small volume. The ceramic oxide interface is receptive to surface functionalization through molecular self-assembly. The marriage of mesoporous ceramics with self-assembled monolayer chemistry creates a powerful new class of environmental sorbent materials called self-assembled monolayers on mesoporous supports (SAMMS). These SAMMS materials are highly efficient sorbents, whose interfacial chemistry can be fine-tuned to selectively sequester a specific target species, such as heavy metals, tetrahedral oxometallate anions and radionuclides. Details addressing the design, synthesis and characterization of SAMMS materials specifically designed to sequester actinides, of central importance to the environmental clean-up necessary after 40 years of weapons grade plutonium production, as well as evaluation of their binding affinities and kinetics are presented

2005-03-01

291

Ordered mesoporous materials based on interfacial assembly and engineering.  

Science.gov (United States)

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

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

2013-10-01

292

Mesoporous NiO-Samaria doped ceria fuel cell materials.  

Science.gov (United States)

The mesoporous NiO-SDC was synthesized using a cationic surfactant (cetyl-trimethylammonium bromide; CTAB) for obtaining wide triple-phase boundary (TPB) in solid oxide fuel cells (SOFCs). The microstructure of mesoporous NiO-SDC was characterized by XRD, SEM, BET, and HRTEM and the results showed that the mesoporous NiO-SDC with 6.3 nm pores could be obtained. After calcined at 600 degrees C, the surface area of NiO-SDC was 206 m2/g, which was sufficiently high for providing large TPB in SOFC anode. In addition, FT-IR measurements revealed that Ni(OH)2 and SDC were incorporated with amine group of CTAB. PMID:19441460

Eom, Tae Wook; Kim, Kyung Hwan; Kim, Jong Sung; Jo, Myung-Chan; Yoon, Hyon Hee; Park, Sang Joon

2009-02-01

293

Synthesis of mesoporous silica microsphere from dual surfactant  

Directory of Open Access Journals (Sweden)

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

Venkatathri Narayanan

2008-12-01

294

Effects of Acid on Synthesis of Mesoporous Titania  

Directory of Open Access Journals (Sweden)

Full Text Available The mesoporous titania was prepared via Sol-Gel process from Ti(n-C4H9O4(TBOT without surfactant templates. Using sulfuric acid or acetic acid as acidity regulator, the TBOT was hydrolyzed in an acidic system, and then its hydrolysate was treated by hydrothermal method. The products were characterized by XRD, N2 adsorption-desorption isotherm and TG-DSC. The results indicate that mesoporous TiO2 can be synthesized through selecting acid, controlling acid concentration and supplementing TEA which can reduce the hydrolysis rate of TBOT. The mesoporous TiO2, prepared with the mole ratio of H2SO4/TBOT/TEA£½1/1/1, shows a surface area of 176m2/g, pore volume of 0.222cm3/g, mean pore size of 5nm, and narrow pore size distribution, and its thermal stability is excellent.ª¤

HE Jing-Ping,ZHANG Zhao,SHEN Jun,ZHANG Yu-Ting,CHEN Yao-Han

2009-01-01

295

Electrophoretic mobility of particles in concentrated solutions of electrolytes  

Energy Technology Data Exchange (ETDEWEB)

The electrophoretic mobility of particles of phenol-formaldehyde and aniline-formaldehyde resins in zinc sulfate solutions has been investigated. It is shown that as the electrolyte concentration rises, the electrophoretic mobility falls, reaches a minimum, and then increases. A possible mechanism for the formation of an electric double layer on the surface of particles in concentrated solutions of electrolytes is proposed.

Deinega, Yu.F.; Polyakova, V.M.; Aleksandrova, L.N.

1986-11-01

296

Method for making adhesive from biomass  

Energy Technology Data Exchange (ETDEWEB)

A method is described for making adhesive from biomass. A liquefaction oil is prepared from lignin-bearing plant material and a phenolic fraction is extracted therefrom. The phenolic fraction is reacted with formaldehyde to yield a phenol-formaldehyde resin.

Russell, Janet A. (Richland, WA); Riemath, William F. (Pasco, WA)

1985-01-01

297

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

298

Release and toxicity of dental resin composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

299

Solid phase synthesis of tertiary amines on amide REM resins: Grignard and metal hydride compatible resins.  

Science.gov (United States)

Four new amide REM resins (AM REM 2-5) are described, and their use is illustrated for the synthesis of tertiary amines 6-9 and 13-16. Amide REM resins 4 and 5, which have a phenyl ring attached to the amide nitrogen, are found to give superior product yields and purities, and the resins are stable to a wider range of reagents and conditions compared to REM resin 1. PMID:11029176

Plater, M J; Murdoch, A M; Morphy, J R; Rankovic, Z; Rees, D C

2000-01-01

300

Novolak resin analogs for resist applications  

Science.gov (United States)

Novolak resins, used to make typical g or i-line resists, are commonly made by condensing phenolic monomers with aldehydes. In the strictest definition of novolaks the aldehyde of choice is always formaldehyde. Under the acid catalyzed conditions generally used to make novolak the resins the carbocations formed by the protonation of the aldehydic carbonyl react with the phenolic reactant(s) to form the resins with elimination of water. Other aldehydes or low molecular weight ketones have been used on occasion to make useful analog for resist applications. Competing aldol condensations may interfere with isolation of pure polymeric resins especially in the case of ketones. Unique novolak resin analogs have been made by condensing `masked' bifunctional electrophiles with phenolic reactants under acidic conditions similar to standard novolak resin techniques. These resins were used as replacements for novolak resins and showed increased image contrast and thermal resistance. They were also used as photoactive compound backbones. Low molecular weight resins made with polyhydroxy aromatic phenolic monomers were especially useful as speed enhancing additives in thick film applications.

Wanat, Stan F.; Jensen, Kathryn H.; Lu, Ping-Hung; McKenzie, Douglas S.

1998-06-01

 
 
 
 
301

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

302

Combining nitrogen, argon, and water adsorption for advanced characterization of ordered mesoporous carbons (CMKs) and periodic mesoporous organosilicas (PMOs).  

Science.gov (United States)

Ordered mesoporous CMK carbons and periodic mesoporous organosilica (PMO) materials have been characterized by combining nitrogen (77.4 K) and argon (87.3 K) adsorption with recently developed quenched solid density functional theory (QSDFT). Systematic, high-resolution water adsorption experiments have been performed in the temperature range from 298 to 318 K in order to ascertain the effect of surface chemistry (using periodic mesoporous organosilicas (PMOs) of given pore size) and pore size/pore geometry (using CMK-3, CMK-8 carbons) on the adsorption, pore filling, condensation and hysteresis behavior. These data reveal how the interplay between confined geometry effects and the strength of the adsorption forces influence the adsorption, wetting, and phase behavior of pore fluids. Further, our results indicate that water adsorption is quite sensitive to both small changes in pore structure and surface chemistry, showing the potential of water adsorption as a powerful complementary tool for the characterization of nanoporous solids. PMID:24188008

Thommes, Matthias; Morell, Jürgen; Cychosz, Katie A; Fröba, Michael

2013-12-01

303

Preparation of mesoporous nanofibers by vapor phase synthesis: control of mesopore structures with the aid of co-surfactants  

International Nuclear Information System (INIS)

Mesoporous nanofibers (MSNFs) can be fabricated in the pores of anodic aluminum oxide (AAO) membrane using diverse methods. Among them vapor phase synthesis (VPS) provides several advantages over sol–gel or evaporation-induced self-assembly (EISA) based methods. One powerful advantage is that we can employ multiple surfactants as structural directing agents (SDAs) simultaneously. By adopting diverse pairs of SDAs, we can control the mesopore structures, i.e. pore size, surface area, and even the morphology of mesostructures. Here, we used F127 as a main SDA, which is relatively robust (thus, difficult to change the mesopore structures), and added a series of cationic co-surfactants to observe the systematical changes in their mesostructure with respect to the chain length of the co-surfactant. (paper)

2013-06-28

304

Preparation of mesoporous nanofibers by vapor phase synthesis: control of mesopore structures with the aid of co-surfactants  

Science.gov (United States)

Mesoporous nanofibers (MSNFs) can be fabricated in the pores of anodic aluminum oxide (AAO) membrane using diverse methods. Among them vapor phase synthesis (VPS) provides several advantages over sol-gel or evaporation-induced self-assembly (EISA) based methods. One powerful advantage is that we can employ multiple surfactants as structural directing agents (SDAs) simultaneously. By adopting diverse pairs of SDAs, we can control the mesopore structures, i.e. pore size, surface area, and even the morphology of mesostructures. Here, we used F127 as a main SDA, which is relatively robust (thus, difficult to change the mesopore structures), and added a series of cationic co-surfactants to observe the systematical changes in their mesostructure with respect to the chain length of the co-surfactant.

Min, Sa Hoon; Bae, Joonwon; Jang, Jyongsik; Lee, Kyung Jin

2013-06-01

305

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

306

21 CFR 520.1242d - Levamisole resinate.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Levamisole resinate. 520.1242d Section 520...FORM NEW ANIMAL DRUGS § 520.1242d Levamisole resinate. (a) Specifications. The drug is levamisole adsorbed on a resin, in a...

2010-04-01

307

Polyurethane resins in underground mining. Properties, rules of handling  

Energy Technology Data Exchange (ETDEWEB)

The nature of polyurethane resins is defined. The handling of polyurethane resin, hazards from the liquid resin and hazards from diphenyl methane-diisocyanate (MDI) are presented. Technical, organisational and personal safety measures are mentioned.

Korte, G.

1985-01-01

308

Synthesis and Characterizations of Melamine-Based Epoxy Resins  

Keywords: epoxy resin; melamine; glycidyl derivative; IR; DSC; DMA; glass transition; ...Title: Synthesis and Characterizations of Melamine-Based Epoxy Resins ...com/journal/ijms ArticleSynthesis and Characterizations of Melamine-Based Epoxy Resins

309

21 CFR 177.2510 - Polyvinylidene fluoride resins.  

Science.gov (United States)

...2009-04-01 2009-04-01 false Polyvinylidene fluoride resins. 177.2510 Section 177...Intended for Repeated Use § 177.2510 Polyvinylidene fluoride resins. Polyvinylidene fluoride resins may be safely used as...

2009-04-01

310

75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan  

Science.gov (United States)

...731-TA-385 and 386 (Third Review)] Granular Polytetrafluoroethylene Resin From Italy...concerning the antidumping duty orders on granular polytetrafluoroethylene resin from Italy...revocation of the antidumping duty orders on granular polytetrafluoroethylene resin from...

2010-11-01

311

76 FR 39896 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

...No. 731-TA-385 (Third Review)] Granular Polytetrafluoroethylene Resin From Italy...revocation of the antidumping duty order on granular polytetrafluoroethylene resin from Italy...Publication 4240 (June 2011), entitled Granular Polytetrafluoroethylene Resin from...

2011-07-07

312

Spectroscopic studies of petroleum resins  

International Nuclear Information System (INIS)

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

1988-01-01

313

Spectroscopic studies of petroleum resins  

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-01-01

314

Polyimide Resins Resist Extreme Temperatures  

Science.gov (United States)

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

2009-01-01

315

Thermoplastic resins for automotive applications  

Energy Technology Data Exchange (ETDEWEB)

Today`s high-performance thermoplastics could potentially shave up to 16 kg (35 lb) from the drivetrains, fuel systems, and chassis of future cars by replacing metal. In applications already commercial, weight savings average 20 to 25%, and it is not uncommon for installed cost of components to be 20 to 25% lower than machined castings, forgings, and stampings. Moreover, plastics have inherent processing and economic advantages in volume production, and will have for the foreseeable future. This article focuses on engineering resins that can satisfy challenging automotive design requirements, discusses selection criteria, and provides examples of metal-replacement applications.

Cronin, K. [Hoechst Technical Polymers, Summit, NJ (United States)

1997-05-01

316

Getting tough with epoxy resins  

Energy Technology Data Exchange (ETDEWEB)

A growth market for polymer-matrix composites (PMCs) is the replacement of metals in aerospace applications to reduced weight and consolidate parts. However, to substitute for metal primary structures, composites must combine improved strength and toughness with moisture resistance and the ability to withstand high temperatures. Even though higher performance composites are in demand, huge cuts in defense spending have caused a dramatic slowdown in R and D on new polymers. Instead, composites manufacturers are seeking ways to extend the limits of existing materials, such as epoxy, the workhorse'' PMC matrix resin. Suppliers have responded by expanding conventional epoxy technology.

Bertram, J.L.; Puckett, P.M. (Dow Chemical Co., Freeport, TX (United States))

1994-03-01

317

Curing kinetics of alkyd/melamine resin mixtures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

318

Synthesis and Characterizations of Melamine-Based Epoxy Resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

319

Template-free fabrication of mesoporous carbons from carbon quantum dots and their catalytic application to the selective oxidation of hydrocarbons.  

Science.gov (United States)

Mesoporous carbons (pore size 5 nm) were successfully synthesized without templates from carbon quantum dots. As catalysts, both mesoporous carbons and Cu nanoparticles on mesoporous carbons show superior catalytic activity and stability for the selective oxidation of cyclooctene. PMID:24752389

Zhou, Lei; Liu, Juan; Zhang, Xing; Liu, Ruihua; Huang, Hui; Liu, Yang; Kang, Zhenhui

2014-06-01

320

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

 
 
 
 
321

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%

1981-01-01

322

Novel silica-based ion exchange resin  

Energy Technology Data Exchange (ETDEWEB)

Shortcomings of chelating resins have been addressed by a new class of ion exchange resins called dual mechanism bifunctional polymers (DMBPs). DMBPs use hydrophilic cation exchange ligands with rapid uptake kinetics and use chelating ligands for selectivity for one or more metals; result is a resin that quickly recognizes and removes targeted metals from waste, remediation, and process streams. Eichrom`s Diphonix {reg_sign} resin is the first DMBP to be widely released as a commercial product; it is polystyrene based. Objective of this work is to synthesize commercial quantities of a silica-based ion exchange resin with the same or better metal ion selectivity, metal uptake kinetics, and acid stability as Diphonix. Feasibility was determined, however the process needs to be optimized. Studies at Eichrom and ANL of the performance of Diphonix resin over a broad range of HNO3 and HCl conditions and inorganic salt loadings are discussed together with the proposed method of incorporating similar characteristics into a silica-based resin. The new, silica-based resin functionalized with diphosphonic acid ligands can be used in environmental restoration and waste management situations involving processing of low-level, transuranic, and high-level radioactive wastes; it can also be used for processing liquid mixed waste including wastes contaminated with organic compounds.

Gula, M.; Harvey, J.

1996-12-31

323

Treatment of Spent Ion-Exchange Resins.  

Science.gov (United States)

PMMA was studied with the aim to evaluate its usefulness as an incorporation medium for the final containment of spent ion-exchange resins. The study of the effect of water content (ranging from 25 to 100%) of the incorporated resin into PMMA on the compr...

N. K. Ghattas N. E. Ikladious S. B. Eskander

1981-01-01

324

Ion exchange resins for uranium recovery  

International Nuclear Information System (INIS)

The density and capacity of macroporous ion exchange resins are increased by incorporating therein at least one of titania hydrate, zirconia hydrate, hydrated titanium phosphorous, and hydrated zirconium phosphate hydrates. Such resin composites are useful, e.g., in removing uranium values from aqueous solutions

1984-01-01

325

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

326

Experience with NuResin, a mobile ion exchange resin reprocessing system  

Energy Technology Data Exchange (ETDEWEB)

Ion exchange resin used in condensate polishing, steam generator blowdown, and radwaste systems is a major contributor to the volume of low-level waste (LLW) at operating nuclear plants. Plant regeneration systems for resins use large quantities of demineralized water for cleaning, separating, and regenerating resins. These systems generate a tremendous volume of LLW from boiling water reactors (BWRs) and those pressurized water reactors (PWRs) that have experienced steam generator tube leaks. At essentially all BWRs and those PWRs that replace rather than regenerate condensate polishing resin, the LLW volume contribution from the resin alone is significant. This report describes a process for the treatment of resins with the objective of returning the resin to service.

Palazzi, K.R.; Bell, M.J.; Concklin, J.R. [B& W Nuclear Technologies, Lynchburg, VA (United States)

1995-12-31

327

Synthesis and characterization of molybdenum incorporated mesoporous aluminophosphate  

Energy Technology Data Exchange (ETDEWEB)

A synthesis of molybdenum incorporated mesoporous aluminophosphate with long-chain n-alkylamine as template material had been prepared under non-aqueous condition. These materials were extensively characterized by using X-ray diffraction (XRD), nitrogen sorption isotherms, nuclear magnetic resonance of {sup 27}Al and {sup 31}P (NMR), inductive coupled plasma (ICP), electron spin resonance (ESR), Fourier transform infrared (FTIR) and thermogravimetric-differential thermal analysis (TG-DTA). Morphology of the materials had been observed by using transmission electron microscope (TEM) that revealed the mesoporous materials possessed wormhole-like structures. Alkaline solvent extraction using n-butylamine/ethanol had been efficiently removed the n-alkylamine from the mesoporous samples which yielded BET surface areas around 550-730m{sup 2}/g. BJH analysis showed a narrow pore size distribution which increased with increasing of the carbon chain length of alkylamine (template). Valence state and coordination of the molybdenum in the obtained samples were investigated by using ESR and FTIR where it was found that Mo{sup 4+} and Mo{sup 6+} molybdenum species existed in the molybdenum incorporated mesoporous aluminophosphate in tetrahedral coordination.

Ho, Li-Ngee [Department of Applied Chemistry, Oita University, Dannoharu 700, Oita (Japan)]. E-mail: holingee@yahoo.com; Ikegawa, Tasuku [Department of Applied Chemistry, Oita University, Dannoharu 700, Oita (Japan); Nishiguchi, Hiroyasu [Department of Applied Chemistry, Oita University, Dannoharu 700, Oita (Japan); Nagaoka, Katsutoshi [Department of Applied Chemistry, Oita University, Dannoharu 700, Oita (Japan); Takita, Yusaku [Department of Applied Chemistry, Oita University, Dannoharu 700, Oita (Japan)

2006-07-15

328

Mesoporous organosilica materials with amine functions : surface characteristics and chirality  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work mesoporous organisilica materials are synthesized through the silica sol-gel process. For this a new class of precursors which are also surfactant are synthesized and self-assembled. This leads to a high surface area functionality which is analysized with copper (II) and water adsorption.

Voß, Rebecca

2005-01-01

329

Self-assembly mechanism of folate-templated mesoporous silica.  

Science.gov (United States)

A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ small-angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy, and in situ conductivity measurements are used to investigate the organic-inorganic interactions and synthesis mechanism. The behavior of folate molecules in solution differs distinctively from that of surfactants commonly used for the preparation of ordered mesoporous silica phases, notably with the absence of a critical micellar concentration. In situ SAXS studies reveal fluctuations in X-ray scattering intensities consistent with the condensation of the silica precursor surrounding the folate template and the growth of the silica mesostructure in the initial stages. High-angle X-ray diffraction shows that the folate template is well-ordered within the pores even after a few minutes of synthesis. Direct structural data for the self-assembly of folates into chiral tetramers within the pores of mesoporous silica provide evidence for the in register stacking of folate tetramers, resulting in a chiral surface of rotated tetramers, with a rotation angle of 30°. Additionally, the self-assembled folates within pores were capable of adsorbing a considerable amount of CO2 gas through the cavity space of the tetramers. The study demonstrates the validity of using a naturally occurring template to produce relevant and functional mesoporous materials. PMID:23971901

Atluri, Rambabu; Iqbal, Muhammad Naeem; Bacsik, Zoltan; Hedin, Niklas; Villaescusa, Luis Angel; Garcia-Bennett, Alfonso E

2013-09-24

330

Chemical vapor deposition of mesoporous graphene nanoballs for supercapacitor.  

Science.gov (United States)

A mass-producible mesoporous graphene nanoball (MGB) was fabricated via a precursor-assisted chemical vapor deposition (CVD) technique for supercapacitor application. Polystyrene balls and reduced iron created under high temperature and a hydrogen gas environment provide a solid carbon source and a catalyst for graphene growth during the precursor-assisted CVD process, respectively. Carboxylic acid and sulfonic acid functionalization of the polystyrene ball facilitates homogeneous dispersion of the hydrophobic polymer template in the metal precursor solution, thus, resulting in a MGB with a uniform number of graphene layers. The MGB is shown to have a specific surface area of 508 m(2)/g and is mesoporous with a mean mesopore diameter of 4.27 nm. Mesopores are generated by the removal of agglomerated iron domains, permeating down through the soft polystyrene spheres and providing the surface for subsequent graphene growth during the heating process in a hydrogen environment. This technique requires only drop-casting of the precursor/polystyrene solution, allowing for mass-production of multilayer MGBs. The supercapacitor fabricated by the use of the MGB as an electrode demonstrates a specific capacitance of 206 F/g and more than 96% retention of capacitance after 10,000 cycles. The outstanding characteristics of the MGB as an electrode for supercapacitors verify the strong potential for use in energy-related areas. PMID:23782238

Lee, Jung-Soo; Kim, Sun-I; Yoon, Jong-Chul; Jang, Ji-Hyun

2013-07-23

331

Alternative chemical route to mesoporous titania from a titanatrane complex  

DEFF Research Database (Denmark)

High-purity, mesoporous titania was prepared by reaction of dimethylaminotitanatrane, [NMe2â??Ti(OCH2CH2)3N] in the presence of micellar aggregates as templating agents followed by thermal treatments in the temperature range 350â??450 °C. The powders were characterized by nitrogen adsorptionâ??desorption isotherms, thermogravimetryâ?? differential thermal analysis, Fourier transform infrared, field-emission scanning electron microscopy, and x-ray diffraction. Analysis of the morphological characteristics of titanium oxide powders calcined at 350 °C for 120 h and at 450 °C for 6 h showed the presence of a mesoporous structure, with an average pore size of about 3.5 nm. Firing temperatures above 450 °C caused the collapse of the mesoporous structure. Composite Nafion-based membranes, containing 5 wt% mesoporous titania fired at 450 °C as a filler were successfully prepared. Preliminary tests in a prototype direct methanol fuel cell demonstrated that the composite membrane allowed cell operation up to 145 °C, thus showing a significant performance improvement over pure Nafion.

Trakanprapai, Chavalit; Esposito, Vincenzo

2005-01-01

332

Design and Functionalization of Photocatalytic Systems within Mesoporous Silica.  

Science.gov (United States)

The Front Cover artwork is provided by the group of Prof. Hiromi Yamashita from Osaka University. The image shows four photocatalytic systems assembled on transparent mesoporous silica materials with the background of environmental remedy and solar energy utilization. The Minireview itself is available at 10.1002/cssc.201400111. PMID:24889157

Qian, Xufang; Fuku, Kojirou; Kuwahara, Yasutaka; Kamegawa, Takashi; Mori, Kohsuke; Yamashita, Hiromi

2014-06-01

333

Relaxivity modulation in Gd-functionalised mesoporous silicas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two hybrid materials based on mesoporous silicas SBA-15 and MCM-41 functionalized with stable and electrically neutral Gd(III) macrocyclic complexes were prepared, and their 1H NMR relaxometric properties investigated as a function of temperature and magnetic field strength.

Dastru, Walter; Botta, Mauro; Marchese, Leonardo

2009-01-01

334

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

335

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

2013-06-01

336

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

International Nuclear Information System (INIS)

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

2001-05-31

337

Continuous metal removal technique for resist resins  

Science.gov (United States)

Modern resists require very pure raw materials to insure highest quality images. Many methods have been developed to reduce metals in resins used to make photoresists. Extractive washing techniques and ion exchange methods have been the predominant methods used to reduce metal levels for these critical raw materials. This has been especially important for the novolak resins because of the generally poor quality of the starting materials used to make them and by the nature of the resin isolation steps traditionally used. Both of the commonly used cleaning methods are time consuming and are predominantly batch processes. Based upon techniques developed to efficiently fractionate resins, we have developed a technique for the rapid, continuous reduction of metal contaminants in film forming resin solutions by an extractive method using a double inlet liquid/liquid centrifuge.

Wanat, Stan F.; McKenzie, Douglas S.; Rahman, M. D.

2001-08-01

338

Release and toxicity of dental resin composite.  

Science.gov (United States)

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 have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined. PMID:23293458

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

2012-09-01

339

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

1982-01-01

340

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

 
 
 
 
341

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 _1_3_7Cs, _8_5Sr, and _6_0Co from resins modified in portland type III and high alumina cements. The cumulative _1_3_7Cs fraction release was at least an order of magnitude greater than that of either _8_5Sr or _6_0Co. Release rates of _1_3_7Cs 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. _1_3_7Cs, _8_5Sr, and _6_0Co fraction releases were about one, two and three orders of magnitude higher, respectively, than in equivalent portland type III cement formulations. As much as 28.6 wt % dry ion exchange resin was successfully solidified using vinyl ester-styrene compared with a maximum of 25 wt % in both portland and gypsum-based cement

1982-01-01

342

Magnetic mesoporous materials for removal of environmental wastes  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-09-15

343

Structurally stabilized organosilane-templated thermostable mesoporous titania.  

Science.gov (United States)

Structurally thermostable mesoporous anatase TiO2 (m-TiO2) nanoparticles, uniquely decorated with atomically dispersed SiO2, is reported for the first time. The inorganic Si portion of the novel organosilane template, used as a mesopores-directing agent, is found to be incorporated in the pore walls of the titania aggregates, mainly as isolated sites. This is evident by transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy, combined with electron dispersive X-ray spectroscopy. This type of unique structure provides exceptional stability to this new material against thermal collapse of the mesoporous structure, which is reflected in its high surface area (the highest known for anatase titania), even after high-temperature (550 °C) calcination. Control of crystallite size, pore diameter, and surface area is achieved by varying the molar ratios of the titanium precursor and the template during synthesis. These mesoporous materials retain their porosity and high surface area after template removal and further NaOH/HCl treatment to remove silica. We investigate their performance for dye-sensitized solar cells (DSSCs) with bilayer TiO2 electrodes, which are prepared by applying a coating of m-TiO2 onto a commercial titania (P25) film. The high surface area of the upper mesoporous layer in the P25-m-TiO2 DSSC significantly increases the dye loading ability of the photoanode. The photocurrent and fill factor for the DSSC with the bilayer TiO2 electrode are greatly improved. The large increase in photocurrent current (ca. 56%) in the P25-m-TiO2 DSSC is believed to play a significant role in achieving a remarkable increase in the photovoltaic efficiency (60%) of the device, compared to DSSCs with a monolayer of P25 as the electrode. PMID:24307405

Amoli, Vipin; Tiwari, Rashmi; Dutta, Arghya; Bhaumik, Asim; Sinha, Anil Kumar

2014-01-13

344

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

345

Proton conductivity of ordered mesoporous materials containing aluminium  

Energy Technology Data Exchange (ETDEWEB)

In order to check the influence of Broensted acidic Al sites in the walls of mesoporous materials on their proton conductivity, we introduced aluminium into the mesoporous SiO{sub 2} framework Si-MCM-41, which possesses hexagonally ordered channels, by using different Al sources, i.e. sodium aluminate, aluminium sulphate and aluminium isopropoxide. The successful synthesis of ordered mesoporous material with incorporated Al species was proven by X-ray diffraction, energy-dispersive X-ray spectroscopy, nitrogen adsorption, scanning electron microscopy and solid state {sup 27}Al MAS NMR. By realizing Si/Al ratios of 8-40 it was found that the proton conductivity of the mesoporous aluminium silicates measured by impedance spectroscopy significantly increases with the Al content, reaching a conductivity of 3 x 10{sup -3} S cm{sup -1} at 140 C. The increase of the proton conductivities compared to Al-free Si-MCM-41 results from (i) an improved hydrophilicity enhancing the water storage capability, (ii) a decreased particle size from the micrometer to the nanometer scale (50-100 nm) and (iii) the existing Broensted acidity in the mesoporous Al-MCM-41. The Al source NaAlO{sub 2} gives clearly the best results because the entire Al incorporated within the framework is tetragonally coordinated, while for samples prepared with Al{sub 2}(SO{sub 4}){sub 3} or AIP also octahedral coordination of oxygen around the Al centers is observed by {sup 27}Al MAS NMR. (author)

Sharifi, Monir; Marschall, Roland; Wilkening, Martin; Wark, Michael [Institute of Physical Chemistry and Electrochemistry, Leibniz Universitaet Hannover, Callinstr. 3A, 30167 Hannover (Germany)

2010-12-01

346

Interaction of the components of a pitch-polymer mixture on heating  

Energy Technology Data Exchange (ETDEWEB)

The behavior of a pitch mixed with a furan resin or with a phenol-formaldehyde resin on heating to 800/sup 0/C has been studied. A basic difference in the behaviors of the pitch-furan resin and pitch-phenol-formaldehyde resin mixtures has been shown by DTA and TG methods. Hypotheses have been put forward according to which the fact that the coke residues for the pitch-furan resin mixtures have the highest values is connected with the occurrence of a chemical interaction between the pitch and polymer components and the formation (in the low temperature region) of condensed structures distinguished by increased resistance to decomposition at temperatures above 500/sup 0/C.

Kulakov, V.V.; Lapina, N.A.; Lein, E.S.; Ostrovskii, V.S.; Tsiruleva, I.M.

1984-01-01

347

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

2010-02-01

348

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

Science.gov (United States)

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

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

2014-06-14

349

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

350

Multitasking mesoporous nanomaterials for biorefinery applications  

Energy Technology Data Exchange (ETDEWEB)

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 ?-tocopherol from microalgae oil. The functional group with electron deficient aromatic rings demonstrated high sequestration capacity and selectivity of {alpha}-tocopherol.

Kandel, Kapil [Ames Laboratory

2013-05-02

351

Template Synthesis of Three-Dimensional Cubic Ordered Mesoporous Carbon With Tunable Pore Sizes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Three-dimensional cubic ordered mesoporous carbons with tunable pore sizes have been synthesized by using cubic Ia3d mesoporous KIT-6 silica as the hard template and boric acid as the pore expanding agent. The prepared ordered mesoporous carbons were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption analysis. The results show that the pore sizes of the prepared ordered...

2009-01-01

352

Preparation of Mesoporous Silica Fibers in Porous Anodic Aluminum Oxide Template  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mesoporous silica fibers were prepared within porous anodic aluminum oxide membrane (AAO) using a simple Sol-Gel method. The sample was characterized by SEM, XRD, nitrogen adsorption-desorption and TEM. The diameter and the length of the mesoporous silica fibers are depend on the pore diameter and thickness of AAO membrane, respectively. The orientation of the nanochannels in mesoporous silica fibers can be readily controlled by changing the aging environment. For the samples aged with the pr...

Wang Wei, Li Xiao-tian

2010-01-01

353

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

354

Selective adsorption and release of cationic organic dye molecules on mesoporous borosilicates  

International Nuclear Information System (INIS)

Mesoporous materials can play a pivotal role as a host material for delivery application to a specific part of a system. In this work we explore the selective adsorption and release of cationic organic dye molecules such as safranine T (ST) and malachite green (MG) on mesoporous borosilicate materials. The mesoporous silica SBA-15 and borosilicate materials (MBS) were prepared using non-ionic surfactant Pluronic P123 as template via evaporation induced self-assembly (EISA) method. After template removal the materials show high surface areas and in some cases ordered mesopores of dimensions ca. 6–7 nm. High surface area, mesoporosity and the presence of heteroatom (boron) help this mesoporous borosilicate material to adsorb high amount of cationic dye molecules at its surface from the respective aqueous solutions. Furthermore, the mesoporous borosilicate samples containing higher percentage adsorbed dyes show excellent release of ST or MG dye in simulated body fluid (SBF) solution at physiological pH = 7.4 and temperature 310 K. The adsorption and release efficiency of mesoporous borosilicate samples are compared with reference boron-free mesoporous pure silica material to understand the nature of adsorbate–adsorbent interaction at the surfaces. - Graphical abstract: Highly ordered 2D-hexagonal mesoporous borosilicate materials have been synthesized by using Pluronic P123 as template. The materials show very good adsorption and release of organic cationic dye molecules under physiological conditions. Highlights: ? Highly ordered 2D-hexagonal mesoporous borosilicate. ? Nonionic Pluoronic P123 templated mesoporous material. ? Adsorption of organic dyes at the mesopore surface. ? Controlled release of dyes under physiological pH and temperature. ? Release of safranine T (ST) and malachite green (MG) dyes in simulated body fluids.

2012-08-01

355

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2011-01-01

356

Selective adsorption and release of cationic organic dye molecules on mesoporous borosilicates  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous materials can play a pivotal role as a host material for delivery application to a specific part of a system. In this work we explore the selective adsorption and release of cationic organic dye molecules such as safranine T (ST) and malachite green (MG) on mesoporous borosilicate materials. The mesoporous silica SBA-15 and borosilicate materials (MBS) were prepared using non-ionic surfactant Pluronic P123 as template via evaporation induced self-assembly (EISA) method. After template removal the materials show high surface areas and in some cases ordered mesopores of dimensions ca. 6-7 nm. High surface area, mesoporosity and the presence of heteroatom (boron) help this mesoporous borosilicate material to adsorb high amount of cationic dye molecules at its surface from the respective aqueous solutions. Furthermore, the mesoporous borosilicate samples containing higher percentage adsorbed dyes show excellent release of ST or MG dye in simulated body fluid (SBF) solution at physiological pH = 7.4 and temperature 310 K. The adsorption and release efficiency of mesoporous borosilicate samples are compared with reference boron-free mesoporous pure silica material to understand the nature of adsorbate-adsorbent interaction at the surfaces. - Graphical abstract: Highly ordered 2D-hexagonal mesoporous borosilicate materials have been synthesized by using Pluronic P123 as template. The materials show very good adsorption and release of organic cationic dye molecules under physiological conditions. Highlights: Black-Right-Pointing-Pointer Highly ordered 2D-hexagonal mesoporous borosilicate. Black-Right-Pointing-Pointer Nonionic Pluoronic P123 templated mesoporous material. Black-Right-Pointing-Pointer Adsorption of organic dyes at the mesopore surface. Black-Right-Pointing-Pointer Controlled release of dyes under physiological pH and temperature. Black-Right-Pointing-Pointer Release of safranine T (ST) and malachite green (MG) dyes in simulated body fluids.

Paul, Manidipa; Pal, Nabanita; Bhaumik, Asim, E-mail: msab@iacs.res.in

2012-08-01

357

Safety evaluation of cation-exchange resins  

International Nuclear Information System (INIS)

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

1977-01-01

358

Magnetic nanocomposite spinel and FeCo core-shell and mesoporous systems  

International Nuclear Information System (INIS)

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

2012-06-01

359

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

1982-01-01

360

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)

1990-01-01

 
 
 
 
361

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)

1990-01-01

362

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

363

Cobalt Ions Improve the Strength of Epoxy Resins  

Science.gov (United States)

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

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

1986-01-01

364

Method of decomposing radioactive spent ion exchange resins  

International Nuclear Information System (INIS)

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

1983-02-01

365

Hydraulic Permeability of Resorcinol-Formaldehyde Resin  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange process using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the Hanford Site, using large scale columns as part of the Waste Treatment Plant (WTP). The RF resin is also being evaluated for use in the proposed small column ion exchange (SCIX) system, which is an alternative treatment option at Hanford and at the Savannah River Site (SRS). A recirculating test loop with a small ion exchange column was used to measure the effect of oxygen uptake and radiation exposure on the permeability of a packed bed of the RF resin. The lab-scale column was designed to be prototypic of the proposed Hanford columns at the WTP. Although the test equipment was designed to model the Hanford ion exchange columns, the data on changes in the hydraulic permeability of the resin will also be valuable for determining potential pressure drops through the proposed SCIX system. The superficial fluid velocity in the lab-scale test (3.4-5.7 cm/s) was much higher than is planned for the full-scale Hanford columns to generate the maximum pressure drop expected in those columns (9.7 psig). The frictional drag from this high velocity produced forces on the resin in the lab-scale tests that matched the design basis of the full-scale Hanford column. Any changes in the resin caused by the radiation exposure and oxygen uptake were monitored by measuring the pressure drop through the lab-scale column and the physical properties of the resin. Three hydraulic test runs were completed, the first using fresh RF resin at 25 C, the second using irradiated resin at 25 C, and the third using irradiated resin at 45 C. A Hanford AP-101 simulant solution was recirculated through a test column containing 500 mL of Na-form RF resin. Known amounts of oxygen were introduced into the primary recirculation loop by saturating measured volumes of the simulant solution with oxygen and reintroducing the oxygenated simulant into the feed tank. The dissolved oxygen (DO) concentration of the recirculating simulant was monitored, and the amount of oxygen that reacted with the resin was determined from the change in the DO concentration of the recirculating simulant solution. Prior to hydraulic testing the resin for runs 2 and 3 was covered with the simulant solution and irradiated in a spent fuel element at the Oak Ridge National Laboratory High Flux Isotope Reactor (HFIR). Both batches of resin were irradiated to a total gamma dose of 177 Mrad, but the resin for run 2 reached a maximum temperature during irradiation of 51 C, while the resin for run 3 reached a temperature of 38 C. The different temperatures were the result of the operating status of HFIR at the time of the irradiation and were not part of the test plan; however, the results clearly show the impact of the higher-temperature exposure during irradiation. The flow rate and pressure drop data from the test loop runs show that irradiating the RF resin reduces both the void fraction and the permeability of the resin bed. The mechanism for the reduction in permeability is not clear because irradiation increases the particle size of the resin beads and makes them deform less under pressure. Microscopic examination of the resin beads shows that they are all smooth regular spheres and that irradiation or oxygen uptake did not change the shape of the beads. The resin reacts rapidly with DO in the simulant solution, and the reaction with oxygen reduces the permeability of a bed of new resin by about 10% but has less impact on the permeability of irradiated resin. Irradiation increases the toughness of the resin beads, probably by initiating cross-linking reactions in them. Oxygen uptake reduces the crush strength of both new and irradiated resin; however, the pressures that caused the beads to crush are much higher than would be expected during the operation of an ion exchange column. There was no visible evidence of broken beads in any of the resin samples taken from the test loop. Reaction with oxygen red

Taylor, Paul Allen [ORNL

2010-01-01

366

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

Science.gov (United States)

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

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

2013-07-01

367

21 CFR 175.380 - Xylene-formaldehyde resins condensed with 4,4â²-isopropylidenediphenol-epichlorohydrin epoxy resins.  

Science.gov (United States)

...isopropylidenediphenol-epichlorohydrin epoxy resins. The resins identified in...articles intended for use in contact with...conditions. (a) The resins are produced by...condensation of xylene-formaldehyde resin and 4,4...or trimethylol phenol and capryl...

2009-04-01

368

Method for regenerating magnetic polyamine-epichlorohydrin resin  

Energy Technology Data Exchange (ETDEWEB)

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately.

Kochen, Robert L. (Boulder, CO); Navratil, James D. (Simi Valley, CA)

1997-07-29

369

Method for regenerating magnetic polyamine-epichlorohydrin resin  

International Nuclear Information System (INIS)

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately. 9 figs

1995-05-31

370

Method for regenerating magnetic polyamine-epichlorohydrin resin  

Energy Technology Data Exchange (ETDEWEB)

Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately. 9 figs.

Kochen, R.L.; Navratil, J.D.

1997-07-29

371

Advanced cement solidification technique for spent resins  

International Nuclear Information System (INIS)

In the past 40 years, the nuclear facilities of China Institute of Atomic Energy (CIAE) produced an amount of radioactive organic resins, a kind of problematic stream in nuclear industry. As these facilities were stepping into decommissioning, the treatment of the spent organic resins was put on the agenda. The various routes for spent resin treatment such as incineration, advanced oxidation, cement immobilization, etc, were considered. Each method has its advantages and disadvantages when applied in the treatment of spent resins. Since the quantities of the spent organic resins were relatively small and an experience with variety of cementation processes existed in CIAE, predominately for immobilization of the evaporated concentrates, the option of direct encapsulation of the spent organic resins into cementitious materials was adopted in 2003, as a preferred method from the point of view of saving the on the cost of the disposal. In order to realize the end goal, the main work consisted of: the survey of the source terms; cementitious material formula investigation; and the process development. This work, which was undertaken in the following years, is addressed as follows. Source terms of the spent resins in CIAE were to be made clear firstly. The results showed that a total of 24-29 m3 of spent resins was generated and accumulated in the past 40 years. Spent resin arose from two research reactors (heavy water reactor and light water reactor), and from the waste management plant. The amount of the spent resins from the heavy water reactor was 1m3 or so, but its radioactive concentration was high to ?108-?109Bq/m3. Two kinds of cements, ASC and OPC cement were selected next, as the solidifying matrix to be investigated. A mixture surface response approach was employed to design experiment and interpret data. In comparison, ASC was superior to OPC cement and it displayed preferable performances to encapsulate spent resins. The optimum formulation is:1) resin: .17(dry w/w); and 2) ASC cement: .43; zeolite: .10; water: .30. The properties of the resulting resin-cement concrete mix met the national criterion and the process requirements. These properties included 104mm for the slump, 9.6(Mpa) for the 28-day compressive strength, 1.2% and 6.0% for the compressive strength loss after 42-day water immersion and 5 thaw-freeze circles, 2.72E-06(cm2/d) and 1.63E-07 (cm2/d) for 137Cs and 60Co diffusivities. Lastly, a scale-up demonstration of 200L and the corresponding process was carried out. The cementation process was performed in batches directly in the final storage container, which was a 200L steel drum. Based on the recommended concrete formulation and on the determined operation conditions, the large volumes of resin-cement concretes were produced. The properties of the resin-cement concretes were examined by analysis of drilling cores. The results showed that homogeneous solidified forms were obtained under the given process parameters, and that mechanical performances and the peak temperature satisfied the regulatory requirements. The source term investigation provided the basis for determination of the status of radioactive ion-exchange resins in CIAE. The cement formula as well as the cold bench scale test reached the required end goal, which established bases for the active pilot process, although some improvement should be done in the future. (author)

2007-12-01

372

Amine chemistry. Update on impact on resin  

International Nuclear Information System (INIS)

Impurity removal in the steam cycle and the associated prevention of corrosion and/or fouling of system components are the goals of ion exchange resins. However, in many instances (such as a switch to amine chemistry or a change in product specifications), resins do not remove, and, in fact, contribute impurities to the steam cycle. This paper reviews recent data compiled to determine the direct and indirect effects of amines on ion exchange resins used in the power industry. Water chemistries have improved in recent years, in large part due to changes in chemistry and resins, but it is necessary to continue to develop products, processes and techniques to reduce impurities and improve overall water chemistry in power plant systems. (orig.)

2012-03-01

373

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

374

Amine chemistry. Update on impact on resin  

Energy Technology Data Exchange (ETDEWEB)

Impurity removal in the steam cycle and the associated prevention of corrosion and/or fouling of system components are the goals of ion exchange resins. However, in many instances (such as a switch to amine chemistry or a change in product specifications), resins do not remove, and, in fact, contribute impurities to the steam cycle. This paper reviews recent data compiled to determine the direct and indirect effects of amines on ion exchange resins used in the power industry. Water chemistries have improved in recent years, in large part due to changes in chemistry and resins, but it is necessary to continue to develop products, processes and techniques to reduce impurities and improve overall water chemistry in power plant systems. (orig.)

Bachman, Gregory; Kellogg, Douglas [Siemens Industry, Inc., Rockford, IL (United States). Technology and Lab Services; Wilkes, Marty [Siemens Industry, Inc., Rockford, IL (United States). Water Technologies Div.

2012-03-15

375

Polymer resins for recovery of valuable metals.  

Science.gov (United States)

Vinylbenzyl chloride/divinylbenzene gel copolymer beads have been modified using piperidine, hexamethyleneimine, piperazine, 1-(2-aminoethyl)piperazine, and N-cyclohexyl-1,3-propanediamine. These resins were then tested for the sorption of noble metal ions, namely, Re(VII), Pd(II), Pt(IV), and Au(III), from a 0.1 M HCl solution. The effect of these resins on the sorption of other coexisting ions, such as Cu, Ni and Fe, was also studied. Of the resins tested, resin 4 [1-(2-aminoethyl)piperazine groups] showed the highest sorption capacity for Pt(IV) and Re(VII) from single and multicomponent solutions, with the sorption of Pt(IV) from the multicomponent solution (Re, Au, Pd, Pt, Cu, Ni Fe) in 0.1 M HCl reaching 68 mg Pt/g. PMID:20387092

Jermakowicz-Bartkowiak, Dorota

2010-08-01

376

An update on resin-bonded bridges.  

Science.gov (United States)

Since the introduction of the 'Rochette' bridge in the 1970s the resin-bonded bridge has undergone a number of developments to become a commonly used technique for replacement of a missing tooth, especially in a minimally restored dentition. One of the major advantages of the resin-bonded bridge is that it requires less tooth preparation than conventional bridgework, with some authorities advising no preparation at all. Some reports have suggested poor long-term success rates, however, if used in appropriate clinical situations, this treatment modality can be extremely successful. The aim of this paper is to review the literature relating to resin-bonded bridges and suggest recommendations for clinicalpractice concerning the provision of resin-bonded bridges. PMID:18468318

Barber, M W; Preston, A J

2008-03-01

377

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...condensation of hexamethylenediamine, terephthalic acid, and isophthalic acid such that 65 to 80 percent of the polymer units...hexamethylenediamine and 31.2+0.3 weight percent azelaic acid. (15) Nylon 46 resins (CAS Reg. No....

2009-04-01

378

XAD2 resin in phenolics separation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

379

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

380

21 CFR 177.1555 - Polyarylate resins.  

Science.gov (United States)

...Identity. Polyarylate resins (1, 3-benzenedicarboxylic acid, diphenyl ester, polymer with diphenyl 1,4-benzenedicarboxylate and 4-4â²-(1-methylethylidine) bis(phenol)) are formed by melt polycondensation of...

2010-01-01

 
 
 
 
381

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

382

Natural dye -sensitized mesoporous ZnO solar cell  

Science.gov (United States)

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

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

2010-10-01

383

Synthesis of Mesoporous Carbon Using Halloyiste As Template  

Directory of Open Access Journals (Sweden)

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

ZHOU Shu-Hui, CHUAN Xiu-Yun

2014-06-01

384

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

385

Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis  

Science.gov (United States)

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

Jin, Zhao

386

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.

2010-02-01

387

Preparation and photoluminescence study of mesoporous indium hydroxide nanorods  

Energy Technology Data Exchange (ETDEWEB)

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, N{sub 2} 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. N{sub 2} 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.

Li, Changyu [College of Material Science and Engineering, Northeast Forestry University, Harbin 150040 (China); Lian, Suoyuan [Functional Nano and Soft Materials Laboratory, Soochow University, No. 199 Renai Road, Suzhou, Jiangsu 215123 (China); School of Chemical Engineering and Materials, Dalian Polytechnic University, Dalian 116034 (China); Liu, Yang [Functional Nano and Soft Materials Laboratory, Soochow University, No. 199 Renai Road, Suzhou, Jiangsu 215123 (China); Liu, Shouxin, E-mail: liushouxin@126.com [College of Material Science and Engineering, Northeast Forestry University, Harbin 150040 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Functional Nano and Soft Materials Laboratory, Soochow University, No. 199 Renai Road, Suzhou, Jiangsu 215123 (China)

2010-02-15

388

Catalytic conversion of cellulose over mesoporous Y zeolite.  

Science.gov (United States)

Mesoporous Y zeolite (Meso-Y) was applied, for the first time, to the catalytic pyrolysis of cellulose which is a major constituent of lignocellulosic biomass, to produce high-quality bio-oil. A representative mesoporous catalyst Al-MCM-41 was also used to compare its catalytic activity with that of Meso-Y. Pyrolysis-gas chromatography/mass spectrometry was used for the experiments. Meso-Y, with higher acidity, led to larger yields of aromatics and furans with high value-added than Al-MCM-41, resulting in the production of bio-oil with higher quality. The effect of temperature on the catalytic pyrolysis was not significant within the range of 400-500 degrees C. When the Meso-Y to cellulose ratio was increased from 1/1 via 2/1 to 3/1, the deoxygenation efficiency increased, leading to increased yield of aromatics. PMID:24757989

Park, Young-Kwon; Jun, Bo Ram; Park, Sung Hoon; Jeon, Jong-Ki; Lee, See Hoon; Kim, Seong-Soo; Jeong, Kwang-Eun

2014-07-01

389

Voltammetric response of ferrocene-grafted mesoporous silica  

International Nuclear Information System (INIS)

The electrochemical behavior of ferrocene moieties immobilized by covalent grafting on ordered mesoporous silica samples has been studied by cyclic voltammetry in aqueous medium using carbon paste electrodes modified with these solids. The functionalized silica samples were obtained using (3-(ferrocenylamide)propyl)triethoxysilane as the grafting agent. The results have been discussed in relation to the ferrocene content in the materials and compared to those obtained with non-ordered ferrocene-grafted silica gels. Well-defined voltammetric signals have been observed in spite of the insulating character of the mesoporous silica matrix and they were found to increase as a function of the ferrocene groups content in the material. They displayed a better stability upon continuous cycling potentials in comparison to those recorded with amorphous gels, suggesting a beneficial effect of the long-range structural order on the electron transfer processes in such confined media

2006-09-15

390

Graphitic mesoporous carbon as a durable fuel cell catalyst support  

Energy Technology Data Exchange (ETDEWEB)

Highly stable graphitic mesoporous carbons (GMPCs) are synthesized by heat-treating polymer-templated mesoporous carbon (MPC) at 2600 C. The electrochemical durability of GMPC as Pt catalyst support (Pt/GMPC) is compared with that of carbon black (Pt/XC-72). Comparisons are made using potentiostatic and cyclic voltammetric techniques on the respective specimens under conditions simulating the cathode environment of PEMFC (proton exchange membrane fuel cell). The results indicate that the Pt/GMPC is much more stable than Pt/XC-72, with 96% lower corrosion current. The Pt/GMPC also exhibits a greatly reduced loss of catalytic surface area: 14% for Pt/GMPC vs. 39% for Pt/XC-72. (author)

Shanahan, Paul V.; Waje, Mahesh; Yan, Y.S. [Department of Chemical and Environmental Engineering, University of California, 900 University Avenue, Riverside, CA 92521 (United States); Xu, Lianbin [Department of Chemical and Environmental Engineering, University of California, 900 University Avenue, Riverside, CA 92521 (United States); Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Liang, Chengdu; Dai, Sheng [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2008-10-15

391

Low temperature crystallisation of mesoporous TiO2.  

Science.gov (United States)

Conducting mesoporous TiO2 is rapidly gaining importance for green energy applications. To optimise performance, its porosity and crystallinity must be carefully fine-tuned. To this end, we have performed a detailed study on the temperature dependence of TiO2 crystallisation in mesoporous films. Crystal nucleation and growth of initially amorphous TiO2 derived by hydrolytic sol-gel chemistry is compared to the evolution of crystallinity from nanocrystalline building blocks obtained from non-hydrolytic sol-gel chemistry, and mixtures thereof. Our study addresses the question whether the critical temperature for crystal growth can be lowered by the addition of crystalline nucleation seeds. PMID:24057082

Kohn, Peter; Pathak, Sandeep; Stefik, Morgan; Ducati, Caterina; Wiesner, Ulrich; Steiner, Ullrich; Guldin, Stefan

2013-11-01

392

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)

2010-11-21

393

Multifunctional behaviour of mesoporous LiNbO3  

Science.gov (United States)

Mesoporous LiNbO3 nanoparticles with BET surface area 185 m2 g-1 were synthesized by using Pluronic P123 as soft template. The samples showed three functionalities, viz., photoluminescence, ferroelectricity, and ferromagnetism. Room temperature photoluminescence was observed at 390 nm wavelength due to oxygen vacancy. The mesoporous LiNbO3 showed ferromagnetic behavior at room temperature. Ferroelectric behavior of the samples was confirmed from the P-E hysteresis loop measurement. The samples showed a magneto-dielectric effect with the dielectric constant increasing by ~4.5% for an applied magnetic field of 10 kOe due to magnetostriction of the material which changed the lattice parameter to bring about an increase in the dipole moment of the unit cell.

Banerjee, Shilpi; Kumar Bhunia, Manas; Bhaumik, Asim; Chakravorty, Dipankar

2012-03-01

394

Mesoporous nickel/nickel oxide electrodes for high power applications  

Energy Technology Data Exchange (ETDEWEB)

It was demonstrated that a method developed for preparing mesoporous materials by electrodeposition of material within the aqueous domains of an homogeneous self-assembled liquid crystal template can also be used to electrodeposit mesoporous nickel films, which by virtue of their greatly reduced cost make them suitable for high volume applications. Cyclic voltammetry showed these materials to have high surface areas and a pore structure that allows extremely rapid diffusion of species to active sites within the structure. These properties suggest application to supercapacitor technology and pulse power devices. This type of nickel coating may also have an application as a low-cost inert, current collector for use in alkaline solution. 5 refs., 3 figs.

Nelson, P. A.; Elliott, J. M.; Attard, G. S.; Owen, J. R. [Southampton Univ., Dept. of Chemistry, Highfield, Southampton (United Kingdom)

2002-01-01

395

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

International Nuclear Information System (INIS)

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.

2012-08-01

396

Fluoride and Chlorhexidine Release from Filled Resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

397

Resin composites : Sandwich restorations and curing techniques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

398

Development of Polymer Resins using Neural Networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Fernandes, Fabiano A. N.; Lona, Liliane M. F.

2002-01-01

399

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

2014-01-10

400

Challenges in biocatalysis: immobilization of pepsin in mesoporous silicates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A facile preparation of Silico-Pepsin biocatalysts within mesoporous silicas, MCM-41 and SBA-15 has been achieved, by encapsulation of the enzyme. The shrinking of the pores was obtained by grafting with 3-aminopropyltriethoxysilane (APTES). The hybrid bio-inorganic materials were characterized by XRD, TEM, Volumetric (N2 sorption), FT-IR and DR-UV-Vis techniques and their catalytic activity was evaluated by peptic hydrolysis of a dipeptide, Z-L-glutamyl-L-tyrosine solution.

Coluccia, Salvatore; Gianotti, Enrica

2008-01-01

 
 
 
 
401

Bioresponsive Mesoporous Silica Nanoparticles for Triggered Drug Release  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mesoporous silica nanoparticles (MSNPs) have garnered a great deal of attention as potential carriers for therapeutic payloads. However, achieving triggered drug release from MSNPs in vivo has been challenging. Here, we describe the synthesis of stimulus-responsive polymer-coated MSNPs and the loading of therapeutics into both the core and shell domains. We characterize MSNP drug-eluting properties in vitro and demonstrate that the polymer-coated MSNPs release doxorubicin in response to prote...

Singh, Neetu; Karambelkar, Amrita D.; Gu, Luo; Lin, Kevin Yu-ming; Miller, Jordan S.; Chen, Christopher S.; Sailor, Michael J.; Bhatia, Sangeeta N.