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1

Formulation of lignin phenol formaldehyde resins as a wood adhesive  

International Nuclear Information System (INIS)

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 Phenol had been replaced by lignin [that was extracted from black liquor of oil palm empty fruit bunch (EFB)] in synthesizing resin with a ratio lignin to phenol 1:1.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

2

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 formalde...

A.S. Hussein; K.I. Ibrahim; K. M. Abdulla

3

Use of in situ polymerized phenol-formaldehyde resin to modify a Nafion ® membrane for the direct methanol fuel cell  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Commercial Nafion ®-115 (trademark registered to DuPont) membranes were modified by in situ polymerized phenol formaldehyde resin (PFR) to suppress methanol crossover, and SO 3 - groups were introduced to PFR by post-sulfonatation. A series of membranes with different sulfonated phenol formaldehyde ...

Wu, Z; Sun, G; Jin, W; Wang, Q; Hou, H; Chan, KY; Xin, Q

4

Acute effect upon pulmonary function of low level exposure to phenol-formaldehyde-resin-coated wood.  

UK PubMed Central (United Kingdom)

In order to determine whether phenol-formaldehyde-resin-coated wood particles would cause an acute decline in pulmonary function, 176 workers in 2 oriented strandboard production plants were given respiratory questionnaires and pulmonary function tests before and during their work shifts. Measurements of dust and adsorbed formaldehyde were made on the same day as the pulmonary function tests. Measured formaldehyde levels were low, and measured dust levels were low to moderate. There was no evidence of an acute effect upon pulmonary function.

Imbus HR; Tochilin SJ

1988-09-01

5

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

UK PubMed Central (United Kingdom)

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

Manivannan D; Starvin M; Biju VM

2010-01-01

6

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

Directory of Open Access Journals (Sweden)

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.

2011-01-01

7

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

8

Flexible mesoporous photonic resins with tunable chiral nematic structures.  

UK PubMed Central (United Kingdom)

Colors of nature: Mimicking of the structural colors of nature was achieved by the preparation of easily accessible chiral nematic polymer composites based on phenol-formaldehyde resins templated by cellulose nanocrystals. Removal of the template led to mesoporous polymer films with unique optical and physical properties. The potential application of these materials in optical sensors was also demonstrated.

Khan MK; Giese M; Yu M; Kelly JA; Hamad WY; Maclachlan MJ

2013-08-01

9

Flexible mesoporous photonic resins with tunable chiral nematic structures.  

Science.gov (United States)

Colors of nature: Mimicking of the structural colors of nature was achieved by the preparation of easily accessible chiral nematic polymer composites based on phenol-formaldehyde resins templated by cellulose nanocrystals. Removal of the template led to mesoporous polymer films with unique optical and physical properties. The potential application of these materials in optical sensors was also demonstrated. PMID:23893465

Khan, Mostofa K; Giese, Michael; Yu, Marcus; Kelly, Joel A; Hamad, Wadood Y; Maclachlan, Mark J

2013-07-26

10

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 c...

11

Physico-chemical characterization of lignins from different sources for use in phenol-formaldehyde resin synthesis.  

Science.gov (United States)

During the last decades lignin has been investigated as a promising natural alternative to petrochemicals in phenol-formaldehyde (PF) resin production, due to their structural similarity. Physico-chemical characterization of three types of lignin, namely kraft pine lignin (L1), soda-anthraquinone flax lignin (L2), and ethanol-water wild tamarind lignin (L3) has been evaluated to determine which one is the most suitable chemical structure for above purpose. Characterization has been performed using Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectrometry ((1)H NMR) to analyse the chemical structure, gel permeation chromatography (GPC) for determining molecular weight (MW) and molecular weight distribution (MWD), differential scanning calorimetry (DSC) to measure the glass transition temperature and thermogravimetric analysis (TGA) to follow the thermal degradation. Both structural and thermal characteristics suggest that kraft pine lignin (L1) would be a better phenol (P) substitute in the synthesis of lignin-phenol-formaldehyde (LPF) resins, as it presents higher amounts of activated free ring positions, higher MW and higher thermal decomposition temperature. PMID:16843657

Tejado, A; Peña, C; Labidi, J; Echeverria, J M; Mondragon, I

2006-07-14

12

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)

1992-01-01

13

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.

2007-01-01

14

Separation and characterization of alkyl phenol formaldehyde resins demulsifier by adsorption chromatography, gel permeation chromatography, infrared spectrometry and nuclear magnetic resonance spectroscopy  

International Nuclear Information System (INIS)

[en] This paper deals with the separation and characterization of alkyl phenol formaldehyde resins demulsifier by infrared spectrometry and nuclear magnetic resonance spectroscopy after separation of the different surfactants and low molecular additives by adsorption chromatography. Firstly, the types of surfactants are identified by methylene blue chloride-chloroform test method and the elemental analysis such as Ca, K, Mg, Na, P, S and N. Then, the different surfactants and low molecular components are separated by adsorption chromatography after parts of low molecular components are dried in an oven, and the molecular weight distribution is measured by gel permeation chromatography also. Finally, the separated surfactants are determined by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectroscopy. The distortionless enhancement by polarization transfer (DEPT), H, C correlated spectroscopy (H, C-COSY), H, H correlated spectroscopy (H, H-COSY) and heteronuclear multiple-bond correlation (HMBC) spectroscopy are applied to determine the molecular structures

2006-05-04

15

Microwave driven trimethylsilylation of phenol-formaldehyde resins: extent of reactions determined by {sup 13}C and {sup 29}Si n.m.r.  

Energy Technology Data Exchange (ETDEWEB)

A phenol-formaldehyde (PF) resite resin and phenol:2,6-di-t-butylphenol-formaldehyde (DTBPF) co-resite were reacted under conditions of microwave heating with N-(trimethylsilyl)imidazole (TMSI). Low degrees of reaction were observed for the PF resin (19%) and for the DTBPF co-resite (0.3-0.4%) as examples of macromolecular systems with very limited porosity. {sup 13}C SPE MAS n.m.r. was an effective method to determine the degree of silylation and {sup 13}C CP MAS n.m.r. gave very similar results. When a different reagent mix (1:1:1 N,O-bis(trimethylsilyl)acetamide: N(trimethylsilyl)imidazole trimethylchlorosilane) was used both {sup 13}C and {sup 29}Si SPE n.m.r. were in agreement that 100% silylation of the OH groups had been achieved for the PF resin. Thus, with proper choice of conditions and reagents, microwave-driven silylation is a very effective method of OH analysis even for systems of significantly more limited porosity compared with coals. 13 refs., 4 figs., 2 tabs.

Monsef-Mirzai, P.; Manak, H.; McWhinnie, W.R.; Snape, C.E.; Sirkecioglu, O.; Andresen, J. [Aston University, Birmingham (United Kingdom). Dept. of Chemical Engineering and Applied Chemistry

1998-04-01

16

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

Scientific Electronic Library Online (English)

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

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

2012-05-01

17

NMR study of the phenol-formaldehyde-water-methanol system  

International Nuclear Information System (INIS)

[en] A quantitative evaluation of the system phenol-formaldehyde-water-methanol was carried out using the method of 1H-NMR spectroscopy. The investigated region of the molar ratios phenol formaldehyde methanol varied within the range 1:29:9.6 to 1:0.2:0.07 and the spectra obtained were compared with the spectrum of water-methanol solution of formaldehyde. The system showed two groups of lines. Four simple singlets of linear polymers of the type C6H5O(CH2O)sub(n)H appeared in the region 5.20 to 5.35 delta whereas in the region 4.7 to 5.4 delta as many as eleven signals of the polymers HO(CH2O)sub(n)H and CH3O(CH2O)sub(n)H could be detected. Another three signals of polymers of the type C6H5O(CH2O)sub(n)CH3 appeared in the region 4.8 to 5.0 delta from the molar ratio phenol formaldehyde 1:2.2. (author)

1978-01-01

18

Novel process of isolating novolac resin fractions  

Science.gov (United States)

Typical phenol/formaldehyde resin syntheses generate a broad distribution of molecular weight fragments with a wide polydispersity. A process was developed to isolate novolak resin fractions of narrow polydispersity from phenol- formaldehyde condensation products in ethyl lactate without any high temperature distillation. The characterization and the performance of these fractions in i-line photoresist composition are discussed.

Rahman, M. Dalil; Lu, Ping-Hung; Cook, Michelle M.

1997-07-01

19

Differential scanning calorimetry characterization of the cure of phenol-formaldehyde adhesive in the presence of copper-based preservative treated wood  

UK PubMed Central (United Kingdom)

The interference of copper based preservative treated southern yellow pine (SYP) on the cure of phenol-formaldehyde adhesives was investigated by using differential scanning calorimetry (DSC). Copper preservatives used in this study include copper azole (NS), alkali copper quat (ACQ)-type C (NW). Three commercial phenol-formaldehyde (PF) adhesives used for oriented strand board (OSB) face area, core area and a plywood adhesive were studied. The curing peak temperature and peak time of OSB core and face PF resin shifted to higher temperature and duration in the presence of CCA, NS, and NW-treated SYP compared to that in untreated SYP. The above treatments interfere with the cure of OSB core and face PF resin. Untreated SYP showed a curing accelerating effect on the cure of plywood adhesive, but the accelerating effect of copper-treated SYP on the cure of plywood resin was not significant.

Jiang Haihong; Kamdem DPascal

2007-12-01

20

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 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 foram 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 2 (more) 4 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 (more) 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

2013-06-01

 
 
 
 
21

Preparation of spherical activated phenol-formaldehyde beads from bamboo tar for adsorption of toluene.  

UK PubMed Central (United Kingdom)

Bamboo tar is a waste by-product from the process of bamboo charcoal production. After distillation under reduced pressure, bamboo tar becomes a highly viscous liquid containing phenolic compounds at more than 70 wt%. Therefore, bamboo tar could be an excellent replacement for the phenolic compounds produced by the decomposition of petroleum. In this study, bamboo tar was mixed with formalin under a weak alkaline condition to form cured phenol-formaldehyde (PF) beads through suspension polymerization. In total, 35% of the obtained PF resin produced spherical beads with a particle size ranging from 9 to 16 mesh. The char yield after 500 degrees C carbonization was 60.4 wt%, according to thermogravimetric analysis. This high char yield is advantageous for the subsequent activation process. After physical activation using CO2 at 900 degrees C for 2 hr the carbide yield was up to 73.0 wt%. The specific surface area of activated PF beads was dependent on the activation time and temperature. Toluene adsorption results suggest that the activated PF beads are applicable to the adsorption and recovery of VOC gases. Monolayer adsorption may limit the VOC adsorption with activated PF beads because the adsorption isotherms were better fitted with the Langmuir model. Implications: Bamboo tar is shown to be a good replacement for the phenolic compounds from decomposition of petroleum to form activated phenol-formaldehyde (PF) beads. Toluene adsorption tests suggest that the activated PF beads have potential to adsorb and recover VOC gases. Nevertheless, due to the low specific surface area of the activated PF beads from bamboo tar, a further enhancement in both meso- and microporosity is needed in the future experiments. The experimental data provide a contribution to better understanding the possibility of resource recovery of waste agricultural by-products and their potential application in environment protection.

Huang YP; Hsi HC; Liu SC

2013-08-01

22

Preparation of spherical activated phenol-formaldehyde beads from bamboo tar for adsorption of toluene.  

Science.gov (United States)

Bamboo tar is a waste by-product from the process of bamboo charcoal production. After distillation under reduced pressure, bamboo tar becomes a highly viscous liquid containing phenolic compounds at more than 70 wt%. Therefore, bamboo tar could be an excellent replacement for the phenolic compounds produced by the decomposition of petroleum. In this study, bamboo tar was mixed with formalin under a weak alkaline condition to form cured phenol-formaldehyde (PF) beads through suspension polymerization. In total, 35% of the obtained PF resin produced spherical beads with a particle size ranging from 9 to 16 mesh. The char yield after 500 degrees C carbonization was 60.4 wt%, according to thermogravimetric analysis. This high char yield is advantageous for the subsequent activation process. After physical activation using CO2 at 900 degrees C for 2 hr the carbide yield was up to 73.0 wt%. The specific surface area of activated PF beads was dependent on the activation time and temperature. Toluene adsorption results suggest that the activated PF beads are applicable to the adsorption and recovery of VOC gases. Monolayer adsorption may limit the VOC adsorption with activated PF beads because the adsorption isotherms were better fitted with the Langmuir model. Implications: Bamboo tar is shown to be a good replacement for the phenolic compounds from decomposition of petroleum to form activated phenol-formaldehyde (PF) beads. Toluene adsorption tests suggest that the activated PF beads have potential to adsorb and recover VOC gases. Nevertheless, due to the low specific surface area of the activated PF beads from bamboo tar, a further enhancement in both meso- and microporosity is needed in the future experiments. The experimental data provide a contribution to better understanding the possibility of resource recovery of waste agricultural by-products and their potential application in environment protection. PMID:24010379

Huang, Ying-Pin; Hsi, Hsing-Cheng; Liu, Szu-Chen

2013-08-01

23

Radiation-chemical hardening of phenol-formaldehyde oligomers  

International Nuclear Information System (INIS)

Radiation-chemical hardening of phenol formaldehyde oligomers of the resol type has been studied in the presence of furfural and diallylphthalate diluents. The samples have been hardened on an electron accelerator at an electron energy of 1.0-1.1 MeV and a dose rate of 2-3 Mrad/s. The kinetics of hardening has been studied on the yield of gel fraction within the range of absorbed doses from 7 to 400 Mrad. Radiation-chemical hardening of the studied compositions is activated with sensitizers, namely, amines, metal chlorides, and heterocyclic derivatives of metals. Furfural and diallylphthalate compositions are suitable for forming glass-fibre plastic items by the wet method and coatings under the action of ionizing radiations

1978-01-01

24

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

25

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

Science.gov (United States)

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.

Singh, G. P.; Mangal, Ravindra; Bhojak, N.; Dixit, Manasvi; Saxena, N. S.

2010-06-01

26

Direct triblock-copolymer-templating synthesis of ordered nitrogen-containing mesoporous polymers.  

UK PubMed Central (United Kingdom)

Ordered nitrogen-containing mesoporous carbonaceous polymers have been synthesized via a direct triblock-copolymer-templating process by using soluble, low-molecular-weight urea-phenol-formaldehyde (UPF) resin as an organic precursor and amphiphilic triblock copolymer Pluronic F127 as a template. Characterization using small-angle X-ray scattering (SAXS), N(2) sorption, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TG), Fourier transform infrared (FTIR), and water adsorption techniques reveals that the obtained nitrogen-containing mesoporous polymers possess ordered structures, high surface areas (385-420 m(2)/g), large pore sizes (3.1-3.6nm) and pore volumes (0.25-0.44cm(3)/g), and high nitrogen content (2.69-2.94%). Various mesostructures, such as two-dimensional (2-D) hexagonal (space group, p6mm) and 3-D body-centered cubic (Im3 m) symmetries, can be obtained by simply adjusting the mass ratio of UPF/F127. The content of nitrogen in the mesoporous polymers can also be easy varied by changing the amount of urea and the reaction time of UPF resin precursors. Compared with the nitrogen-free mesoporous polymer, the obtained mesoporous carbonaceous polymers show a more hydrophilic nature and thus evidently higher water adsorption capacity. The presence of nitrogen groups can also significantly improve the adsorption performance of Fe(III) ions.

Yang J; Zhai Y; Deng Y; Gu D; Li Q; Wu Q; Huang Y; Tu B; Zhao D

2010-02-01

27

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

28

PYROLYSIS OF FOUNDRY SAND RESINS: A DETERMINATION OF ORGANIC PRODUCTS BY MASS SPECTROMETRY  

Science.gov (United States)

Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was used to identify the major organic products produced by pyrolysis of three foundry sand resins: 1) Novolac and 2) phenolic urethane (PU) [both phenol-formaldehyde based resins], and 3) furan (furfuryl alcohol based resin). These resins a...

29

Laboratory evaluation of phenol-formaldehyde/polymer gelants for high-temperature applications  

Energy Technology Data Exchange (ETDEWEB)

Polymer gels are attractive tools for stopping unwanted fluid production from oil and gas wells, but conventional gelant formulations become increasingly difficult to apply at higher formation temperatures. In contrast phenol-formaldehyde cross-linked polymer gelants remain viable to at least 140C. Choice of polymer composition permits control of the gelation delay, and the gelants display good injectivity even when the residence time approaches the gelation time. Cross-linking occurs over a wide range of pH and is insensitive to lithology. Although retention of the gelant components on formation rock is negligible, phenol strongly partitions into oil phases contacted by the gelant. Experiments and numerical modelling show that a preflush of phenol is an effective method of compensating for phenol partitioning in the formation

Bryant, Steven L.; Bartosek, Martin; Lockhart, Thomas P. [Eniricerche S.p.A., San Donato Milanese (Italy)

1997-05-01

30

PYROLYSIS OF FOUNDRY SAND RESINS: A PRELIMINARY DETERMINATION OF ORGANIC PRODUCTS BY MASS SPECTROMETRY  

Science.gov (United States)

Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was used to identify the major organic products produced by pyrolysis of three foundry sand resins: 1) Phenolic Urethane Cold-Box, 2) Novolac (both phenol-formaldehyde based resins), and 3) Furan Warm-Box (furfuryl alcohol based resin). Thes...

31

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

32

Challenges in fabrication of mesoporous carbon films with ordered cylindrical pores via phenolic oligomer self-assembly with triblock copolymers.  

UK PubMed Central (United Kingdom)

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 L; Feng D; Fredin NJ; Yager KG; Jones RL; Wu Q; Zhao D; Vogt BD

2010-01-01

33

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

34

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

2007-01-01

35

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 mesopor...

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

36

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 k...

Mohamad Jani Saad; Izran Kamal

37

White-rot fungi demonstrate first biodegradation of phenolic resin.  

Science.gov (United States)

Phenolic resins, phenol-formaldehyde polymers previously thought to be nonbiodegradable, are produced at an annual rate of 2.2 million metric tons in the United States for many industrial and commercial applications. Three independent lines of evidence established their biodegradability with the white-rot fungus Phanerochaete chrysosporium. Chromatic transformation of growth medium (yellow to pink) indicated initial biodegradation of the resin 3 days after inoculation. A degradation product, 13C-labeled phenol, was detected with gas chromatography-mass spectroscopy. Scanning electron micrographs revealed physical evidence of degradation. This is the first demonstrated biodegradation of these phenol-formaldehyde polymers and stands as a platform for investigation into bioremediation and biorecycling of phenolic resins. PMID:16856735

Gusse, Adam C; Miller, Paul D; Volk, Thomas J

2006-07-01

38

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...

F.A. Nur Izreen; A. Zaidon; M.A. Rabia`tol Adawiah; E.S. Bakar; M.T. Paridah; S. Mohd. Hamami; U.M.K. Anwar

39

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

Science.gov (United States)

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

Xiao, Guqing; Long, Liping

2012-06-01

40

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 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 (more) 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 (more) 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

2012-12-01

 
 
 
 
41

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

42

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).

1996-01-01

43

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

UK PubMed Central (United Kingdom)

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

Cao LY; Sood A; Taylor JS

2009-07-01

44

Synthesis of a boron modified phenolic resin  

Directory of Open Access Journals (Sweden)

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; Luiz Cláudio Pardini*; Milton Faria Diniz; Vera Lúcia Lourenço; Marta Ferreira K. Takahashi

2010-01-01

45

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; Cláudio H. S Del Menezzi; Divino E Teixeira; Priscila C de Araújo

2011-01-01

46

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

Energy Technology Data Exchange (ETDEWEB)

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

Zhao Mu [State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, P.O. Box 34, Beijing University of Chemical Technology, 100029 Beijing (China); Song Huaihe [State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, P.O. Box 34, Beijing University of Chemical Technology, 100029 Beijing (China)], E-mail: songhh@mail.buct.edu.cn; Chen Xiaohong; Lian Wentao [State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, P.O. Box 34, Beijing University of Chemical Technology, 100029 Beijing (China)

2007-10-15

47

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

48

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

Science.gov (United States)

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

Dai, Mingzhi; Vogt, Bryan D

2012-07-06

49

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

UK PubMed Central (United Kingdom)

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

Dai M; Vogt BD

2012-12-01

50

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; Izran Kamal

2012-01-01

51

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-12-31

52

Effect of outdoor exposure on some properties of resin-treated plybamboo  

UK PubMed Central (United Kingdom)

The objective of this investigation was to evaluate some of the physical and mechanical properties of resin-treated plywood type panels manufactured from bamboo strips (Gigantochloa scortechinii). Experimental plybamboo samples were made from low molecular weight phenol formaldehyde (LMwPF) treated bamboo strips. They were exposed to outdoor condition ranging from 1 to 12 months. Modulus of elasticity (MOE), modulus of rupture (MOR), compression strength, and surface roughness of treated and untreated samples were evaluated. Resin impregnated samples had the highest bending and compression strength properties. While the untreated samples failed after 3-month of outdoor exposure. Treated specimens exposed for 12-month had the MOE, MOR, and compression strength values of 14,253N/mm², 101.3N/mm², and 34.63N/mm², respectively. Surface quality of both treated and untreated samples was adversely influenced as the function of outdoor exposure time, based on numerical values obtained from a stylus type equipment. Overall properties of treated samples tested in work resulted in higher values than those of untreated samples. It appears that resin impregnation could be considered as an alternative method to enhance the characteristics of plybamboo exposed to environmental conditions as can be concluded from the results of this study.

Anwar UMK; Hiziroglu S; Hamdan H; Abd.Latif M

2011-01-01

53

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.

VINETA SREBRENKOSKA; GORDANA BOGOEVA-GACEVA; DIMKO DIMESKI

2009-01-01

54

Mesoporous carbon materials  

Energy Technology Data Exchange (ETDEWEB)

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

Dai, Sheng (Knoxville, TN); Wang, Xiqing (Oak Ridge, TN)

2012-02-14

55

Mesoporous carbon materials  

Energy Technology Data Exchange (ETDEWEB)

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

Dai, Sheng; Wang, Xiqing

2013-08-20

56

Templating mesoporous zeolites  

DEFF Research Database (Denmark)

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

Egeblad, Kresten; Christensen, Christina Hviid

2008-01-01

57

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

Directory of Open Access Journals (Sweden)

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

M. Kubecki; M. Holtzer; A. Bobrowski; R. Da?ko; B. Grabowska; S. ?ymankowska-Kumon

2012-01-01

58

Mesoporous materials and electrochemistry.  

UK PubMed Central (United Kingdom)

Ordered mesoporous materials prepared by the template route have attracted increasing interest from the electrochemists community due to their plenty of unique properties and functionalities that can be effectively exploited in electrochemical devices. This review will cover the whole field of the intersection between electrochemistry and ordered mesoporous materials. The latter are either electronically insulating (silica and some other metal oxides, as well as silica-based organic-inorganic hybrid materials), semi-conducting (metal oxides), or conducting (metals, carbons). The three main intersection areas are: (1) the development/use of electrochemical methods to characterize the properties of mesoporous materials (i.e., charge and mass transfer processes); (2) the generation of mesostructured solids by electro-assisted deposition using appropriate templates; and (3) the application of these novel materials for electrochemical purposes. The most common devices to date are based on a bulk composite or thin film configuration and the resulting electrodes modified with such mesoporous materials have been successfully applied in various fields, including mainly electrochemical sensing and biosensing as well as energy conversion and storage (620 references).

Walcarius A

2013-05-01

59

Mesoporous materials and electrochemistry.  

Science.gov (United States)

Ordered mesoporous materials prepared by the template route have attracted increasing interest from the electrochemists community due to their plenty of unique properties and functionalities that can be effectively exploited in electrochemical devices. This review will cover the whole field of the intersection between electrochemistry and ordered mesoporous materials. The latter are either electronically insulating (silica and some other metal oxides, as well as silica-based organic-inorganic hybrid materials), semi-conducting (metal oxides), or conducting (metals, carbons). The three main intersection areas are: (1) the development/use of electrochemical methods to characterize the properties of mesoporous materials (i.e., charge and mass transfer processes); (2) the generation of mesostructured solids by electro-assisted deposition using appropriate templates; and (3) the application of these novel materials for electrochemical purposes. The most common devices to date are based on a bulk composite or thin film configuration and the resulting electrodes modified with such mesoporous materials have been successfully applied in various fields, including mainly electrochemical sensing and biosensing as well as energy conversion and storage (620 references). PMID:23334166

Walcarius, Alain

2013-01-18

60

Molecularly imprinted mesoporous organosilica.  

UK PubMed Central (United Kingdom)

We have prepared molecularly imprinted mesoporous organosilica (MIMO) using a semicovalent imprinting technique. A thermally reversible covalent bond was used to link a bisphenol A (BPA) imprint molecule to a functional alkoxysilane monomer at two points to generate a covalently bound imprint precursor. This precursor was incorporated into a cross-linked periodic mesoporous silica matrix via a typical acid-catalyzed, triblock copolymer-templated, sol-gel synthesis. Evidence of imprint sites buried in the pore walls was found through careful characterization of the imprinted material and its comparison to similarly prepared non-imprinted mesoporous organosilica (NIMO) and pure periodic mesoporous silica (PMS). After thermal treatment, the imprinted material (MIMO-ir) removed more than 90% of appropriately sized bisphenol species from water, yet showed significantly lower binding for both smaller and larger molecules containing phenol moieties. Identically treated NIMO-ir showed much poorer retention behavior than MIMO-ir for the same bisphenol species and behaved only slightly better than PMS-ir.

Lofgreen JE; Moudrakovski IL; Ozin GA

2011-03-01

 
 
 
 
61

From polymeric "plasticine" to shape-controlled mesoporous carbon.  

UK PubMed Central (United Kingdom)

A soft-phase intercalating process to synthesize mesostructured plasticine by using amphiphilic triblock copolymer F127 as a structure-directing agent, reverse triblock copolymer 25R4 as an intercalating soft matter, and soluble phenolic resin as a carbon source is demonstrated. The "plasticine" has interlayer organic-organic hybrid structure, which is emplastic, sticky, and able to be easily shaped at will. After template removal at 350 degrees C and further carbonization at 600 degrees C, highly ordered mesoporous polymers and carbons can be successively obtained with the maintenance of the original shape. The self-supported, shape-controlled, ordered mesoporous carbon products possess high surface areas (495-777 m(2)/g), large pore volumes (0.32-0.47 cm(3)/g), uniform pore sizes (2.5-4.3 nm) in the nanoscale and hollow tremella-like morphology in the micronscale which may facilitate mass transportation.

Qian XF; Wang Z; Wan Y

2009-07-01

62

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

Science.gov (United States)

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

Sridhar, Manasa

63

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

64

Mesoporous materials for antihydrogen production.  

UK PubMed Central (United Kingdom)

Antimatter is barely known by the chemist community and this article has the vocation to explain how antimatter, in particular antihydrogen, can be obtained, as well as to show how mesoporous materials could be used as a further improvement for the production of antimatter at very low temperatures (below 1 K). The first experiments with mesoporous materials highlighted in this review show very promising and exciting results. Mesoporous materials such as mesoporous silicon, mesoporous material films, pellets of MCM-41 and silica aerogel show remarkable features for antihydrogen formation. Yet, the characteristics for the best future mesoporous materials (e.g. pore sizes, pore connectivity, shape, surface chemistry) remain to be clearly identified. For now among the best candidates are pellets of MCM-41 and aerogel with pore sizes between 10 and 30 nm, possessing hydrophobic patches on their surface to avoid ice formation at low temperature. From a fundamental standpoint, antimatter experiments could help to shed light on open issues, such as the apparent asymmetry between matter and antimatter in our universe and the gravitational behaviour of antimatter. To this purpose, basic studies on antimatter are necessary and a convenient production of antimatter is required. It is exactly where mesoporous materials could be very useful.

Consolati G; Ferragut R; Galarneau A; Di Renzo F; Quasso F

2013-05-01

65

Mesoporous materials for antihydrogen production.  

Science.gov (United States)

Antimatter is barely known by the chemist community and this article has the vocation to explain how antimatter, in particular antihydrogen, can be obtained, as well as to show how mesoporous materials could be used as a further improvement for the production of antimatter at very low temperatures (below 1 K). The first experiments with mesoporous materials highlighted in this review show very promising and exciting results. Mesoporous materials such as mesoporous silicon, mesoporous material films, pellets of MCM-41 and silica aerogel show remarkable features for antihydrogen formation. Yet, the characteristics for the best future mesoporous materials (e.g. pore sizes, pore connectivity, shape, surface chemistry) remain to be clearly identified. For now among the best candidates are pellets of MCM-41 and aerogel with pore sizes between 10 and 30 nm, possessing hydrophobic patches on their surface to avoid ice formation at low temperature. From a fundamental standpoint, antimatter experiments could help to shed light on open issues, such as the apparent asymmetry between matter and antimatter in our universe and the gravitational behaviour of antimatter. To this purpose, basic studies on antimatter are necessary and a convenient production of antimatter is required. It is exactly where mesoporous materials could be very useful. PMID:23250616

Consolati, Giovanni; Ferragut, Rafael; Galarneau, Anne; Di Renzo, Francesco; Quasso, Fiorenza

2012-12-18

66

Adsorption of alkaloids on ordered mesoporous carbon.  

Science.gov (United States)

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

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

2013-07-29

67

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

UK PubMed Central (United Kingdom)

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

Tan MX; Zhang Y; Ying JY

2013-07-01

68

Resin Film Infusion  

UK PubMed Central (United Kingdom)

This investigation completed the verification of a three-dimensional resin transfer molding/resin film infusion (RTM/RFI) process simulation model. The model incorporatesresin flow through an anisotropic carbon fiber preform, cure kinetics of the resin, and heattransfer within the preform/tool assembly. The computer model can predict the flow frontlocation, resin pressure distribution, and thermal profiles in the modeled part.

Prof Romesh; C. Batra; Prof Eric; R. Johnson; Aaron C. Caba

69

Impact of film thickness on the morphology of mesoporous carbon films using organic-organic self-assembly.  

UK PubMed Central (United Kingdom)

Mesoporous polymer and carbon thin films are prepared by the organic-organic self-assembly of an oligomeric phenolic resin with an amphiphilic triblock copolymer template, Pluronic F127. The ratio of resin to template is selected such that a body-centered cubic (Im3m) mesostructure is formed in the bulk. However, well-ordered mesoporous films are not always obtained for thin films (<100 nm), and this behavior is found to be directly correlated with the initial phenolic resin to template ratio. Furthermore, the symmetry of ordered phases is highly dependent on the number of layers of spheres in the film: Monolayers and bilayers are characterized by hexagonal close-packed (HCP) symmetry, while films with approximately 5 layers of spheres exhibit a mixture of HCP and face-centered orthorhombic (FCO) structures. Ultrathick films having more than 30 layers of spheres are similar to the bulk body-centered cubic symmetry with a preferential orientation of the closest-packed (110) plane parallel to the substrate. Film thickness and initial composition of the carbonizable precursors in the template are critical factors in determining the morphology of mesoporous carbon films. These results provide insight into why difficulties have been reported in producing ultrathin ordered mesoporous carbon films using cooperative organic-organic self-assembly.

Vogt BD; Chavez VL; Dai M; Arreola MR; Song L; Feng D; Zhao D; Perera GM; Stein GE

2011-05-01

70

Impact of film thickness on the morphology of mesoporous carbon films using organic-organic self-assembly.  

Science.gov (United States)

Mesoporous polymer and carbon thin films are prepared by the organic-organic self-assembly of an oligomeric phenolic resin with an amphiphilic triblock copolymer template, Pluronic F127. The ratio of resin to template is selected such that a body-centered cubic (Im3m) mesostructure is formed in the bulk. However, well-ordered mesoporous films are not always obtained for thin films (<100 nm), and this behavior is found to be directly correlated with the initial phenolic resin to template ratio. Furthermore, the symmetry of ordered phases is highly dependent on the number of layers of spheres in the film: Monolayers and bilayers are characterized by hexagonal close-packed (HCP) symmetry, while films with approximately 5 layers of spheres exhibit a mixture of HCP and face-centered orthorhombic (FCO) structures. Ultrathick films having more than 30 layers of spheres are similar to the bulk body-centered cubic symmetry with a preferential orientation of the closest-packed (110) plane parallel to the substrate. Film thickness and initial composition of the carbonizable precursors in the template are critical factors in determining the morphology of mesoporous carbon films. These results provide insight into why difficulties have been reported in producing ultrathin ordered mesoporous carbon films using cooperative organic-organic self-assembly. PMID:21466222

Vogt, Bryan D; Chavez, Vicki L; Dai, Mingzhi; Arreola, M Regina Croda; Song, Lingyan; Feng, Dan; Zhao, Dongyuan; Perera, Ginusha M; Stein, Gila E

2011-04-05

71

Engineered monodisperse mesoporous materials  

Energy Technology Data Exchange (ETDEWEB)

Porous materials technology has developed products with a wide variety of pore sizes ranging from 1 angstrom to 100`s of microns and beyond. Beyond 15{angstrom} it becomes difficult to obtain well ordered, monodisperse pores. In this report the authors describe efforts in making novel porous material having monodisperse, controllable pore sizes spanning the mesoporous range (20--500 {angstrom}). They set forth to achieve this by using unique properties associated with block copolymers--two linear homopolymers attached at their ends. Block copolymers phase separate into monodisperse mesophases. They desired to selectively remove one of the phases and leave the other behind, giving the uniform monodisperse pores. To try to achieve this the authors used ring-opening metathesis polymerization to make the block copolymers. They synthesized a wide variety of monomers and surveyed their polymers by TGA, with the idea that one phase could be made thermally labile while the other phase would be thermally stable. In the precipitated and sol-gel processed materials, they determined by porosimetry measurements that micropores, mesopores, and macropores were created. In the film processed sample there was not much porosity present. They moved to a new system that required much lower thermal treatments to thermally remove over 90% of the labile phase. Film casting followed by thermal treatment and solvent extraction produced the desired monodisperse materials (based solely on SEM results). Modeling using Density Functional Theory was also incorporated into this project. The modeling was able to predict accurately the domain size and spacing vs. molecular weight for a model system, as well as accurate interfacial thicknesses.

Saunders, R.S.; Small, J.H.; Lagasse, R.R.; Schroeder, J.L.; Jamison, G.M.

1997-08-01

72

Surfactant-Templated Mesoporous Metal Oxide Nanowires  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 Zn...

Hongmei Luo; Qianglu Lin; Stacy Baber; Mahesh Naalla

73

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

UK PubMed Central (United Kingdom)

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

Niu X; Wan L; Hou Z; Wang T; Sun C; Sun J; Zhao P; Jiang T; Wang S

2013-08-01

74

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

Science.gov (United States)

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

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

2013-05-17

75

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.

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

2008-01-01

76

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

77

Epoxy resin composition.  

UK PubMed Central (United Kingdom)

An epoxy resin composition comprising an epoxy resin component containing at least 5% by weight of an epoxy resin of Formula [I], an epoxy hardener, and an inorganic filler as essential constituents: [wherein R and R<1> denote alkyl of C2 to C6, and n is an integer repetition unit from 0 to 10.]. The epoxy resin composition, when used as a molding material, is low in water absorption rate and flexural modulus (low stress).

ASAKAGE HIDEYASU; ARITOMI MICHIO NO. 5 INAGE HAITSU 504; LI WU XIAO; ASAKAGE HIDEYASU; ARITOMI MICHIO NO INAGE HAITSU; LI WU XIAO; ARITOMI MICHIO

78

Postsynthetic functionalization of mesoporous silica  

Science.gov (United States)

Functionalized mesoporous silica offers promising possibilities for numerous applications, including drug delivery, catalysis, and adsorption. This minireview focuses on recent developments related to the postsynthetic positioning of functional groups on mesoporous silica. After briefly introducing the reagents that are commonly used for this purpose, methods to control and to analyze the distribution of the grafted functional groups are discussed, with particular emphasis on concepts that allow the placement of the groups at specific distances from each other, as well as on approaches towards the selective functionalization of the external particle surface.

Brühwiler, Dominik

2010-06-01

79

Postsynthetic functionalization of mesoporous silica.  

UK PubMed Central (United Kingdom)

Functionalized mesoporous silica offers promising possibilities for numerous applications, including drug delivery, catalysis, and adsorption. This minireview focuses on recent developments related to the postsynthetic positioning of functional groups on mesoporous silica. After briefly introducing the reagents that are commonly used for this purpose, methods to control and to analyze the distribution of the grafted functional groups are discussed, with particular emphasis on concepts that allow the placement of the groups at specific distances from each other, as well as on approaches towards the selective functionalization of the external particle surface.

Brühwiler D

2010-06-01

80

Mesoporous materials as gas sensors.  

UK PubMed Central (United Kingdom)

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

Wagner T; Haffer S; Weinberger C; Klaus D; Tiemann M

2013-05-01

 
 
 
 
81

Encapsulation of enzyme in large mesoporous material with small mesoporous windows.  

UK PubMed Central (United Kingdom)

Trypsin has been encapsulated in the mesopores of a hierarchical mesoporous silica material synthesized via Cu(I) catalyzed azide-alkyne click reaction between azide functionalized large spherical SBA-15 particles and alkyne functionalized mesoporous silica nanoparticles (MSNs). Encapsulated trypsin functions as an efficient biocatalyst and can be recycled several times.

Malvi B; Gupta SS

2012-08-01

82

Encapsulation of enzyme in large mesoporous material with small mesoporous windows.  

Science.gov (United States)

Trypsin has been encapsulated in the mesopores of a hierarchical mesoporous silica material synthesized via Cu(I) catalyzed azide-alkyne click reaction between azide functionalized large spherical SBA-15 particles and alkyne functionalized mesoporous silica nanoparticles (MSNs). Encapsulated trypsin functions as an efficient biocatalyst and can be recycled several times. PMID:22786692

Malvi, Bharmana; Gupta, Sayam Sen

2012-07-02

83

Synthesis of non-siliceous mesoporous oxides.  

UK PubMed Central (United Kingdom)

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

Gu D; Schüth F

2013-08-01

84

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

85

Curable resin composition.  

UK PubMed Central (United Kingdom)

Disclosed herein is a curable resin composition comprising (A) a curable phosphazene compound, (B) a multifunctional (meth)acrylate-based compound such as dipentaerythritol hexaacrylate and (C) a crosslinkable compound having a cure shrinkage of 6% or less such as (meth)acrylate modified polymer which is a product modified by epoxy. This resin composition provides a cured resin film having a high rate of cure, tractable to coat in a great thickness and further excellent in surface hardness, transparency and weathering resistance.

ANDO HIROYUKI

86

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

UK PubMed Central (United Kingdom)

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

Ren J; Yang W; Hua M; Pan B; Zhang W

2013-08-01

87

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; Roberto Carlos Costa Lelis; José Tarcísio da Silva Oliveira

2008-01-01

88

Heat resistant epoxy resin composition.  

UK PubMed Central (United Kingdom)

Heat-resistant epoxy resin composition obtained by incorporation of 2-(4-hydroxyphenyl)-2-(4-maleimidophenyl)propane in a resin composition consisting essentially of epoxy resin and an epoxy hardener is disclosed.

KITAHARA MIKIO; MACHIDA KOICHI; KUBO TAKAYUKI; TORIKAI MOTOYUKI; ASAHINA KOUTAROU; TANABE YOSHIMITSU; YAMAGUCHI KEIZABURO; YAMAGUCHI AKIHIRO

89

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

90

Pseudomorphic synthesis of mesoporous zeolite Y crystals.  

UK PubMed Central (United Kingdom)

A simple method for the conception of mesoporous zeolite Y crystals with a narrow intracrystalline mesopore size distribution is reported. It involves the pseudomorphic transformation of parent zeolite crystals by recrystallisation in the presence of surfactants, and leads to two interconnected pore systems in the zeolite crystals.

Chal R; Cacciaguerra T; van Donk S; Gérardin C

2010-11-01

91

Pseudomorphic synthesis of mesoporous zeolite Y crystals.  

Science.gov (United States)

A simple method for the conception of mesoporous zeolite Y crystals with a narrow intracrystalline mesopore size distribution is reported. It involves the pseudomorphic transformation of parent zeolite crystals by recrystallisation in the presence of surfactants, and leads to two interconnected pore systems in the zeolite crystals. PMID:20714567

Chal, Robin; Cacciaguerra, Thomas; van Donk, Sander; Gérardin, Corine

2010-08-16

92

Fabrication and analytical applications of hybrid mesoporous membranes.  

UK PubMed Central (United Kingdom)

Recently, a hybrid mesoporous membrane composed of surfactant-templated mesoporous silica inside a porous anodic alumina membrane has been developed. Since this membrane allows the use of columnar silica-mesopores (silica-nanochannels) as nanofluidic channels, separation of molecules can be realized by mass transport through the silica-nanochannel with molecular dimensions. Here, we review the methods to fabricate the hybrid mesoporous membranes, their structural features, and the analytical applications of hybrid mesoporous membranes.

Yamaguchi A; Teramae N

2008-01-01

93

Fabrication and analytical applications of hybrid mesoporous membranes.  

Science.gov (United States)

Recently, a hybrid mesoporous membrane composed of surfactant-templated mesoporous silica inside a porous anodic alumina membrane has been developed. Since this membrane allows the use of columnar silica-mesopores (silica-nanochannels) as nanofluidic channels, separation of molecules can be realized by mass transport through the silica-nanochannel with molecular dimensions. Here, we review the methods to fabricate the hybrid mesoporous membranes, their structural features, and the analytical applications of hybrid mesoporous membranes. PMID:18187846

Yamaguchi, Akira; Teramae, Norio

2008-01-01

94

Self-healing surface hydrophobicity by consecutive release of hydrophobic molecules from mesoporous silica.  

UK PubMed Central (United Kingdom)

The paper reports a novel approach to achieve self-healing surface hydrophobicity. Mesoporous silica is used as the reservoir for hydrophobic molecules, i.e., octadecylamine (ODA), that can release and refresh the surface hydrophobicity consecutively. A polymdopamine layer is used to further encapsulate silica-ODA, providing a reactive layer, governing release of the underlying ODA, and improving the dispersivity of silica nanoparticles in bulk resin. The approach arrives at self-healing (super)hydrophobicity without using any fluoro-containing compounds.

Liu Q; Wang X; Yu B; Zhou F; Xue Q

2012-04-01

95

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Na fabricação de aglomerados à base de madeira são utilizados adesivos sintéticos como melamina-formaldeído (MF), fenol-formaldeído (FF), uréia-formaldeído (UF), entre outros. Devido ao alto custo desses adesivos, pesquisas que visam a introdução de alterações nas suas formulações são importantes 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 d (more) e Acacia mearnsii em uma resina comercial à base de uréia-formaldeído nas propriedades físicas e mecânicas de chapas aglomeradas. As chapas aglomeradas foram confeccionadas com madeira de Eucalyptus urophylla. Foram avaliadas quatro composições de adesivo: T1 - 100% de resina UF (testemunha); (T2) 90% de resina UF + 10% de tanino 50%; (T3) 85% de resina UF + 15% de tanino 50% e (T4) 70% de resina UF + 30% de tanino 50%. Através dos ensaios, conclui-se que é possível adicionar tanino à resina uréia-formaldeído sem com isso prejudicar as propriedades físicas e mecânicas das chapas. Abstract in english In the production of the wood base particleboards, synthetic adhesives are used as melamina-formaldehyde (MF), phenol-formaldehyde (FF), urea-formaldehyde (UF), among others. Due to the high cost of these adhesives, researches that a seek the introduction of alterations in their formulations are 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 resi (more) n 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.

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

2008-08-01

96

Resin impregnated fibre batt  

Energy Technology Data Exchange (ETDEWEB)

A bonded fibre insulation batt is produced by ragging, teasing and otherwise doffering fibres of wool and/or synthetic or other natural fibres such as monoacrylic, acrylic, polyamide, polyester or cotton fibres, so as to form a sliver with said fibres randomly dispersed and lapping the sliver to produce a mat of the desired thickness. The mat is then impregnated with a resin, such as a fireproofing resin, and preferably with a pesticide and a smoke retardant. The impregnated mat is placed in an oven to cure the resin thus forming the insulating batt which can be cut to desired size.

Lewellin, R.L.

1989-10-03

97

Mesoporous silica nanoparticles in nanotechnology.  

UK PubMed Central (United Kingdom)

Mesoporous silica nanoparticles (MSNs) are a versatile drug delivery system that can be used for loading of different guest molecules such as peptides, proteins, anticancer agents, and genetic material. MSNs are considered promising drug carriers due to their tuneable particle size, pore structure, and surface functionalization. Thus, MSNs provide opportunities for their effective application in a wide variety of fields. In the current review, we discuss both conventional and advanced MSNs synthesis methods, including their applications for drug delivery, gatekeepers, and biosensors. In addition, the research progress in biocompatibility, cytotoxicity, and internalization mechanisms is reported.

Douroumis D; Onyesom I; Maniruzzaman M; Mitchell J

2013-09-01

98

Electrochemical fabrication of electroactive ordered mesoporous electrode.  

UK PubMed Central (United Kingdom)

A novel and simple method for the electrochemical modification of ordered mesoporous silica is described. A well-organized thin film of amine-functionalized ordered mesoporous silica has been deposited electrochemically on the electrode surface. The resulting amine-functionalized electrodes were then subjected to post-functionalization with catechol moieties through electrochemical generation of reactive o-quinone followed by covalent bonding to the anchored amine groups inside the mesoporous channels of silica to afford the corresponding modified electrodes bearing aminocatechol electroactive groups. This simply obtained nanoporous modified electrode with adequate loading of electroactive groups shows very good electrochemical responses.

Rafiee M; Karimi B; Asl YA; Vali H

2013-03-01

99

Ecodesign of ordered mesoporous silica materials.  

UK PubMed Central (United Kingdom)

Characterized by a regular porosity in terms of pore size and pore network arrangement, ordered mesoporous solids have attracted increasing interest in the last two decades. These materials have been identified as potential candidates for several applications. However, more environmentally friendly and economical synthesis routes of mesoporous silica materials were found to be necessary in order to develop these applications on an industrial scale. Consequently, ecodesign of ordered mesoporous silica has been considerably developed with the objective of optimizing the chemistry and the processing aspects of the material synthesis. In this review, the main strategies developed with this aim are presented and discussed.

Gérardin C; Reboul J; Bonne M; Lebeau B

2013-05-01

100

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

 
 
 
 
101

Preparation of irregular mesoporous hydroxyapatite  

International Nuclear Information System (INIS)

[en] 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

102

Mechanical properties of experimental dental composites containing a combination of mesoporous and nonporous spherical silica as fillers.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Mesoporous fillers have been investigated for use in dental composites because of their potential for creating micromechanical filler/resin matrix interphase bonding. Such a micromechanical bonding could eliminate the need for the silane treatment of fillers for interfacial chemical bonding that is prone to hydrolysis in the oral environment. In the case of micromechanical bonding, dental polymer chains are threaded mechanically (like a "necklace") through nanosized channels in the fillers. METHODS: A combination of mesoporous silica, which was synthesized using the non-surfactant templating method, and nonporous spherical silica (500nm) was used to prepare experimental dental composites. The porous silica used in this study contained interconnected pores and channels as opposed to porous fillers containing surface pores. The compressive strength, compressive modulus, flexural modulus, and flexural strength of these composites were evaluated. RESULTS: The results showed that composites containing a combination of mesoporous and nonporous fillers have better mechanical properties than the composites having either of these fillers alone. SIGNIFICANCE: The results showed that a combination of mesoporous and nonporous materials can be used to prepare stronger dental materials that may resist hydrolysis and wear.

Samuel SP; Li S; Mukherjee I; Guo Y; Patel AC; Baran G; Wei Y

2009-03-01

103

Pluronic polymer capped biocompatible mesoporous silica nanocarriers.  

UK PubMed Central (United Kingdom)

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.

Yildirim A; Demirel GB; Erdem R; Senturk B; Tekinay T; Bayindir M

2013-09-01

104

Sample Desorption/Onization From Mesoporous Silica  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-10-25

105

Aggregation-free gold nanoparticles in ordered mesoporous carbons: toward highly active and stable heterogeneous catalysts.  

UK PubMed Central (United Kingdom)

A coordination-assisted synthetic approach is reported here for the synthesis of highly active and stable gold nanoparticle catalysts in ordered mesoporous carbon materials using triblock copolymer F127 as a structure-directing agent, thiol-containing silane as a coordination agent, HAuCl4 as a gold source, and phenolic resin as a carbon source. Upon carbonization, the gold precursor becomes reduced to form monodispersed Au nanoparticles of ca. 9.0 nm, which are entrapped or confined by the "rigid" mesoporous carbonaceous framework. Nanoparticle aggregation is inhibited even at a high temperature of 600 °C. After removal of the silica component, the materials possess the ordered mesostructure, high surface area (?1800 m(2)/g), large pore volume (?1.19 cm(3)/g), and uniform bimodal mesopore size (<2.0 and 4.0 nm). The monodispersed gold nanoparticles are highly exposed because of the interpenetrated bimodal pores in the carbon framework, which exhibit excellent catalytic performance. A completely selective conversion of benzyl alcohol in water to benzoic acid can be achieved at 90 °C and 1 MPa oxygen. Benzyl alcohol can also be quantitatively converted to benzoic acid at 60 °C even under an atmospheric pressure, showing great advantages in green chemistry. The catalysts are stable, poison resistant, and reusable with little activity loss due to metal leaching. The silane coupling agent played several functions in this approach: (1) coordinating with gold species by the thiol group to benefit formation of monodispersed Au nanoparticles; (2) reacting with phenolic resins by silanol groups to form relatively "rigid" composite framework; (3) pore-forming agent to generate secondary pores in carbon pore walls, which lead to higher surface area, larger pore volumes, and higher accessibility to to the gold nanoparticles. Complete removal of the silica component proves to have little effect on the catalytic performance of entrapped Au nanoparticles.

Wang S; Zhao Q; Wei H; Wang JQ; Cho M; Cho HS; Terasaki O; Wan Y

2013-08-01

106

Mesoporous Materials: Ordered Mesoporous Materials Based on Interfacial Assembly and Engineering (Adv. Mater. 37/2013).  

UK PubMed Central (United Kingdom)

The two-phase interface provides a rich and crucial site for the construction of ordered mesoporous materials, as reviewed by Dongyuan Zhao, Yonghui Deng and co-workers on page 5129. Based on interfacial assembly and engineering strategies, diverse mesoporous materials have been synthesized and used in a wide range of applications.

Li W; Yue Q; Deng Y; Zhao D

2013-10-01

107

Synthesis of mesoporous silica nanoparticles.  

UK PubMed Central (United Kingdom)

Good control of the morphology, particle size, uniformity and dispersity of mesoporous silica nanoparticles (MSNs) is of increasing importance to their use in catalyst, adsorption, polymer filler, optical devices, bio-imaging, drug delivery, and biomedical applications. This review discusses different synthesis methodologies to prepare well-dispersed MSNs and hollow silica nanoparticles (HSNs) with tunable dimensions ranging from a few to hundreds of nanometers of different mesostructures. The methods include fast self-assembly, soft and hard templating, a modified Stöber method, dissolving-reconstruction and modified aerogel approaches. In practical applications, the MSNs prepared by these methods demonstrate good potential for use in high-performance catalysis, antireflection coating, transparent polymer-MSNs nanocomposites, drug-release and theranostic systems.

Wu SH; Mou CY; Lin HP

2013-05-01

108

Water repellent periodic mesoporous organosilicas.  

Science.gov (United States)

This paper demonstrates for the first time thermally induced gradual hydrophobization, monitored quantitatively by ellipsometric porosimetry, of four prototypical periodic mesoporous organosilicas (PMOs) that are tailored through materials chemistry for use as low-dielectric-constant (low k) materials in microprocessors. Theoretical aspects of this quantification are briefly discussed. A comparison of structural, mechanical, dielectric, and hydrophobic properties of ethane, methane, ethene, and 3-ring PMOs is made. Particularly, ethane, methane, and 3-ring PMOs show impressive water repellency at post-treatment temperatures as low as 350 °C, with corresponding Young's modulus values greater than 10 GPa and k values smaller than 2, a figure of merit that satisfies the technological requirements of future generation microchips. PMID:21204583

Wang, Wendong; Grozea, Daniel; Kohli, Sandeep; Perovic, Douglas D; Ozin, Geoffrey A

2011-01-04

109

Synthesis of mesoporous silica nanoparticles.  

Science.gov (United States)

Good control of the morphology, particle size, uniformity and dispersity of mesoporous silica nanoparticles (MSNs) is of increasing importance to their use in catalyst, adsorption, polymer filler, optical devices, bio-imaging, drug delivery, and biomedical applications. This review discusses different synthesis methodologies to prepare well-dispersed MSNs and hollow silica nanoparticles (HSNs) with tunable dimensions ranging from a few to hundreds of nanometers of different mesostructures. The methods include fast self-assembly, soft and hard templating, a modified Stöber method, dissolving-reconstruction and modified aerogel approaches. In practical applications, the MSNs prepared by these methods demonstrate good potential for use in high-performance catalysis, antireflection coating, transparent polymer-MSNs nanocomposites, drug-release and theranostic systems. PMID:23403864

Wu, Si-Han; Mou, Chung-Yuan; Lin, Hong-Ping

2013-02-12

110

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

UK PubMed Central (United Kingdom)

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

Gao Y; De Canck E; Leermakers M; Baeyens W; Van Der Voort P

2011-12-01

111

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

Science.gov (United States)

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

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

2011-10-17

112

A highly ordered cubic mesoporous silica/graphene nanocomposite.  

UK PubMed Central (United Kingdom)

A highly ordered cubic mesoporous silica (KIT-6)/graphene nanocomposite and 2D KIT-6 nanoflakes were synthesized using a novel synthesis methodology. The non-ionic triblock copolymer, P123, played a dual role as a structure-directing agent in the formation of the cubic mesoporous structure and as a cross-linking agent between mesoporous silica and graphene. The prepared (KIT-6)/graphene nanocomposite could act as a template for the preparation of mesoporous material/graphene nanocomposites.

Lee CW; Roh KC; Kim KB

2013-09-01

113

A highly ordered cubic mesoporous silica/graphene nanocomposite.  

Science.gov (United States)

A highly ordered cubic mesoporous silica (KIT-6)/graphene nanocomposite and 2D KIT-6 nanoflakes were synthesized using a novel synthesis methodology. The non-ionic triblock copolymer, P123, played a dual role as a structure-directing agent in the formation of the cubic mesoporous structure and as a cross-linking agent between mesoporous silica and graphene. The prepared (KIT-6)/graphene nanocomposite could act as a template for the preparation of mesoporous material/graphene nanocomposites. PMID:24057016

Lee, Chang-Wook; Roh, Kwang Chul; Kim, Kwang-Bum

2013-09-26

114

Method for removing contaminants from plastic resin  

Energy Technology Data Exchange (ETDEWEB)

A resin recycling method that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The method includes receiving the resin in container form. The containers are then ground into resin particles. The particles are exposed to a solvent, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. After separating the particles and the resin, a solvent removing agent is used to remove 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)

2008-12-09

115

Resin binders in ramming paste  

Energy Technology Data Exchange (ETDEWEB)

Resin bonded carbon refractories avoid the emission of PAH associated with tar based binders. Six prototype novolak resins were tested as binders in ramming paste for aluminum electrolysis cells. The resins were compared with two reference binders, one tar based and one resin based. The resins were tested in the laboratory as well as in actual operation. The mixing and ramming properties were satisfactory. The baking shrinkage was low and the mechanical strength was reasonably high. Even if resin binders are baked to a glassy structure, the sodium resistance was good. The viscosity of the resin binders can be adjusted to provide the desired range of temperature of use for the ramming paste. Elkem Aluminum installed the first cell of resin bonded ramming paste in September 1991.

Kvam, K.R.; Oeye, H.A. [Univ. of Trondheim (Norway); Johansen, J.A.; Ugland, R. [Elkem a/s Carbon, Kristiansand (Norway)

1996-10-01

116

Phosphonic acid based exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1995-09-12

117

Phosphonic acid based exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1995-01-01

118

Influence of synthesis conditions and mesoporous structures on the gold nanoparticles supported on mesoporous silica hosts  

Energy Technology Data Exchange (ETDEWEB)

Loading gold on mesoporous materials via different methods has been actively attempted in the literature, but the knowledge about the influences of synthesis details and different mesoporous structures on the size and thermal stability of gold nanoparticles supported on mesoporous hosts is still limited. In this study, Au/HMS, Au/MCM-41, Au/MCM-48, Au/SBA-15, and Au/SBA-16 samples were prepared by modifying a variety of mesoporous silicas by amine ligands followed by loading HAuCl4 and calcination. The influences of different amine ligands ((3-aminopropyl)triethoxysilane versus N-[3-(trimethoxysilyl)propyl]ethylenediamine), solvents (water versus ethanol), calcination temperatures (200 or 550 C), and mesoporous structures on the size of supported gold nanoparticles were systematically investigated employing nitrogen adsorption-desorption measurement, X-ray diffraction (XRD), diffuse reflectance UV-vis spectroscopy, and transmission electron microscopy (TEM). Interestingly, while big and irregular gold particles situate on MCM-48 with bicontinuous three-dimensional pore structure and relatively small pore size (2.4 nm) upon calcination at 550 C, homogeneous and small gold nanoparticles maintain inside SBA-15 with one-dimensional pore structure and relatively big pore size (6.8 nm). Apparently, the pore structure and pore size of mesoporous silica hosts play a key role in determining the size and thermal stability of the supported gold nanoparticles. Our results may provide some useful clues for the rational design of supported metal catalysts by choosing suitable mesoporous hosts.

Lee, Byunghwan [Korea Institute of Industrial Technology, ChonAn, Korea; Ma, Zhen [ORNL; Zhang, Zongtao [ORNL; Park, Chulhwan [Kwangwoon University; Dai, Sheng [ORNL

2009-01-01

119

Radiation curable epoxy resin  

International Nuclear Information System (INIS)

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

1978-01-01

120

Resins for condensate polishing  

Energy Technology Data Exchange (ETDEWEB)

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

Grantham, J.G. (DISA (UK) Ltd., Walsall (UK))

1985-06-01

 
 
 
 
121

Resins for condensate polishing  

International Nuclear Information System (INIS)

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

1985-01-01

122

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.

Isabel Izquierdo-Barba; Montserrat Colilla; María Vallet-Regí

2008-01-01

123

Mesoporous carbon for capacitive deionization of saline water.  

UK PubMed Central (United Kingdom)

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 C; Mayes R; Kiggans J; Sharma K; Yiacoumi S; DePaoli D; Dai S

2011-12-01

124

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.

2011-01-01

125

Preparation of mesoporous silica fiber matrix for VOC removal  

Energy Technology Data Exchange (ETDEWEB)

A novel method for the preparation of the mesoporous silica fiber matrix was introduced for a removal of volatile organic compounds (VOCs). Paper making technology was applied to make a sheet of mesoporous silica fiber matrix. Reinforcing the mesoporous silica fiber with the ceramic fibers (50wt.%) increased the mechanical strength of the matrix. Mesoporous silica fibers using TMOS (tetramethoxysilane) as a silica source and CTAC (cetyltrimethyl-ammoniumchloride) as a surfactant were drawn by the spinning method. The spinning process increased both the crystallinity and the fraction of mesopores (1.9nm) of the fiber. As the spinning rate was increased both the crystallinity and the specific area of the mesoporous silica fiber increased, but the diameter of fiber decreased. We could control the size and morphology of mesoporous silica fiber matrix by changing the shape of substrates. This leads to easy fabrication of honeycomb-structured adsorbent which can be used for the VOC removal.

Chu, Young-Hwan; Kim, Hyun-Jong; Song, Keun-Young; Shul, Yong-Gun; Jung, Kyeong-Taek; Lee, Kangtaek [Department of Chemical Engineering, Yonsei University, 134 Shinchon-Dong, Seodaemun-ku, 120-749 Seoul (Korea, Republic of); Han, Moon-Hee [Korea Institute of Energy Research, P.O. Box 103, Yusung, 305-343 Taejon (Korea, Republic of)

2002-06-05

126

Synthesis of Polymer—Mesoporous Silica Nanocomposites  

Directory of Open Access Journals (Sweden)

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

Liangming Wei; Nantao Hu; Yafei Zhang

2010-01-01

127

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.

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

2013-01-01

128

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

129

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.; Khanadeev V.A.; Terentyuk G.S.; Chumakov D.S.; Basko M.V.; Bucharskaya A.B.; Genina E.A.; Bashkatov A.N.; Khlebtsov N.G.

2013-01-01

130

Resin composite restorative materials.  

UK PubMed Central (United Kingdom)

This paper surveys the most important developments in resin-based dental composites and focuses on the deficits (e.g. polymerization shrinkage) and strengths of the materials and their clinical implications. Moreover, differences between composite categories, such as hybrid, nanohybrid, microfilled, packable, ormocer-based, silorane-based, polyacid-modified composites (compomers) and flowable composites are highlighted, especially in view of their mechanical behaviour. In addition to the classical dimethacrylate-based composites, special attention is given to alternative monomers, such as siloranes, ormocers or high-molecular-weight dimethacrylate monomers (e.g. dimer acid-based dimethacrylates and tricyclodecane (TCD)-urethane), analysing their advantages, behaviour and abilities. Finally, the paper attempts to establish the needs and wishes of clinicians for further development of resin-based composites.

Ilie N; Hickel R

2011-06-01

131

Resin composite restorative materials.  

Science.gov (United States)

This paper surveys the most important developments in resin-based dental composites and focuses on the deficits (e.g. polymerization shrinkage) and strengths of the materials and their clinical implications. Moreover, differences between composite categories, such as hybrid, nanohybrid, microfilled, packable, ormocer-based, silorane-based, polyacid-modified composites (compomers) and flowable composites are highlighted, especially in view of their mechanical behaviour. In addition to the classical dimethacrylate-based composites, special attention is given to alternative monomers, such as siloranes, ormocers or high-molecular-weight dimethacrylate monomers (e.g. dimer acid-based dimethacrylates and tricyclodecane (TCD)-urethane), analysing their advantages, behaviour and abilities. Finally, the paper attempts to establish the needs and wishes of clinicians for further development of resin-based composites. PMID:21564116

Ilie, N; Hickel, R

2011-06-01

132

[Chemical durability of composite resins  

UK PubMed Central (United Kingdom)

To evaluate their chemical durability, samples of posterior composite resins were stored in NaOH (0.1 mol, 1 mol), HCl (0.1 mol, 1 mol), acetone (99%), and distilled water at 37 degrees C for a week and subjected to the direct tensile test, measurement of surface roughness and SEM observation. NaOH caused the degradation of composite resins, decrease of tensile strength and increase of surface roughness. The SEM photograph of fractured surface of tensile specimens revealed the degradation zone under the surface. It was considered that NaOH caused the hydrolysis of silan coupling of composite resins. HCl also caused the degradation of composite resins, but some resins showed the durability in this condition. More examination is needed to clarify the mechanism of degradation. Acetone caused the degradation of matrix resin and some composite resins. It was considered to dissolve the low degree of polymerized matrix resin of composite resins. Immersion in chemicals of composite resins was thought to be useful to evaluate the chemical durability and to accelerate the degradation in water.

Fujishima A; Miyazaki T; Takatama M; Suzuki E; Miyaji T

1989-03-01

133

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

UK PubMed Central (United Kingdom)

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 D; Getman RB; Wei Z; Snurr RQ; Zhou HC

2012-04-01

134

WATER-ABSORBING RESIN COMPOSITION  

UK PubMed Central (United Kingdom)

A water-absorbent resin composition having an antimicrobial property, which suppresses the generation of dust of the antimicrobial agent. A water-absorbent resin composition comprising a water-absorbent resin and an antimicrobial agent comprising an inorganic compound carrying an antimicrobial metal, the water-absorbent resin composition being characterized in that the degree of generated dust of the water-absorbent resin composition is at most 100 CPM. The water-absorbent resin composition of the present invention can be suitably used as hygienic materials such as disposable diaper, sanitary napkin and incontinence pad urine-absorbent materials for pets materials for civil engineering and construction such as packing materials drip absorbents food freshness retaining materials such as cold-reserving agents horticultural articles such as water-retaining materials for soils and the like.

TANIGUCHI TAKAYASU; OIDA TATSUYA; NAWATA YASUHIRO

135

Synthesis of Vanadium-mesoporous Hollow Spheres  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

136

Mesoporous systems for poorly soluble drugs.  

UK PubMed Central (United Kingdom)

Utilization of inorganic mesoporous materials in formulations of poorly water-soluble drugs to enhance their dissolution and permeation behavior is a rapidly growing area in pharmaceutical materials research. The benefits of mesoporous materials in drug delivery applications stem from their large surface area and pore volume. These properties enable the materials to accommodate large amounts of payload molecules, protect them from premature degradation, and promote controlled and fast release. As carriers with various morphologies and chemical surface properties can be produced, these materials may even promote adsorption from the gastrointestinal tract to the systemic circulation. The main concern regarding their clinical applications is still the safety aspect even though most of them have been reported to be safely excreted, and a rather extensive toxicity screening has already been conducted with the most frequently studied mesoporous materials. In addition, the production of the materials on a large scale and at a reasonable cost may be a challenge when considering the utilization of the materials in industrial processes. However, if mesoporous materials could be employed in the industrial crystallization processes to produce hybrid materials with poorly soluble compounds, and hence to enhance their oral bioavailability, this might open new avenues for the pharmaceutical industry to employ nanotechnology in their processes.

Xu W; Riikonen J; Lehto VP

2013-08-01

137

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

138

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

International Nuclear Information System (INIS)

[en] The electronics industry is one of the world’s fastest growing manufacturing industries. However, e-waste has become a serious pollution problem. This study reports the recovery of e-waste for preparing valuable MCM-48 and ordered mesoporous carbon for the first time. Specifically, this study adopts an alkali-extracted method to obtain sodium silicate precursors from electronic packaging resin ash. The influence of synthesis variables such as gelation pH, neutral/cationic surfactant ratio, hydrothermal treatment temperature, and calcination temperature on the mesophase of MCM-48 materials is investigated. Experimental results confirm that well-ordered cubic MCM-48 materials were synthesized in strongly acidic and strongly basic media. The resulting mesoporous silica had a high surface area of 1,317 m2/g, mean pore size of about 3.0 nm, and a high purity of 99.87 wt%. Ordered mesoporous carbon with high surface area (1,715 m2/g) and uniform pore size of CMK-1 type was successfully prepared by impregnating MCM-48 template using the resin waste. The carbon structure was sensitive to the sulfuric acid concentration and carbonization temperature. Converting e-waste into MCM-48 materials not only eliminates the disposal problem of e-waste, but also transforms industrial waste into a useful nanomaterial.

2012-01-01

139

Vitrification of ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-01-01

140

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

UK PubMed Central (United Kingdom)

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

Kiba S; Suzuki N; Okawauchi Y; Yamauchi Y

2010-09-01

 
 
 
 
141

Powder Solidifyers of Epoxy Resins  

International Science & Technology Center (ISTC)

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

142

Porous Copolymer Resins: Tuning Pore Structure and Surface Area with Non Reactive Porogens  

Directory of Open Access Journals (Sweden)

Full Text Available In this review, the preparation of porous copolymer resin (PCR) materials via suspension polymerization with variable properties are described by tuning the polymerization reaction, using solvents which act as porogens, to yield microporous, mesoporous, and macroporous materials. The porogenic properties of solvents are related to traditional solubility parameters which yield significant changes in the surface area, porosity, pore volume, and morphology of the polymeric materials. The mutual solubility characteristics of the solvents, monomer units, and the polymeric resins contribute to the formation of porous materials with tunable pore structures and surface areas. The importance of the initiator solubility, surface effects, the temporal variation of solvent composition during polymerization, and temperature effects contribute to the variable physicochemical properties of the PCR materials. An improved understanding of the factors governing the mechanism of formation for PCR materials will contribute to the development and design of versatile materials with tunable properties for a wide range of technical applications.

Mohamed H. Mohamed; Lee D. Wilson

2012-01-01

143

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.

Els De Canck; Inmaculada Dosuna-Rodríguez; Eric M. Gaigneaux; Pascal Van Der Voort

2013-01-01

144

Resin regeneration device for condensate desalter  

International Nuclear Information System (INIS)

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

1997-01-08

145

Functionalized mesoporous silica particles for application in drug delivery system.  

UK PubMed Central (United Kingdom)

In these years, ordered mesoporous silica materials have shown promising applications in drug delivery system as drug carriers. These carriers with stable mesoporous structure, large surface area, good biocompatibility and tailored size of mesopores exhibit significant property of higher drug loading. However, silica-based mesoporous materials cannot control the release of the loaded drug without modifications. In this paper, we review the recent research work discussing functionalization of mesoporous materials by various components and methods for application in drug delivery systems. All the examples show that these functionalized mesoporous silica-based systems have great potential for a variety of drug delivery applications, specifically in the fields of the drug targeted and controlled delivery systems.

Pang J; Luan Y; Yang X; Jiang Y; Zhao L; Zong Y; Li Z

2012-07-01

146

Functionalized mesoporous silica particles for application in drug delivery system.  

Science.gov (United States)

In these years, ordered mesoporous silica materials have shown promising applications in drug delivery system as drug carriers. These carriers with stable mesoporous structure, large surface area, good biocompatibility and tailored size of mesopores exhibit significant property of higher drug loading. However, silica-based mesoporous materials cannot control the release of the loaded drug without modifications. In this paper, we review the recent research work discussing functionalization of mesoporous materials by various components and methods for application in drug delivery systems. All the examples show that these functionalized mesoporous silica-based systems have great potential for a variety of drug delivery applications, specifically in the fields of the drug targeted and controlled delivery systems. PMID:22512562

Pang, J; Luan, Y; Yang, X; Jiang, Y; Zhao, L; Zong, Y; Li, Z

2012-07-01

147

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery  

Science.gov (United States)

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples’ structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft=ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

Gao, Lin; Sun, Jihong; Li, Yuzhen

2011-08-01

148

Production of Acetal, Amino, and Phenolic Resins.  

Science.gov (United States)

The document provides information obtained on the manufacturing processes of three formaldehyde-based resins - phenolic, amino, and acetal resins. It also provides information on the companies that produce these resins and determines those facilities that...

1992-01-01

149

Resin regenerating device in condensate desalting system  

International Nuclear Information System (INIS)

Purpose: To improve the accuracy in the separation of anionic and cationic exchange resins. Constitution: Resins transferred from a condensate desalting column are charged in a cationic exchange resin column. The temperature of water for separating and transferring the resins is measured by a temperature detector disposed in a purified water injection line, and water is adjusted to a suitable flow rate for the separation and transfer of the resins by an automatic flow rate control valve, and then is injected. The resins are separated into cationic exchange resins and anionic exchange resins, in which only the anionic exchange resins are transferred, through an anionic exchange transfer line, into an anionic exchange resin column. By controlling the flow rate depending on the temperature of the injected water, the developing rate of the resin layer is made constant to enable separation and transfer of the resins at high accuracy. (Seki, T.)

1983-04-01

150

Mesoporous and Nanoporous Materials, and Methods of Synthesizing the Same  

UK PubMed Central (United Kingdom)

A method for synthesizing a phosphonic acid functionalized mesoporous metal oxide material (e.g., silica, titania, alumina, preferably silica material) is provided. Further, a method of using the phosphonic acid functionalized mesoporous silica material as a solid acid catalyst in a pinicole-pinacolone rearrangement reaction, and a method of using a phosphonic acid functionalized mesoporous silica material as a solid acid catalyst in a transesterification reaction is provided. A method for preparing a mesoporous titania film for use in a dye sensitized solar cell is also provided.

ASEFA TEWODROS; MISHLER II RICHARD E; SCHIFF ERIC A

151

Surface functionalized mesoporous material and method of making same  

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-01-01

152

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

153

Phosphorous-Containing Imide Resins.  

Science.gov (United States)

Flame-resistant reinforced bodies are disclosed which are composed of reinforcing fibers, filaments or fabrics in a cured body of bis- and tris-imide resins. These resins are derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydr...

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

1983-01-01

154

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

UK PubMed Central (United Kingdom)

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(2+)>Zn(2+)>Cd(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(2+), Zn(2+) and Cd(2+) 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 HNO(3). The activities of the recovered mesoporous silicas were between 80 and 90% of the original materials.

Alothman ZA; Apblett AW

2010-10-01

155

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

Science.gov (United States)

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(2+)>Zn(2+)>Cd(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(2+), Zn(2+) and Cd(2+) 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 HNO(3). The activities of the recovered mesoporous silicas were between 80 and 90% of the original materials. PMID:20663609

Alothman, Zeid A; Apblett, Allen W

2010-06-25

156

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

157

Synthesis of periodic mesoporous silica thin films  

Energy Technology Data Exchange (ETDEWEB)

We have synthesized periodic mesoporous silica thin films from homogeneous solutions. To synthesize the films, a thin layer of a pH 7 micellar coating solution that contains TMOS (tetramethoxysilane) is dip or spin-coated onto Si wafers, borosilicate glass, or quartz substrates. NH3 gas is diffused into the solution and causes rapid hydrolysis and condensation of the TMOS and the formation of periodic mesoporous thin films within 10 seconds. Combination of homogenous solutions and rapid product formation maximizes the concentration of the desired product and provides a controlled, predictable microstructure. The films have been made continuous and crack-free by optimizing initial silica concentration and film thickness. The films are being evaluated as high surface area, size-selective coatings for surface acoustic wave (SAW) sensors.

Anderson, M.T.; Martin, J.E.; Odinek, J.G.; Newcomer, P.

1996-06-01

158

Diffraction analysis of mesostructured mesoporous materials.  

UK PubMed Central (United Kingdom)

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

Solovyov LA

2013-05-01

159

Recycle of silicate waste into mesoporous materials.  

Science.gov (United States)

Template synthesis of porous carbon materials usually requires selective removal of template silica from the carbon/silica composites. It not only involves waste of valuable chemicals, but also poses significant environmental concerns including high waste treatment cost. Recycling of silicates released from such nanocasting methods is successfully performed for the first time to regenerate valuable mesoporous MCM and SBA type silica materials, which will not only help in saving valuable chemicals, but also in decreasing chemical waste, contributing in improvement of our environmental standards. This approach can thus improve cost effectiveness for the mass production of nanostructured carbon and others utilizing silica directed nanocasting method by recycling otherwise silicate waste into highly desirable valuable mesoporous silica. PMID:21417445

Kim, Jung Ho; Kim, Minwoo; Yu, Jong-Sung

2011-03-21

160

Recycle of silicate waste into mesoporous materials.  

UK PubMed Central (United Kingdom)

Template synthesis of porous carbon materials usually requires selective removal of template silica from the carbon/silica composites. It not only involves waste of valuable chemicals, but also poses significant environmental concerns including high waste treatment cost. Recycling of silicates released from such nanocasting methods is successfully performed for the first time to regenerate valuable mesoporous MCM and SBA type silica materials, which will not only help in saving valuable chemicals, but also in decreasing chemical waste, contributing in improvement of our environmental standards. This approach can thus improve cost effectiveness for the mass production of nanostructured carbon and others utilizing silica directed nanocasting method by recycling otherwise silicate waste into highly desirable valuable mesoporous silica.

Kim JH; Kim M; Yu JS

2011-04-01

 
 
 
 
161

Nonsurfactant supramolecular synthesis of ordered mesoporous silica.  

UK PubMed Central (United Kingdom)

Hoogsteen-bonded tetrads and pentamers are formed by a large variety of organic molecules through H-donor and acceptor groups capable of inducing self-organization to form columnar and hexagonal mesophases. The biological importance of such macromolecular structures is exemplified by the assembly of guanosine-rich groups of telomere units and their implication in chromosomal replication. Folic acid is composed of a pterin group, chemically and structurally similar to guanine, conjugated to an l-glutamate moiety via a p-amino benzoic acid. Our aim has been to develop a delivery vehicle for folic acid and at the same time provide a novel synthetic route for ordered mesoporous materials without the use of amphiphilic surfactants. We present a new nonsurfactant route for the synthesis of highly ordered mesoporous materials, based on the supramolecular templating of stacked arrays of the tetramer-forming pterin groups of folic acid under a variety of synthetic conditions. This method leads to hexagonally ordered mesoporous structures with gyroid, spherical, and chiral morphologies with pores on the order of 25-30 A in diameter and surface areas above 1000 m(2)/g. More importantly circular dichroism studies reveal that the folate template possesses a chiral signature within the pores in the as-synthesized solid and that chirality is transferred from the folate template to the pore surface via the aminopropyl triethoxysilane costructure directing agent used in the supramolecular assembly. This novel templating approach for ordered mesoporous materials breaks the hegemony of surfactant micellar systems for the preparation of these exciting high surface area solids and opens new opportunities for structural control, design of pore geometry, and novel applications.

Atluri R; Hedin N; Garcia-Bennett AE

2009-03-01

162

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

163

The Synthesis of Functional Mesoporous Materials  

Energy Technology Data Exchange (ETDEWEB)

The ability to decorate a silica surface with specific ligand fields and/or metal complexes creates powerful new capabilities for catalysis, chemical separations and sensor development. Integrating this with the ability to control the spacing of these complexes across the surface, as well as the symmetry and size of the pore structure, allows the synthetic chemist to hierarchically tailor these structured nanomaterials to specific needs. The next step up the “scale ladder” is provided by the ability to coat these mesoporous materials onto complex shapes, allowing for the intimate integration of these tailored materials into device interfaces. The ability to tailor the pore structure of these mesoporous supports is derived from the surfactant templated synthesis of mesoporous materials, an area which has seen an explosion of activity over the last decade.[1,2] The ability to decorate the surface with the desired functionality requires chemical modification of the oxide interface, most commonly achieved using organosilane self-assembly.[3-6] This manuscript describes recent results from the confluence of these two research areas, with a focus on synthetic manipulation of the morphology and chemistry of the interface, with the ultimate goal of binding metal centers in a chemically useful manner.

Fryxell, Glen E.

2006-11-01

164

Mesoporous Silica from Rice Husk Ash  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as 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

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

2010-01-01

165

Organic functionalization of mesopore walls in hierarchically porous zeolites.  

UK PubMed Central (United Kingdom)

Mesopore walls of hierarchically meso-/microporous zeolites (MFI, BEA and LTA) are covered with silanol groups, so that the zeolites can be functionalized with various organic groups via silylation; the organic-functionalized hierarchical zeolites exhibit hydrothermal stability and reusability in catalytic applications, as compared with organic-functionalized mesoporous silica.

Lee DH; Choi M; Yu BW; Ryoo R

2009-01-01

166

An ordered mesoporous aluminosilicate with completely crystalline zeolite wall structure.  

Science.gov (United States)

An ordered mesoporous aluminosilicate with completely crystalline zeolite pore wall structure, denoted as OMZ-1, was successfully synthesized by recrystallization of SBA-15 using in situ formed CMK-5 as the hard template. The role of carbon material not only serves as a hard template to preserve ordered mesoporous structure but also kinetically controls the crystallization process to form large crystals. PMID:16910631

Fang, Yunming; Hu, Haoquan

2006-08-23

167

Synthesis and Catalytic Performance of Mesoporous Material by Twostep Crystallization  

Directory of Open Access Journals (Sweden)

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

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

2010-01-01

168

Phosphorylated Mesoporous Carbon as a Solid Acid Catalyst  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing masstransport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a 10 phosphorylated mesoporous carbon solid-acid catalyst characterized by NH3-TPD and isopropanol dehydration.

Dai, Sheng [ORNL; Mayes, Richard T [ORNL; Fulvio, Pasquale F [ORNL; Ma, Zhen [ORNL

2011-01-01

169

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

170

Highly ordered cubic mesoporous electrospun SiO2 nanofibers.  

UK PubMed Central (United Kingdom)

Cubic (Im3[combining macron]m) mesoporous silica nanofibers were successfully prepared using a new F127-PVA-SiO2 tri-constituent assembly approach by the electrospinning technique. PVA was used to protect the F127 directed cubic micelles which usually deform during electrospinning. The preformed Au NPs can be loaded inside the mesopores of the nanofibers.

Saha J; De G

2013-07-01

171

Transport properties of fast proton conducting mesoporous silica xerogels  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous acid-free silica xerogels exhibiting a proton conductivity of 2.0 x 10{sup -2} S cm{sup -1} at 80 C and 81% RH is reported for the first time. The proton conductivity values, lower cost and higher hydrophilicity of mesoporous silica xerogels make them potential substitutes for Nafion membranes in proton exchange membranes fuel cells (PEMFCs). (author)

Colomer, M.T.; Rubio, F.; Jurado, J.R. [Instituto de Ceramica y Vidrio, CSIC, C/Kelsen n 5, Campus de la Universidad Autonoma, 28049 Madrid (Spain)

2007-05-01

172

Grafted methylenediphosphonate ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Trochimcznk, Andrzej W. (Knoxbille, TN); Gatrone, Ralph C. (Plymouth, PA); Alexandratos, Spiro (Knoxville, TN); Horwitz, E. Philip (Naperville, IL)

1997-01-01

173

Grafted methylenediphosphonate ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange-resin are also disclosed.

Trochimcznk, Andrzej W. (Knoxville, TN); Gatrone, Ralph C. (Plymouth, PA); Alexandratos, Spiro (Knoxville, TN); Horwitz, E. Philip (Naperville, IL)

1998-01-27

174

Organized thiol functional groups in mesoporous core shell colloids  

International Nuclear Information System (INIS)

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 SiO2 colloids with “onion-like” chemical environments. Thiol groups were anchored to an inner selected SiO2 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 SiO2 colloids with organized thiol groups. Highlights: ? Double shell mesoporous silica colloids templated with CTAB. ? Sequential deposition of mesoporous SiO2 layers with different chemistries. ? XPS shows the selective functionalization of mesoporous layers with thiol groups.

2012-01-01

175

Synthesis and catalytic applications of combined zeolitic/mesoporous materials  

Directory of Open Access Journals (Sweden)

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

Jarian Vernimmen; Vera Meynen; Pegie Cool

2011-01-01

176

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

177

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

178

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

179

Bending characteristics of resin concretes  

Scientific Electronic Library Online (English)

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

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

2003-06-01

180

RESIN COMPOSITION AND MOLDING THEREOF  

UK PubMed Central (United Kingdom)

A resin composition comprising 100 parts by mass of lactic acid resin (A), 50 to 100 parts by mass of metal hydroxide (B) and 0.1 to 30 parts by mass of fiber (C), wherein the fiber (C) is a natural fiber or/and a fiber derived from natural material. Moldings thereof satisfy the V-0 standard or VTM-0 standard according to UL94 vertical flame test (UL94V, UL94VTM).

TANAKA Kazuya;; NISHIDA Miki;; TAKAGI Jun;; FUJIHIRA Yuko; MORI Hiroyuki; YAMADA Shinichiro

 
 
 
 
181

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

Science.gov (United States)

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

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

2011-11-21

182

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

UK PubMed Central (United Kingdom)

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

Lin YS; Abadeer N; Hurley KR; Haynes CL

2011-12-01

183

Oil absorption in mesoporous silica particles  

Directory of Open Access Journals (Sweden)

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

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

2010-01-01

184

Mesoporous silica-titania composed materials.  

UK PubMed Central (United Kingdom)

Titania mesosized particles were obtained by TiCl4 hydrolysis in Aerosol OT/water/n-hexane microemulsion. These particles were incorporated in surfactant templated silica mesoporous materials of MCM-41 and MCM-50 structures. Results depended on the surfactant: hexadecyltrimethylammonium bromide templated materials retained the honeycomb structure with small modifications in their characteristics. The dodecyltrimethylammonium bromide templated material changed from honeycomb to lamellar structure when the titania particles were included, with dramatic changes in the structure characteristics. The didodecyldimethylammonium bromide templated lamellar structure was retained after TIO2 inclusion, with a slight increase in the specific area, pore diameter and pore walls thickness.

Messina PV; Morini MA; Sierra MB; Schulz PC

2006-08-01

185

Mesoporous silica-titania composed materials.  

Science.gov (United States)

Titania mesosized particles were obtained by TiCl4 hydrolysis in Aerosol OT/water/n-hexane microemulsion. These particles were incorporated in surfactant templated silica mesoporous materials of MCM-41 and MCM-50 structures. Results depended on the surfactant: hexadecyltrimethylammonium bromide templated materials retained the honeycomb structure with small modifications in their characteristics. The dodecyltrimethylammonium bromide templated material changed from honeycomb to lamellar structure when the titania particles were included, with dramatic changes in the structure characteristics. The didodecyldimethylammonium bromide templated lamellar structure was retained after TIO2 inclusion, with a slight increase in the specific area, pore diameter and pore walls thickness. PMID:16600274

Messina, Paula V; Morini, Marcela A; Sierra, María B; Schulz, Pablo C

2006-03-24

186

Mesoporous magnetically recyclable photocatalysts for water treatment.  

UK PubMed Central (United Kingdom)

Photocatalysis over titanium dioxide is a promising technology for water purification and degradation of emerging contaminants, however, catalyst efficiency and recovery after the photocatalytic reaction are key challenges that have limited the practical deployment of TiO2 in water treatment applications. Herein we report the synthesis of core-shell, superparamagnetic gamma-Fe2O3@SiO2@TiO2 colloidal nanospheres with a mesoporous TiO2 shell, their characterization, and application in photocatalysis. The final surface area of the particles was - 100 m2 g(-1), and their photocatalytic efficiency matched that of P25 TiO2.

Leshuk T; Everett P; Krishnakumar H; Wong K; Linley S; Gu F

2013-04-01

187

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

188

Incorporation of antimicrobial compounds in mesoporous silica film monolith.  

UK PubMed Central (United Kingdom)

Incorporation of the antimicrobial peptide LL-37 (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES), as well as low molecular weight antimicrobial chlorhexidine, into mesoporous silica was obtained using an EISA one-pot synthesis method. FTIR confirmed efficient encapsulation of both LL-37 and chlorhexidine into mesoporous silica, while XRD and TEM showed that antimicrobial agent incorporation can be achieved without greatly affecting the structure of the mesoporous silica. The modified mesoporous silica released LL-37 and chlorhexidine slowly, reaching maximum release after about 200 h. The release rate could also be controlled through incorporation of SH groups in the pore walls, adding to pore hydrophobicity and reducing the release rate by about 50% compared to the unmodified mesoporous silica. Mesoporous silica containing either LL-37 or chlorhexidine displayed potent bactericidal properties against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. While chlorhexidine-loaded mesoporous silica displayed an accompanying high toxicity, as judged from hemolysis, LDH release, and MTT assay, the corresponding material containing LL-37 showed very low toxicity by all these assays, comparable to that observed for mesoporous silica in the absence of antibacterial drug, as well as to the negative controls in the respective assays. Mesoporous silica containing LL-37 therefore holds potential as an implantable material or a surface coating for such materials, as it combines potent bactericidal action with low toxicity, important features for controlling implant-related infections, e.g., for multi-resistant pathogens or for cases where access to the infection site of systemically administered antibiotics is limited due to collagen capsule formation or other factors.

Izquierdo-Barba I; Vallet-Regí M; Kupferschmidt N; Terasaki O; Schmidtchen A; Malmsten M

2009-10-01

189

Silica-based mesoporous nanoparticles for controlled drug delivery  

Science.gov (United States)

Drug molecules with lack of specificity and solubility lead patients to take high doses of the drug to achieve sufficient therapeutic effects. This is a leading cause of adverse drug reactions, particularly for drugs with narrow therapeutic window or cytotoxic chemotherapeutics. To address these problems, there are various functional biocompatible drug carriers available in the market, which can deliver therapeutic agents to the target site in a controlled manner. Among the carriers developed thus far, mesoporous materials emerged as a promising candidate that can deliver a variety of drug molecules in a controllable and sustainable manner. In particular, mesoporous silica nanoparticles are widely used as a delivery reagent because silica possesses favourable chemical properties, thermal stability and biocompatibility. Currently, sol-gel-derived mesoporous silica nanoparticles in soft conditions are of main interest due to simplicity in production and modification and the capacity to maintain function of bioactive agents. The unique mesoporous structure of silica facilitates effective loading of drugs and their subsequent controlled release. The properties of mesopores, including pore size and porosity as well as the surface properties, can be altered depending on additives used to fabricate mesoporous silica nanoparticles. Active surface enables functionalisation to modify surface properties and link therapeutic molecules. The tuneable mesopore structure and modifiable surface of mesoporous silica nanoparticle allow incorporation of various classes of drug molecules and controlled delivery to the target sites. This review aims to present the state of knowledge of currently available drug delivery system and identify properties of an ideal drug carrier for specific application, focusing on mesoporous silica nanoparticles.

Kwon, Sooyeon; Singh, Rajendra K; Perez, Roman A; Abou Neel, Ensanya A

2013-01-01

190

Resin composition for coatings  

International Nuclear Information System (INIS)

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

1968-01-01

191

POLYCARBONATE RESIN COMPOSITION AND FORMED PRODUCT THEREOF  

UK PubMed Central (United Kingdom)

In a polycarbonate resin composition containing a polycarbonate resin and a polycarbosilane compound, the use of the polycarbosilane compound modifies the surface properties of the polycarbonate resin composition without adversely affecting the intrinsic characteristics of the polycarbonate resin, such as transparency, heat resistance, and mechanical properties, e.g., impact resistance. A polycarbonate resin composition containing 100 parts by mass of a polycarbonate resin, 0.001 to 1 part by mass of a metal salt compound, and 0.005 to 5 parts by mass of a polycarbosilane compound has significantly improved flame resistance and high transparency and causes markedly reduced outgassing and mold fouling, without losing impact resistance and heat resistance.

MONDEN TOSHIKI

192

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

193

Synthesis of surfactant-templated mesoporous materials from homogeneous solutions  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous is defined as 20{le}d{le}500{angstrom}. Mesoporous materials with narrow pore size distributions may be useful as hosts, supports, catalysts, or separation media for small molecules. An ensemble of organic molecules to create a larger template has been used to synthesize ordered mesoporous materials. The silicon alkoxide precursors TEOS and TMOS were examined. Cosolvents were used to control pore size and the structure of the mesophase. Effects of anions (salts) on mesophase formation were examined. Properties of mesophases made from homogeneous solutions are discussed.

Anderson, M.T.; Martin, J.E.; Odinek, J.; Newcomer, P.

1995-08-01

194

Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure  

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-01-01

195

Ordered iron nanowires in the mesoporous silica matrix  

Energy Technology Data Exchange (ETDEWEB)

We report a novel synthetic method for preparation of ordered magnetic iron nanowires in mesoporous silica matrix. The method is based on the incorporation of a hydrophobic metal compound, Fe(CO){sub 5}, into the hydrophobic part of a freshly prepared mesoporous silica-surfactant composite. Shape and size of obtained iron nanowires is consistent with the dimensions of porous framework. Particles are uniform and well ordered in the silica matrix. Thus, mesoporous silica serves as nanoreactor for the formation of Fe-nanoparticles.

Eliseev, A.A. E-mail: eliseev@inorg.chem.msu.ru; Napolskii, K.S.; Lukashin, A.V.; Tretyakov, Y.D

2004-05-01

196

Ordered iron nanowires in the mesoporous silica matrix  

International Nuclear Information System (INIS)

We report a novel synthetic method for preparation of ordered magnetic iron nanowires in mesoporous silica matrix. The method is based on the incorporation of a hydrophobic metal compound, Fe(CO)5, into the hydrophobic part of a freshly prepared mesoporous silica-surfactant composite. Shape and size of obtained iron nanowires is consistent with the dimensions of porous framework. Particles are uniform and well ordered in the silica matrix. Thus, mesoporous silica serves as nanoreactor for the formation of Fe-nanoparticles.

2003-08-01

197

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

198

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

199

Ordered mesoporous non-oxide materials.  

UK PubMed Central (United Kingdom)

Ordered mesoporous inorganic non-oxide materials attract increasing interest due to their plenty of unique properties and functionalities and potential applications. Lots of achievements have been made on their synthesis and structural characterization, especially in the last five years. In this critical review, the ordered mesoporous non-oxide materials are categorized by compositions, including non-oxide ceramics, metal chalcogenides, metal nitrides, carbides and fluorides, and systematically summarized on the basis of their synthesis approaches and mechanisms, as well as properties. Two synthesis routes such as hard-templating (nanocasting) and soft-templating (surfactant assembly) routes are demonstrated. The principal issues in the nanocasting synthesis including the template composition and mesostructure, pore surface chemistry, precursor selection, processing and template removal are emphatically described. A great number of successful cases from the soft-templating method are focused on the surfactant liquid-crystal mesophases to synthesize mesostructured metal chalcogenide composites and the inorganic-block-organic copolymer self-assembly to obtain non-oxide ceramics (296 references).

Shi Y; Wan Y; Zhao D

2011-07-01

200

Poisoning of resin supported catalyst  

Energy Technology Data Exchange (ETDEWEB)

A method is described of enhancing performance of a combined hydroformylation/reduction reaction of an olefin liquid feed in the presence of a resin-supported transition metal complex catalyst. The method comprises: (a) preparing a resin-supported transition metal complex catalyst for use in a combined hydroformylation/reduction reaction substantially free of halides and halide salts in the metal complex catalyst; and (b) introducing an olefin liquid feed to the resin-supported catalyst for conducting a combined hydroformylation/reduction reaction, in the presence of CO and H/sub 2/. The olefin feed has a specified maximum limit of halide concentration sufficiently low to enable continued indefinite operation of the combined hydroformylation/reduction reaction process without halide poisoning.

Hunter, D.L.; Moore, S.E.

1987-02-10

 
 
 
 
201

Preparation of mesoporous Si-C-O fibers with a narrow mesopore size distribution.  

UK PubMed Central (United Kingdom)

Mesoporous Si-C-O fibers were fabricated by air activation of a kind of carbon-rich SiC-C fibers at 600 degrees C. The SiC-C fibers were prepared from the hybrid precursor of polycarbosilane and pitch through melt-spinning, air curing and pyrolysis in nitrogen. The carbon content of the SiC-C fibers was 54.4 wt%, and decreased to lower than 25 wt% after activation for more than 5 hours. Meanwhile, the surface area increased up to 260 m2/g, with a narrow mesopore size distribution mainly in the range of 2-5 nm. The SiC-phase derived from the polycarbosilane and the C-phase derived from the pitch form a bicontinuous interpenetrating network, which plays an important role for the narrow pore size distribution.

Li C; He R; Zhang S; Liu J; Yang N

2013-03-01

202

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

203

Phosphonic acid based ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene disphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1994-01-01

204

Phosphonic acid based ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 9 figures.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1994-01-25

205

Phosphonic acid based ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1996-07-23

206

Phosphonic acid based ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1996-01-01

207

Ordered mesoporous silica-(ZIF-8) core-shell spheres.  

Science.gov (United States)

Silica-(ZIF-8) core-shell spheres with tuneable ordered meso-microporosity have been synthesized, showing that the hydrophobic micropore ZIF-8 shell controls the access of guest molecules into the hydrophilic silica mesoporous structure. PMID:22892418

Sorribas, Sara; Zornoza, Beatriz; Téllez, Carlos; Coronas, Joaquín

2012-08-14

208

Electrochemical performance of a novel ionic liquid derived mesoporous carbon.  

UK PubMed Central (United Kingdom)

A novel nano-fibrillated mesoporous carbon (IFMC) was found to be an effective modifier in combination with ionic liquid 1-octylpyridinum hexafluorophosphate (OPFP) as a binder to give impregnated graphite electrodes with outstanding electrochemical performances.

Karimi B; Behzadnia H; Rafiee M; Vali H

2012-03-01

209

Synthesis of mesoporous nano-hydroxyapatite by using zwitterions surfactant  

Science.gov (United States)

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

210

High signal contrast gating with biomodified Gd doped mesoporous nanoparticles.  

UK PubMed Central (United Kingdom)

Internally Gd doped mesoporous nanoparticles have been prepared and exhibit unprecedented relaxivities that are retained on external biomodification. In tuning diffusive water access, image contrast can be reversibly switched in the presence of a specific protein target.

Huang WY; Davies GL; Davis JJ

2013-01-01

211

A stable luminescent hybrid mesoporous copper complex-silica.  

UK PubMed Central (United Kingdom)

Surfactant-assisted co-condensation of an emissive tetranuclear alkynyl-phosphine copper cluster with TEOS affords a hydrothermally stable blue-emitter mesoporous hybrid metal complex-silica material.

Rico M; Sepúlveda AE; Ruiz S; Serrano E; Berenguer JR; Lalinde E; Garcia-Martinez J

2012-09-01

212

Enzyme catalytic membrane based on a hybrid mesoporous membrane.  

UK PubMed Central (United Kingdom)

Immobilization of glucose oxidase (GOD) within a hybrid mesoporous membrane with 12 nm pore diameter was successfully achieved, resulting in catalytically high efficiency during flow of a glucose solution across the membrane.

Fu W; Yamaguchi A; Kaneda H; Teramae N

2008-02-01

213

Ordered mesoporous silica-(ZIF-8) core-shell spheres.  

UK PubMed Central (United Kingdom)

Silica-(ZIF-8) core-shell spheres with tuneable ordered meso-microporosity have been synthesized, showing that the hydrophobic micropore ZIF-8 shell controls the access of guest molecules into the hydrophilic silica mesoporous structure.

Sorribas S; Zornoza B; Téllez C; Coronas J

2012-09-01

214

Enzyme catalytic membrane based on a hybrid mesoporous membrane.  

Science.gov (United States)

Immobilization of glucose oxidase (GOD) within a hybrid mesoporous membrane with 12 nm pore diameter was successfully achieved, resulting in catalytically high efficiency during flow of a glucose solution across the membrane. PMID:18253526

Fu, Wensheng; Yamaguchi, Akira; Kaneda, Hideaki; Teramae, Norio

2007-12-18

215

Electrochemical performance of a novel ionic liquid derived mesoporous carbon.  

Science.gov (United States)

A novel nano-fibrillated mesoporous carbon (IFMC) was found to be an effective modifier in combination with ionic liquid 1-octylpyridinum hexafluorophosphate (OPFP) as a binder to give impregnated graphite electrodes with outstanding electrochemical performances. PMID:22314280

Karimi, Babak; Behzadnia, Hesam; Rafiee, Mohammad; Vali, Hojatollah

2012-02-07

216

PHOSPHORUS-CONTAINING PHENOL NOVOLAC RESIN, HARDENER COMPRISING THE SAME AND EPOXY RESIN COMPOSITION  

UK PubMed Central (United Kingdom)

This invention relates to a novel phosphorus-containing phenol novolac resin, use of the phosphorus-containing phenol novolac resin as a halogen-free flame retardant epoxy hardener, and an epoxy resin composition having high phosphorus content because it includes the phosphorus-containing phenol novolac resin, thereby exhibiting superior flame retardancy and heat resistance.

KONG JI WOONG; LEE SANG MIN; SUNG ICK KYUNG

217

Recent Progress in Preparation of Ordered Mesoporous Film  

Directory of Open Access Journals (Sweden)

Full Text Available The film containing oriented mesochannels in uniform direction at large scales can be defined as ordered mesoporous thin film. Various preparation methods of ordered mesoporous silica thin films are reviewed in recent years. These preparation methods can be summarized into three kinds in mechanism. The factors influencing the mesoporons film preparation are also discussed and analyzed based on the viewpoint of 'order'. In addition, the progress tendencies of those preparation methods in the future are also introduced.

SU Bin; LU Xue-Min, LU Qing-Hua

2007-01-01

218

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

219

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

220

Method of removing contaminants from plastic resins  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-08-07

 
 
 
 
221

Method of removing contaminants from plastic resins  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-11-18

222

Removal of cyanocobalamine from aqueous solution using mesoporous activated carbon  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-07-01

223

Progress on the Multifunctional Mesoporous Silica-based Nanotheranostics  

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

224

Radiation crosslinked vinyl chloride resin  

International Nuclear Information System (INIS)

A blended composition comprising a vinyl chloride resin and a specific epoxy compound derived from a conjugated diene homopolymer and/or copolymer can advantageously be crosslinked by means of an ionizing radiation. Said epoxy compound is bonded with an ethylenically unsaturated organic acid having a double bond adjacent the carboxyl group to a part of the epoxy group of the epoxy compound

1975-01-01

225

A Review: Mesoporous Santa Barbara Amorphous-15, Types, Synthesis and Its Applications towards Biorefinery Production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem statement: Santa Barbara Amorphous (SBA-15) is significant mesoporous silica with exclusive and important properties of highly ordered mesopores, hydrothermally stable and thick wall, profusely large surface area and huge pore volume which render it as promising catalyst for...

Norhasyimi Rahmat; Ahmad Z. Abdullah; Abdullah R. Mohamed

226

(129)Xe NMR of Mesoporous Silicas  

Energy Technology Data Exchange (ETDEWEB)

The porosities of three mesoporous silica materials were characterized with {sup 129}Xe NMR spectroscopy. The materials were synthesized by a sol-gel process with r = 0, 25, and 70% methanol by weight in an aqueous cetyltrimethylammonium bromide solution. Temperature dependent chemical shifts and spin lattice relaxation times reveal that xenon does not penetrate the pores of the largely disordered (r= 70%) silica. For both r = 0 and 25%, temperature dependent resonances corresponding to physisorbed xenon were observed. An additional resonance for the r = 25% sample was attributed to xenon between the disordered cylindrical pores. 2D NMR exchange experiments corroborate the spin lattice relaxation data which show that xenon is in rapid exchange between the adsorbed and the gas phase.

Anderson, M.T.; Asink, R.A.; Kneller, J.M.; Pietrass, T.

1999-04-23

227

Tunable Mesoporous Defects in Photonic Crystals  

Science.gov (United States)

Similar to doping in semiconductors, the incorporation of defects into photonic crystals introduces defect-based states in the photonic bad gap, resulting in an increase in its functionality. In this work, we have introduced a planar-defect into a colloidal photonic crystal, and have investigated the evolution of its optical properties with respect to the infiltration of various foreign constituents. A periodic mesoporous silica film (i.e., the defect) was deposited on a silica-based colloidal photonic crystal, and a second photonic crystal was deposited subsequently to encompass the defect-layer. UV-VIS spectroscopy, scanning electron microscopy and X-ray diffraction experiments confirm the existence of the meso-layer. Subsequently, water vapor and tetramethyl orthosilicate (TMOS) were infiltrated into the structure and the defect-based signature corresponding to the optical spectra was monitored. In both cases, a noticeable shift in wavelength was observed, providing evidence that the structure performs as a chemical sensor.

Peiris, F. C.; Rodriguez, J. R.; Kitaev, V.; Ozin, G. A.

2007-03-01

228

Mesoporous organohydrogels from thermogelling photocrosslinkable nanoemulsions  

Science.gov (United States)

We report the formation of mesoporous organohydrogels from oil-in-water nanoemulsions containing an end-functionalized oligomeric gelator in the aqueous phase. The nanoemulsions exhibit an abrupt thermoreversible transition from a low-viscosity liquid to a fractal-like colloidal gel of droplets with mesoscale porosity and solid-like viscoelasticity with moduli approaching 100?kPa, possibly the highest reported for an emulsion-based system. We hypothesize that gelation is brought about by temperature-induced interdroplet bridging of the gelator, as shown by its dependence on the gelator chemistry. The use of photocrosslinkable gelators enables the freezing of the nanoemulsion’s microstructure into a soft hydrogel nanocomposite containing a large fraction of dispersed liquid hydrophobic compartments, and we show its use in the encapsulation and release of lipophilic biomolecules. The tunable structural, mechanical and optical properties of these organohydrogels make them a robust material platform suitable for a wide range of applications.

Helgeson, Matthew E.; Moran, Shannon E.; An, Harry Z.; Doyle, Patrick S.

2012-04-01

229

Immobilisation of enzymes on mesoporous silicate materials.  

UK PubMed Central (United Kingdom)

Mesoporous silicates (MPS) are attractive materials for the immobilisation of enzymes. They possess ordered pore structures, narrow pore size distributions, large surface areas, high stability and can be chemically modified with various functional groups. The properties of MPS materials are reviewed in terms of their ability to act as supports for enzymes for use in biocatalysis with a particular focus on the ability to tailor the surface functionalization of the MPS to suit a specific enzyme. While many reports of the immobilisation of enzymes on MPS have been described, their use as biocatalytic supports is limited. Large scale reactors based on MPS will require continuous flow systems where the properties of the support can be tailored while allowing fluid flow at reasonable low pressure.

Magner E

2013-08-01

230

Grafting Sulfated Zirconia on Mesoporous Silica  

Energy Technology Data Exchange (ETDEWEB)

Sulfated zirconia has received considerable attention as a potential solid acid catalyst in recent years. In this paper, the preparation and properties of acid catalysts obtained by grafting ziconia with atomic precision on MCM-41 mesoporous silica were studied. TEM and potential titration characterizations revealed that ZrO2/MCM-41 with monolayer coverage can be obtained using this grafting technique. Sulfated ZrO2/MCM-41 exhibits improved thermal stability than that of bulk sulfated zirconia, as evidenced by temperature programmed characterizations and XRD analysis. Temperature programmed reaction of isopropanol was used to evaluate the acidity of sulfated ZrO2/MCM-41. It was found that the acid strength of sulfated ZrO2/MCM-41 with monolayer coverage is weaker than bulk sulfated zirconia but stronger than SiO2-Al2O3, a common strong acid catalyst.

Wang, Yong; Lee, Kwan Young; Choi, Saemin; Liu, Jun; Wang, Li Q.; Peden, Charles HF

2007-06-01

231

Ordered cobalt nanowires in mesoporous aluminosilicate  

International Nuclear Information System (INIS)

The present paper reports a study of ordered anisotropic cobalt nanoparticles arrays formed in mesoporous aluminosilicate matrices with pore diameters of 2 nm (MAS). The strategy of synthesis was based on intercalation of hydrophobic cobalt complex (Co2(CO)8) to the hydrophobic part of MAS/CTAB composite with subsequent reduction of metal. Ordering parameters and magnetic structure of nanocomposites were investigated by small-angle neutron scattering (SANS) and SQUID measurements. It was shown that the suggested method leads to formation of well-ordered magnetic nanowire arrays with periodicity of 4.32-4.37 nm. SANS studies indicate spatial correlation between magnetic and nuclear structure of nanocomposites. The composites demonstrate high blocking temperatures exceeding 300 K, large enough coercive force (up to 18,700 A/m) and saturation magnetization (16 A*m2/kg) at room temperature.

2006-06-02

232

Antistatic resin protection lens for electric welding  

UK PubMed Central (United Kingdom)

The utility model relates to an antistatic resin welding protection lens used on a welding mask, which has the advantages of high safety performance, good wear resistance and light transmittance, shock resistance property and anti-static property, comprises resin welding protection lenses, and is characterized in that an antistatic layer is coated on each resin welding protection lens and the resin welding protection lens is made of allyl diglycol carbonate resin. The utility model has the advantages of high safety performance, good abrasiveness and luminousness, good shock resistance and anti-static effects, and non-dust and non-welding slag adhesion.

XINJING HE

233

Cycloaliphatic epoxy resin and preparation method thereof  

UK PubMed Central (United Kingdom)

The invention relates to cycloaliphatic epoxy resin and a preparation method thereof. The method comprises the following steps of: taking dicycloacrylate as a raw material, hydrogen peroxide solutionas an oxidizing agent and halocarbon or halogenated hydrocarbon as a catalyst and synthesizing the cycloaliphatic epoxy resin under the action of a heteropolyacid catalyst, wherein the main reaction product of the cycloaliphatic epoxy resin, namely epoxy cyclohexane-4-carboxylic epoxycyclohexane-4-methylene ester accounts for over 90 weight percent and the epoxy equivalent weight is between 120 and 140. Each quality index of the cycloaliphatic epoxy resin of the invention is the same as that of the cycloaliphatic epoxy resin prepared by using a peroxyacetic acid as the oxidizing agent. The cycloaliphatic epoxy resin of the invention can be used as an automobile paint, a metal surface paint and an insulative substrate resin in the field of electronic and electric appliances.

YUMIN ZHANG; RUTIAN ZHUANG; FENGLEI ZHEN

234

A new, versatile Class A SMC resin  

Energy Technology Data Exchange (ETDEWEB)

Alpha/Owens-Corning`s Ultryl{trademark} resin is a new Class A SMC resin that displays interesting and versatile characteristics. First, this resin system can be formulated to make Class A automotive exterior body panels, using conventional molding pressures, that display excellent surfaces in both horizontal and vertical walls. Other attributes of this resin include excellent paint and bond adhesion, good flow in the tool, and mechanical properties that compare favorably to automotive Class A specifications. Second, this resin can be formulated to be used at low pressure, as low as 2.1 MPa (300 psi), to produce parts with Class A surfaces without sacrificing the aforementioned attributes. Large truck parts (greater than 45 kilograms) have been successfully molded under low pressures using this resin. Additional benefits of this resin in low pressure formulations include ease of compounding on existing equipment, excellent material flow in the tool, good glass carry, low porosity, and satisfactory handling compound.

Young, J.J.; Lucas, R.L.; Wade, C.B. [Alpha/Owens-Corning, Valparaiso, IN (United States)

1996-11-01

235

3-D flowerlike architectures constructed by ultrathin perpendicularly aligned mesoporous nanoflakes for enhanced asymmetric catalysis.  

UK PubMed Central (United Kingdom)

3-D flowerlike mesoporous architectures constructed by the ultrathin perpendicularly aligned mesoporous nanoflakes synthesized via a cooperative layered calcium silicate hydrates and liquid crystal dual-templating approach show an enhanced asymmetric catalytic activity owing to the facilitated diffusion from the reduced thickness of perpendicularly aligned mesoporous nanoflakes.

Zhang L; Guo Y; Peng J; Liu X; Yuan P; Yang Q; Li C

2011-04-01

236

Crystallization of Tungsten Trioxide Having Small Mesopores: Highly Efficient Photoanode for Visible-Light-Driven Water Oxidation.  

UK PubMed Central (United Kingdom)

Small mesopores are more efficient: A mesoprous oxide semiconductor (tungsten trioxide) having small mesopores was crystallized at high temperature (550?°C) by a simple one-step procedure. The highly crystalline mesoporous WO3 has an extremely high surface area which improves the visible-light-driven photoelectrochemical performance of water oxidation relative to WO3 having interparticle mesopores.

Chandra D; Saito K; Yui T; Yagi M

2013-10-01

237

Uranium sorption by tannin resins  

International Nuclear Information System (INIS)

[en] 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

238

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

239

Removing tar and resinous sediments  

Energy Technology Data Exchange (ETDEWEB)

For removing sediments of resin and resinous substances in devices for fuel gasification, resin solvents, for instance, oil, are sprayed into the part of the installation (which operates under pressure) into the fuel layer and (or) to this layer or above this layer in the gas generator. The introduction of solvents into the pipeline beyond the generator or into the devices for further processing of the gas beyond the generator in a volume required (relative to the temperature and pressure) for condensing solvent vapors is also possible. A solvent formed by heavy benzene and oil is sprayed in a volume of 0.3 liters per meter per hours into an experimental device which models the operational conditions of gasification under pressure above a checker at 2.5 megapascals into a stream of petroleum gas at 300 degrees. Of this volume of solvent 18 percent was condensed at a temperature of 190 to 195 degrees which corresponds to the precooler of the generator. The residue was isolated in the form of a condensate at the points of sequential cooling of the gas at 170, 140, 120 and 30 degrees. Samples which consist of heavy coal tar slags were placed in all of these points. During the tests the resinous substances of these slags were extracted from the slags to a significant degree, where the maximum of extraction occurred at 170 and 140 degrees. In these same conditions with introduction of a solvent which contained 0.13 liters of heavy benzene and 0.28 liters of light benzene to 1 cubic meter per hour of gas, the tar and oil were isolated at 195 degrees, while the light benzene began to be extracted at 120 degrees, while the maximum was isolated at 30 degrees. The insignificant parts of the benzene vapors in the gas could only be condensed by strong cooling.

Zufnicek, J.; Buryan, P.; Jelinek, L.

1983-05-15

240

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

 
 
 
 
241

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((PEO)106(PRO)70(PEO)106)as a structure-directing agent. Columnar mesoporoussilica was formed inside the anodic aluminium membrane (AAM) pores and had a length of ca. (50±2)um. 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 (LOD)encapsulation 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.

FU Wen-sheng; LUO Xing-ping; HUANG Jun-fei; GAO Li-li; HUANG Xiao-long; TAN Yu-ling; HE Jiao

2010-01-01

242

Coloration phenomenon of mefenamic acid in mesoporous silica FSM-16.  

UK PubMed Central (United Kingdom)

Coloration of mefenamic acid (MFA) was investigated in the presence of mesoporous silica FSM-16 with 16.0 A (Oc) and 45.0 A (Doc) pore diameter. The color change of MFA/FSM-16 physical mixture from white to deep blue was observed by sealed-heating (SH) and the subsequent humidification (HU). The coloration and the color difference were caused by the changes of chroma and lightness. In the case of MFA/FSM-16 (Oc), coloration was not observed by SH treatment only. Powder X-ray diffraction data indicated that difference of the dispersed states of MFA molecules in FSM-16 mesopore affected the coloration. MFA adsorbed on the silica surface and MFA in the mesopore were differentiated by thermogravimetric analysis. Solid-state (13)C-NMR showed that the molecular mobility of MFA was increased in the dispersed state in FSM-16 mesopores compared to the crystalline state. Structural changes of silanol groups in FSM-16 by humidification were observed by solid-state (29)Si-NMR. MFA adsorption in FSM-16 mesopore by SH as well as changes of the surface state of FSM-16 by HU affected the coloration of MFA.

Moribe K; Kinoshita R; Higashi K; Tozuka Y; Yamamoto K

2010-02-01

243

High Activity Mesoporous Pt/Ru catalysts for methanol oxidation.  

UK PubMed Central (United Kingdom)

High activity mesoporous Pt/Ru catalysts with 2D-hexagonal structure were synthesized using a triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer (Pluronic F127®) template. The normalized mass activities for the methanol oxidation reaction (MOR) of the Pt/Ru catalysts with a regular array of pores is higher than those reported for nanoparticulated Pt/Ru catalysts. Different kinetic parameters, as Tafel slope and activation energy, were obtained for the MOR on the mesoporous catalysts. Results indicated that catalysts performance depends on pore size. Mass activities and the CO2 conversion efficiency for large pore size mesoporous catalysts (10 nm) are greater than those reported for smaller pore size mesoporous catalysts with similar composition. The effect of pore size on catalysts performance is related to the greater accessibility of methanol to the active areas inside large pores. Consequently, the overall residence time of methanol increases as compared with mesoporous catalyst with small pores.

Franceschini EA; Bruno MM; Williams FJ; Viva FA; Corti HR

2013-10-01

244

Micropores and mesopores in the cell wall of dry wood  

UK PubMed Central (United Kingdom)

To investigate micropores and mesopores in the cell walls of dry wood, CO? gas and N? gas adsorption onto dry wood were measured at ice-water temperature (273 K) and liquid nitrogen temperature (77 K). CO? gas adsorption isotherms obtained were used for determining micropore volumes smaller than 0.6 nm by the HK method (Horvath-Kawazoe method), and N? gas adsorption isotherms obtained were used for determining the mesopore volume between 2 nm and 50 nm by the Barrett-Joyner-Halenda (BJH) method. Micropores and mesopores existed in cell walls of dry wood, and the cumulative pore volume was much larger for micropores than for mesopores. Micropores in the cell wall of dry wood decreased with elevating heat treatment temperature, and the decreased micropore was reproducible by wetting and drying. Mesopores did not decrease so much with elevating heat treatment temperature. Micropore volumes for the softwood Hinoki and the hardwood Buna were compared. A larger amount of micropores existed in hardwood Buna than in softwood Hinoki, and this relationship was considered to correspond to the difference in thermal softening properties for lignin in water-swollen Hinoki and Buna. This result probably indicates that micropores in the cell walls of dry wood relate to the structure of lignin.

Kojiro Keisuke; Miki Tsunehisa; Sugimoto Hiroyuki; Nakajima Masamitsu; Kanayama Kozo

2010-04-01

245

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

246

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

247

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

248

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

Scientific Electronic Library Online (English)

Full Text Available 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 (more) 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.

Gao, Wei; Li, Jianzhang

2012-01-01

249

Preparation, characterization, and photocatalytic activity of mesoporous TiO2 thin films.  

UK PubMed Central (United Kingdom)

Cubic-based ordered mesoporous TiO2 thin films were prepared by an evaporation-induced self-assembly method through a carefully controlling the hydrolysis/condensation conditions. The obtained sample exhibits mesoporous structure with a narrow pore size distribution. The TiO2 thin films have thick inorganic walls composed of nanocrystalline anatase. A reasonable explanation is also proposed to elucidate the formation of thick and stable mesoporous TiO2 films. The mesoporous TiO2 exhibits good photocatalytic activity. Nearly all the methyl orange has been degraded by the mesoporous TiO2 calcined at 500 degrees C.

Wang J; Li H; Li H; Wang H; Cai Q

2013-02-01

250

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

Science.gov (United States)

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 deposition. An additional advantage of this surfactant is an increase the yield of product. These mesoporous carbon spheres, which have good electrochemical properties is suitable for supercapacitors.

2012-01-01

251

Preparation, characterization, and photocatalytic activity of mesoporous TiO2 thin films.  

Science.gov (United States)

Cubic-based ordered mesoporous TiO2 thin films were prepared by an evaporation-induced self-assembly method through a carefully controlling the hydrolysis/condensation conditions. The obtained sample exhibits mesoporous structure with a narrow pore size distribution. The TiO2 thin films have thick inorganic walls composed of nanocrystalline anatase. A reasonable explanation is also proposed to elucidate the formation of thick and stable mesoporous TiO2 films. The mesoporous TiO2 exhibits good photocatalytic activity. Nearly all the methyl orange has been degraded by the mesoporous TiO2 calcined at 500 degrees C. PMID:23646668

Wang, Jinshu; Li, Hui; Li, Hongyi; Wang, Hong; Cai, Qian

2013-02-01

252

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

253

Dual-Mesoporous ZSM-5 Zeolite with Highly b-Axis-Oriented Large Mesopore Channels for the Production of Benzoin Ethyl Ether.  

UK PubMed Central (United Kingdom)

Dual-mesoporous ZSM-5 zeolite with highly b axis oriented large mesopores was synthesized by using nonionic copolymer F127 and cationic surfactant CTAB as co-templates. The product contains two types of mesopores-smaller wormlike ones of 3.3?nm in size and highly oriented larger ones of 30-50?nm in diameter along the b axis-and both of them interpenetrate throughout the zeolite crystals and interconnect with zeolite microporosity. The dual-mesoporous zeolite exhibits excellent catalytic performance in the condensation of benzaldehyde with ethanol and greater than 99?% selectivity for benzoin ethyl ether at room temperature, which can be ascribed to the zeolite lattice structure offering catalytically active sites and the hierarchical and oriented mesoporous structure providing fast access of reactants to these sites in the catalytic reaction. The excellent recyclability and high catalytic stability of the catalyst suggest prospective applications of such unique mesoporous zeolites in the chemical industry.

Zhou X; Chen H; Zhu Y; Song Y; Chen Y; Wang Y; Gong Y; Zhang G; Shu Z; Cui X; Zhao J; Shi J

2013-07-01

254

Dual-mesoporous ZSM-5 zeolite with highly b-axis-oriented large mesopore channels for the production of benzoin ethyl ether.  

Science.gov (United States)

Dual-mesoporous ZSM-5 zeolite with highly b axis oriented large mesopores was synthesized by using nonionic copolymer F127 and cationic surfactant CTAB as co-templates. The product contains two types of mesopores--smaller wormlike ones of 3.3?nm in size and highly oriented larger ones of 30-50?nm in diameter along the b axis--and both of them interpenetrate throughout the zeolite crystals and interconnect with zeolite microporosity. The dual-mesoporous zeolite exhibits excellent catalytic performance in the condensation of benzaldehyde with ethanol and greater than 99?% selectivity for benzoin ethyl ether at room temperature, which can be ascribed to the zeolite lattice structure offering catalytically active sites and the hierarchical and oriented mesoporous structure providing fast access of reactants to these sites in the catalytic reaction. The excellent recyclability and high catalytic stability of the catalyst suggest prospective applications of such unique mesoporous zeolites in the chemical industry. PMID:23775816

Zhou, Xiaoxia; Chen, Hangrong; Zhu, Yan; Song, Yudian; Chen, Yu; Wang, Yongxia; Gong, Yun; Zhang, Guobin; Shu, Zhu; Cui, Xiangzhi; Zhao, Jinjin; Shi, Jianlin

2013-06-17

255

Decomposition of ion exchange resins by pyrolysis  

International Nuclear Information System (INIS)

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

1986-01-01

256

Decomposition of ion exchange resins by pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

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/sup 0/C, while that of anion resins was 90 wt% at 400/sup 0/C. 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/sup 0/C.

Matsuda, M.; Funabashi, K.; Nishi, T.; Yusa, H.; Kikuchi, M.

1986-11-01

257

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

258

Scintillating 99Tc Selective Ion Exchange Resins  

Energy Technology Data Exchange (ETDEWEB)

Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

Mitchell Greenhalgh; Richard D. Tillotson

2012-07-01

259

Mesoporous bioactive glass scaffolds for efficient delivery of vascular endothelial growth factor.  

UK PubMed Central (United Kingdom)

In this article, we, for the first time, investigated mesoporous bioactive glass scaffolds for the delivery of vascular endothelial growth factor. We have found that mesoporous bioactive glass scaffolds have significantly higher loading efficiency and more sustained release of vascular endothelial growth factor than non-mesoporous bioactive glass scaffolds. In addition, vascular endothelial growth factor delivery from mesoporous bioactive glass scaffolds has improved the viability of endothelial cells. The study has suggested that mesopore structures in mesoporous bioactive glass scaffolds play an important role in improving the loading efficiency, decreasing the burst release, and maintaining the bioactivity of vascular endothelial growth factor, indicating that mesoporous bioactive glass scaffolds are an excellent carrier of vascular endothelial growth factor for potential bone tissue engineering applications.

Wu C; Fan W; Chang J; Xiao Y

2013-09-01

260

Morphogenesis of Highly Ordered Mixed-Valent Mesoporous Molybdenum Oxides  

Energy Technology Data Exchange (ETDEWEB)

Control of the size, shape, and structure of mesoporous transition metal oxide materials is important in their correlations with corresponding optoelectronic and photocatalytic properties. Highly ordered cubic phases of mixed-valent mesoporous molybdenum oxides have been prepared by the reduction and decomposition of aqueous molybdenum precursor solution in the presence of poly(ethylene oxide) under ultrasonic irradiation. Large-scale uniform molybdenum oxide particles with well-defined crystal-like morphologies (ball-like, rhombic dodecahedral, and cubic shapes) were synthesized and found to be controllable by modifying the molecular chain length of the polymeric additive. Molybdenum oxides with an average oxidation state of 4.8 form a cubic lattice of open mesoporous structures.

Chen,J.; Burger, C.; Krishnan, C.; Chu, B.

2005-01-01

 
 
 
 
261

Mesoporous silica and organosilica films templated by nanocrystalline chitin.  

Science.gov (United States)

Liquid crystalline phases can be used to impart order into inorganic solids, creating materials that mimic natural architectures. Herein, mesoporous silica and organosilica films with layered structures and high surface areas have been templated by nanocrystalline chitin. Aqueous suspensions of spindle-shaped chitin nanocrystals were prepared by sequential deacetylation and hydrolysis of chitin fibrils isolated from king crab shells. The nanocrystalline chitin self-assembles into a nematic liquid-crystalline phase that has been used to template silica and organosilica composites. Removal of the chitin template by either calcination or sulfuric-acid-catalyzed hydrolysis gave mesoporous silica and ethylene-bridged organosilica films. The large, crack-free mesoporous films have layered structures with features that originate from the nematic organization of the nanocrystalline chitin. PMID:24150881

Nguyen, Thanh-Dinh; Shopsowitz, Kevin E; Maclachlan, Mark J

2013-09-25

262

Actinide Sequestration Using Self-Assembled Monolayers on Mesoporous Supports  

Energy Technology Data Exchange (ETDEWEB)

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.

Fryxell, Glen E.; Lin, Yuehe; Fiskum, Sandra K.; Birnbaum, Jerome C.; Wu, Hong; Kemner, K. M.; Kelly, Shelley

2005-03-01

263

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

264

Functionalized mesoporous silica for microgravimetric sensing of trace chemical vapors.  

UK PubMed Central (United Kingdom)

Featuring a huge surface-to-volume ratio, synthesized SBA-15 mesoporous silica is functionalized by inner-channel-wall modification of sensing groups for highly specific chemical-vapor detection at trace level. With the developed sensing material loaded on resonant microcantilevers, the specifically adsorbed chemical-vapor molecules act as an added mass to shift the cantilever resonant frequency for gravimetric sensing signal readout. Two kinds of sensing materials for trinitrotoluene (TNT) and ammonia/amine are respectively prepared by inner-wall layer-by-layer grafting functionalization. By using hexafluoro-2-propanol-functionalized mesoporous silica (HFMS), experimental results show highly specific and rapid detection of TNT vapor, with a ppt-level detection limit; functionalized with a carboxyl (COOH) group, the mesoporous silica is loaded onto the cantilever resonating sensor that experimentally exhibits an ultrafine detection limit of tens of ppb to ammonia/amine gases.

Xu P; Yu H; Li X

2011-05-01

265

Functionalized mesoporous silica materials for controlled drug delivery.  

Science.gov (United States)

In the past decade, non-invasive and biocompatible mesoporous silica materials as efficient drug delivery systems have attracted special attention. Great progress in structure control and functionalization (magnetism and luminescence) design has been achieved for biotechnological and biomedical applications. This review highlights the most recent research progress on silica-based controlled drug delivery systems, including: (i) pure mesoporous silica sustained-release systems, (ii) magnetism and/or luminescence functionalized mesoporous silica systems which integrate targeting and tracking abilities of drug molecules, and (iii) stimuli-responsive controlled release systems which are able to respond to environmental changes, such as pH, redox potential, temperature, photoirradiation, and biomolecules. Although encouraging and potential developments have been achieved, design and mass production of novel multifunctional carriers, some practical biological application, such as biodistribution, the acute and chronic toxicities, long-term stability, circulation properties and targeting efficacy in vivo are still challenging. PMID:22441299

Yang, Piaoping; Gai, Shili; Lin, Jun

2012-03-22

266

Functionalized mesoporous silica for microgravimetric sensing of trace chemical vapors.  

Science.gov (United States)

Featuring a huge surface-to-volume ratio, synthesized SBA-15 mesoporous silica is functionalized by inner-channel-wall modification of sensing groups for highly specific chemical-vapor detection at trace level. With the developed sensing material loaded on resonant microcantilevers, the specifically adsorbed chemical-vapor molecules act as an added mass to shift the cantilever resonant frequency for gravimetric sensing signal readout. Two kinds of sensing materials for trinitrotoluene (TNT) and ammonia/amine are respectively prepared by inner-wall layer-by-layer grafting functionalization. By using hexafluoro-2-propanol-functionalized mesoporous silica (HFMS), experimental results show highly specific and rapid detection of TNT vapor, with a ppt-level detection limit; functionalized with a carboxyl (COOH) group, the mesoporous silica is loaded onto the cantilever resonating sensor that experimentally exhibits an ultrafine detection limit of tens of ppb to ammonia/amine gases. PMID:21462917

Xu, Pengcheng; Yu, Haitao; Li, Xinxin

2011-04-04

267

Functionalized mesoporous silica materials for controlled drug delivery.  

UK PubMed Central (United Kingdom)

In the past decade, non-invasive and biocompatible mesoporous silica materials as efficient drug delivery systems have attracted special attention. Great progress in structure control and functionalization (magnetism and luminescence) design has been achieved for biotechnological and biomedical applications. This review highlights the most recent research progress on silica-based controlled drug delivery systems, including: (i) pure mesoporous silica sustained-release systems, (ii) magnetism and/or luminescence functionalized mesoporous silica systems which integrate targeting and tracking abilities of drug molecules, and (iii) stimuli-responsive controlled release systems which are able to respond to environmental changes, such as pH, redox potential, temperature, photoirradiation, and biomolecules. Although encouraging and potential developments have been achieved, design and mass production of novel multifunctional carriers, some practical biological application, such as biodistribution, the acute and chronic toxicities, long-term stability, circulation properties and targeting efficacy in vivo are still challenging.

Yang P; Gai S; Lin J

2012-05-01

268

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

269

Plutonium complexation by phosphonate-functionalized mesoporous silica  

International Nuclear Information System (INIS)

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

2010-01-01

270

Polymorphism of the glass former ethanol confined in mesoporous silicon  

CERN Multimedia

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

271

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

2008-01-01

272

Mesoporous NiO-Samaria doped ceria fuel cell materials.  

UK PubMed Central (United Kingdom)

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.

Eom TW; Kim KH; Kim JS; Jo MC; Yoon HH; Park SJ

2009-02-01

273

Synthesis of mesoporous silica microsphere from dual surfactant  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english A new procedure is reported to synthesis mesoporous silica micro sphere for the first time. In these method two surfactants namely Span 80 and Tween 80 were used. Small angle X ray diffraction and N2 adsorption analysis shows the synthesized material has mesoporous property. The material has 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 (more) 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.

Narayanan, Venkatathri

2008-12-01

274

Nanostructured materials based on mesoporous silica and mesoporous silica/apatite as osteogenic growth peptide carriers.  

UK PubMed Central (United Kingdom)

The aim of this work was the preparation of inorganic mesoporous materials from silica, calcium phosphate and a nonionic surfactant and to evaluate the incorporation and release of different concentrations of osteogenic growth peptide (OGP) for application in bone regeneration. The adsorption and release of the labeled peptide with 5,6-carboxyfluorescein (OGP-CF) from the mesoporous matrix was monitored by fluorescence spectroscopy. The specific surface area was 880 and 484 m(2) g(-1) for pure silica (SiO) and silica/apatite (SiCaP), respectively; the area influenced the percentage of incorporation of the peptide. The release of OGP-CF from the materials in simulated body fluid (SBF) was dependent on the composition of the particles, the amount of incorporated peptide and the degradation of the material. The release of 50% of the peptide content occurred at around 4 and 30 h for SiCaP and SiO, respectively. In conclusion, the materials based on SiO and SiCaP showed in vitro bioactivity and degradation; thus, these materials should be considered as alternative biomaterials for bone regeneration.

Mendes LS; Saska S; Martines MA; Marchetto R

2013-10-01

275

Transport container for radioactive ion exchanger resins  

International Nuclear Information System (INIS)

A container is described which meets the safety regulations for transporting highly concentrated radioactive ion exchangers resins on public roads. For shielding serves a double-walled outer container. Into it a container for holding the resins is inserted which is provided with a perforated bottom and which disposes of supply and drain lines for the resins and the supply and flushing water. Furthermore, a level gauge is provided and a reserve volume which can be isolated by a valve. (UWI)

1976-01-01

276

Resin regeneration device for condensate desalting device  

International Nuclear Information System (INIS)

In a condensate desalting device disposed in a facility of condensate cleanup circuit, a cation exchange resin regeneration tower and an anion exchanger resin regeneration tower are connected to a condensate desalting tower by way of resin transfer pipelines. Gas supply systems are connected to both of the regeneration towers respectively for supplying a gas not containing oxygen upon back-washing regeneration. With such a constitution, organic impurities leached from ion exchange resins in the condensate desalting tower can be reduced to prevent the organic impurities from flowing into the reactor, thereby enabling to maintain the quality of the reactor water at a high purity. (T.M.).

1992-01-13

277

Flexible heat resistant neutron shielding resin  

International Nuclear Information System (INIS)

A flexible heat resistant neutron shielding material has been developed, which consists of polymer resin with 1 wt% boron. The neutron shielding performance of the developed resin, examined by the 252Cf neutron source, is almost the same as that of the polyethylene. The outgas of H2, H2O, CO and CO2 from the resin have been measured at ?250 deg. C environment. The resin will be applied around the port of the vacuum vessel as an additional shielding material and reduce the neutron streaming from a superconducting tokamak device such as JT-60SA.

2011-10-01

278

Novel silica-based ion exchange resin  

Energy Technology Data Exchange (ETDEWEB)

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

NONE

1997-11-01

279

RADIATION-SENSITIVE RESIN COMPOSITION AND COMPOUND  

UK PubMed Central (United Kingdom)

Disclosed are: a radiation-sensitive resin composition which fulfils both exposure latitude and MEEF performance and a compound which can be used suitably in the radiation-sensitive resin composition. The radiation-sensitive resin composition comprises: (A) a compound having such a structure that a group represented by formula (1) is bound to a nitrogen atom (B) a resin which has an acid-dissociative solubility-suppressing group and of which the alkali solubility can be increased by the action of an acid and (C) a radiation-sensitive acid-generating agent.

NAKAHARA KAZUO; SATO MITSUO

280

Radiation degradation in organic ion exchange resins  

International Nuclear Information System (INIS)

The EPICOR-2 Resin/Liner Investigation: Low-Level Waste Data Base Development Program, funded by the US Nuclear Regulatory Commission, studied the degradation effects in EPICOR-II organic ion exchange resins caused by internal radiation. Results of the third sampling analysis of ion exchange resins from prefilters PF-8 and PF-20 are compared with baseline data from tests performed on unirradiated resins and with results from the first and second samplings to determine if degradation has occurred because of the high internal radiation dose. Those results are also compared to findings of other researchers.

1993-01-01

 
 
 
 
281

Periodic mesoporous organosilica in confined environments.  

UK PubMed Central (United Kingdom)

Periodic mesoporous organosilica (PMO) mesophases based on bis(triethoxysilyl)ethane (BTSE) were synthesized within the confined tubular environment of anodic alumina membrane (AAM) channels. The resulting mesophases were investigated by transmission small angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR), nitrogen sorption, and transmission electron microscopy (TEM). Two different surfactants--nonionic Brij 56 and ionic cetyltrimethylammonium bromide (CTAB)--were used in an acid-catalyzed evaporation-induced self-assembly (EISA) process. Brij 56 as the structure-directing agent (SDA) resulted in the formation of either the hexagonal circular or the cubic mesophase. While the hexagonal circular mesophase is common for such kinds of composites, the cubic mesophase has never been reported before. The template could be removed from the mesophases by template extraction and calcination after annealing the samples. When using CTAB as the SDA during EISA, the only mesophase observed was the hexagonal circular structure. This is in contrast to previous experiments and reports on pure silica mesophases, where the only mesophase formed with CTAB is hexagonal columnar.

Keilbach A; Döblinger M; Köhn R; Amenitsch H; Bein T

2009-07-01

282

Mesoporous Silica Supported Solid Acid Catalysts  

Energy Technology Data Exchange (ETDEWEB)

In this brief proceedings paper, we summarize the results of recent studies of the preparation and characterization of mesoporous silica supported tungstophosphoric acid (TPA/MS) and Cs-substituted tungstophosphoric acid salt (Cs-TPA/MS). In particular, we demonstrate that we have synthesized MS-supported Cs-substituted catalysts having significantly improved dispersion of the active clusters compared to materials described previously in the literature. Transmission electron micrographs and the activity results for a model reaction, the alkylation of 1,3,5-trimethylbenzene by cyclohexene are presented as evidence for the enhanced dispersion and performance. In addition, we demonstrate improvements in the physical and thermal stability of these materials with Cs substitution using various characterization techniques. Finally, we also briefly describe the characterization and catalytic activity of TPA/MS materials, providing evidence for shape selectivity that is likely imparted by the structure of the MS support. The promising results with TPA/MS and Cs-TPA/MS catalysis indicate that they have potential applications in a variety of acid-catalyzed organic reactions involving large-sized reacting, intermediate, and/or product molecules with desired shape selectivity to products and/or intermediates.

Choi, Saemin (ASSOC WESTERN UNIVERSITY); Wang, Yong (BATTELLE (PACIFIC NW LAB)); Nie, Zimin (BATTELLE (PACIFIC NW LAB)); Khmbapati, D (N/A); Liu, Jun (BATTELLE (PACIFIC NW LAB)); Peden, Charles HF (BATTELLE (PACIFIC NW LAB)); A. Corma, F.Melo, S. Mendioroz et al

2000-01-01

283

Rhodium catalysts bound to functionalized mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-07-20

284

The ITQ-37 mesoporous chiral zeolite.  

UK PubMed Central (United Kingdom)

The synthesis of crystalline molecular sieves with pore dimensions that fill the gap between microporous and mesoporous materials is a matter of fundamental and industrial interest. The preparation of zeolitic materials with extralarge pores and chiral frameworks would permit many new applications. Two important steps in this direction include the synthesis of ITQ-33, a stable zeolite with 18 x 10 x 10 ring windows, and the synthesis of SU-32, which has an intrinsically chiral zeolite structure and where each crystal exhibits only one handedness. Here we present a germanosilicate zeolite (ITQ-37) with extralarge 30-ring windows. Its structure was determined by combining selected area electron diffraction (SAED) and powder X-ray diffraction (PXRD) in a charge-flipping algorithm. The framework follows the SrSi(2) (srs) minimal net and forms two unique cavities, each of which is connected to three other cavities to form a gyroidal channel system. These cavities comprise the enantiomorphous srs net of the framework. ITQ-37 is the first chiral zeolite with one single gyroidal channel. It has the lowest framework density (10.3 T atoms per 1,000 A(3)) of all existing 4-coordinated crystalline oxide frameworks, and the pore volume of the corresponding silica polymorph would be 0.38 cm(3) g(-1).

Sun J; Bonneau C; Cantín A; Corma A; Díaz-Cabañas MJ; Moliner M; Zhang D; Li M; Zou X

2009-04-01

285

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

Science.gov (United States)

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

286

Mesoporous silicates prepared using preorganized templates in supercritical fluids.  

Science.gov (United States)

Well-ordered mesoporous silicate films were prepared by infusion and selective condensation of silicon alkoxides within microphase-separated block copolymer templates dilated with supercritical carbon dioxide. Confinement of metal oxide deposition to specific subdomains of the preorganized template yields high-fidelity, three-dimensional replication of the copolymer morphology, enabling the preparation of structures with multiscale order in a process that closely resembles biomineralization. Ordered mesoporous silicate films were synthesized with dielectric constants as low as 1.8 and excellent mechanical properties. The films survive the chemical-mechanical polishing step required for device manufacturing. PMID:14739454

Pai, Rajaram A; Humayun, Raashina; Schulberg, Michelle T; Sengupta, Archita; Sun, Jia-Ning; Watkins, James J

2004-01-23

287

Mesoporous silicates prepared using preorganized templates in supercritical fluids.  

UK PubMed Central (United Kingdom)

Well-ordered mesoporous silicate films were prepared by infusion and selective condensation of silicon alkoxides within microphase-separated block copolymer templates dilated with supercritical carbon dioxide. Confinement of metal oxide deposition to specific subdomains of the preorganized template yields high-fidelity, three-dimensional replication of the copolymer morphology, enabling the preparation of structures with multiscale order in a process that closely resembles biomineralization. Ordered mesoporous silicate films were synthesized with dielectric constants as low as 1.8 and excellent mechanical properties. The films survive the chemical-mechanical polishing step required for device manufacturing.

Pai RA; Humayun R; Schulberg MT; Sengupta A; Sun JN; Watkins JJ

2004-01-01

288

Acid-base equilibria inside amine-functionalized mesoporous silica.  

UK PubMed Central (United Kingdom)

Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (?pH(pore)=1.8) for the pH(bulk) change from 2.1 to 9.1 (?pH(bulk)=7.0); (2) pH(pore) was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore.

Yamaguchi A; Namekawa M; Kamijo T; Itoh T; Teramae N

2011-04-01

289

Acid-base equilibria inside amine-functionalized mesoporous silica.  

Science.gov (United States)

Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (?pH(pore)=1.8) for the pH(bulk) change from 2.1 to 9.1 (?pH(bulk)=7.0); (2) pH(pore) was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore. PMID:21417214

Yamaguchi, Akira; Namekawa, Manato; Kamijo, Toshio; Itoh, Tetsuji; Teramae, Norio

2011-03-21

290

Thermally induced Ostwald ripening of mesoporous Ge nanostructures  

Science.gov (United States)

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

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

2013-01-01

291

Hierarchical mesoporous silica nanotubes derived from natural cellulose substance.  

UK PubMed Central (United Kingdom)

Bioinspired synthesis of hierarchical mesoporous silica nanotubes by using natural cellulose substance (filter paper) and cetyltrimethylammonium bromide (CTAB) micelles as dual templates was achieved. CTAB micelles were adsorbed onto the surfaces of ultrathin titania film precoated cellulose nanofibers, followed by hydrolysis and condensation of tetraethyl orthosilicate around these micelles to form silica. After calcination and sulfuric acid treatment to remove the organic templates and the thin titania film, bulk white sheets composed of natural hierarchical silica nanotubes with mesopores in the walls were obtained, to which silver nanoparticles were further induced to give a silica-nanotube/metal-nanoparticle hybrid.

Zhang Y; Liu X; Huang J

2011-09-01

292

Positronium annihilation and pore surface chemistry in mesoporous silica films  

International Nuclear Information System (INIS)

Lifetimes of ortho-positronium in mesoporous silica films were measured before and after surface trimethylsilylation of -OH groups. Variations of positronium lifetimes in the mesopores upon the surface modification indicate that the interaction between positronium and the pore surface is weakened in the pores, whose surface is covered with -CH3 groups, in comparison with those covered with -OH groups. This is consistent with the authors' previous observation that positronium slowing down is less efficient in the pores covered with -CH3 groups. The present work demonstrates that in the porosimetric application of positron annihilation lifetime spectroscopy, the interaction between positronium and the pore surface has to be properly taken into consideration

2007-07-09

293

Low temperature crystallisation of mesoporous TiO2.  

UK PubMed Central (United Kingdom)

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.

Kohn P; Pathak S; Stefik M; Ducati C; Wiesner U; Steiner U; Guldin S

2013-09-01

294

Vapor infiltration techniques for spin-on mesoporous silica films  

Energy Technology Data Exchange (ETDEWEB)

Ordered mesoporous silica films have been prepared by spin-coating using tetraethoxysilane (TEOS) as a silica source and nonionic surfactant Brij 30 as a templating agent. Sulfuric acid (H{sub 2}SO{sub 4}), nitric acid (HNO{sub 3}), or hydrochloric acid (HCl) was mixed as a catalyst in coating solutions. A vapor infiltration treatment was performed using TEOS or trimethylethoxysilane (TMES). The vapor infiltration treatments effectively improved mechanical strength, hydrothermal stability and film adhesive. The dielectric constant of the TMES-treated mesoporous silica film was 1.8.

Tanaka, Shunsuke [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Tada, Hiromi [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Maruo, Takanori [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Nishiyama, Norikazu [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: nisiyama@cheng.es.osaka-u.ac.jp; Egashira, Yasuyuki [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Ueyama, Korekazu [Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

2006-01-20

295

Vapor infiltration techniques for spin-on mesoporous silica films  

International Nuclear Information System (INIS)

Ordered mesoporous silica films have been prepared by spin-coating using tetraethoxysilane (TEOS) as a silica source and nonionic surfactant Brij 30 as a templating agent. Sulfuric acid (H2SO4), nitric acid (HNO3), or hydrochloric acid (HCl) was mixed as a catalyst in coating solutions. A vapor infiltration treatment was performed using TEOS or trimethylethoxysilane (TMES). The vapor infiltration treatments effectively improved mechanical strength, hydrothermal stability and film adhesive. The dielectric constant of the TMES-treated mesoporous silica film was 1.8

2006-01-20

296

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

UK PubMed Central (United Kingdom)

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 SH; Bae J; Jang J; Lee KJ

2013-06-01

297

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

298

Ion exchange on phenolic ion exchangers  

International Nuclear Information System (INIS)

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

1991-01-01

299

Method for making adhesive from biomass  

Science.gov (United States)

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. 2 figures.

Russell, J.A.; Riemath, W.F.

1984-03-30

300

75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan  

Science.gov (United States)

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

2010-11-01

 
 
 
 
301

76 FR 39896 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

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

2011-07-07

302

21 CFR 573.120 - Acrylamide-acrylic acid resin.  

Science.gov (United States)

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

2010-04-01

303

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

304

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

Science.gov (United States)

...2010-07-01 2010-07-01 false Phosphorous modified epoxy resin (generic...Chemical Substances § 721.3135 Phosphorous modified epoxy resin (generic...substance identified generically as a phosphorous modified epoxy resin (PMNs...

2010-07-01

305

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

306

Resin cultivating base, water purifying device and method using resin cultivating base  

UK PubMed Central (United Kingdom)

A resin cultivating base serves as seedling beds for vegetation which are planted and are partially immersed in a river, lake, marsh, pond or waterway. The resin cultivating base is a three-dimensional structure constituted by long and short filaments of thermoplastic resin. The long and short filaments are curled or looped at random, and contacted, entwined and gathered, thereby forming a low density portion and a high density portion. Vegetables planted on the low density portion of the resin cultivating base suck nutritious salt such as phosphor and nitride. Microorganisms living in the resin cultivating base decompose organisms in the water, thereby purifying the water.

Nishibori Sadao; Kikuchi Takeyasu; Shirai Maki; Nakamura Yuichiro; Sasaki Emi

307

Resin composite for sealing and its use in a solar cell. Fushiyo jushi soseibutsu oyobi sore wo mochiita taiyo denchi  

Energy Technology Data Exchange (ETDEWEB)

This invention presents resin composites for sealing of a solar cell composed of a hardening resin and a thermoplastic resin which has a number average molecular weight larger than that of the hardening resin and is soluble in the hardening resin, and the invention affords a solar cell to endure a long-term stable operation and to give a good performance. The hardening resin includes unsaturated polyester resin, phenolic resin, alkyd resin, unsaturated acrylic resin, epoxy resin, polyurethane resin, melamine resin, diallyl phthalate resin, their oligomers and their modifications. The thermoplastic resin includes saturated polyester resin, phenolic resin, acrylic resin, styrene resin, epoxy resin, polyurethane resin, polyvinyl acetate resin, polyvinyl chloride resin, polyvinyl alcohol resin, polyacetal resin, their modifications and their copolymer resin. 2 figs., 3 tabs.

Toma, H.; Mimura, T.; Takehara, N.

1994-01-28

308

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

Energy Technology Data Exchange (ETDEWEB)

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

Hallman, D.F.

2001-07-10

309

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

International Nuclear Information System (INIS)

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

2001-01-01

310

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

311

Measurement of opalescence of resin composites.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Opalescence is an optical property, where there is light scattering of the shorter wavelengths of the visible spectrum, giving the material a bluish appearance under reflected light and an orange/brown appearance under transmitted light. The objective of this study was to determine the opalescence of resin composites with a color measuring spectrophotometer. METHODS: Colors of A2 and enamel or translucent shades of four resin composites and of an unfilled resin measured in the reflectance and transmittance modes were compared, and the opalescence parameter (OP) was calculated as the difference in blue-yellow coordinate (Deltab*) and red-green parameter (Deltaa*) between the reflected and transmitted colors of 1-mm thick specimens. The masking effect was calculated as the color difference between the color of a black background and the color of specimen over the black background. RESULTS: The range of OP in resin composites was 5.7-23.7, which was higher than that of the unfilled resin. However, there were significant differences among the brands and shades of the resin composites. SIGNIFICANCE: Opalescence varied by brand and shade of the resin composites, and contributed to the masking of background color along with translucency parameter. Some of the resin composites actually displayed opalescence.

Lee YK; Lu H; Powers JM

2005-11-01

312

Ion exchange resins for uranium recovery  

Energy Technology Data Exchange (ETDEWEB)

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.

Lee, J.M.; Bauman, W.C.

1984-02-28

313

Epoxidation of linseed oil-Alkyd resins  

International Nuclear Information System (INIS)

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

2004-01-01

314

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

315

Volumetric polymerization shrinkage of contemporary composite resins  

Directory of Open Access Journals (Sweden)

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

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

2007-01-01

316

Fracture toughness of posterior resin composites.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The purpose of this study was to evaluate and compare the resistance to crack propagation, as measured by the fracture toughness, of some packable posterior resin composites with other posterior resin composite materials. METHOD AND MATERIALS: Fracture toughness determinations were made for the 5 packable and the other posterior resin composites using 3-point flexure of beams with a standardized central single-edge notch. Ten beams of each material were tested on an Instron test machine. The maximum loads were determined, from which the fracture toughness values (KIC) were calculated. The data were analyzed statistically using ANOVA and t tests. RESULTS: The resin composites tested demonstrated a range of KIC values. The materials were separated according to the mean KIC values into 5 groups that were statistically different. While 2 packable resin composites had KIC values that were among the highest, the other packables were substantially lower than nonpackables. The intermediate value group consisted of 3 of the conventional posterior resin composites. CONCLUSION: There was a very weak correlation between fracture toughness and reported volume concentration of particulate reinforcing elements. The posterior resin composites tested exhibited a spectrum of KIC values. The packable resin composites were distributed along this spectrum, with 2 products exhibiting high potential for resistance to crack propagation.

Bonilla ED; Mardirossian G; Caputo AA

2001-03-01

317

Mesoporous silica nanoparticle nanocarriers: biofunctionality and biocompatibility.  

UK PubMed Central (United Kingdom)

The study of ordered mesoporous silica materials has exploded since their discovery by Mobil researchers 20 years ago. The ability to make uniformly sized, porous, and dispersible nanoparticles using colloidal chemistry and evaporation-induced self-assembly has led to many applications of mesoporous silica nanoparticles (MSNPs) as "nanocarriers" for delivery of drugs and other cargos to cells. The exceptionally high surface area of MSNPs, often exceeding 1000 m²/g, and the ability to independently modify pore size and surface chemistry, enables the loading of diverse cargos and cargo combinations at levels exceeding those of other common drug delivery carriers such as liposomes or polymer conjugates. This is because noncovalent electrostatic, hydrogen-bonding, and van der Waals interactions of the cargo with the MSNP internal surface cause preferential adsorption of cargo to the MSNP, allowing loading capacities to surpass the solubility limit of a solution or that achievable by osmotic gradient loading. The ability to independently modify the MSNP surface and interior makes possible engineered biofunctionality and biocompatibility. In this Account, we detail our recent efforts to develop MSNPs as biocompatible nanocarriers (Figure 1 ) that simultaneously display multiple functions including (1) high visibility/contrast in multiple imaging modalities, (2) dispersibility, (3) binding specificity to a particular target tissue or cell type, (4) ability to load and deliver large concentrations of diverse cargos, and (5) triggered or controlled release of cargo. Toward function 1, we chemically conjugated fluorescent dyes or incorporated magnetic nanoparticles to enable in vivo optical or magnetic resonance imaging. For function 2, we have made MSNPs with polymer coatings, charged groups, or supported lipid bilayers, which decrease aggregation and improve stability in saline solutions. For functions 3 and 4, we have enhanced passive bioaccumulation via the enhanced permeability and retention effect by modifying the MSNP surfaces with positively charged polymers. We have also chemically attached ligands to MSNPs that selectively bind to receptors overexpressed in cancer cells. We have used encapsulation of MSNPs within reconfigurable supported lipid bilayers to develop new classes of responsive nanocarriers that actively interact with the target cell. Toward function 4, we exploit the high surface area and tailorable surface chemistry of MSNPs to retain hydrophobic drugs. Finally, for function 5, we have engineered dynamic behaviors by incorporating molecular machines within or at the entrances of MSNP pores and by using ligands, polymers, or lipid bilayers. These provide a means to seal-in and retain cargo and to direct MSNP interactions with and internalization by target cells. Application of MSNPs as nanocarriers requires biocompatibility and low toxicity. Here the intrinsic porosity of the MSNP surface reduces the extent of hydrogen bonding or electrostatic interactions with cell membranes as does surface coating with polymers or lipid bilayers. Furthermore, the high surface area and low extent of condensation of the MSNP siloxane framework promote a high rate of dissolution into soluble silicic acid species, which are found to be nontoxic. Potential toxicity is further mitigated by the high drug capacity of MSNPs, which greatly reduces needed dosages compared with other nanocarriers. We anticipate that future generations of MSNPs incorporating molecular machines and encapsulated by membrane-like lipid bilayers will achieve a new level of controlled cellular interactions.

Tarn D; Ashley CE; Xue M; Carnes EC; Zink JI; Brinker CJ

2013-03-01

318

Effect of Resin Viscosity in Fiber Reinforcement Compaction in Resin Injection Pultrusion Process  

Science.gov (United States)

In resin injection pultrusion, the liquid resin is injected through the injection slots into the fiber reinforcement; the liquid resin penetrates through the fibers as well as pushes the fibers towards the centerplane causing fiber compaction. The compacted fibers are more difficult to penetrate, thus higher resin injection pressure becomes necessary to achieve complete reinforcement wetout. Lower injection pressures below a certain range (depending upon the fiber volume fraction and resin viscosity) cannot effectively penetrate through the fiber bed and thus cannot achieve complete wetout. Also, if the degree of compaction is very high the fibers might become essentially impenetrable. The more viscous the resin is, the harder it is to penetrate through the fibers and vice versa. The effect of resin viscosity on complete wetout achievement with reference to fiber-reinforcement compaction is presented in this study.

Shakya, N.; Roux, J. A.; Jeswani, A. L.

2013-06-01

319

[Immobilization of lignin peroxidase on spherical mesoporous material].  

UK PubMed Central (United Kingdom)

The spherical mesoporous particles with two-dimensional (2D) hexagonal mesopores in diameter up to 11.6 nm was fabricated in acetic acid/sodium buffer solution (pH = 3.5) by using tetramethoxysilane (TMOS) as silica source, Pluronic P123 as template and 1,3,5-triisopropylbenzene (TIPB) as swelling agent. Then the mesoporous particles were employed as carriers for the immobilization of lignin peroxidase (LiP). The effect of immobilization time, the amount of added enzyme on the immobilized enzyme amount and activities were investigated. The characteristic and stability of immobilized LiP were also studied. The results showed that, as the mass ratio of enzyme (E) and mesoporous material (MS) was 76.8 mg/g,immobilizing time was 12 h, the largest immobilized enzyme amount (8.87 mg/g) and highest apparent activity (41.45 U/mg) of immobilization LiP were achieved. Comparing with free LiP, the optimum pH and temperature of the immobilized LiP were almost the same, while whose pH stability and thermal stability were significantly improved. No obvious activity loss was observed for the immobilized LiP after 7 weeks storage at 4 degrees C. After 6 times of usage, almost 30% of the initial activity could still remain.

Xu LQ; Wen XH; Ding HJ

2010-10-01

320

[Immobilization of lignin peroxidase on spherical mesoporous material].  

Science.gov (United States)

The spherical mesoporous particles with two-dimensional (2D) hexagonal mesopores in diameter up to 11.6 nm was fabricated in acetic acid/sodium buffer solution (pH = 3.5) by using tetramethoxysilane (TMOS) as silica source, Pluronic P123 as template and 1,3,5-triisopropylbenzene (TIPB) as swelling agent. Then the mesoporous particles were employed as carriers for the immobilization of lignin peroxidase (LiP). The effect of immobilization time, the amount of added enzyme on the immobilized enzyme amount and activities were investigated. The characteristic and stability of immobilized LiP were also studied. The results showed that, as the mass ratio of enzyme (E) and mesoporous material (MS) was 76.8 mg/g,immobilizing time was 12 h, the largest immobilized enzyme amount (8.87 mg/g) and highest apparent activity (41.45 U/mg) of immobilization LiP were achieved. Comparing with free LiP, the optimum pH and temperature of the immobilized LiP were almost the same, while whose pH stability and thermal stability were significantly improved. No obvious activity loss was observed for the immobilized LiP after 7 weeks storage at 4 degrees C. After 6 times of usage, almost 30% of the initial activity could still remain. PMID:21229767

Xu, Long-Qian; Wen, Xiang-Hua; Ding, Hang-Jun

2010-10-01

 
 
 
 
321

Synthesis, characterisation and catalytic properties of vanadium substituted mesoporous aluminophosphates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vanadium substituted mesoporous AlPO have been synthesized using structure-directing surfactant under hydrothermal synthesis conditions. The presence of V in the framework of AlPO has been established by ESR, XPS, UV-vis DRS and ICP-AES measurements. This system is capable of promoting the oxidn. of...

Subrahmanyam, Ch; Louis, B.; Viswanathan, B.; Renken, A.; Varadarajan, T. K.

322

Preparation and Characterization of Cyano―functionalized Mesoporous Silica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cyano―functionalized mesoporous silicas were synthesized by one―pot co―condensation of tetraethoxysilane (TEOS) and 2―cyanoethyltriethoxysilane (CTES), using Pluronic P123 triblock copolymer as the structure― directing agent under strongly aci...

GUO Feng, ZHU Gui-Ru, GAO Cong-Jie

323

Inhibition of a protein tyrosine phosphatase using mesoporous oxides.  

UK PubMed Central (United Kingdom)

The feasibility of utilizing mesoporous matrices of alumina and silica for the inhibition of enzymatic activity is presented here. These studies were performed on a protein tyrosine phosphatase by the name chick retinal tyrosine phosphotase-2 (CRYP-2), a protein that is identical in sequence to the human glomerular epithelial protein-1 and involved in hepatic carcinoma. The inhibition of CRYP-2 is of tremendous therapeutic importance. Inhibition of catalytic activity was examined using the sustained delivery of p-nitrocatechol sulfate (pNCS) from bare and amine functionalized mesoporous silica (MCM-48) and mesoporous alumina (Al(2)O(3)). Among the various mesoporous matrices employed, amine functionalized MCM-48 exhibited the best release of pNCS and also inhibition of CRYP-2. The maximum speed of reaction v(max) (=160 +/- 10 micromol/mnt/mg) and inhibition constant K(i) (=85.0 +/- 5.0 micromol) estimated using a competitive inhibition model were found to be very similar to inhibition activities of protein tyrosine phosphatases using other methods.

Kapoor S; Girish TS; Mandal SS; Gopal B; Bhattacharyya AJ

2010-03-01

324

Inhibition of a protein tyrosine phosphatase using mesoporous oxides.  

Science.gov (United States)

The feasibility of utilizing mesoporous matrices of alumina and silica for the inhibition of enzymatic activity is presented here. These studies were performed on a protein tyrosine phosphatase by the name chick retinal tyrosine phosphotase-2 (CRYP-2), a protein that is identical in sequence to the human glomerular epithelial protein-1 and involved in hepatic carcinoma. The inhibition of CRYP-2 is of tremendous therapeutic importance. Inhibition of catalytic activity was examined using the sustained delivery of p-nitrocatechol sulfate (pNCS) from bare and amine functionalized mesoporous silica (MCM-48) and mesoporous alumina (Al(2)O(3)). Among the various mesoporous matrices employed, amine functionalized MCM-48 exhibited the best release of pNCS and also inhibition of CRYP-2. The maximum speed of reaction v(max) (=160 +/- 10 micromol/mnt/mg) and inhibition constant K(i) (=85.0 +/- 5.0 micromol) estimated using a competitive inhibition model were found to be very similar to inhibition activities of protein tyrosine phosphatases using other methods. PMID:20163174

Kapoor, S; Girish, T S; Mandal, S S; Gopal, B; Bhattacharyya, A J

2010-03-11

325

Mesoporous diphosphine-transition metal complex catalyst for hydroformylation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The invention pertains to a diphosphine-transition metal complex comprising a diphosphine-transition metal ligand that is covalently bonded to an insoluble mesoporous support having an average pore diameter of from 4.5 nm to 50 nm, characterized in that the ligand as attached to the support has the ...

Reek, J.N.H.; Coppens, M.O.

326

Facile synthesis of mesoporous aluminosilicates constructed with crystalline microporous frameworks  

Science.gov (United States)

A bifunctional surfactant as a porogen for hierarchically structured zeolites was synthesized.The surfactant can interact with aluminosilicate species via self-assembly.The surfactant could generate micropores and mesopores simultaneously.The DFT method was used for understanding molecular properties of surfactant.

Liu, Baoyu; Ren, Yanqun; Duan, Qianqian; Chen, Fei; Xi, Hongxia; Qian, Yu

2013-08-01

327

Self-assembly mechanism of folate-templated mesoporous silica.  

UK PubMed Central (United Kingdom)

A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ methods such as small angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy and conductivity measurements are used to describe 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 provides evidence for the in register stacking of folate tetramers resulting in a chiral surface of rotated tetramers, with a rotation angle of 300. 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.

Atluri R; Iqbal MN; Bacsik Z; Hedin N; Villaescusa LA; Garcia-Bennett AE

2013-08-01

328

Self-assembly mechanism of folate-templated mesoporous silica.  

UK PubMed Central (United Kingdom)

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.

Atluri R; Iqbal MN; Bacsik Z; Hedin N; Villaescusa LA; Garcia-Bennett AE

2013-09-01

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

2013-09-11

330

Solidification of ion exchange resin wastes  

International Nuclear Information System (INIS)

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

1982-01-01

331

Solidification of ion exchange resin wastes  

Energy Technology Data Exchange (ETDEWEB)

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

1982-08-01

332

Synthesis of mesoporous zeolite single crystals with cheap porogens  

International Nuclear Information System (INIS)

Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, 27Al magic angle spinning nuclear magnetic resonance (27Al MAS NMR), temperature-programmed desorption of ammonia (NH3-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. 27Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites. - Graphical abstract: Mesoporous zeolite single crystals were synthesized by using cheap porogens as template. Highlights: ? Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. ? Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. ? The mesoporous zeolites had connected mesopores although closed pores existed. ? Higher catalytic activities were obtained.

2002-01-00

333

Mesoporous-silica films, fibers, and powders by evaporation  

Energy Technology Data Exchange (ETDEWEB)

This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s). 24 figs.

Bruinsma, P.J.; Baskaran, S.; Bontha, J.R.; Liu, J.

1999-07-13

334

Mesoporous-silica films, fibers, and powders by evaporation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-01-01

335

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

336

The formation of ordered bismuth nanowire arrays within mesoporous silica templates  

Energy Technology Data Exchange (ETDEWEB)

Bismuth nanowire arrays have been synthesized within the pores of ordered mesoporous silica templates using a supercritical fluid (SCF) inclusion technique. The formation of nanowires within the mesopores was confirmed by powder X-ray diffraction (PXRD), N{sub 2} adsorption experiments and transmission electron microscopy (TEM). The formation of the bismuth nanowire arrays occurred through the initial binding of the bismuth precursor to the inner walls of the mesoporous channels, forming bismuth crystal seeds, which subsequently developed into wire-like structures. By varying the concentration of the bismuth precursor in the SCF phase, the loading of bismuth nanocrystals within the mesoporous channels can be controlled. The effect that temperature had on the formation of bismuth nanocrystals within the mesopores was also investigated. The highest loading of bismuth nanocrystals inside the mesopores was obtained at reaction temperatures near the critical point of toluene.

Xu Ju [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Zhang Wenhua [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Morris, Michael A. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Holmes, Justin D. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland)], E-mail: j.holmes@ucc.ie

2007-07-15

337

The formation of ordered bismuth nanowire arrays within mesoporous silica templates  

International Nuclear Information System (INIS)

Bismuth nanowire arrays have been synthesized within the pores of ordered mesoporous silica templates using a supercritical fluid (SCF) inclusion technique. The formation of nanowires within the mesopores was confirmed by powder X-ray diffraction (PXRD), N2 adsorption experiments and transmission electron microscopy (TEM). The formation of the bismuth nanowire arrays occurred through the initial binding of the bismuth precursor to the inner walls of the mesoporous channels, forming bismuth crystal seeds, which subsequently developed into wire-like structures. By varying the concentration of the bismuth precursor in the SCF phase, the loading of bismuth nanocrystals within the mesoporous channels can be controlled. The effect that temperature had on the formation of bismuth nanocrystals within the mesopores was also investigated. The highest loading of bismuth nanocrystals inside the mesopores was obtained at reaction temperatures near the critical point of toluene.

2007-07-15

338

Self-templating synthesis of hollow mesoporous silica and their applications in catalysis and drug delivery  

Science.gov (United States)

Hollow mesoporous silica materials have been intensively pursued because of their unique properties for various applications. Yolk/shell structured hollow mesoporous silica with functional cores inside their hollow interior can further broaden the applications of hollow mesoporous silica. The self-templating strategy has been developed as one of the most important strategies to effectively fabricate hollow mesoporous silicas and their yolk/shell counterparts. In this feature article, we provide an overview of advances in the self-templating synthesis of hollow mesoporous silica based on the following three strategies: surface-protected etching, structural difference-based selective etching, and cationic surfactant assisted self-templating. We then discuss some important applications of these self-templating strategy-derived hollow mesoporous silicas, such as nanoreactors for confined catalysis and multifunctional platforms for combined therapy. Finally, some perspectives for the future development of this active research field are provided.

Fang, Xiaoliang; Zhao, Xiaojing; Fang, Weijun; Chen, Cheng; Zheng, Nanfeng

2013-02-01

339

Polymer composite for obtaining rolled fiber glass plastic  

Energy Technology Data Exchange (ETDEWEB)

The purpose of the invention is to reduce combustability, improve the breaking load and improve the sanitary-hygienic conditions during production and use of rolled fiber glass plastic. The polymer deposit for obtaining the rolled fiber glass plastic including an epoxy compound, a phenol formaldehyde resin of the resol type, a thermal plastic and a diluent. It contains as the epoxy compound, epoxy ether which is a product of etherification of epoxy resin by fatty acids of linoleic acid, and the phenol formaldehyde resin used is bakelite varnish. The thermal plastic is polystyrene and the diluent is toluene, butanal xylol. It additionally contains alumoethylsiloxane resin and trichloroethylphosphate with the following ratio of components (parts by mass): epoxy ether 100.0, bakelite varnish 10.0-30.0, polystyrene 3.0-7.0, toluene 2.5-5.0, butanal 2.5-5.0, xylol 6-14.0, alumoethylsiloxane resin 510.0, trichloroethylphosphate 5-15.0.

Koskov, I.G.; Cherkasov, V.V.; Minina, Ye.V.; Muchnik, P.I.; Semikina, N.I.; Surov, Yu.N.

1982-01-01

340

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

UK PubMed Central (United Kingdom)

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

Türker Y; Karakaya C; Dag Ö

2012-03-01

 
 
 
 
341

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

Science.gov (United States)

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

Türker, Yurdanur; Karakaya, Cüneyt; Dag, Ömer

2012-02-16

342

Polytetrafluorethylene added to acrylic resins: mechanical properties.  

UK PubMed Central (United Kingdom)

The addition of different polymers, such as polytetrafluorethylene (PTFE), to denture base resins could be an option to modify acrylic resin mechanical properties. This study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% PTFE. Four groups were formed according to the polymerization cycle and addition or not of PTFE. Forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. The results of the flexural strength test allowed calculating flexural modulus and peak of load values. All tests were performed in accordance with the ISO 1567:1999 standard. Data were analyzed statistically by ANOVA and Tukey's test with the level of significance set at 5%. No statistically significant differences (p>0.05) were found for surface hardness. Flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added PTFE. The flexural modulus of the acrylic resin with incorporated 2% PTFE polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. Within the limits of this study, it may be concluded that the addition of PTFE did not improve the mechanical properties of the evaluated acrylic resins.

Straioto FG; Ricomini Filho AP; Fernandes Neto AJ; Del Bel Cury AA

2010-01-01

343

Immobilization of ion exchange resins in polymers  

International Nuclear Information System (INIS)

In this work a thermoplastic, low density polyethylene (LDPE), and two kinds thermosetting, epoxy and vinyl-ester resins, were used as binders in alternative purpose to replace the binders traditionally employed (cement and bitumen). Several mixtures were prepared with different proportions between polymer and ion exchange resin. It was possible to burn 60% wt of resin in LDPE and 50% wt in thermo settings. The mixtures were exposed to gamma radiation from the cobalt-60 source in several doses. After that they were characterized by mechanical tests, such as tensile strength, Shore D hardness and density. The radiolytic degradation of polymers was evaluated by absorption of spectroscopy in infra red region. The changes of LDPE crystallinity degree and glass transition temperature of thermo settings were evaluated by the Differential Scan Calorimeter (DSC), in regard to irradiation dose. The homogeneity and adherence between polymers and resins were showed by micrographs from Scan Electronic Microscope (SEM) and stereoscope. The results showed that the three studied polymers were compatible with ion-exchange resins since the free water was removed previously. The used processes showed good homogeneity of mixtures and good adherence between polymer and ion exchange resins. The mechanical properties of polymers were comparable for the three polymers presented good radiolytic stability up to 1 MGy. Considering the studied properties, the epoxy presented the best behavior when 50% wt of resin was burned. (author). 60 refs., 34 figs., 23 tabs

1994-01-01

344

Preparation of strontium hexaferrite nanowires in the mesoporous silica matrix (MCM-41)  

Energy Technology Data Exchange (ETDEWEB)

We report a novel method of synthesis of ordered magnetic strontium hexaferrite nanowires in the mesoporous silica matrix by incorporation of metal complexes into the freshly prepared mesoporous silica-surfactant composite. The shape and size of obtained nanowires are consistent with the dimensions of the porous framework. The obtained nanocomposites are characterized by high blocking temperatures up to 160 K. Mesoporous silica serves as nanoreactor for the formation of nanowires.

Eliseev, A.A. [Department of the Materials Sciences, Moscow State University, Leninskie Gory 1-3, 119992, Moscow (Russian Federation)]. E-mail: eliseev@inorg.chem.msu.ru; Gorozhankin, D.F. [Department of the Materials Sciences, Moscow State University, Leninskie Gory 1-3, 119992, Moscow (Russian Federation); Zaitsev, D.D. [Department of the Materials Sciences, Moscow State University, Leninskie Gory 1-3, 119992, Moscow (Russian Federation); Lukashin, A.V. [Department of the Materials Sciences, Moscow State University, Leninskie Gory 1-3, 119992, Moscow (Russian Federation); Knotko, A.V. [Department of the Materials Sciences, Moscow State University, Leninskie Gory 1-3, 119992, Moscow (Russian Federation); Tretyakov, Yu.D. [Department of the Materials Sciences, Moscow State University, Leninskie Gory 1-3, 119992, Moscow (Russian Federation); Goernert, P. [INNOVENT e.V., Pruessingstrasse 27 B, D-07745 Jena (Germany)

2005-04-15

345

Preparation of strontium hexaferrite nanowires in the mesoporous silica matrix (MCM-41)  

International Nuclear Information System (INIS)

We report a novel method of synthesis of ordered magnetic strontium hexaferrite nanowires in the mesoporous silica matrix by incorporation of metal complexes into the freshly prepared mesoporous silica-surfactant composite. The shape and size of obtained nanowires are consistent with the dimensions of the porous framework. The obtained nanocomposites are characterized by high blocking temperatures up to 160 K. Mesoporous silica serves as nanoreactor for the formation of nanowires.

2005-01-01

346

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

347

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

348

Hypercrosslinked poly(styrene-co-divinylbenzene) resin as a specific polymeric adsorbent for purification of berberine hydrochloride from aqueous solutions.  

UK PubMed Central (United Kingdom)

A hypercrosslinked poly(styrene-co-divinylbenzene) resin (TEPA) was synthesized and characterized as a specific polymeric adsorbent for concentrating berberine hydrochloride from aqueous solutions. Three organic molecules of different sizes (2-naphthol, berberine hydrochloride, and Congo red) were used as target molecules to elucidate the molecular sieving effect of the TEPA adsorbent. Because the TEPA adsorbent has a pore structure consisting mainly of micropores and mesopores, the adsorption of 2-naphthol from aqueous solutions is very efficient due to the micropore filling effect. The adsorption of berberine hydrochloride mostly takes place in the mesopores as well as macropores, while the adsorption of Congo red mainly occurs in the macropores. The smaller adsorbate molecule (2-naphthol) reaches the adsorption equilibrium much faster than the larger ones (berberine hydrochloride and Congo red). An adsorption breakthrough experiment with an aqueous solution containing 2-naphthol and berberine hydrochloride demonstrated that the TEPA adsorbent could effectively remove 2-naphthol from berberine hydrochloride at 0-107 BV (bed volume, 1 BV=10 ml), and the berberine hydrochloride concentration was increased from 66.7% to 99.4%, suggesting that this polymeric adsorbent is promising for purifying berberine hydrochloride and similar alkaloids from herbal plant extracts.

Li Y; Cao R; Wu X; Huang J; Deng S; Lu X

2013-06-01

349

Magnetic nanocomposite spinel and FeCo core-shell and mesoporous systems  

International Nuclear Information System (INIS)

[en] 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.

2012-01-01

350

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

UK PubMed Central (United Kingdom)

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

Grant SM; Woods SM; Gericke A; Jaroniec M

2011-11-01

351

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

Science.gov (United States)

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

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

2011-10-25

352

Effect of mesoporous silica under Neisseria meningitidis transformation process: environmental effects under meningococci transformation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background This study aimed the use of mesoporous silica under the naturally transformable Neisseria meningitidis, an important pathogen implicated in the genetic horizontal transfer of DNA causing a escape of the principal vaccination measures worldwide by the capsular switching process. This study verified the effects of mesoporous silica under N. meningitidis transformation specifically under the capsular replacement. Methods we used three different mesoporous silica particles to verify their action in N. meningitis transformation frequency. Results we verified the increase in the capsular gene replacement of this bacterium with the three mesoporous silica nanoparticles. Conclusion the mesouporous silica particles were capable of increasing the capsule replacement frequency in N. meningitidis.

Hollanda Luciana M; Cury Gisele CG; Pereira Rafaella FC; Ferreira Gracielle A; Sousa Andreza; Sousa Edesia MB; Lancellotti Marcelo

2011-01-01

353

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

Science.gov (United States)

A mesoporous hydroxyapatite (HA) coating was prepared on a ?-tricalcium phosphate (?-TCP) porous scaffold by a sol-gel dip-coating method using the block copolymer Pluronic F127 (EO106PO70EO106) as the template. For application as a bone graft, in vitro cell response and bone-related protein expression of mesoporous HA coated ?-TCP scaffold were investigated, using the non-mesoporous HA coated scaffold as the control group, to evaluate the influence of the mesoporous structure on the biological properties of HA coating. It was found that the increased surface area of the mesoporous HA coating greatly affected the response of MC3T3-E1 osteoblasts and the expression of proteins. An enzyme-linked immunosorbent assay recorded a significantly higher expression of alkaline phosphatase (ALP) and bone sialoprotein (BSP) in the mesoporous group than those in the control group (*p<0.05) after different incubation periods. The introduction of mesopores enhanced the expression of ALP and BSP in the cells grown on the mesoporous HA coatings, on the premise of maintaining the protein expression in a sequence to ensure the correct temporo-spatial expression in osteogenesis. These results indicated that the mesoporous HA coating would provide a good environment for cell growth, suggesting that it could be used as the coating material for the surface modification of the tissue engineering scaffolds. PMID:24094217

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

2013-08-31

354

Facile H2O2 Hydrothermal Synthesis of Bimodal Mesoporous Silica MCM-48 Spheres  

Science.gov (United States)

The ordered bimodal mesoporous silica MCM-48 spheres were facile synthesized by mild-temperature post-synthesis H2O2 hydrothermal treatment of as-synthesized MCM-48. The results showed that H2O2 is indispensable for simultaneously removing organic templates and forming ordered bimodal mesoporous silica MCM-48 spheres. The bimodal mesoporous MCM-48 was characterized by X-ray diffraction, transmission electron micrographs, FT-IR, and N2 adsorption-desorption, and a possible mechanism was proposed for the formation of bimodal mesoporous MCM-48.

Tian, Dong; Yong, Guo-ping; Tong, Hong-wu; Liu, Shao-min

2010-08-01

355

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

UK PubMed Central (United Kingdom)

A mesoporous hydroxyapatite (HA) coating was prepared on a ?-tricalcium phosphate (?-TCP) porous scaffold by a sol-gel dip-coating method using the block copolymer Pluronic F127 (EO106PO70EO106) as the template. For application as a bone graft, in vitro cell response and bone-related protein expression of mesoporous HA coated ?-TCP scaffold were investigated, using the non-mesoporous HA coated scaffold as the control group, to evaluate the influence of the mesoporous structure on the biological properties of HA coating. It was found that the increased surface area of the mesoporous HA coating greatly affected the response of MC3T3-E1 osteoblasts and the expression of proteins. An enzyme-linked immunosorbent assay recorded a significantly higher expression of alkaline phosphatase (ALP) and bone sialoprotein (BSP) in the mesoporous group than those in the control group (*p<0.05) after different incubation periods. The introduction of mesopores enhanced the expression of ALP and BSP in the cells grown on the mesoporous HA coatings, on the premise of maintaining the protein expression in a sequence to ensure the correct temporo-spatial expression in osteogenesis. These results indicated that the mesoporous HA coating would provide a good environment for cell growth, suggesting that it could be used as the coating material for the surface modification of the tissue engineering scaffolds.

Ye X; Cai S; Xu G; Dou Y; Hu H; Ye X

2013-12-01

356

Transport container for radioactive ion exchanger resins  

International Nuclear Information System (INIS)

A container for the transport of spent, i.e. strongly enriched ion exchanger resins is described which complies with the safety regulations for the transport on public roads. A double-walled outer container is used for shielding. A container equipped with a screen floor and feed and drain pipes for the resin and the water for handling and flushing out is placed in this outer container to take the resin. Furthermore, a filling level measuring instrument and a reserve capacity area shut off by means of a valve are also provided. (UWI)

1976-01-01

357

Ion exchange resin immobilization in polymers  

International Nuclear Information System (INIS)

Epoxy resin was used for ion exchange resins immobilization. In order to assure the integrity during storage, transport and final disposal, the waste form's properties were verified through physical tests, such as density and Shore D hardness, and mechanical test, such as tensile strength. The results showed that properties's values were comparable with values of traditional agents (cement and bitumen), mentioned in papers. Also up to I MGy no significant changes of the waste form's properties were noted and, up to this dose, the radiation effects were less than the effects of the ion exchange resins incorporated with 50% wt. (author).

1994-09-02

358

Immobilisation of ion exchange resins in cement  

International Nuclear Information System (INIS)

[en] 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

359

Immobilisation of ion exchange resins in cement  

International Nuclear Information System (INIS)

[en] 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

360

Studies on cesium uptake by phenolic resins  

International Nuclear Information System (INIS)

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

1992-01-01

 
 
 
 
361

Method for selective plugging using resin emulsions  

Energy Technology Data Exchange (ETDEWEB)

Methods and compositions are provided for selectively plugging the water-rich strata of subterranean formations, including injection into the formation of a water-insoluble, oil-soluble resin emulsion. A series of chemical reactions is initiated insitu such that the emulsion demulsifies, resulting in the coalescence of resin droplets. The coalesced water-insoluble, oil-soluble resin droplets are effective to selectively plug the water-rich strata over a relatively long distance and over a relatively long period of time.

Friedman, R.H.

1982-10-05

362

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...

Jovi?i? Mirjana C.; Radi?evi? Radmila Ž.

363

Durability of adhesion between feldspathic ceramic and resin cements: effect of adhesive resin, polymerization mode of resin cement, and aging.  

UK PubMed Central (United Kingdom)

PURPOSE: Adhesive cementation is an important step for restorations made of feldspathic ceramic as it increases the strength of such materials. Incorrect selection of the adhesive resin and the resin cement to adhere to the ceramic surface and their durability against aging can affect the adhesion between these materials and the clinical performance. This study evaluated the effect of adhesive resins with different pHs, resin cements with different polymerization modes, and aging on the bond strength to feldspathic ceramic. MATERIALS AND METHODS: One surface of feldspathic ceramic blocks (VM7) (N = 90) (6.4 × 6.4 × 4.8 mm(3) ) was conditioned with 10% hydrofluoric acid for 20 seconds, washed/dried, and silanized. Three adhesive resins (Scotchbond Multi-Purpose Plus [SBMP], pH: 5.6; Single Bond [SB], pH: 3.4; and Prime&Bond NT [NT], pH: 1.7) were applied on the ceramic surfaces (n = 30 per adhesive). For each adhesive group, three resin cements with different polymerization modes were applied (n = 10 per cement): photo-polymerized (Variolink II base), dual polymerized (Variolink II base + catalyst), and chemically polymerized (C&B). The bonded ceramic blocks were stored in water (37°C) for 24 hours and sectioned to produce beam specimens (cross-sectional bonded area: 1 ± 0.1 mm(2) ). The beams of each block were randomly divided into two conditions: Dry, microtensile test immediately after cutting; TC, test was performed after thermocycling (12,000×, 5°C to 55°C) and water storage at 37°C for 150 days. Considering the three factors of the study (adhesive [3 levels], resin cement [3 levels], aging [2 levels]), 18 groups were studied. The microtensile bond strength data were analyzed using 3-way ANOVA and Tukey's post hoc test (?= 0.05). RESULTS: Adhesive resin type (p < 0.001) and the resin cement affected the mean bond strength (p= 0.0003) (3-way ANOVA). The NT adhesive associated with the chemically polymerized resin cement in both dry (8.8 ± 6.8 MPa) and aged conditions (6.9 ± 5.9 MPa) presented statistically lower bond strength results, while the SBMP adhesive resin, regardless of the resin cement type, presented the highest results (15.4 to 18.5 and 14.3 to 18.9 MPa) in both dry and aged conditions, respectively (Tukey's test). CONCLUSION: Application of a low-pH adhesive resin onto a hydrofluoric acid etched and silanized feldspathic ceramic surface in combination with chemically polymerized resin cement did not deliver favorable results. The use of adhesive resin with high pH could be clinically advised for the photo-, dual-, and chemically polymerized resin cements tested.

Vanderlei A; Passos SP; Özcan M; Bottino MA; Valandro LF

2013-04-01

364

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

365

Large-scale, three-dimensional, free-standing, and mesoporous metal oxide networks for high-performance photocatalysis.  

UK PubMed Central (United Kingdom)

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 H; Li X; Hu C; Zhang X; Li J; Yan Y; Xi G

2013-01-01

366

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

367

Shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins.  

Science.gov (United States)

Abstract Objective. This study investigated the shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins. Materials and methods. Four injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) were used in this study. The specimens were divided into eight groups according to the type of surface treatment given: (1) no treatment, (2) air abrasion with alumina, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) alumina and 4-META/MMA-TBB resin, (7) tribochemical silica coating or (8) tribochemical silica coating and 4-META/MMA-TBB resin. Half of the specimens in groups 1, 5, 6 and 8 were thermocycled for 10,000 cycles in water between 5-55°C with a dwell time of 1 min at each temperature. The shear bond strengths were determined. Results. The shear bond strengths to the two polyamides treated with alumina, dichloromethane and ethyl acetate and no treatment were very low. The greatest post-thermocycling bond strengths to polyamides were recorded for the specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (PA12: 16.4 MPa, PACM12: 17.5 MPa). The greatest post-thermocycling bond strengths to polyethylene terephthalate copolymer and polycarbonate were recorded for the treatment with alumina and 4-META/MMA-TBB resin (22.7 MPa, 20.8 MPa). Conclusion. Polyamide was exceedingly difficult to bond to an autopolymerizing repair resin; the shear bond strength improved using tribochemical silica coating followed by the application of 4-META/MMA-TBB resin. Both polyethylene terephthalate copolymer and polycarbonate were originally easy to bond to an autopolymerizing repair resin. However, with 4-META/MMA-TBB resin, the bond was more secure. PMID:23339746

Hamanaka, Ippei; Shimizu, Hiroshi; Takahashi, Yutaka

2013-01-23

368

Shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins.  

UK PubMed Central (United Kingdom)

OBJECTIVE: This study investigated the shear bond strength of an autopolymerizing repair resin to injection-molded thermoplastic denture base resins. MATERIALS AND METHODS: Four injection-molded thermoplastic resins (two polyamides, a polyethylene terephthalate copolymer and a polycarbonate) were used in this study. The specimens were divided into eight groups according to the type of surface treatment given: (1) no treatment, (2) air abrasion with alumina, (3) dichloromethane, (4) ethyl acetate, (5) 4-META/MMA-TBB resin, (6) alumina and 4-META/MMA-TBB resin, (7) tribochemical silica coating or (8) tribochemical silica coating and 4-META/MMA-TBB resin. Half of the specimens in groups 1, 5, 6 and 8 were thermocycled for 10,000 cycles in water between 5-55°C with a dwell time of 1 min at each temperature. The shear bond strengths were determined. RESULTS: The shear bond strengths to the two polyamides treated with alumina, dichloromethane and ethyl acetate and no treatment were very low. The greatest post-thermocycling bond strengths to polyamides were recorded for the specimens treated with tribochemical silica coating and 4-META/MMA-TBB resin (PA12: 16.4 MPa, PACM12: 17.5 MPa). The greatest post-thermocycling bond strengths to polyethylene terephthalate copolymer and polycarbonate were recorded for the treatment with alumina and 4-META/MMA-TBB resin (22.7 MPa, 20.8 MPa). CONCLUSION: Polyamide was exceedingly difficult to bond to an autopolymerizing repair resin; the shear bond strength improved using tribochemical silica coating followed by the application of 4-META/MMA-TBB resin. Both polyethylene terephthalate copolymer and polycarbonate were originally easy to bond to an autopolymerizing repair resin. However, with 4-META/MMA-TBB resin, the bond was more secure.

Hamanaka I; Shimizu H; Takahashi Y

2013-09-01

369

Resin-bound triaryl bismuthanes and bismuth diacetates: novel multidirectional linkers and novel resin-bound arylation reagents.  

UK PubMed Central (United Kingdom)

A general synthesis of resin-bound triaryl bismuthanes and resin-bound triaryl bismuth diacetates starting from commercially available chloromethyl polystyrene is reported. For the first time resin-bound bismuth has been utilized as part of a multidirectional linker system for solid-phase organic synthesis and as a resin-bound arylation reagent.

Rasmussen LK; Begtrup M; Ruhland T

2004-10-01

370

Resin-bound triaryl bismuthanes and bismuth diacetates: novel multidirectional linkers and novel resin-bound arylation reagents.  

Science.gov (United States)

A general synthesis of resin-bound triaryl bismuthanes and resin-bound triaryl bismuth diacetates starting from commercially available chloromethyl polystyrene is reported. For the first time resin-bound bismuth has been utilized as part of a multidirectional linker system for solid-phase organic synthesis and as a resin-bound arylation reagent. PMID:15387617

Rasmussen, L Kyhn; Begtrup, Mikael; Ruhland, Thomas

2004-10-01

371

Resin Flow Analysis in the Injection Cycle of a Resin Transfer Molded Radome  

Science.gov (United States)

Resin flow analysis in the injection cycle of an RTM process was investigated. Fiberglass and carbon fiber mats were used as reinforcements with EPON 826 epoxy resin. Numerical models were developed in ANSYS finite element software to simulate resin flow behavior into a mold of conical shape. Resin flow into the woven fiber mats is modeled as flow through porous media. The injection time for fiberglass/epoxy composite is found to be 4407 seconds. Required injection time for the carbon/epoxy composite is 27022 seconds. Higher injection time for carbon/epoxy part is due to lower permeability value of the carbon fibers compared to glass fiber mat.

Golestanian, Hossein

2007-04-01

372

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

373

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

374

Method of Obtaining Phenol-Furfural Resins.  

Science.gov (United States)

Invention relates to improvement of method of obtaining phenol-furfural resins, utilized in different branches of national economy as cationites (for purification of waste water from ions of calcium, magnesium, etc., sorption of different metals). Method ...

A. Y. Yuldashev D. R. Tursunova N. U. Rizayev Y. Z. Rakhman-Zade

1990-01-01

375

Epoxide resins for use at low temperatures  

International Nuclear Information System (INIS)

[en] This chapter reports on the development and characterization of a number of unfilled epoxide resin systems offering improved resistance to thermal shock. Points out that the low temperature physical properties of cured resin systems are little changed by formulation variables. Finds that it is during cool down from room temperature that these newly developed resin systems demonstrate their ability to absorb the strains induced by differential thermal contraction. Concludes that the new epoxide resin systems demonstrate excellent resistance to thermal shock and have impregnation characteristics suitable for the preparation of fiber reinforced composites by vacuum impregnation or by wet lay up procedures. Notes that their improved resistance to thermal shock allows them to be used in situations where some inhomogeneity of reinforcement is unavoidable or where large temperature gradients may be present. Recommends that polymers used in low temperature applications should contain, wherever possible, reinforcement in the form of glass fabrics, rovings or chopped strands

1980-08-05

376

Polypropylene resin for manufacturing medical syringe  

UK PubMed Central (United Kingdom)

This invention is polypropylene resin used for making medical injector. The resin is propene and ethane atactic multipolymer, the ethane content is 0.5-5wt%. The resin contains transparent nucleating agent, acid neutralizer and antioxidant. The weigh ratios are: propene ethane atactic multipolymer/transparent nucleating agent=100/(0.08-0.40)propene ethane atactic multipolymer/ acid neutralizer=100/(0.01-0.10) propene ethane atactic multipolymer/antioxidant=100/(0.02-0.30). The transparent nucleating agent is sorbitol or organic phosphate compound, the acid neutralizer is one of calcium stearate or hydro-saponite or the mixture of the two, the antioxidant is one of or mixture of hindered phenol and phosphate ester. The polypropylene resin provided by this invention has good heat endurance, intension and tenacity.

TAO HONG; CHEN HAILIN; LIU YONG; DONG CHAO; LU GUOHUA; JIANG ZHONGHUI; MOU DAN; YANG HUIHUA; GAO GUOQIANG

377

Polypropylene resin for manufacturing medical transfusion container  

UK PubMed Central (United Kingdom)

This invention is polypropylene resin used for making medical transfusion container. The resin is propene and ethane atactic multipolymer, the ethane content is 0.5-4wt%, the melting temperature is 140-165deg.C, the flowing speed is 1.0-4.1g/10min. the resin contains acid neutralizer and antioxidant, propene ethane atactic multipolymer/acid neutralizer=100/(0.01-0.10)(weight ratio) propene ethane atactic multipolymer/antioxidant=100/(0.02-0.30)(weight ratio). The acid neutralizer is one of calcium stearate or hydro-saponite or the mixture of the two, the antioxidant is one of or mixture of hindered phenol and phosphate ester. The polypropylene resin provided by this invention not only has good heat endurance, intension and tenacity, but also has better transparency.

TAO HONG; CHEN HAILIN; LIU YONG; DONG CHAO; LU GUOHUA; JIANG ZHONGHUI; MOU DAN; YANG HUIHUA; GAO GUOQIANG

378

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.)

2012-01-01

379

Film of fluorocarbon resin. Fusso jushi film  

Energy Technology Data Exchange (ETDEWEB)

This paper introduced characteristics and applications of film of fluorocarbon resin. Fluorocarbon resin is a general term of plastomer where fluorine atoms are contained in a polymer molecule. A fluorocarbon resin having the most excellent features is polychlorotrifluoroethylene (PCTEF). Features of fluorocarbon resin film are excellent heat resistance, weathering resistance, chemical resistance, electric properties, untackiness, optical permeability and gas permeability. Film is manufactured by the cutting method and melt extrusion method. This film is used as lining material for many chemical plants, mold release matrial, moisture proof film, electric and electronic appliances, solar collector, and insulating material for extra high voltage transmitting cables. In order to raise the function of this film, surface is treated to improve the workability of laminates or heat sealers, or composite molding is carried out by using polymer alloy. Further, this film aims wider applications including stretched product, 9 refs., 5 figs., 8 tabs.

Nakata, Y. (Daikin Industries, Ltd., Osaka (Japan))

1990-07-05

380

Resins for high-purity water production  

Energy Technology Data Exchange (ETDEWEB)

In plants for the production of feedwater for high-pressure boilers, it is important to specify appropriate parameters for the ion exchange resins used. The parameters proposed for all make-up plant resins are total exchange capacity, bead integrity and physical strength (resistance to osmotic shock and attrition), supplemented by maximum, minimum and harmonic mean bead sizes appropriate for use in cation exchange, anion exchange and mixed bed units. (author).

Ball, M.; Harries, R.R.

1989-01-01

 
 
 
 
381

Isolating phenols from primary and coke resins  

Energy Technology Data Exchange (ETDEWEB)

To isolate phenols (F) from primary and coke resins the first stage accomplishes continuous or periodic extraction (Ek) of the phenols from the resin using aqueous solutions of Na/sub 3/P0/sub 4/ with 12H/sub 2/0, best with a concentration of 5 to 10 percent, at 20 to 80/sup 0/C and the second phase repeats the extraction of the phenols from the phosphate solution using butylacetate, amylacetate, acetal or other organic solvents.

Pietranek, W.; Bogucki, J.; Frysztacki, Z.; Krzton, A.; Rymarowicz, A.; Tokarzewski, L.

1982-05-31

382

Clinical applications of preheated hybrid resin composite.  

UK PubMed Central (United Kingdom)

This clinical article describes and discusses the use of preheated nanohybrid resin composite for the placement of direct restorations and luting of porcelain laminate veneers. Two clinical cases are presented. Preheating hybrid composite decreases its viscosity and film thickness offering the clinician improved handling. Preheating also facilitates the use of nanohybrid composite as a veneer luting material with relatively low polymerisation shrinkage and coefficient of thermal expansion compared to currently available resin luting cements.

Rickman LJ; Padipatvuthikul P; Chee B

2011-07-01

383

Tc-99 Ion Exchange Resin Testing  

International Nuclear Information System (INIS)

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

2010-01-01

384

Biocompatibility of Resin-based Dental Materials  

Directory of Open Access Journals (Sweden)

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

Keyvan Moharamzadeh; Ian M. Brook; Richard Van Noort

2009-01-01

385

Composition of resin acids in different rosins  

Energy Technology Data Exchange (ETDEWEB)

Absolute contents were determined by summing the contents of individual compounds separated by GC. Data are tabulated for the total and individual resin acids and total fatty acids in samples of Scots pine gum and wood rosins, larch gum rosin and Pinus sibirica wood rosin from the USSR. All contained the same range of compounds apart from the presence of lambertianic acid in Pinus sibirica only. The total resin acid content was highest (90-95%) in Scots pine gum rosin. (Refs. 5).

Druskina, E.Z.; Tabachkova, T.P.

1982-01-01

386

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.

Dai, Sheng [ORNL; Liang, Chengdu [ORNL; Shanahan, Paul [University of California; Xu, Lianbin [University of California; Waje, Mahesh [University of California; Yan, Y.S. [University of California

2008-01-01

387

Novel nanofluids based on mesoporous silica for enhanced heat transfer  

International Nuclear Information System (INIS)

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

2011-01-01

388

Electrochemical detection of ultratrace nitroaromatic explosives using ordered mesoporous carbon.  

UK PubMed Central (United Kingdom)

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

Zang J; Guo CX; Hu F; Yu L; Li CM

2011-01-01

389

Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study  

Science.gov (United States)

A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N2 adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption.

Alyoshina, Nonna A.; Parfenyuk, Elena V.

2013-09-01

390

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction  

International Nuclear Information System (INIS)

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

2012-08-01

391

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-01

392

Enzyme-functionalized mesoporous silica for bioanalytical applications.  

UK PubMed Central (United Kingdom)

The unique properties of mesoporous silica materials (MPs) have attracted substantial interest for use as enzyme-immobilization matrices. These features include high surface area, chemical, thermal, and mechanical stability, highly uniform pore distribution and tunable pore size, high adsorption capacity, and an ordered porous network for free diffusion of substrates and reaction products. Research demonstrated that enzymes encapsulated or entrapped in MPs retain their biocatalytic activity and are more stable than enzymes in solution. This review discusses recent advances in the study and use of mesoporous silica for enzyme immobilization and application in biosensor technology. Different types of MPs, their morphological and structural characteristics, and strategies used for their functionalization with enzymes are discussed. Finally, prospective and potential benefits of these materials for bioanalytical applications and biosensor technology are also presented.

Ispas C; Sokolov I; Andreescu S

2009-01-01

393

Liquid-phase synthesized mesoporous electrochemical supercapacitors of nickel hydroxide  

International Nuclear Information System (INIS)

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

2008-06-01

394

Preparation of mesoporous silica films SBA-15 over different substrates  

International Nuclear Information System (INIS)

[en] 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)

2010-01-01

395

Magnetic properties of iron nanoparticles in mesoporous silica matrix  

International Nuclear Information System (INIS)

Anisotropic iron nanoparticles were successfully synthesized within the pores of mesoporous silica matrix by intercalation of hydrophobic iron complex (Fe(CO)5) into the hydrophobic part of the mesoporous silica-surfactant composite. It was shown that the particles are uniform and well ordered in the matrix and their shape and size are in good agreement with that of the pores. The samples demonstrate spin-glass-like behavior at low temperatures, which transforms to the superparamagnetic one with temperature increases. Nanoscale-related magnetic properties were investigated by polarized SANS. It was shown that hysteretic and the spin-glass-like behavior may be attributed to bunches of the iron nanowires with average radius of 4.7 nm.

2006-01-01

396

Magnetic properties of iron nanoparticles in mesoporous silica matrix  

Energy Technology Data Exchange (ETDEWEB)

Anisotropic iron nanoparticles were successfully synthesized within the pores of mesoporous silica matrix by intercalation of hydrophobic iron complex (Fe(CO){sub 5}) into the hydrophobic part of the mesoporous silica-surfactant composite. It was shown that the particles are uniform and well ordered in the matrix and their shape and size are in good agreement with that of the pores. The samples demonstrate spin-glass-like behavior at low temperatures, which transforms to the superparamagnetic one with temperature increases. Nanoscale-related magnetic properties were investigated by polarized SANS. It was shown that hysteretic and the spin-glass-like behavior may be attributed to bunches of the iron nanowires with average radius of 4.7 nm.

Grigorieva, N.A. [St-Petersburg State University, St-Petersburg 198504 (Russian Federation); Grigoriev, S.V. [Petersburg Nuclear Physics Institute, Gatchina, St-Petersburg 188300 (Russian Federation); Eckerlebe, H. [GKSS Forschungszentrum, 21502 Geesthacht (Germany); Eliseev, A.A. [Department of Materials Science, Moscow State University, Moscow 119992 (Russian Federation)]. E-mail: eliseev@inorg.chem.msu.ru; Napolskii, K.S. [Department of Materials Science, Moscow State University, Moscow 119992 (Russian Federation); Lukashin, A.V. [Department of Materials Science, Moscow State University, Moscow 119992 (Russian Federation); Tretyakov, Yu.D. [Department of Materials Science, Moscow State University, Moscow 119992 (Russian Federation)

2006-05-15

397

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.

Rocco Savino; Francesca Casadonte; Rosa Terracciano

2011-01-01

398

Voltammetric response of ferrocene-grafted mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

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.

Delacote, Cyril [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement, UMR 7564, CNRS-Universite Henri Poincare Nancy I, 405, Rue de Vandoeuvre, F-54600 Villers-les-Nancy (France); Bouillon, Jean-Philippe [Laboratoire Synthese et Chromatographie, Sciences et Methodes Separatives (SMS), EA 3233, Universite de Rouen, IRCOF, F-76821 Mont-Saint-Aignan Cedex (France); Walcarius, Alain [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement, UMR 7564, CNRS-Universite Henri Poincare Nancy I, 405, Rue de Vandoeuvre, F-54600 Villers-les-Nancy (France)]. E-mail: walcarius@lcpme.cnrs-nancy.fr

2006-09-15

399

[Resin-bonded fixed partial dentures].  

UK PubMed Central (United Kingdom)

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

Kreulen CM; Creugers NH

2013-02-01

400

Cleanup of TMI-2 demineralizer resins  

International Nuclear Information System (INIS)

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

1985-05-03

 
 
 
 
401

Electrosynthesis of Epoxy Resins via Superoxide Anion  

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

Rajni Mathur; Meeta Trivedi

2013-01-01

402

Mesoporous silica nanoparticles: synthesis, biocompatibility and drug delivery.  

UK PubMed Central (United Kingdom)

In the past decade, mesoporous silica nanoparticles (MSNs) have attracted more and more attention for their potential biomedical applications. With their tailored mesoporous structure and high surface area, MSNs as drug delivery systems (DDSs) show significant advantages over traditional drug nanocarriers. In this review, we overview the recent progress in the synthesis of MSNs for drug delivery applications. First, we provide an overview of synthesis strategies for fabricating ordered MSNs and hollow/rattle-type MSNs. Then, the in vitro and in vivo biocompatibility and biotranslocation of MSNs are discussed in relation to their chemophysical properties including particle size, surface properties, shape, and structure. The review also highlights the significant achievements in drug delivery using mesoporous silica nanoparticles and their multifunctional counterparts as drug carriers. In particular, the biological barriers for nano-based targeted cancer therapy and MSN-based targeting strategies are discussed. We conclude with our personal perspectives on the directions in which future work in this field might be focused.

Tang F; Li L; Chen D

2012-03-01

403

Mesoporous silica nanoparticles: synthesis, biocompatibility and drug delivery.  

Science.gov (United States)

In the past decade, mesoporous silica nanoparticles (MSNs) have attracted more and more attention for their potential biomedical applications. With their tailored mesoporous structure and high surface area, MSNs as drug delivery systems (DDSs) show significant advantages over traditional drug nanocarriers. In this review, we overview the recent progress in the synthesis of MSNs for drug delivery applications. First, we provide an overview of synthesis strategies for fabricating ordered MSNs and hollow/rattle-type MSNs. Then, the in vitro and in vivo biocompatibility and biotranslocation of MSNs are discussed in relation to their chemophysical properties including particle size, surface properties, shape, and structure. The review also highlights the significant achievements in drug delivery using mesoporous silica nanoparticles and their multifunctional counterparts as drug carriers. In particular, the biological barriers for nano-based targeted cancer therapy and MSN-based targeting strategies are discussed. We conclude with our personal perspectives on the directions in which future work in this field might be focused. PMID:22378538

Tang, Fangqiong; Li, Linlin; Chen, Dong

2012-02-29

404

Synthesis and characterization of nanocrystalline and mesoporous zeolites  

Science.gov (United States)

Mesoporous aggregates of nanocrystalline zeolites with MFI and BEA frameworks have been synthesized using a one-pot and single structure directing agent. The effect of different reaction conditions, such as temperature, time, pH and water content, on the particle size, surface area and mesopore volume has been studied. Nanocrystalline and mesoporous ZSM-5, beta and Y zeolites were modified with different transition metals and the resulting single- and double metal containing catalyst materials were characterized. Nanocrystalline Silicalite-1 zeolite samples with varying particle size were functionalized with different organosilane groups and the cytotoxic activity of the zeolite nanocrystals was studied as a function of particle size, concentration, organic functional group type, as well as the type of cell line. Framework stability of nanocrystalline NaY zeolite was tested under different pH conditions. The synthesized zeolites used in this work were characterized using a variety of physico-chemical methods, including powder X-ray diffraction, Solid State NMR, nitrogen sorption, electron microscopy, Inductively Coupled Plasma -- Optical Emission Spectroscopy and X-ray Photoelectron Spectroscopy.

Petushkov, Anton

405

Direct method for surface silyl functionalization of mesoporous silica.  

UK PubMed Central (United Kingdom)

A direct method of surface silyl modification and simultaneous surfactant removal of mesoporous silica is investigated in its physicochemical details. Twelve different silanes of various functionalities are studied. The method employs an alcohol solution of silanes to allow the simultaneous surfactant/silyl exchange process, which results in a more uniform monolayer coverage of the surface and a higher amount of surface attachments of silane. We vary the solution concentration of silanes to study the effect on loadings. It is found that the variation of the surface loading of the silyl group follows a Langmuir adsorption model closely. The method gives one a well-controlled monolayer coverage of the surface. The loadings are determined by the exchange equilibrium. Fittings of the loading data to Langmuir adsorption isotherms give one the adsorption equilibrium constants and maximum surface loadings. We categorize the silanes into three different groups according to the values of the equilibrium constants and discuss them with respect to molecular structures. We also report on the extensive characterizations of the surface-functionalized mesoporous materials, such as nitrogen adsorptions, X-ray diffraction, 29Si magic-angle spinning NMR, 13C magic-angle spinning NMR, and IR spectroscopy. The method provides one with a convenient and highly controllable approach to the surface functionalization of mesoporous silica.

Liu YH; Lin HP; Mou CY

2004-04-01

406

Antibacterial properties of mesoporous copper-doped silica xerogels  

International Nuclear Information System (INIS)

Mesoporous copper-doped silica xerogels (m-SXCu) with antibacterial properties were synthesized by a sol-gel process, and the morphology, structure and composition of m-SXCu were characterized. The results show that m-SXCu5 with a high surface area of 463.1 m2 g-1 have a mesoporous structure with a pore size of about 2 nm. The addition of Cu from 1 to 5 wt% to m-SXCu had a slight effect on the surface area and a not-so-obvious effect on the mesoporous size of m-SXCu. Cu ions can be released from m-SXCu into the simulated body fluid, and the release rate depends significantly on their number. The m-SXCu possessed good antibacterial activity against both E. coli and S. aureus, in which the antibacterial rate reached 99% for m-SXCu5 at 1 h while reaching 99% for all m-SXCu at 24 h. The antibacterial rate was improved with the increase of the amount of Cu, indicating that addition of Cu ions to m-SX enhanced its antibacterial activity.

2009-01-01

407

Conductivity of liquid lithium electrolytes with dispersed mesoporous silica particles  

International Nuclear Information System (INIS)

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

2012-01-15

408

Tuning single-molecule dynamics in functionalized mesoporous silica.  

UK PubMed Central (United Kingdom)

Mesoporous silica materials are promising host structures for diverse applications in nanoscience. Many applications can profit significantly from the ability to influence guest dynamics in the host matrix. To this end, we introduce covalently attached organic functionalization into the walls of mesoporous silica networks. Using single-molecule fluorescence microscopy, we study the diffusion behavior of single terrylene diimide dye molecules in functionalized mesoporous silica films. We show that, through variation of the chemical nature and density of the functional groups, the diffusion dynamics of the dye molecules, in the presence of the surfactant template, can be controlled precisely. The mean diffusion coefficient of the dye molecules increases or decreases depending on the functional group attached to the silica wall. This allows fine-tuning of the diffusion dynamics of the dye by approximately one order of magnitude. The observed changes in the mean diffusion coefficients can be explained by shielding of hydroxyl groups on the silica surface in combination with changes in the rigidity of the micellar packing in the film, as well as direct interactions between the functional groups and the dye molecules.

Lebold T; Mühlstein LA; Blechinger J; Riederer M; Amenitsch H; Köhn R; Peneva K; Müllen K; Michaelis J; Bräuchle C; Bein T

2009-01-01

409

A Review: Fundamental Aspects of Silicate Mesoporous Materials  

Directory of Open Access Journals (Sweden)

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

Zeid A. ALOthman

2012-01-01

410

Ordered mesoporous carbon for electrochemical sensing: A review  

International Nuclear Information System (INIS)

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

1300-01-00

411

Benzylation of Toluene over Iron Modified Mesoporous Ceria  

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Full Text Available 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 surface area. Mesoporous ceria modified with Fe can be successfully utilized for the selective benzylation of toluene to more desirable product methyl diphenyl methane with 100% conversion and selectivity in 2 hours using only 50mg of the catalyst under milder condition. The reusability, regenerability, high selectivity, 100% conversion, moderate reaction temperature and absence of solvent, etc. make these catalysts to be used in a truly heterogeneous manner and make the benzylation reaction an environment friendly one. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 30th June 2012; Revised: 7th November 2012; Accepted: 10th November 2012[How to Cite: K.J. Rose Philo, S. Sugunan. (2012). Benzylation of Toluene over Iron Modified Mesoporouxs Ceria. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2): 158-164. (doi:10.9767/bcrec.7.2.3759.158-164)][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3759.158-164 ] | View in

K.J. Rose Philo; S. Sugunan

2012-01-01

412

Cumene cracking on modified mesoporous material type MCM-41  

Directory of Open Access Journals (Sweden)

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

Ahmed Belhakem; Abdelkader Bengueddach

2006-01-01

413

Ordered nanowire arrays in the mesoporous silica thin films  

International Nuclear Information System (INIS)

In the present study we report synthesis and investigation of the magnetic iron nanowire arrays in the mesoporous silica thin films. The films were deposited on SiC/Si(100) substrate by spin-coating technique, enabling one to obtain all mesopores parallel to the substrate surface and aligned radially by centrifugal force. Very high level of local alignment (90% on 2 cm2) of the pores was proved by small angle X-ray scattering and neutron reflectivity. Magnetic iron nanowires were synthesized in the mesoporous silica channels by intercalation of a hydrophobic iron compound into a hydrophobic part of the silica-surfactant composite followed by decomposition of the complex and additional crystallization of iron in hydrogen flow. Nanocomposites were studied by TEM, ED, SAXS, BET, BJH and neutron reflectometry. It was found that an ordered structure preserves after the chemical modification, while iron nanowires uniformly fill porous structure, making this system highly promising for high-density data recording media.

2006-01-20

414

Antibacterial properties of mesoporous copper-doped silica xerogels  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous copper-doped silica xerogels (m-SXCu) with antibacterial properties were synthesized by a sol-gel process, and the morphology, structure and composition of m-SXCu were characterized. The results show that m-SXCu5 with a high surface area of 463.1 m{sup 2} g{sup -1} have a mesoporous structure with a pore size of about 2 nm. The addition of Cu from 1 to 5 wt% to m-SXCu had a slight effect on the surface area and a not-so-obvious effect on the mesoporous size of m-SXCu. Cu ions can be released from m-SXCu into the simulated body fluid, and the release rate depends significantly on their number. The m-SXCu possessed good antibacterial activity against both E. coli and S. aureus, in which the antibacterial rate reached 99% for m-SXCu5 at 1 h while reaching 99% for all m-SXCu at 24 h. The antibacterial rate was improved with the increase of the amount of Cu, indicating that addition of Cu ions to m-SX enhanced its antibacterial activity.

Wu Xiaohui; Liu Kun; Wang Wei; Wei Jie; Chen Fangping; Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, and Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Ye Liang, E-mail: csliu@sh163.ne [Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou (China)

2009-08-15

415

Three dimensional mesoporous silica strucutres with templated macropores  

Science.gov (United States)

A novel approach to fabricate three dimensional macroporous structures comprised of mesoporous silica is demonstrated. Well-ordered mesoporous silica structures with macroporosity were obtained by using humidified supercritical carbon dioxide as a carrier medium to infuse and domain selectively condense silica alkoxide precursor in a microphase separated block copolymer/small molecule additive blend solution casted on macroporous supports such as cellulose filter