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Sample records for mesoporous phenol-formaldehyde resins

  1. Formulation of lignin phenol formaldehyde resins as a wood adhesive

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 Phenol had been replaced by lignin [that was extracted from black liquor of oil palm empty fruit bunch (EFB)] in synthesizing resin with a ratio lignin to phenol 1:1.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

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

    MONIKA ŠUPOVÁ

    2012-03-01

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

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

    Liu Weihua; Li Yingmin; Qu Xueliang

    2008-01-01

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

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

    Liu Weihua

    2008-05-01

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

  5. Phenol-formaldehyde resins of novolac type with unsaturated side bonds

    Bratychak, Michael; Strap, Galyna; Astakhova, Olena; Shyshchak, Olena

    2013-01-01

    The reaction between novolac phenolformaldehyde resin and glycidylmethacrylate has been studied in the presence of potassium hydroxide and the synthesis procedure of phenol-formaldehyde resin with unsaturated side bonds has been suggested. The effective rates and activation energy of the mentioned reaction have been calculated. The structure of synthesized resin was confirmed by IR-spectroscopy. The synthesized resin may be used as active component of polymeric blends based on ED-20 industria...

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

    Nour Eddine El Mansouri,; Qiaolong Yuan Mail; Farong Huang

    2011-01-01

    Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignins in thermosetting materials. To evaluate the potential application of lignin raw materials in phenol formaldehyde and epoxy resins, three types of alkaline lignins were characterized in terms of their structures and thermal properties. The lignin samples analyzed were kraft lignin (LIG-1), soda–rice straw lignin (LIG-2), and soda-wheat straw lignin (LIG-3). FTIR and 1H-NMR ...

  7. A novel thermal degradation mechanism of phenol-formaldehyde type resins

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

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

    Young, Philip R.

    1999-01-01

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

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

    Nour Eddine El Mansouri

    2011-05-01

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

  10. Synthesis of fluorescent and low cytotoxicity phenol formaldehyde resin (PFR)@Ag composites for cell imaging and antibacterial activity.

    Yang, Ping; Dong, Hao; Xia, Jun; Xu, Andong; Shi, Jianjun; He, Jie; Ding, Jianzhong; Li, Dewei

    2015-12-01

    Ag nanoparticles (NPs) were loaded onto the surface of phenol formaldehyde resin (PFR) NPs without any reducing agent. The as-synthesized PFR@Ag composites have low cytotoxicity, which makes them promising antibacterial agents. Furthermore, the good fluorescence of PFR could be used for cell imaging. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25873524

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

    Yanhui Huang

    2013-02-01

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

  12. Fluorescent glutathione probe based on MnO2-phenol formaldehyde resin nanocomposite.

    Wang, Xudong; Wang, Dan; Guo, Yali; Yang, Chengduan; Liu, Xiaoyu; Iqbal, Anam; Liu, Weisheng; Qin, Wenwu; Yan, Dan; Guo, Huichen

    2016-03-15

    MnO2-phenol formaldehyde resin (MnO2-PFR) nanocomposite is successfully prepared by a simple chemical reduction process. The resultant MnO2-PFR nanocomposite is well characterized. The absorption band of non-fluorescent MnO2 nanosheets overlaps well with the fluorescence emission of PFR nanoparticles. The green fluorescence of PFR in this nanocomposite can be effectively quenched by fluorescence resonance energy transfer from PFR to MnO2. In the presence of glutathione (GSH), the fluorescence of PFR could be recovered due to MnO2 was reduced to Mn(2+) by GSH. The nanocomposite can be use for detecting glutathione in blood serum. PMID:26426853

  13. PEMBUATAN AYAKAN MOLEKULER BERBASIS KARBON UNTUK PEMISAHAN N2/O2 DARI PIROLISIS RESIN PHENOL FORMALDEHYDE

    Imam Prasetyo

    2012-02-01

    Full Text Available Proses pemisahan campuran gas dengan menggunakan carbon molecular sieve (CMS atau ayakan molekuler berbasis karbon merupakan teknologi proses pemisahan yang mulai banyak diterapkan di dalam industri kimia. Dalam penelitian ini, CMS untuk pemisahan N2 dari udara dibuat dari pirolisis bahan polimer sintetis yaitu resin phenol formaldehyde (PF. Prekursor yang berupa resin tersebut dipanaskan dalam retort pada suhu 400-950oC selama 0,5-3 jam yang disertai dengan pengaliran gas N2 ke dalam retort dengan laju 100 mL/jam. Dengan proses pirolisis, atom-atom non-karbon penyusun bahan polimer akan terurai dan menguap sehingga hanya menyisakan arang karbon dengan struktur kerangka atom karbon yang sesuai dengan struktur kerangka dasar rantai polimer. Kemudian karbon hasil prolisis tersebut dipanaskan lebih lanjut pada suhu 750-950oC sambil dialiri gas CO2 selama 1 jam. Pada kondisi ini karbon akan mengalami proses gasifikasi parsial sehingga terbentuk karbon dengan porositas tinggi. Melalui rekayasa proses polimerisasi dan karbonisasi dihasilkan material karbon berpori yang mayoritas porinya adalah mikropori dengan ukuran pori efektif < 2 nm yang dapat dikategorikan sebagai CMS yang dapat dipergunakan untuk memisahkan campuran gas N2-O2. Pada penelitian ini dihasilkan CMS dengan selektifitas kinetis DN2/DO2 sekitar 3.

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

    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

    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)

  15. Phenol-Formaldehyde Resin-Based Carbons for CO2 Separation at Sub-Atmospheric Pressures

    Noelia Álvarez-Gutiérrez

    2016-03-01

    Full Text Available The challenge of developing effective separation and purification technologies that leave much smaller energy footprints is greater for carbon dioxide (CO2 than for other gases. In addition to its involvement in climate change, CO2 is present as an impurity in biogas and bio-hydrogen (biological production by dark fermentation, in post-combustion processes (flue gas, CO2-N2 and many other gas streams. Selected phenol-formaldehyde resin-based activated carbons prepared in our laboratory have been evaluated under static conditions (adsorption isotherms as potential adsorbents for CO2 separation at sub-atmospheric pressures, i.e., in post-combustion processes or from biogas and bio-hydrogen streams. CO2, H2, N2, and CH4 adsorption isotherms at 25 °C and up to 100 kPa were obtained using a volumetric equipment and were correlated by applying the Sips model. Adsorption equilibrium was then predicted for multicomponent gas mixtures by extending the multicomponent Sips model and the Ideal Adsorbed Solution Theory (IAST in conjunction with the Sips model. The CO2 uptakes of the resin-derived carbons from CO2-CH4, CO2-H2, and CO2-N2 at atmospheric pressure were greater than those of the reference commercial carbon (Calgon BPL. The performance of the resin-derived carbons in terms of equilibrium of adsorption seems therefore relevant to CO2 separation in post-combustion (flue gas, CO2-N2 and in hydrogen fermentation (CO2-H2, CO2-CH4.

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

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

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

    Lewatit DN is a phenol formaldehyde based ion exchange resin used to remove radioactive caesium from liquid waste streams such as fuel cooling ponds and effluents. This paper presents the results of a study of the encapsulation of the bead form of the resin in cement with particular reference to the mechanisms of its interaction with the encapsulant. When incorporated in pure ordinary Portland cement (OPC) at loadings in excess of 15 wt % an unstable product results due to expansion of the systems and at higher waste loadings failure results after only a few days. Evidence from differential scanning calorimetry, X-ray diffraction and scanning electron microscopy all indicate the cause of the expansive reaction to be the formation of crystals of calcium salts around and within the resin beads. Addition of BFS and sodium hydroxide prevent the formation of these salts by removal of calcium hydroxide from the system in other reactions. (author)

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

    Badamkhand Sukhbaatar

    2009-05-01

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

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

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

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

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

  1. [Modified Mechanism of Cell Walls from Chinese Fir Treated with Low-Molecular-Weight Phenol Formaldehyde Resin].

    Huang, Yan-hui; Fei, Ben-hua; Zhao, Rong-jun

    2015-12-01

    Study on the modified mechanism of wood cell walls, it is very important for improving treatment reagents, optimizing treatment technology, and enhancing wood density, mechanical properties, dimensional stability, and so on. Samples of plantation Chinese fir were treated gradually with synthesized water-soluble low-molecular-weight phenol formaldehyde (PF) resins under vacuum and pressure. The correlated physical and chemical properties of the treated and untreated reference samples were determined by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), and nuclear magnetic resonance spectrometer(NMR) (Using method of Cross Polarization/Magic Angle Spinning for continuous testing) with high precision and resolution. The results showed that, after treated with water-soluble low-molecular-weight PF resin, the average values of crystallinity from the treated samples were decreased obviously, and the average reduction rate was 12.67%, 11.91% and 6.26%, respectively. Comparing water-soluble, low-molecular-weight PF resin modified Chinese fir with untreated reference samples, no new chemical shifts and characteristic peaks of functional groups from esters, ethers, etc. were present by using FTIR and ¹³C NMR spectrum. It was considered that there was no distinct chemical reaction between the water-soluble low-molecular-weight PF resin and Chinese Fir cell walls. But water-soluble low-molecular-weight PF resin could enter into the structure relatively loose, large size spaces, relatively area large amorphous regions in cell walls of Chinese fir tracheids, and form physical filling, which resulting in the decreasing of relative crystallinity. This study has important reference value for the development of new wood modification reagents and the optimization of wood modification process. The findings also provide important theoretical foundation for further proving the modification mechanisms of wood cell walls and enriching the modified theories of wood cell walls. PMID:26964209

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

    2007-10-01

    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.

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

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

    1996-09-01

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

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

    Graciela Ines Bolzon de Muniz

    2013-06-01

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

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

    2009-12-01

    Full Text Available This paper describes the curing behaviours, thermal properties and flame-resistance of a novel halogen-free epoxy hybrid thermoset, prepared by the curing reaction of hexakis (methoxymethyl melamine (HMMM, a phosphorouscontaining epoxy resin (EPN-D with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO group and phenol formaldehyde novolac (n-PF. The resultant thermosets showed high glass-transition temperatures (Tg, 123147C as determined by thermal mechanical analysis (TMA, excellent thermal stability with high 5 wt% decomposition temperatures (Td,5% ??308C and high char yields (Yc ??39.4 wt% from the thermogravimetric analysis (TGA. All the cured EPND/ HMMM/n-PF hybrid resins achieved the UL 94 V-0 grade with high limited oxygen indices (LOI > 45.7. It is found that phosphorous and nitrogen elements in the cured EPN-D/HMMM/n-PF hybrid resins had a positive synergistic effect on the improvement of the flame retardancy.

  6. Adsorption characteristics of molecular sieving carbons produced from coal and phenol-formaldehyde resin modified with various organic substances. Kakushu yukibutsu de kaishitsushita sekitan, fenoru jushi kara seizoshita bunshi furui tanso (MSC) no kyuchaku tokusei

    Miura, K.; Hayashi, J.; Domoto, T.; Hashimoto, K.

    1993-11-10

    The adsorptive separation process using the pressure swing adsorption (PSA) which utilizes differences between adsorption amount and adsorption rate has recently attracted attention in chemical, food, and pharmaceutical industries. The separation efficiency of PSA mainly depends on the characteristics of adsorbents such as zeolite and molecular sieving carbon (MSC) put in the equipment. The authors have previously proposed a method of preparing MSC different from conventional manufacturing methods, by mixing various organic substances such as pitch and anthracene with coal, and hardening with a phenol-formaldehyde resin before carbonizing, or by carbonizing a phenol-formaldehyde resin to which a small amount of organic substances. In this study, the applicability of MSC produced by the method to the operation of gas separation has been examined. Three separations of propylene-propane, carbon dioxide-methane, and 1-butene-isoprene, has been studied. 16 refs., 7 figs., 5 tabs.

  7. Microwave Assisted Synthesis of Phenol-Formaldehyde Resole

    Subhash Chandra Bajia; Pawan Swarnkar; Sudesh Kumar; Birbal Bajia

    2007-01-01

    An efficient synthesis of phenol-formaldehyde resin has been achieved by using conventional as well as microwave irradiation. Resin samples were tested for their physical and chemical properties. The structures of the resins have been supported by their spectral analysis.

  8. Synthesis, Characterization and Mechanical Evaluation of the Phenol-Formaldehyde Composites

    B. S. Kaith; Chauhan, Aashish

    2008-01-01

    Phenol: formaldehyde ratio was varied in the synthesis of phenol- formaldehyde resin and used to prepare the composites. These composites were then evaluated for their mechanical strength on the basis of tensile strength, compressive strength and wear resistance. Composite with better strength was characterized by IR, SEM, XRD, TGA/DTA and further studies were carried out for its physico-chemical and mechanical properties like viscosity, modulus of rupture (MOR), modulus of elasticity (MOE) a...

  9. Development and Characterization of Phenol - Formaldehyde Molding Powder

    M .O. Edoga; A. S. KOVO

    2006-01-01

    The synthesis of phenol-formaldehyde resin was carried out at pH 4.0-4.3, formaldehyde to phenol (F/P) of 0.881 in the presence of acid catalyst (hydrochloric acid and oxalic acid), at operating temperature and pressure of 115°C and 1 atmospheric pressure respectively. Forty-six grams of the resin produced was formulated into molding powder by incorporating the following: 44.6 grams of water-free- wood-floor, 6.7 g of hexamethylene-tetramine, 2.0 g of magnesium oxide and 1.0 g of magnesium st...

  10. Properties of particleboard produced with liquefaction-modified phenol-formaldehyde adhesive

    Lee, Jung-Uk; OH, Yong-Sung

    2010-01-01

    Pinus densiflora wood flour was liquefied in the presence of phenol, using sulfuric acid as a catalyst. Liquefaction-modified phenol-formaldehyde (LPF) resins were synthesized as particleboard binder. The physical characteristics of the laboratory-synthesized control PF resin and the LPF resins are described. Laboratory particleboard (PB) was made using Korean hybrid poplar (Populus alba × glandulosa) particles with the control PF resin and LPF resins. The physical strength and dimensional st...

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

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

  12. Structure and distribution of cross-links in boron-modified phenol-formaldehyde resins designed for soft magnetic composites: a multiple-quantum 11B-11B MAS NMR correlation spectroscopy study

    Kobera, Libor; Czernek, Jiří; Strečková, M.; Urbanová, Martina; Abbrent, Sabina; Brus, Jiří

    2015-01-01

    Roč. 48, č. 14 (2015), s. 4874-4881. ISSN 0024-9297 R&D Projects: GA MŠk(CZ) LD14010 Grant ostatní: European Commission(XE) COST Action MP1202 HINT Institutional support: RVO:61389013 Keywords : phenol-formaldehyde polymers * boron crosslinks * soft magnetic composites Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.800, year: 2014

  13. Development and Characterization of Phenol - Formaldehyde Molding Powder

    M .O. Edoga

    2006-01-01

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

  14. Synthesis of white light emitting mesoporous carbon-silica nanocomposite

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

    2011-05-15

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

  15. Synthesis of white light emitting mesoporous carbon-silica nanocomposite

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

    2011-05-01

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

  16. Synthesis of white light emitting mesoporous carbon-silica nanocomposite

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

  17. Radiation-chemical hardening of phenol-formaldehyde oligomers

    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

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

    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.

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

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

  20. Peculiarities of coalescence during extraction of scandium by phenol formaldehyde oligomer from sulfate solutions

    Different types of coalescence in extraction system of 0.5 M solution of phenol formaldehyde oligomer in toluene - aqueous scandium sulfuric acid solutions are detected and studied. Condition under the which scandium is extracted in organic phase completely within 30 second are established. Extraction and reextraction of scandium in the cases of different duration of phase contact are investigated. Reproducible regularities of changes of light scattering of extracts and pH values of raffinates in different conditions are revealed. Empirical equation describing coalescence for one of the considered case is presented

  1. Relation between Mechanical Properties and Pyrolysis Temperature of Phenol Formaldehyde Resin for Gas Separation Membranes

    Šupová, Monika; Svítilová, Jaroslava; Chlup, Zdeněk; Černý, Martin; Weishauptová, Zuzana; Suchý, Tomáš; Machovič, Vladimír; Sucharda, Zbyněk; Žaloudková, Margit

    2012-01-01

    Roč. 56, č. 1 (2012), s. 40-49. ISSN 0862-5468 R&D Projects: GA ČR GA203/09/1327 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z20410507 Keywords : glassy carbon * membranes * mechanical properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.418, year: 2012 http://www. ceramics -silikaty.cz/2012/pdf/2012_01_40.pdf

  2. Stabilizing diamond surface conductivity by phenol-formaldehyde and acrylate resins

    Rezek, Bohuslav; Kozak, Halyna; Kromka, Alexander

    2009-01-01

    Roč. 517, č. 13 (2009), s. 3738-3741. ISSN 0040-6090 R&D Projects: GA AV ČR KAN400100701; GA MŠk LC510 Institutional research plan: CEZ:AV0Z10100521 Keywords : diamond * surface conductivity * polymer * passivation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.727, year: 2009

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

    J. Lv

    2012-10-01

    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 γ-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.

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

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

  5. Mesoporous carbon adsorbents from melamine-formaldehyde resin using nanocasting technique for CO2 adsorption.

    Goel, Chitrakshi; Bhunia, Haripada; Bajpai, Pramod K

    2015-06-01

    Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepared by varying the carbonization temperature from 400 to 700C. Adsorbents were characterized thoroughly by nitrogen sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), elemental (CHN) analysis, Fourier transform infrared (FTIR) spectroscopy and Boehm titration. Carbonization temperature controlled the properties of the synthesized adsorbents ranging from surface area to their nitrogen content, which play major role in their application as adsorbents for CO2 capture. The nanostructure of these materials was confirmed by XRD and TEM. Their nitrogen content decreased with an increase in carbonization temperature while other properties like surface area, pore volume, thermal stability and surface basicity increased with the carbonization temperature. These materials were evaluated for CO2 adsorption by fixed-bed column adsorption experiments. Adsorbent synthesized at 700C was found to have the highest surface area and surface basicity along with maximum CO2 adsorption capacity among the synthesized adsorbents. Breakthrough time and CO2 equilibrium adsorption capacity were investigated from the breakthrough curves and were found to decrease with increase in adsorption temperature. Adsorption process for carbon adsorbent-CO2 system was found to be reversible with stable adsorption capacity over four consecutive adsorption-desorption cycles. From three isotherm models used to analyze the equilibrium data, Temkin isotherm model presented a nearly perfect fit implying the heterogeneous adsorbent surface. PMID:26040750

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

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

    2015-01-01

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

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

    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

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

    T. K. Ghosh

    1974-04-01

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

  9. Phenolic resins a century of progress

    Pilato, Louis

    2010-01-01

    The legacy of Leo Hendrik Baekeland and his development of phenol formal- hyde resins are recognized as the cornerstone of the Plastics Industry in the early twentieth century, and phenolic resins continue to ?ourish after a century of robust growth. On July 13, 1907, Baekeland ?led his "heat and pressure" patent related to the processing of phenol formaldehyde resins and identi?ed their unique utility in a plethora of applications. The year 2010 marks the Centennial Year of the prod- tion of phenolic resins by Leo Baekeland. In 1910, Baekeland formed Bakelite GmbH and launched the manufacture

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

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

    2011-11-01

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

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

    Ramazan Kurt

    2012-11-01

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

  12. Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,

    Mathew Obichukwu EDOGA

    2006-01-01

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

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

    Badamkhand Sukhbaatar; Philip H. Steele; Moon G. Kim

    2009-01-01

    Bio-oil produced from fast pyrolysis of biomass has been investigated as a renewable fuel and as a source of industrial chemicals. The lignin fraction of bio-oil produced from wood in our fast pyrolysis reactor was separated by using only water and methanol with a 25% yield based on bio-oil weight. This separation procedure appears to be of lower cost than the reported extraction procedure using ethyl acetate as solvent. The isolated pyrolytic lignin was smoothly incorporated into phenol-for...

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

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

    2011-01-01

    Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignins in thermosetting materials. To evaluate the potential application of lignin raw materials in phenol formaldehyde and epoxy resins, three types of alkaline lignins were characterized in terms of their structures and thermal properties. The lignin samples analyzed were kraft lignin (LIG-1), soda–rice straw lignin (LIG-2), and soda-wheat straw lignin (LIG-3). FTIR and 1H-NMR ...

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

    Wei-Cheng Chu

    2013-11-01

    Full Text Available After blending the triblock copolymer, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide (PEO-b-PPO-b-PEO with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH groups of phenolic resin than were the ether groups of the PPO block. Thermal curing with hexamethylenetetramine as the curing agent resulted in the triblock copolymer being incorporated into the phenolic resin, forming a nanostructure through a mechanism involving reaction-induced microphase separation. Mild pyrolysis conditions led to the removal of the PEO-b-PPO-b-PEO triblock copolymer and formation of mesoporous phenolic resin. This approach provided a variety of composition-dependent nanostructures, including disordered wormlike, body-centered-cubic spherical and disorder micelles. The regular mesoporous novolac-type phenolic resin was formed only at a phenolic content of 4060 wt %, the result of an intriguing balance of hydrogen bonding interactions among the phenolic resin and the PEO and PPO segments of the triblock copolymer.

  16. Activation neutron detector consisting of a hardened mixture of neutron activation materials with a polycondensation resin

    The activation neutron detector presents a formed and hardened mixture whose material is a conglomerate of powder of element and a solid solution of salts of the elements that can be activated in a polymer mixture. Phenol formaldehyde resol and phenol benzaldehyde novolak resin are suitable amongst others as polymer mixture. Integral neutron fluxes of 1020 neutrons/cm2 are measurable. Many examples are given for the elements and salts to be activated. (DG)

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

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

    1996-09-01

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

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

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

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

    1992-04-01

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

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

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

    2014-01-01

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

  1. Mesoporous Carbon-based Materials for Alternative Energy Applications

    Cross, Kimberly Michelle

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

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

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

    2011-01-01

    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 ...

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

    1990-02-01

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

  4. Radiation testing of organic ion exchange resins

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

  5. Moisture insensitive adsorption of ammonia on resorcinol-formaldehyde resins.

    Seredych, Mykola; Ania, Conchi; Bandosz, Teresa J

    2016-03-15

    Phenolic-formaldehyde resins aged at 85, 90 and 95C were used as ammonia adsorbents at dynamic conditions in dry and moist air. To avoid pressure drops 10% bentonite was added as a binder. The initial and hybrid materials (before and after ammonia adsorption) were extensively characterized from the point of view of their porosity and surface chemistry. The results showed that the addition of the binder had various effects on materials' properties depending on the chemistry of their surface groups. When the phenolic acidic groups were predominant, the largest increase in surface acidity upon the addition of the binder was found. It was linked to the exfoliation of bentonite by polar moieties of the resins, which made acidic groups from aluminosilicate layers available for ammonia adsorption. On this sample, a relatively high amount of ammonia was strongly adsorbed in dry conditions. Insensitivity to moisture is a significant asset of ammonia adsorbents. PMID:26651066

  6. Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,

    Mathew Obichukwu EDOGA

    2006-07-01

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

  7. Multicenter Patch Testing With a Resol Resin Based on Phenol and Formaldehyde Within the International Contact Dermatitis Research Group

    Isaksson, M.; Ale, I.; Andersen, Klaus Ejner; Diepgen, Thomas; Elsner, P.; Goossens, A.; Goh, C. L.; Jerajani, H.; Maibach, Howard; Matsunaga, K.; McFadden, J.; Nixon, R.; Sasseville, D.; Bruze, M.

    2015-01-01

    Background Contact allergy to phenol-formaldehyde resins (PFRs) based on phenol and formaldehyde is not detected by a p-tertiary-butylphenol-formaldehyde resin included in most baseline patch test series. Objective The aims of this study were to investigate the contact allergy rate to PFR-2 in an...... international population and to investigate associated simultaneous allergic reactions. Methods Thirteen centers representing the International Contact Dermatitis Research Group included PFR-2 into their patch test baseline series during a period of 6 months in 2012. Results Of 2259 patients tested, 28 (1...... the tested population (1.2%) merits its inclusion into the international baseline series and possibly also into other baseline series after appropriate investigations. Significantly, overrepresented simultaneous allergic reactions were noted for M. pereirae and fragrance mix I....

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

    Larissa M Arruda

    2011-01-01

    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%.

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

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

  10. Photocurable bioactive bone cement based on hydroxyethyl methacrylate-poly(acrylic/maleic) acid resin and mesoporous sol gel-derived bioactive glass.

    Hesaraki, S

    2016-06-01

    This paper reports on strong and bioactive bone cement based on ternary bioactive SiO2-CaO-P2O5 glass particles and a photocurable resin comprising hydroxyethyl methacrylate (HEMA) and poly(acrylic/maleic) acid. The as-cured composite represented a compressive strength of about 95MPa but it weakened during soaking in simulated body fluid, SBF, qua its compressive strength reached to about 20MPa after immersing for 30days. Biodegradability of the composite was confirmed by reducing its initial weight (~32%) as well as decreasing the molecular weight of early cured resin during the soaking procedure. The composite exhibited in vitro calcium phosphate precipitation in the form of nanosized carbonated hydroxyapatite, which indicates its bone bonding ability. Proliferation of calvarium-derived newborn rat osteoblasts seeded on top of the composite was observed during incubation at 37°C, meanwhile, an adequate cell supporting ability was found. Consequently, it seems that the produced composite is an appropriate alternative for bone defect injuries, because of its good cell responses, high compressive strength and ongoing biodegradability, though more in vivo experiments are essential to confirm this assumption. PMID:27040248

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

    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

  12. Magnetic motive, ordered mesoporous carbons with partially graphitized framework and controllable surface wettability: preparation, characterization and their selective adsorption of organic pollutants in water

    Zhang, Bin; Liu, Chen; Kong, Weiping; Qi, Chenze

    2016-02-01

    Magnetically active, ordered and stable mesoporous carbons with partially graphitized networks and controllable surface wettability (PR-Fe-P123-800 and PR-Ni-P123-800) have been synthesized through direct carbonization of Fe or Ni functionalized, and ordered mesoporous polymers at 800°C, which could be synthesized from self assembly of resol (phenol/formaldehyde) with block copolymer template (P123) in presence of Fe3+ or Ni2+, and hydrothermal treatment at 200°C. PR-Fe-P123-800 and PR-Ni-P123-800 possess ordered and uniform mesopores, large BET surface areas, good stabilities, controllable surface wettability and partially graphitized framework. The above structural characteristics result in their enhanced selective adsorption property and good reusability for organic pollutants such as RhB, p-nitrophenol and n-heptane in water, which could be easily regenerated through separation under constant magnetic fields and washing with ethanol solvent. The unique magnetically active and adsorptive property found in PR-Fe-P123-800 and PR-Ni-P123-800 will be very important for them to be used as efficient absorbents for removal of various organic pollutants in water.

  13. Jute fiber composites from coal, super clean coal, and petroleum vacuum residue-modified phenolic resin

    Ahmaruzzaman, M.; Sharma, D.K. [Indian Institute of Technology, New Delhi (India). Center of Energy Studies

    2005-07-01

    Jute fiber composites were prepared with novolac and coal, phenolated-oxidized super clean coal (POS), petroleum vacuum residue (XVR)-modified phenol-formaldehyde (novolac) resin. Five different type of resins, i.e., coal, POS, and XVR-modified resins were used by replacing (10% to 50%) with coal, POS, and XVR. The composites thus prepared have been characterized by tensile strength, hardness, thermogravimetric analysis (TGA), Fourier-transfer infrared (FT-IR), water absorption, steam absorption, and thickness swelling studies. Twenty percent POS-modified novolac composites showed almost the same tensile strength as that of pure novolac composites. After 30% POS incorporation, the tensile strength decreased to 25.84MPa from 33.96MPa in the case of pure novolac resin composites. However, after 50% POS incorporation, the percent retention of tensile strength was appreciable, i.e., 50.80% retention of tensile strength to that of pure novolac jute composites. The tensile strength of coal and XVR-rnodified composites showed a trend similar to that shown by POS-modified novolac resin composites. However, composites prepared from coal and XVR-modified resin with 50% phenol replacement showed 25.4% and 42% tensile strength retention, respectively, compared to that of pure novolac jute composites. It was found that the hardness of the modified composites slightly decreased with an increase in coal, POS, and XVR incorporation in the resin. The XVR-modified composites showed comparatively lower steam absorption than did coal or POS-modified composites. The thermal stability of the POS-modified composites was the highest among the composites studied. The detailed results obtained are being reported.

  14. Multifunctional mesoporous silica catalyst

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

    2015-03-31

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

  15. Composite material based on an ablative phenolic resin and carbon fibers

    DIMKO DIMESKI

    2009-04-01

    Full Text Available In this study, a technological procedure for the production of a molding compound based on short carbon fibers and an ablative phenolformaldehyde 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 mm10 mm and 91 kJ/m2 (for test moldings 15 mm15 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.

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

    Sivasubramanian, Shivshankar

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

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

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

    2014-01-01

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

  18. 21 CFR 173.25 - Ion-exchange resins.

    2010-04-01

    ... requirement in paragraph (c)(4) of this section by using dilute sulfuric acid, pH 3.5 as a substitute for...-modified cross-linked phenol-formaldehyde, with modification resulting in sulfonic acid groups on side chains. (4) Methacrylic acid-divinylbenzene copolymer. (5) Cross-linked polystyrene,...

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

    M. Kubecki

    2012-09-01

    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.

  20. Resin composites

    Benetti, Ana Raquel; Peutzfeldt, Anne; Lussi, Adrian; Flury, Simon

    2014-01-01

    OBJECTIVE: To investigate how the modulus of elasticity of resin composites influences marginal quality in restorations submitted to thermocyclic and mechanical loading. METHODS: Charisma, Filtek Supreme XTE and Grandio were selected as they were found to possess different moduli of elasticity but...... of resin composite (p=0.81) on the quality of dentine margins was observed, before or after loading. Deterioration of all margins was evident after loading (p<0.0001). More paramarginal enamel fractures were observed after loading in teeth restored with Grandio when compared to Charisma (p=0.......008). CONCLUSIONS: The resin composite with the highest modulus of elasticity resulted in the highest number of gap-free enamel margins but with an increased incidence of paramarginal enamel fractures. CLINICAL SIGNIFICANCE: The results from this study suggest that the marginal quality of restorations can be...

  1. Templating mesoporous zeolites

    Egeblad, Kresten; Christensen, Christina Hviid; Kustova, Marina; Christensen, Claus H.

    2008-01-01

    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 c...

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

    Jheng-Guang Li

    2014-06-01

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

  3. Mesoporous aluminum phosphite

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

  4. Surface-functionalized mesoporous carbon materials

    Dai, Sheng; Gorka, Joanna; Mayes, Richard T.

    2016-02-02

    A functionalized mesoporous carbon composition comprising a mesoporous carbon scaffold having mesopores in which polyvinyl polymer grafts are covalently attached, wherein said mesopores have a size of at least 2 nm and up to 50 nm. Also described is a method for producing the functionalized mesoporous composition, wherein a reaction medium comprising a precursor mesoporous carbon, vinyl monomer, initiator, and solvent is subjected to sonication of sufficient power to result in grafting and polymerization of the vinyl monomer into mesopores of the precursor mesoporous carbon. Also described are methods for using the functionalized mesoporous carbon, particularly in extracting metal ions from metal-containing solutions.

  5. Review: Resin Composite Filling

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

    2010-01-01

    The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinical procedures involved and finishing and polishing techniques for resin restoration. Although resin ...

  6. Studies on Lignin-Based Adhesives for Particleboard Panels

    ÇETİN, Nihat Sami; Özmen, Nilgül

    2003-01-01

    The ultimate aim of this work was to develop a phenolic resin for partially replacing phenol with modified organosolv lignin in phenol-formaldehyde (PF) resin production. The lignin-formaldehyde relationship was determined in a reactivity test. Organosolv lignin-phenol-formaldehyde (LPF) resins were produced in a two-step preparation with different additions of lignin. The method selected for the manufacture of lignin resins dealt with modification of the lignin by the methylolation route. Th...

  7. Review: Resin Composite Filling

    Desmond Ng

    2010-02-01

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

  8. Monodispersed mesoporous silica spheres with various mesopore symmetries.

    Yano, Kazuhisa; Katz, Michael B; Pan, Xiaoqing; Tatsuda, Narihito

    2014-03-15

    Monodispersed mesoporous silica spheres (MMSS) with different mesopore symmetries, such as hexagonal, cubic, or the mixture of hexagonal/cubic, are synthesized changing synthesis conditions. It seems that the direction of mesopores is retained through the particle in MMSS with cubic symmetry. In the case of hexagonal/cubic mixed symmetry, cubic structure is observed at the center of the particle, while hexagonal structure is observed near the surface. It is assumed that cubic structure forms at early stage of the particle growth and hexagonal symmetry forms at the later stage, leading to the formation of cubic core/hexagonal shell structure. PMID:24461818

  9. Mesoporous materials for antihydrogen production.

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

    2013-05-01

    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

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

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

    2013-07-01

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

  11. Asphaltene-resin association

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

    2008-07-01

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

  12. Resin type neutron absorbers

    Purpose: To obtain poison rack materials which are firm as structural materials and having high boron carbide content by using resin materials reinforced by admixing single glass fibers. Constitution: Boron carbide and or gadolinium oxide is added to a resin material selected from the group consisting of polyamide bismaleimide resin, epoxy resin, phenol resin and lipoxy resin reinforced by admixing 1 to 5 % by weight of single glass fibers within a range from 1 to 50 % by weight of the neutron absorber (poison material) based on the resin material. Rack structural materials having heat resistance, radiation resistance and durability together can thus be obtained. Accordingly, it is possible to adsorb neutrons, reduct the interval between spent fuel racks and increase the storage amount of the pit. (Takahashi, M.)

  13. Resin type neutron absorbers

    Iida, Shigeo; Noguchi, Shigeru; Najima, Kenji

    1987-01-16

    Purpose: To obtain poison rack materials which are firm as structural materials and having high boron carbide content by using resin materials reinforced by admixing single glass fibers. Constitution: Boron carbide and or gadolinium oxide is added to a resin material selected from the group consisting of polyamide bismaleimide resin, epoxy resin, phenol resin and lipoxy resin reinforced by admixing 1 to 5% by weight of single glass fibers within a range from 1 to 50% by weight of the neutron absorber (poison material) based on the resin material. Rack structural materials having heat resistance, radiation resistance and durability together can thus be obtained. Accordingly, it is possible to adsorb neutrons, reduct the interval between spent fuel racks and increase the storage amount of the pit. (Takahashi, M.).

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

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

  15. Biocompatibility of composite resins

    Mousavinasab, Sayed Mostafa

    2011-01-01

    Dental materials that are used in dentistry should be harmless to oral tissues, so they should not contain any leachable toxic and diffusible substances that can cause some side effects. Reports about probable biologic hazards, in relation to dental resins, have increased interest to this topic in dentists. The present paper reviews the articles published about biocompatibility of resin-restorative materials specially resin composites and monomers which are mainly based on Bis-GMA and concern...

  16. Interactions of Plutonium and Lanthanides with Ordered Mesoporous Materials

    Parsons-Moss, Tashi

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

  17. Studies of mesoporous inorganic materials

    Khushalani, Deepa

    Studies in synthesis and characterization of mesoporous silica have been performed. In particular, four aspects have been studied. Primarily, a new synthetic route to enlarge the porosity of mesoporous silica materials has been developed. The synthetic strategy involves aging the syntheses mixture in the mother liquor and depending on the aging time, a gradual increase in pore sizes is observed from 40 to 65 A. The growth process involves restructuring of the mesopores under mild aqueous conditions without changing the length of the alkyl chain of the surfactant or addition of auxiliary hydrocarbon molecules. The pore-enlarged products retain the crystal morphology of the starting materials and appreciable solubilization of the structure is not observed during the aging process. Templating behavior of cetylpyridinium chloride in the synthesis of mesoporous silica has also been evaluated. Noticeable improvement in the quality of the resulting product is observed through PXRD, TEM, and adsorption analyses. Synthesis of mesoporous silica is also demonstrated using templating behavior of a mixture of two surfactants: cetylpyridinium chloride (CPCl) and cetyltrimethylammonium chloride (CTACl). As the CPCl :CTACl molar ratio is decreased, a gradual increase in the d100-spacing is observed starting at ca. 41 A and in sub-angstrom increments reaching to that of ca. 43 A. A model is presented that simultaneously accounts for the higher degree of structural order of the mesoporous silica templated with CPCl and the ability to fine tune d-spacings on a sub-angstrom length scale using CPCl/CTACl mixtures. In addition, a novel non-aqueous route to formation of lamellar and hexagonal phase of mesoporous silica has been developed. Ethylene glycol is employed as a solvent and as a chelating agent. The chelate effect results in stable glycosilicate(IV) complexes which are necessary for the syntheses and the framework thermal stability of the products has been found to increase via chemical vapor deposition of disilane. This synthetic route has been extended to the synthesis of a novel mesostructured titanium oxide and mixed mesostructured titanium/silicon oxides. The mesoporous mixed titanium/silicon oxides are envisaged to have diverse applications in catalysis, large molecule adsorption and separation science, and the synthetic route developed provides the potential for synthesis of other mesoporous mixed metal oxides over a wide range of compositions.

  18. Aligned mesoporous architectures and devices.

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

    2011-03-01

    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.

  19. Research Update: Mesoporous sensor nanoarchitectonics

    Katsuhiko Ariga

    2014-03-01

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

  20. Mesoporous Silicate Materials in Sensing

    Paul T. Charles

    2008-08-01

    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.

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

    López Guerrero, María del Mar; Siles Cordero, María Teresa; Vereda Alonso, Elisa Isabel; García de Torres, Amparo; Cano Pavón, José Manuel

    2013-01-01

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

  2. Single crystalline mesoporous silicon nanowires

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

    2009-08-18

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

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

    Suárez García, Fabián; Vilaplana Ortego, Eduardo; Kunowsky, Mirko; Kimura, M.; Oya, Asao; Linares Solano, Ángel

    2009-01-01

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

  4. Facile synthesis of hypercrosslinked resins via chloromethylation and continuous condensation of simple aryl molecules

    Xiaoyan Zhang; Qiu Jin; Libo Dai; Siguo Yuan

    2011-07-01

    A sort of non-polystyrene type hypercrosslinked resin was firstly synthesized through chloromethylation of simple aryl molecules (benzene, toluene, naphthalene, diphenyl), succedent continuous Friedel–Crafts alkylation polymerization and post-crosslinking reaction. The chemical and porous structures of these novel resins were characterized with BET, FT–IR and elementary analysis, respectively. The results showed that these novel adsorptive materials possessing abundant crosslinked networks had high specific surface areas (up to 1191.26 m2/g), large pore volumes (0.2–1.4 ml/g), narrow pore size distributions (mainly in the range of micropores and small mesopores).

  5. Magnetic mesoporous material for the sequestration of algae

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

    2014-09-09

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

  6. Bimodal mesoporous silica with bottleneck pores.

    Reber, M J; Brühwiler, D

    2015-11-01

    Bimodal mesoporous silica consisting of two sets of well-defined mesopores is synthesized by a partial pseudomorphic transformation of an ordered mesoporous starting material (SBA-15 type). The introduction of a second set of smaller mesopores (MCM-41 type) establishes a pore system with bottlenecks that restricts the access to the core of the bimodal mesoporous silica particles. The particle size and shape of the starting material are retained, but micropores present in the starting material disappear during the transformation, leading to a true bimodal mesoporous product. A varying degree of transformation allows the adjustment of the pore volume contribution of the two mesopore domains. Information on the accessibility of the mesopores is obtained by the adsorption of fluorescence-labeled poly(amidoamine) dendrimers and imaging by confocal laser scanning microscopy. This information is correlated with nitrogen sorption data to provide insights regarding the spatial distribution of the two mesopore domains. The bimodal mesoporous materials are excellent model systems for the investigation of cavitation effects in nitrogen desorption isotherms. PMID:26399172

  7. Synthesis and characterization of mesoporous materials

    Cheng, Wei

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

  8. Reduction of polyester resin shrinkage by means of epoxy resin

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

  9. Synthesis of N-Doped Hollow-Structured Mesoporous Carbon Nanospheres for High-Performance Supercapacitors.

    Liu, Chao; Wang, Jing; Li, Jiansheng; Zeng, Mengli; Luo, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing; Wang, Lianjun

    2016-03-23

    We have demonstrated a facile and controllable synthesis of monodispersed N-doped hollow mesoporous carbon nanospheres (N-HMCSs) and yolk-shell hollow mesoporous carbon nanospheres (N-YSHMCSs) by a modified "silica-assisted" route. The synthesis process can be carried out by using resorcinol-formaldehyde resin as a carbon precursor, melamine as a nitrogen source, hexadecyl trimethylammonium chloride as a template, and silicate oligomers as structure-supporter. The morphological (i.e., particle size, shell thickness, cavity size, and core diameter) and textural features of the carbon nanospheres are easily controlled by varying the amount of ammonium. The resultant carbon nanospheres possess high surface areas (up to 2464 m(2) g(-1)), large pore volumes (up to 2.36 cm(3) g(-1)), and uniform mesopore size (∼2.4 nm for N-HMCSs, ∼ 4.5 nm for N-YSHMCSs). Through combining the hollow mesoporous structure, high porosity, large surface area, and N heteroatomic functionality, the as-synthesized N-doped hollow-structured carbon nanospheres manifest excellent supercapacitor performance with high capacitance (up to 240 F/g), favorable capacitance retention (97.0% capacitive retention after 5000 cycles), and high energy density (up to 11.1 Wh kg(-1)). PMID:26942712

  10. Thermally stable laminating resins

    Jones, R. J.; Vaughan, R. W.; Burns, E. A.

    1972-01-01

    Improved thermally stable laminating resins were developed based on the addition-type pyrolytic polymerization. Detailed monomer and polymer synthesis and characterization studies identified formulations which facilitate press molding processing and autoclave fabrication of glass and graphite fiber reinforced composites. A specific resin formulation, termed P10P was utilized to prepare a Courtaulds HMS reinforced simulated airfoil demonstration part by an autoclave molding process.

  11. Cleanup of demineralizer resins

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

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

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

    2012-01-01

    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.

  13. Templated mesoporous carbons for supercapacitor application

    Fuertes Arias, Antonio Benito; Lota, G.; Álvarez Centeno, Teresa; Frackowiak, E.

    2005-01-01

    Mesoporous carbons prepared by an inverse replica technique have been used as electrodes for electrochemical capacitors. Such well-sized carbons were prepared from mesostructured SBA-16 silica materials that served as templates whereas polyfurfuryl alcohol was the carbon precursor. Two highly mesoporous carbons characterized by 3 and 8 nm average pore diameter were tested in various electrolytic solutions (acidic, alkaline and aprotic). It can be concluded that templated mesoporous carbon...

  14. Mesoporous metal oxide graphene nanocomposite materials

    Liu, Jun; Aksay, Ilhan A.; Kou, Rong; Wang, Donghai

    2016-05-24

    A nanocomposite material formed of graphene and a mesoporous metal oxide having a demonstrated specific capacity of more than 200 F/g with particular utility when employed in supercapacitor applications. A method for making these nanocomposite materials by first forming a mixture of graphene, a surfactant, and a metal oxide precursor, precipitating the metal oxide precursor with the surfactant from the mixture to form a mesoporous metal oxide. The mesoporous metal oxide is then deposited onto a surface of the graphene.

  15. Mesoporous Silica: A Suitable Adsorbent for Amines

    Abdollahzadeh-Ghom Sara

    2009-01-01

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

  16. Phenol-formaldehyde oligomers application for coatings production применение фенолоформальдегидных олигомеров для производства покровныХ материалов

    Orlova Anzhela Manvelovna

    2011-11-01

    Full Text Available The description developed by the authors of structures and technologies production safety coatings based on glass fiber and paper, modified phenol-formaldehyde oligomers, which are possessed high physicochemical properties, durability and chemical durability, is presented.Приведено описание разработанных авторами составов и технологий получения защитно-покровных материалов на основе модифицированных фенолформальдегидными олигомерами стеклотканей и бумаги, обладающих высокими физико-химическими свойствами, долговечностью и химической стойкостью.

  17. Cellular membrane trafficking of mesoporous silica nanoparticles

    Fang, I-Ju

    2012-06-21

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

  18. Ordered mesoporous silica materials with complicated structures

    Han, Yu

    2012-05-01

    Periodically ordered mesoporous silicas constitute one of the most important branches of porous materials that are extensively employed in various chemical engineering applications including adsorption, separation and catalysis. This short review gives an introduction to recently developed mesoporous silicas with emphasis on their complicated structures and synthesis mechanisms. In addition, two powerful techniques for solving complex mesoporous structures, electron crystallography and electron tomography, are compared to elucidate their respective strength and limitations. Some critical issues and challenges regarding the development of novel mesoporous structures as well as their applications are also discussed. © 2011 Elsevier Ltd.

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

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

    2011-03-30

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

  20. 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

    Fabrício Gomes Gonçalves

    2008-08-01

    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.

  1. General strategy for fabricating thoroughly mesoporous nanofibers

    Hou, Huilin

    2014-12-03

    Recently, preparation of mesoporous fibers has attracted extensive attentions because of their unique and broad applications in photocatalysis, optoelectronics, and biomaterials. However, it remains a great challenge to fabricate thoroughly mesoporous nanofibers with high purity and uniformity. Here, we report a general, simple and cost-effective strategy, namely, foaming-assisted electrospinning, for producing mesoporous nanofibers with high purity and enhanced specific surface areas. As a proof of concept, the as-fabricated mesoporous TiO2 fibers exhibit much higher photocatalytic activity and stability than both the conventional solid counterparts and the commercially available P25. The abundant vapors released from the introduced foaming agents are responsible for the creation of pores with uniform spatial distribution in the spun precursor fibers. The present work represents a critically important step in advancing the electrospinning technique for generating mesoporous fibers in a facile and universal manner.

  2. Preparation of nanosized micro/mesoporous composites

    Prokesova, P.; Mintova, S.; Cejka, J.; Bein, T

    2003-12-15

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

  3. Preparation of nanosized micro/mesoporous composites

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

  4. Synthesis and catalytic applications of mesoporous metal oxides

    Li, Quanchang

    2007-01-01

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

  5. Radiation curable epoxy resin

    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

  6. Thermally conductive polymers

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

    1971-01-01

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

  7. Resin impregnation process for producing a resin-fiber composite

    Palmer, Raymond J. (Inventor); Moore, William E. (Inventor)

    1994-01-01

    Process for vacuum impregnation of a dry fiber reinforcement with a curable resin to produce a resin-fiber composite, by drawing a vacuum to permit flow of curable liquid resin into and through a fiber reinforcement to impregnate same and curing the resin-impregnated fiber reinforcement at a sufficient temperature and pressure to effect final curing. Both vacuum and positive pressure, e.g. autoclave pressure, are applied to the dry fiber reinforcement prior to application of heat and prior to any resin flow to compact the dry fiber reinforcement, and produce a resin-fiber composite of reduced weight, thickness and resin content, and improved mechanical properties. Preferably both a vacuum and positive pressure, e.g. autoclave pressure, are also applied during final curing.

  8. Nontoxic Resins Advance Aerospace Manufacturing

    2009-01-01

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

  9. Single crystalline mesoporous silicon nanowires

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

    2009-08-04

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

  10. Metallic mesoporous nanocomposites for electrocatalysis.

    Ding, Yi; Chen, Mingwei; Erlebacher, Jonah

    2004-06-01

    We describe the fabrication, characterization, and applications of ultrathin, free-standing mesoporous metal membranes uniformly decorated with catalytically active nanoparticles. Platinum-plated nanoporous gold leaf (Pt-NPG) made by confining a plating reaction to occur within the pores of dealloyed silver/gold leaf is 100 nm thick and contains an extremely high, uniform dispersion of 3 nm diameter catalytic particles. This nanostructured composite holds promise as a prototypical member of a new class of fuel cell electrodes, showing good electrocatalytic performance at low platinum loading (less than 0.05 mg cm-2), while also maintaining long-term stability against coarsening and aggregation of catalytic nanoparticles. PMID:15174851

  11. Preparation of Mesoporous Bimetallic Au-Pt with a Phase-Segregated Heterostructure Using Mesoporous Silica.

    Kitahara, Masaki; Kubara, Saori; Takai, Azusa; Takimoto, Daisuke; Enomoto, Shinpei; Yamauchi, Yusuke; Sugimoto, Wataru; Kuroda, Kazuyuki

    2015-12-21

    Mesoporous bimetallic Au-Pt with a phase-segregated heterostructure has been prepared by using mesoporous silica SBA-15 as a template. Au nanoparticles were prepared as a seed metal within the mesopores, and subsequently Pt was deposited, sandwiching the Au seeds. Energy-dispersive X-ray (EDX) spectral mapping showed that the framework of mesoporous bimetallic Au-Pt, prepared by removing the silica template with HF, was composed of Au nanoparticles joined with Pt nanowires. The Au/Pt ratio of the mesoporous bimetallic Au-Pt could be varied by controlling the number of Au deposition cycles. Pre-adsorbed CO (COad ) stripping voltammetry of the mesoporous bimetallic Au-Pt showed that the surfaces of the joined bimetallic structure were electrochemically active. This could be attributed to the open framework structure having a high ratio of exposed bimetallic mesopore surfaces. The described preparative approach, involving a mesoporous silica template and stepwise deposition within the mesopores, enables control of the nanostructure of the bimetallic material, which is greatly promising for the further development of synthetic methodologies for bimetallic structures. PMID:26586355

  12. Surfactant-Templated Mesoporous Metal Oxide Nanowires

    Stacy Baber

    2010-01-01

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

  13. Hydrothermal Synthesis of Loessial Mesoporous Materials

    Lu, L.; Jing, Z.; Wang, Z.; Pan, X.; Ishida, E. H.

    2010-11-01

    In order to sustain the inherent porous properties of loess, hydrothermal synthesis of mesoporous materials from loess was carried out under saturated steam pressure at 100-200 °C for up to 24h. The experimental results showed that the curing temperature and time exerted a positive influence on the strength development, which was believed to be due to tobermorite formation. Moreover, during the hydrothermal process, a huge number of new mesopores could be formed within the matrix. Therefore a tough and mesoporous material could be produced from loess hydrothermally, which is expected to provide a good humidity regulating property.

  14. Preparation of irregular mesoporous hydroxyapatite

    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

  15. Drug Loading of Mesoporous Silicon

    Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

    2011-03-01

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

  16. Flame Retardant Epoxy Resins

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

    2004-01-01

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

  17. Amine-functionalized mesoporous polymer as potential sorbent for nickel preconcentration from electroplating wastewater.

    Islam, Aminul; Zaidi, Noushi; Ahmad, Hilal; Kumar, Suneel

    2015-05-01

    In this study, mesoporous glycidyl methacrylate-divinylbenzene-based chelating resin was synthesized and grafted with diethylenetriamine through epoxy ring-opening reaction. The synthesized resin was characterized by elemental analysis, infrared spectroscopy, surface area and pore size analysis, scanning electron microscopy, energy-dispersive spectroscopy, and thermogravimetry. The resin was used for the first time as an effective sorbent for the preconcentration of nickel in electroplating wastewater samples. The analytical variables like pH, flow rate for sorption/desorption, and eluate selection were systematically investigated and optimized. The uniform and monolayer sorption behavior of resin for nickel was proved by an evident fit of the equilibrium data to a Langmuir isotherm model. Under optimized conditions, the resin was observed to show a good sorption capacity of 20.25 mg g(-1) and >96% recovery of nickel even in the presence of a large number of competitive matrix ions. Its ability to extract trace amount of nickel was exhibited by low preconcentration limit (5.9 μg L(-1)). The calibration curve was found to be linear (R(2) = 0.998) in the concentration range of 6.0-400.0 μg L(-1). Coefficient of variation of less than 5 for all the analysis indicated good reproducibility. The reliability was evaluated by the analysis of standard reference material (SRM) and recovery experiments. The applicability of the resin for the systematic preconcentration of nickel is substantiated by the analysis of electroplating wastewater and river water samples. Graphical abstract ᅟ. PMID:25561258

  18. Mesoporous Silicon Far Infrared Filters Project

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes a novel method to make optical filters based on mesoporous silicon multilayers, for use at cold temperatures in the far...

  19. Mesoporous Silicon Far Infrared Filters Project

    National Aeronautics and Space Administration This SBIR Phase I proposal describes a novel method to make optical filters based on mesoporous silicon multilayers, for use at cold temperatures in the far...

  20. Moderate Temperature Synthesis of Mesoporous Carbon

    Dua, Rubal

    2013-01-03

    Methods and composition for preparation of mesoporous carbon material are provided. For example, in certain aspects methods for carbonization and activation at selected temperature ranges are described. Furthermore, the invention provides products prepared therefrom.

  1. 40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.

    2010-07-01

    ...-Maleic Anhydride Resins *Unsaturated Polyester Resins *Vinyl Toluene Resins *Vinyl Toluene-Acrylate... *Polycarbonates *Polyester Resins *Polyester Resins, Polybutylene Terephthalate *Polyester Resins,...

  2. Location of laccase in ordered mesoporous materials

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

    2014-11-01

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

  3. Location of laccase in ordered mesoporous materials

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

  4. Mesoporous hybrid organosilica containing urethane moieties

    Mesoporous hybrid material containing urethane moieties in functionalized long chain organic group have been synthesized by using bis[3-(triethoxysilyl) propyl urethane]ethane (BTESPUE) and tetraethoxysilane as structural ingredients. The incorporation of BTESPUE within the framework of mesoporous material was confirmed by Fourier transform-infrared, X-ray photoelectron spectroscopy, solid-state NMR spectroscopy and thermogravimetric analysis. This material had a thick wall and uniform pore, which may be attributed to the hydrogen bonding inside framework due to urethane moieties

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

    Wei Gao; Jianzhang Li,

    2012-01-01

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

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

    Yu, Yanjie

    2012-05-01

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

  7. 40 CFR 721.7220 - Polymer of substituted phenol, formaldehyde, epichlorohydrin, and disubstituted benzene.

    2010-07-01

    ..., formaldehyde, epichlorohydrin, and disubstituted benzene. 721.7220 Section 721.7220 Protection of Environment..., formaldehyde, epichlorohydrin, and disubstituted benzene. (a) Chemical substance and significant new uses..., formaldehyde, epichlorohydrin, and disubstituted benzene (PMN P-89-1104) is subject to reporting under...

  8. Mesoporous zeolite single crystals for catalytic hydrocarbon conversion

    Schmidt, I.; Christensen, C.H.; Hasselriis, Peter; Kustova, Marina; Nielsen, Michael Brorson; Dahl, Søren; Johannsen, K.; Christensen, Claus H.

    Recently, mesoporous zeolite single crystals were discovered. They constitute a novel family of materials that features a combined micropore and mesopore architecture within each individual crystal. Here, we briefly summarize recent catalytic results from cracking and isomerization of alkalies, a...

  9. Mesoporous Carbon for Capacitive Deionization of Saline Water

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

    2011-01-01

    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.

  10. Mesoporous carbon for capacitive deionization of saline water.

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

    2011-12-01

    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. PMID:22032802

  11. Properties of the Carboxylate ion exchange resins

    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)

  12. Contact allergy to epoxy resin

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil; Andersen, Klaus Ejner; Mörtz, Charlotte; Paulsen, Evy; Sommerlund, Mette; Veien, Niels Kren; Laurberg, Grete; Kaaber, Knud; Thormann, Jens; Andersen, Bo Lasthein; Danielsen, Anne; Avnstorp, Christian; Kristensen, Berit; Kristensen, Axel Ove; Vissing, Susanne; Nielsen, Niels Henrik; Johansen, Jeanne Duus

    2012-01-01

    Background. Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown....... Objectives. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. Patients/methods. The dataset comprised 20 808 consecutive dermatitis...... patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire. Results. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to...

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

    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.

  14. Chromatography resin support

    Dobos, James G. (North Augusta, SC)

    2002-01-01

    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.

  15. Templated mesoporous carbons for supercapacitor application

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

    2005-05-05

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

  16. Resin polymerization problems--are they caused by resin curing lights, resin formulations, or both?

    Christensen, R P; Palmer, T M; Ploeger, B J; Yost, M P

    1999-01-01

    Negative effects of rapid, high-intensity resin curing have been predicted for both argon lasers and plasma-arc curing lights. To address these questions, six different resin restorative materials were cured with 14 different resin curing lights representing differences in intensities ranging from 400 mW/cm2 to 1,900 mW/cm2; delivery modes using constant, ramped, and stepped methods; cure times ranging from 1 second to 40 seconds; and spot sizes of 6.7 mm to 10.9 mm. Two lasers, five plasma-arc lights, and seven halogen lights were used. Shrinkage, modulus, heat generation, strain, and physical changes on the teeth and resins during strain testing were documented. Results showed effects associated with lights were not statistically significant, but resin formulation was highly significant. Microfill resins had the least shrinkage and the lowest modulus. An autocure resin had shrinkage and modulus as high as or higher than the light-cured hybrid resins. Lasers and plasma-arc lights produced the highest heat increases on the surface (up to 21 degrees C) and within the resin restorations (up to 14 degrees C), and the halogen lights produced the most heat within the pulp chamber (up to 2 degrees C). Strain within the tooth was least with Heliomolar and greatest with Z100 Restorative and BISFIL II autocure resin. Clinical effects of strain relief were evident as white lines at the tooth-resin interface and cracks in enamel adjacent to the margins. This work implicates resin formulation, rather than light type or curing mode, as the important factor in polymerization problems. Lower light intensity and use of ramped and stepped curing modes did not provide significant lowering of shrinkage, modulus, or strain, and did not prevent enamel cracking adjacent to margins and formation of "white line" defects at the margins. Until materials with lower shrinkage and modulus are available, use of low-viscosity surface sealants as a final step in resin placement is suggested to seal defects. PMID:11908396

  17. Orientation specific deposition of mesoporous particles

    Tomas Kjellman

    2014-11-01

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

  18. A Single-Crystalline Mesoporous Quartz Superlattice.

    Matsuno, Takamichi; Kuroda, Yoshiyuki; Kitahara, Masaki; Shimojima, Atsushi; Wada, Hiroaki; Kuroda, Kazuyuki

    2016-05-10

    There has been significant interest in the crystallization of nanostructured silica into α-quartz because of its physicochemical properties. We demonstrate a single-crystalline mesoporous quartz superlattice, a silica polymorph with unprecedentedly ordered hierarchical structures on both the several tens of nanometers scale and the atomic one. The mesoporous quartz superlattice consists of periodically arranged α-quartz nanospheres whose crystalline axes are mostly oriented in an assembly. The superlattice is prepared by thermal crystallization of amorphous silica nanospheres constituting a colloidal crystal. We found that the deposition of a strong flux of Li(+) only on the surface of silica nanospheres is effective for crystallization. PMID:27060365

  19. Location of laccase in ordered mesoporous materials

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

    2014-11-01

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

  20. Nanocasted synthesis of mesoporous metal oxides and mixed oxides from mesoporous cubic (Ia3d) vinylsilica.

    Wang, Yangang; Wang, Yanqin; Liu, Xiaohui; Guo, Yun; Guo, Yanglong; Lu, Guanzhong; Schth, Ferdi

    2008-11-01

    Mesoporous metal oxides and mixed oxides, such as NiO, CeO2, Cr2O3, Fe203, Mn2O3, NiFe2O4 and Ce(x)Zr(1-x)O2 (x=0.8 and 0.6) have been synthesized by nanocasting from mesoporous cubic (la3d) vinyl-functionalized silica (vinylsilica). Their structural properties were characterized by XRD, TEM, N2-sorption and Raman spectra. Thus-prepared mesoporous materials possess a high BET surface area (110-190 m2g(-1)), high pore volume (0.25-0.40 cm3g(-1)) and relatively ordered structures. The catalytic properties of Cr2O3 were tested in the oxidation of toluene. The mesoporous Cr2O3 exhibits unusually high catalytic activity in the complete oxidation of toluene as compared with commercial Cr2O3. PMID:19198284

  1. Bending characteristics of resin concretes

    Ribeiro Maria Cristina Santos

    2003-01-01

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

  2. Bulk-Fill Resin Composites

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel; Pedersen, Maiken K; Pallesen, Ulla

    2015-01-01

    restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and...... three low-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low...

  3. 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

    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.

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

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

    2013-08-01

    Surfactant or block copolymer-templated mesoporous films have been extensively explored, but achieving mesostructure coherence and unidirectional orientation over macroscopic dimensions has remained quite challenging for these self-assembled systems. Here, we extend the concepts associated with zone refinement of crystalline materials to soft templated mesoporous carbon films based on the cooperative assembly of commercial non-ionic surfactants (block copolymers) and phenolic resin oligomers (resol) to provide macroscopic alignment of both cubic (FDU-16) and hexagonal (FDU-15) mesostructures. The average orientation of these mesophases is determined from rotation grazing incidence small angle X-ray scattering (GISAXS) measurements. For FDU-15 templated by Pluronic P123, the orientation factor for the zone-annealed film is 0.98 based on the average of the second Legendre polynomial, but this orientation deteriorates significantly during carbonization. Notably, a thermal stabilization step following zone annealing preserves the orientation of the mesostructure during carbonization. The orientation factor for an isotropic cubic structure (FDU-16 templated by Pluronic F127) is only 0.48 (based on the 111 reflection with incident angle 0.15°) for the same zone annealing protocol, but this illustrates the versatility of zone annealing to different mesostructures. Unexpectedly, zone annealing of FDU-15 templated by Pluronic F127 leads to stabilization of the mesostructure through carbonization, whereas this structure collapses fully during carbonization even after extended oven annealing; despite no clear macroscopic orientation of the cylindrical mesostructure from zone annealing. Thermal zone annealing provides a simple methodology to produce highly ordered and macroscopically oriented stable mesoporous carbon films, but the efficacy is strongly tied to the mobility of the template during the zone annealing.Surfactant or block copolymer-templated mesoporous films have been extensively explored, but achieving mesostructure coherence and unidirectional orientation over macroscopic dimensions has remained quite challenging for these self-assembled systems. Here, we extend the concepts associated with zone refinement of crystalline materials to soft templated mesoporous carbon films based on the cooperative assembly of commercial non-ionic surfactants (block copolymers) and phenolic resin oligomers (resol) to provide macroscopic alignment of both cubic (FDU-16) and hexagonal (FDU-15) mesostructures. The average orientation of these mesophases is determined from rotation grazing incidence small angle X-ray scattering (GISAXS) measurements. For FDU-15 templated by Pluronic P123, the orientation factor for the zone-annealed film is 0.98 based on the average of the second Legendre polynomial, but this orientation deteriorates significantly during carbonization. Notably, a thermal stabilization step following zone annealing preserves the orientation of the mesostructure during carbonization. The orientation factor for an isotropic cubic structure (FDU-16 templated by Pluronic F127) is only 0.48 (based on the 111 reflection with incident angle 0.15°) for the same zone annealing protocol, but this illustrates the versatility of zone annealing to different mesostructures. Unexpectedly, zone annealing of FDU-15 templated by Pluronic F127 leads to stabilization of the mesostructure through carbonization, whereas this structure collapses fully during carbonization even after extended oven annealing; despite no clear macroscopic orientation of the cylindrical mesostructure from zone annealing. Thermal zone annealing provides a simple methodology to produce highly ordered and macroscopically oriented stable mesoporous carbon films, but the efficacy is strongly tied to the mobility of the template during the zone annealing. Electronic supplementary information (ESI) available: GISAXS profiles for the FDU-15-F127 at φ = 0° and φ = 90° is included along with 2D GISAXS data for all azimuthal data associated with FDU-15-P123 to illustrate the azimuthal dependence on the diffraction patterns. See DOI: 10.1039/c3nr02821f

  5. Mesoporous Transition Metal Oxides for Supercapacitors

    Yan Wang

    2015-10-01

    Full Text Available Recently, transition metal oxides, such as ruthenium oxide (RuO2, manganese dioxide (MnO2, nickel oxides (NiO and cobalt oxide (Co3O4, have been widely investigated as electrode materials for pseudo-capacitors. In particular, these metal oxides with mesoporous structures have become very hot nanomaterials in the field of supercapacitors owing to their large specific surface areas and suitable pore size distributions. The high specific capacities of these mesoporous metal oxides are resulted from the effective contacts between electrode materials and electrolytes as well as fast transportation of ions and electrons in the bulk of electrode and at the interface of electrode and electrolyte. During the past decade, many achievements on mesoporous transition metal oxides have been made. In this mini-review, we select several typical nanomaterials, such as RuO2, MnO2, NiO, Co3O4 and nickel cobaltite (NiCo2O4, and briefly summarize the recent research progress of these mesoporous transition metal oxides-based electrodes in the field of supercapacitors.

  6. Very high titanium content mesoporous silicas

    El Haskouri, Jamal; Cabrera, Saúl; Beltrán Porter, Aurelio; Marcos, María Dolores; Amorós del Toro, Pedro José

    2001-01-01

    Titanium content in mesoporous titanosilicate catalysts has been modulated up to a minimum Si/Ti value of 1.9 by using complexing agents able to coordinate both Si and Ti atoms and harmonize the reactivity of the resulting precursors avoiding subsequent phase segregation and leading to chemically very homogeneous materials.

  7. Curing of phenylethynl terminated resins

    Full text: The curing of two phenylethynyl terminated composite resins was investigated under thermal and γ-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, γ- 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 γ-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

  8. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    Gao, Lin; Sun, Jihong; Li, Yuzhen

    2011-08-01

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

  9. Functionalized Mesoporous Silica Membranes for CO2 Separation Applications

    Hyung-Ju Kim; Hee-Chul Yang; Dong-Yong Chung; In-Hwan Yang; Yun Jung Choi; Jei-kwon Moon

    2015-01-01

    Mesoporous silica molecular sieves are emerging candidates for a number of potential applications involving adsorption and molecular transport due to their large surface areas, high pore volumes, and tunable pore sizes. Recently, several research groups have investigated the potential of functionalized mesoporous silica molecular sieves as advanced materials in separation devices, such as membranes. In particular, mesoporous silica with a two- or three-dimensional pore structure is one of the...

  10. Low Melt Viscosity Resins for Resin Transfer Molding

    Harris, Frank W.

    2002-01-01

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

  11. Preparation of superhydrophilic mesoporous SiO2 thin films

    Using a simple sol-gel/spin-coating method, mesoporous SiO2 thin films were prepared on glass slides. All of the prepared thin films were colorless and transparent as original glass substrates. XRD and TEM measurements revealed that the prepared SiO2 thin films coated 3-12 times possess hexagonal mesoporous structure. The mesoporous SiO2 thin films performed the superhydrophilicity and antifogging property in the absence of UV light irradiation. The results suggested that the appropriate film thickness and mesoporous structures can improve the surface superhydrophilic behavior of SiO2 thin films.

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

    Zhang, Li [Carnegie Inst. of Washington, Washington, DC (United States); Mohanty, Paritosh [Lehigh Univ., Bethlehem, PA (United States); Coombs, Neil [Univ. of Toronto, ON (Canada); Fei, Yingwei [Carnegie Inst. of Washington, Washington, DC (United States); Mao, Ho-kwang [Carnegie Inst. of Washington, Washington, DC (United States); Landskrom, Kai [Lehigh Univ., Bethlehem, PA (United States)

    2010-07-19

    We report on the synthesis of optically transparent, mesoporous, monolithic diamond from periodic mesoporous carbon CMK-8 at a pressure of 21 GPa. The phase transformation is already complete at a mild synthesis temperature of 1,300 °C without the need of a catalyst. Surprisingly, the diamond is obtained as a mesoporous material despite the extreme pressure. X-ray diffraction, SEM, transmission electron microscopy, selected area electron diffraction, high-resolution transmission electron microscopy, and Z-contrast experiments suggest that the mesoporous diamond is composed of interconnected diamond nanocrystals having diameters around 5–10 nm. The Brunauer Emmett Teller surface area was determined to be 33 m2 g-1 according Kr sorption data. The mesostructure is diminished yet still detectable when the diamond is produced from CMK-8 at 1,600 °C and 21 GPa. The temperature dependence of the porosity indicates that the mesoporous diamond exists metastable and withstands transformation into a dense form at a significant rate due to its high kinetic inertness at the mild synthesis temperature. The findings point toward ultrahard porous materials with potential as mechanically highly stable membranes.

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

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

  14. Ion exchange resins embedding in cement

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

  15. Method for loading resin beds

    Notz, K.J.; Rainey, R.H.; Greene, C.W.; Shockley, W.E.

    1978-01-24

    An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145 to 200/sup 0/C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145/sup 0/C with a second aqueous component to provide a gaseous phase containing HNO/sub 3/ and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate.

  16. Method for loading resin beds

    Notz, Karl J. (Oak Ridge, TN); Rainey, Robert H. (Knoxville, TN); Greene, Charles W. (Knoxville, TN); Shockley, William E. (Oak Ridge, TN)

    1978-01-01

    An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H.sup.+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145.degree.-200.degree. C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145.degree. C with a second aqueous component to provide a gaseous phase containing HNO.sub.3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate.

  17. Aerosol-generated mesoporous silicon oxycarbide particles

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

  18. Porosity of micro/mesoporous composites

    Fojtíková, P.; Mintova, S.; Čejka, Jiří; Žilková, Naděžda; Zukal, Arnošt

    2006-01-01

    Roč. 92, 1-3 (2006), s. 154-160. ISSN 1387-1811 R&D Projects: GA ČR GA203/05/0197; GA MPO FT-TA/040 Institutional research plan: CEZ:AV0Z40400503 Keywords : micro/mesoporous composite * nitrogen adsorption * porous structure development Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.796, year: 2006

  19. Stimuli-Responsive Shapeshifting Mesoporous Silica Nanoparticles.

    Sun, Yao; Sai, Hiroaki; Spoth, Katherine A; Tan, Kwan Wee; Werner-Zwanziger, Ulrike; Zwanziger, Josef; Gruner, Sol M; Kourkoutis, Lena F; Wiesner, Ulrich

    2016-01-13

    Stimuli-responsive materials have attracted great interest in catalysis, sensing, and drug delivery applications and are typically constituted by soft components. We present a one-pot synthetic method for a type of inorganic silica-based shape change material that is responsive to water vapor exposure. After the wetting treatment, the cross-sectional shape of aminated mesoporous silica nanoparticles (MSNs) with hexagonal pore lattice changed from hexagonal to six-angle-star, accompanied by the loss of periodic mesostructural order. Nitrogen sorption measurements suggested that the wetting treatment induced a shrinkage of mesopores resulting in a broad size distribution and decreased mesopore volume. Solid-state (29)Si nuclear magnetic resonance (NMR) spectroscopy of samples after wetting treatment displayed a higher degree of silica condensation, indicating that the shape change was associated with the formation of more siloxane bonds within the silica matrix. On the basis of material characterization results, a mechanism for the observed anisotropic shrinkage is suggested based on a buckling deformation induced by capillary forces in the presence of a threshold amount of water vapor available beyond a humidity of about 50%. The work presented here may open a path toward novel stimuli-responsive materials based on inorganic components. PMID:26669906

  20. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    Akram, Muhammad; Alshemary, Ammar Z.; Goh, Yi-Fan; Wan Ibrahim, Wan Aini [Department of Chemistry, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Lintang, Hendrik O. [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia)

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca{sup 2+} ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA.

  1. Immobilization of Methyltrioxorhenium on Mesoporous Aluminosilicate Materials

    Martina Stekrova

    2014-03-01

    Full Text Available The presented report focuses on an in-depth detailed characterization of immobilized methyltrioxorhenium (MTO, giving catalysts with a wide spectra of utilization. The range of mesoporous materials with different SiO2/Al2O3 ratios, namely mesoporous alumina (MA, aluminosilicates type Siral (with Al content 60%90% and MCM-41, were used as supports for immobilization of MTO. The tested support materials (aluminous/siliceous exhibited high surface area, well-defined regular structure and narrow pore size distribution of mesopores, and therefore represent excellent supports for the active components. Some of the supports were modified by zinc chloride in order to obtain catalysts with higher activities for instance in metathesis reactions. The immobilization of MTO was optimized using these supports and it was successful using all supports. The success of the immobilization of MTO and the properties of the prepared heterogeneous catalysts were characterized using X-ray Fluorescence (XRF, atomic absorption spectroscopy (AAS, X-ray powder diffraction (XRD, scanning electron microscopy (SEM, physical adsorption of N2, ultraviolet-visible spectroscopy (UV-Vis, infrared spectroscopy (FTIR, Fourier Transform Infrared Spectroscopy (FTIR using pyridine as a probe molecule and X-ray photoelectron spectroscopy (XPS. Furthermore, the catalytic activity of the immobilized MTO on the tested supports was demonstrated on metathesis reactions of various substrates.

  2. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca2+ ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA

  3. Mesoporous Silica from Rice Husk Ash

    S.A. Mandavgane

    2010-12-01

    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

  4. 21 CFR 177.1580 - Polycarbonate resins.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polycarbonate resins. 177.1580 Section 177.1580... Components of Single and Repeated Use Food Contact Surfaces § 177.1580 Polycarbonate resins. Polycarbonate... with the following prescribed conditions: (a) Polycarbonate resins are polyesters produced by: (1)...

  5. Method for removing contaminants from plastic resin

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

    2008-12-30

    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.

  6. Method of removing contaminants from plastic resins

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

    2008-11-18

    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.

  7. Radiation crosslinked vinyl chloride resin

    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

  8. Protection of Organic Matter from Enzyme Degradation by Mineral Mesopores

    Zimmerman, A. R.; Chorover, J. D.; Brantley, S. L.

    2003-12-01

    Mineral mesopores (2-50 nm diameter) may sequester organic matter (natural and pollutant) and protect it from microbial and fungal enzymatic degradation in soils and sediments. Synthetic mesoporous alumina and silica minerals with uniform pore sizes and shapes were used to test the role of mesopores in protecting organic matter from enzymatic degradation. A model humic compound, L-3-4-dihydroxyphenylalanine (L-DOPA), was sorbed to the internal surfaces of mesoporous alumina (8.2 nm diameter pores) and mesoporous silica (3.4 nm diameter pores) as well as to the external surfaces of nonporous alumina and silica analogues. A fungal derived enzyme, laccase, was added to these sorbate-sorbent pairs in aqueous solution and activity was monitored by oxygen consumption. Though enzyme activity was suppressed in both cases by mineral-enzyme interaction (enzyme inhibition likely due to adsorption of the enzyme), both the rate and total extent of enzyme-mediated degradation of mesopore-sorbed L-DOPA was 3-40 times lower than that of the externally-sorbed analogue. These results provide, for the first time, direct evidence for the viability of the proposed mesopore protection mechanism for the sequestration and preservation of sedimentary organic matter and organic contaminants. Mesopore adsorption/desorption phenomena may also help explain the slow degradation of organic contaminants in soil and sediment and may prove useful as delivery vehicles for organic compounds to agricultural, medical or environmental systems.

  9. Generalized synthesis of mesoporous shells on zeolite crystals

    Han, Yu

    2010-12-30

    A simple and generalized synthetic approach is developed for creating mesoporous shells on zeolite crystals. This method allows for the tailoring of thickness, pore size, and composition of the mesoporous shell, and can be applied to zeolites of various structures, compositions, and crystal sizes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Aqueous colloidal mesoporous nanoparticles with ethenylene-bridged silsesquioxane frameworks.

    Urata, Chihiro; Yamada, Hironori; Wakabayashi, Ryutaro; Aoyama, Yuko; Hirosawa, Shota; Arai, Satoshi; Takeoka, Shinji; Yamauchi, Yusuke; Kuroda, Kazuyuki

    2011-06-01

    Aqueous colloidal mesoporous nanoparticles with ethenylene-bridged silsesquioxane frameworks with a uniform diameter of ?20 nm were prepared from bis(triethoxysilyl)ethenylene in a basic aqueous solution containing cationic surfactants. The nanoparticles, which had higher hydrolysis resistance under aqueous conditions, showed lower hemolytic activity toward bovine red blood cells than colloidal mesoporous silica nanoparticles. PMID:21539358

  11. Synthesis and catalytic applications of combined zeolitic/mesoporous materials

    Jarian Vernimmen

    2011-11-01

    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.

  12. Shape matters when engineering mesoporous silica-based nanomedicines.

    Hao, Nanjing; Li, Laifeng; Tang, Fangqiong

    2016-04-22

    Mesoporous silica nanomaterials have been successfully employed in the development of novel carriers for drug delivery. Numerous studies have been reported on engineering mesoporous silica-based carriers for drug loading, release, cellular uptake, and biocompatibility. A number of design parameters that govern the in vitro and in vivo performance of the carriers, including particle diameter, surface chemistry, and pore size, have been tuned to optimize nanomedicine efficacy. However, particle shape, which may generate a high impact on nanomedicine performance, has still not been thoroughly investigated. This is probably due to the limited availability of strategies and techniques to produce non-spherical mesoporous silica nanomaterials. Recent breakthroughs in controlling the particle shape of mesoporous silica nanomaterials have confirmed the important roles of shape on nanomedicine development. This review article introduces various fabrication methods for non-spherical mesoporous silica nanomaterials, including rod, ellipsoid, film, platelet/sheet, and cube, and the roles of particle shape in nanomedicine applications. PMID:26818852

  13. Iron oxide nanoparticles stabilized inside highly ordered mesoporous silica

    A Bhaumik; S Samanta; N K Mal

    2005-11-01

    Nanosized iron oxide, a moderately large band-gap semiconductor and an essential component of optoelectrical and magnetic devices, has been prepared successfully inside the restricted internal pores of mesoporous silica material through in-situ reduction during impregnation. The samples were characterized by powder XRD, TEM, SEM/EDS, N2 adsorption, FT-IR and UV–visible spectroscopies. Characterization data indicated well-dispersed isolated nanoclusters of (Fe2O3),` within the internal surface of 2D-hexagonal mesoporous silica structure. No occluded Fe/Fe2O3 crystallites were observed at the external surface of the mesoporous silica nanocomposites. Inorganic mesoporous host, such as hydrophilic silica in the pore walls, directs a physical constraint necessary to prevent the creation of large Fe2O3 agglomerates and enables the formation of nanosized Fe2O3 particles inside the mesopore.

  14. Spray drying of bead resins: feasibility tests

    Rockwell International has developed a volume reduction system for low-level reactor wastes based on drying the wastes in a heated-air spray dryer. The drying of slurries of sodium sulfate, boric acid, and powdered ion exchange resins was demonstrated in previous tests. The drying of bead ion exchange resins can be especially difficult due to the relatively large size of bead resins (about 500 to 800 microns) and their natural affinity for water. This water becomes part of the pore structure of the resins and normally comprises 50 t 60 wt % of the resin weight. A 76-cm-diameter spray dryer was used for feasibility tests of spray drying of cation and anion bead resins. These resins were fed to the dryer in the as-received form (similar to dewatered resins) and as slurries. A dry, free-flowing product was produced in all the tests. The volume of the spray-dried product was one-half to one-third the volume of the as-received material. An economic analysis was made of the potential cost savings that can be achieved using the Rockwel spray dryer system. In-plant costs, transportation costs, and burial costs of spray-dried resins were compared to similar costs for disposal of dewatered resins. A typical utility producing 170 m3 (6,000 ft3) per year of dewatered resins can save $600,000 to $700,000 per year using this volume reduction system

  15. A highly ordered cubic mesoporous silica/graphene nanocomposite

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

    2013-09-01

    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.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. Electronic supplementary information (ESI) available: S1: TEM images of disordered mesoporous silica/graphene nanocomposite; S2: TEM images of KIT-6/GO nanocomposite; S3: Thermogravimetric analysis of KIT-6/GO and KG-400-700; S4: SEM and TEM images of KIT-6; S5: Low angle XRD, Raman spectra, N2 adsorption isotherms, pore size distribution and photographic images of the prepared samples; S6: TEM image and N2 adsorption isotherms of mesoporous carbon/graphene nanocomposite; S7: XPS C1s spectra of the prepared samples. See DOI: 10.1039/c3nr03108j

  16. Platinum nanopeapods: spatial control of mesopore arrangements by utilizing a physically confined space.

    Takai, Azusa; Sakamoto, Yasuhiro; Terasaki, Osamu; Yamauchi, Yusuke; Kuroda, Kazuyuki

    2013-08-26

    Spherical mesopores: Mesoporous Pt rods containing cage-type mesopores were prepared with porous anodic alumina membranes (PAAMs). It is noteworthy that spherical mesopores are aligned in the rods due to physical confinement by the PAAM channels. Both the mesopore alignment and the morphological control are realized simultaneously, which could be important for bottom-up approaches to nanometals with desirable structural features (see figure). PMID:23868357

  17. EDF specifications on nuclear grade resins

    Ion exchange resins are widely used across EDF, especially within the nuclear division for the purification of water. Important applications include primary circuit, secondary circuit and effluent treatment, which require high quality nuclear grade resins to retain the dissolved species, some of which may be radioactive. There is a need for more and more efficient purification in order to decrease worker dose during maintenance but also to decrease volumes of radioactive resin waste. Resin performance is subject to several forms of degradation, including physical, chemical, thermal and radioactive, therefore appropriate resin properties have to be selected to reduce such effects. Work has been done with research institutes, manufacturers and on EDF sites to select these properties, create specifications and to continuously improve on these specifications. An interesting example of research regarding resin performance is the resin degradation under irradiation. Resins used in the CVCS circuit of EDF nuclear power plants are subject to irradiation over their lifetime. A study was carried out on the effects of total integrated doses of 0.1, 1 and 10 MGy on typically used EDF mixed bed resins in a 'mini-CVCS' apparatus to simultaneously test actual primary circuit fluid. The tests confirmed that the resins still perform efficiently after a typical CVCS radiation dose. Certain resins also need additional specifications in order to maintain the integrity of the particular circuits they are used in. Recently, EDF has updated its requirements on these high purity nuclear grade resins, produced generic doctrines for all products and materials used on site which include resins of all grades, and as a result have also updated a guide on recommended resin usage for the French fleet of reactors. An overview of the evolutions will be presented. (authors)

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

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

  19. The development of chiral nematic mesoporous materials.

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

    2014-04-15

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

  20. Comparison of marginal adaptation between a monoincremental resin with sonic activation and a conventional resin.

    Javier Villa; Rosemarie Meier; Patricio Ruiz; Diego Halabí

    2015-01-01

    Aim: To determine differences in marginal adaptation between a conventional composite resin and a monoincremental resin with sonic activation. Materials and methods: 32 composite resin discs of 2.5mm in diameter and 2mm thick were fabricated in a propylene matrix and distributed in 2 groups of 16 samples each. Groups 1 FiltekTMZ350XT resin; Group 2 SonicFillTM resin with sonic activation. The gap generated between the resin and the matrix as a result of the polymerization shrinkage was analyz...

  1. Bending characteristics of resin concretes

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

    2003-01-01

    In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodolog...

  2. Fluorescence properties of dye doped mesoporous silica

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

    2014-10-21

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

  3. Ordered mesoporous silica-based inorganic nanocomposites

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

  4. Oil absorption in mesoporous silica particles

    Radislav Filipovi?

    2010-12-01

    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.

  5. Fluorescence properties of dye doped mesoporous silica

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

  6. Boron sorption characteristics in resins

    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

  7. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

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

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

    Wei Gao

    2012-01-01

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

  9. Reinforcement of Denture Base Resins

    T Nejatiant

    2005-10-01

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

  10. Development of tough, moisture resistant laminating resins

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

    1982-01-01

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

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

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

    2010-06-01

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

  12. VOLUMETRIC POLYMERIZATION SHRINKAGE OF CONTEMPORARY COMPOSITE RESINS

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

    2007-01-01

    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 ...

  13. Resin selection criteria for tough composite structures

    Chamis, C. C.; Smith, G. T.

    1983-01-01

    Resin selection criteria are derived using a structured methodology consisting of an upward integrated mechanistic theory and its inverse (top-down structured theory). These criteria are expressed in a "criteria selection space" which are used to identify resin bulk properties for improved composite "toughness". The resin selection criteria correlate with a variety of experimental data including laminate strength, elevated temperature effects and impact resistance.

  14. CALORIFIC APPRECIATION OF SOME RESINOUS SPECIES

    Aurel LUNGULEASA; Tatiana DOBREV; Adriana FOTIN

    2015-01-01

    This paper aims to show some results about using the resinous species as fuels. Some calorific features to characterize the biomass resulting from resinous trees are considered, namely the net and gross calorific value, burning speed, calorific density and combustion speed. The moisture content of biomass is identified as the main factor of calorific influence. All results come to confirm the ability of resinous biomass to be used as fuel. As resulted from the experiments, the bio...

  15. Release and toxicity of dental resin composite

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

    2012-01-01

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

  16. Electrosynthesis of Epoxy Resins via Superoxide Anion

    Rajni Mathur; Meeta Trivedi

    2013-01-01

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

  17. Silylation and metalation of periodic mesoporous silica

    Deschner, Thomas Christian

    2011-07-01

    Surface functionalization via silylation or SOMC (Surface Organometallic Chemistry) is a prosperous field for producing organic-inorganic hybrid materials. These concepts are proven by numerous applications in various topical areas like catalysis, chromatography, adsorption processes, as well as gas sensing and storage. The combination of a thermally stable high surface area inorganic host and a reactive surface chemistry which allows the control of dispersion of the surface species and fine tuning of the properties of the subsequent hybrid material is an endeavour especially in heterogeneous catalysis. The subgroup of cage-like PMS (Periodic Mesoporous Silica) materials comprising of SBA-1, SBA-2, SBA-6, SBA-I6 or KIT-5 are currently attractive candidates for designing size and shape selective catalysts. (Silyl)amides enjoy great popularity in (surface) organometallic chemistry because most of the metals of the periodic table form stable complexes with these ligands. Chapter A gives a brief summary of microporous and mesoporous materials in general and introduces compendiously possible surface modifications with special emphasis on silylation. In addition an overview of metal (silyl)amides[et]porous and metal (silyl)amides[et]nonporous support is presented. Chapter C deals with the summary of the main results placing emphasis on: distinct reactivity of various silylation reagents; distinct reactivity of metal (silyl)amides of the elements Mg, Ti, and Fe; o occurrence of any size effects; feasibility of consecutive intrapore chemistry. (Author)

  18. Smart Mesoporous Nanomaterials for Antitumor Therapy

    Marina Martínez-Carmona

    2015-11-01

    Full Text Available The use of nanomaterials for the treatment of solid tumours is receiving increasing attention by the scientific community. Among them, mesoporous silica nanoparticles (MSNs exhibit unique features that make them suitable nanocarriers to host, transport and protect drug molecules until the target is reached. It is possible to incorporate different targeting ligands to the outermost surface of MSNs to selectively drive the drugs to the tumour tissues. To prevent the premature release of the cargo entrapped in the mesopores, it is feasible to cap the pore entrances using stimuli-responsive nanogates. Therefore, upon exposure to internal (pH, enzymes, glutathione, etc. or external (temperature, light, magnetic field, etc. stimuli, the pore opening takes place and the release of the entrapped cargo occurs. These smart MSNs are capable of selectively reaching and accumulating at the target tissue and releasing the entrapped drug in a specific and controlled fashion, constituting a promising alternative to conventional chemotherapy, which is typically associated with undesired side effects. In this review, we overview the recent advances reported by the scientific community in developing MSNs for antitumor therapy. We highlight the possibility to design multifunctional nanosystems using different therapeutic approaches aimed at increasing the efficacy of the antitumor treatment.

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

    Schuster, Joerg David

    2011-06-07

    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 material in lithium-sulfur batteries. The fifth and last part focuses on the synthesis of spherical mesoporous carbon nanoparticles. Therefore the triconstituent coassembly was applied on a silica template with spherical pores, which was derived from the opal structure of colloidal crystals made from 400 nm PMMA spheres. The spherical ordered mesoporous carbon nanoparticles feature extremely high inner porosity of 2.32 cm{sup 3}/g and 2445 m{sup 2}/g, respectively They were successfully applied as cathode material in Li-S batteries, where they showed high reversible capacity up to 1200 mAh/g and good cycle efficiency. The final product consists of spherical mesoporous carbon particles with a diameter of around 300 nm and 2D-hexagonal porosity. The particles could be completely separated by sonification to form stable colloidal suspensions. This could be the base for further applications such drug delivery.

  20. Novel silica-based ion exchange resin

    NONE

    1997-11-01

    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.

  1. The absorption of plutonium by anion resins

    Equilibrium experiments have shown Pu+4 to be absorbed from nitric acid onto an anion resin as a complex anion Pu(NO3)6-2. The amount of absorption is dependent on the plutonium and nitric acid concentrations in the equilibrium solution with a maximum at 7N to 8N HNO3. A low cross-linked resin has a higher capacity and reaches equilibrium more rapidly than the normally supplied resin. Saturation capacity of one per cent cross-linked Nalcite SBR (Dowex 1), 50 -- 100 mesh, is 385 mg Pu/gram dry resin. (author)

  2. 21 CFR 175.380 - Xylene-formaldehyde resins condensed with 4,4?-isopropylidenediphenol-epichlorohydrin epoxy resins.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Xylene-formaldehyde resins condensed with 4,4... Xylene-formaldehyde resins condensed with 4,4?-isopropylidenediphenol-epichlorohydrin epoxy resins. The...) The resins are produced by the condensation of xylene-formaldehyde resin and...

  3. Micro/mesoporous composites based on colloidal zeolite grown in mesoporous matrix

    Prokešová, Pavla; Petkov, N.; Čejka, Jiří; Mintova, S.; Bein, T.

    2005-01-01

    Roč. 70, - (2005), s. 1829-1847. ISSN 0010-0765 R&D Projects: GA ČR GA203/05/0197; GA AV ČR KJB4040402 Institutional research plan: CEZ:AV0Z40400503 Keywords : micro/mesoporous composite * colloidal zeolites * colloids * molecular sieves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.949, year: 2005

  4. Application of mesoporous carbon and modified mesoporous carbon for treatment of DMF sewage

    Liu, Fang, E-mail: liufangfw@163.com; Gao, Ya; Zhang, Shuang; Yan, Xi; Fan, Fengtao; Zhao, Chaocheng; Sun, Juan [China University of Petroleum(East China), Department of Chemical Engineering (China)

    2016-02-15

    Mesoporous carbon (MC) was prepared in soft template, and potassium ferricyanide was added into MC to prepare the modified mesoporous carbon (MMC). TEM, SEM, FT-IR, and N{sub 2} adsorption–desorption were used to characterize the textural properties of mesoporous materials. The BET specific surface area, pore volume, and the pore size of MC and MMC were 607.6321 and 304.7475 m{sup 2}/g, 0.313552 and 0.603573 cm{sup 3}/g, and 5.4356 and 7.9227 nm, respectively. The adsorption capabilities of MC and MMC were compared with the silica mesoporous material MCM-41. The influences of different adsorption conditions were optimized. For MC, the optimums of adsorbent dose, DMF initial concentration, rotating speed, and pH were 0.002 mg/50 mL, 200 mg/L, 200 r/min, and 4, respectively. MMC showed the highest DMF adsorption capacity at adsorbent dose 0.002 g/50 mL, DMF initial concentration 1000 mg/L, rotating speed 1000 r/min, pH more than 9, and contact time of less than 20 min. Meanwhile for MC, MMC, Pseudo-second-order equation was used to fit adsorption kinetics data. And adsorption process could be well fitted by Langmuir and Freundlich adsorption isotherms of MC, MMC. The results showed that MMC was a perfect adsorbent for DMF, and it was easy to separation and recycle. The recycling property of MMC was still relatively better than other two adsorbents.

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

    Nikola Ž. Knežević

    2014-01-01

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

  6. Mesoporous carbon incorporated metal oxide nanomaterials as supercapacitor electrodes

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

    2012-08-08

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

  7. Mesoporous silica magnetite nanocomposite synthesized by using a neutral surfactant

    Souza, K. C.; Salazar-Alvarez, G.; Ardisson, J. D.; Macedo, W. A. A.; Sousa, E. M. B.

    2008-05-01

    Magnetite nanoparticles coated by mesoporous silica were synthesized by an alternative chemical route using a neutral surfactant and without the application of any functionalization method. The magnetite (Fe3O4) nanoparticles were prepared by precipitation from aqueous media, and then coated with mesoporous silica by using nonionic block copolymer surfactants as the structure-directing agents. The mesoporous SiO2-coated Fe3O4 samples were characterized by x-ray diffraction, Fourier-transform infrared spectroscopy, N2 adsorption-desorption isotherms, transmission electron microscopy, 57Fe Mössbauer spectroscopy, and vibrating sample magnetometry. Our results revealed that the magnetite nanoparticles are completely coated by well-ordered mesoporous silica with free pores and stable (~8 nm thick) pore walls, and that the structural and magnetic properties of the Fe3O4 nanoparticles are preserved in the applied synthesis route.

  8. BITEMPLATE SYNTHESIS OF MESOPOROUS SILICAS WITH THIOUREA GROUPS

    O. I. Gona

    2009-06-01

    Full Text Available Mesoporous silicas with the thiourea functional group ?Si(CH23NHC(SNHC2H5 have been synthesized by monotemplate and bitemplate route (bitemplate is cetylpyridinium chloride as micelle-forming surfactant and monoethanolamide of saturated n-aliphatic acid as non-micelle-forming surfactant. The infl uence of a number of factors on mesoporous silicas structure has been studied: alkoxysilanes and surfactants concentration, and as well as the nature of medium in hydrothermal treatment of mesophases. The optimum conditions under which functionalized mesoporous silicas have possessing highly ordered hexagonal structure have been found. The surface area of mesoporous silicas synthesized using optimum bitemplate solubilization composition reaches 1055-1350 m2/g and sorption volume and pore diameter are 0.75-0.95 cm3/g and 2.5-2.9 nm respectively.

  9. Synthesis of mesoporous nano-hydroxyapatite by using zwitterions surfactant

    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...

  10. Structure and optical properties of mesoporous tungsten oxide

    Mesoporous WO3 was prepared by the sol-gel process and the structure and the optical properties have been investigated. Various techniques were used for characterization of mesoporous WO3, including Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption isotherms and UV-vis spectroscopy. TEM and XRD analyses demonstrated that the mesoporous WO3 was nanocrystalline. The estimated optical band gap (E g) for the mesoporous WO3 was 3.5 eV. We present evidence for a photoreduction of W6+ into W5+ following the irradiation with UV-light. The change in coloration is almost reversible as exposed in oxidation environment. These results suggest that the potential applications of mesostructured WO3 with nanocrystals in the design of optical devices

  11. BITEMPLATE SYNTHESIS OF MESOPOROUS SILICAS WITH THIOUREA GROUPS

    O. I. Gona; N. V. Stolyarchuk; Zub, Yu L.; N. A. Yaroshenko

    2009-01-01

    Mesoporous silicas with the thiourea functional group ?Si(CH2)3NHC(S)NHC2H5 have been synthesized by monotemplate and bitemplate route (bitemplate is cetylpyridinium chloride as micelle-forming surfactant and monoethanolamide of saturated n-aliphatic acid as non-micelle-forming surfactant). The infl uence of a number of factors on mesoporous silicas structure has been studied: alkoxysilanes and surfactants concentration, and as well as the nature of medium in hydrothermal treatment of mesopha...

  12. Solar hydrogen and solar electricity using mesoporous materials

    Mahoney, Luther

    The development of cost-effective materials for effective utilization of solar energy is a major challenge for solving the energy problems that face the world. This thesis work relates to the development of mesoporous materials for solar energy applications in the areas of photocatalytic water splitting and the generation of electricity. Mesoporous materials were employed throughout the studies because of their favorable physico-chemical properties such as high surface areas and large porosities. The first project was related to the use of a cubic periodic mesoporous material, MCM-48. The studies showed that chromium loading directly affected the phase of mesoporous silica formed. Furthermore, within the cubic MCM-48 structure, the loading of polychromate species determined the concentration of solar hydrogen produced. In an effort to determine the potential of mesoporous materials, titanium dioxide was prepared using the Evaporation-Induced Self-Assembly (EISA) synthetic method. The aging period directly determined the amount of various phases of titanium dioxide. This method was extended for the preparation of cobalt doped titanium dioxide for solar simulated hydrogen evolution. In another study, metal doped systems were synthesized using the EISA procedure and rhodamine B (RhB) dye sensitized and metal doped titania mesoporous materials were evaluated for visible light hydrogen evolution. The final study employed various mesoporous titanium dioxide materials for N719 dye sensitized solar cell (DSSC) materials for photovoltaic applications. The materials were extensively characterized using powder X-ray diffraction (XRD), nitrogen physisorption, diffuse reflectance spectroscopy (DRS), UV-Vis spectroscopy, Fourier-Transform-Infrared Spectroscopy (FT-IR), Raman spectroscopy, chemisorption, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In addition, photoelectrochemical measurements were completed using current-voltage (I-V) curves, external quantum efficiency (EQE) curves, electrochemical impedance spectroscopy (EIS), and transient spectroscopy. The thesis work presented provides a better understanding of the role of mesoporous materials for solar hydrogen and solar electricity production.

  13. Synthesis and functionalization of ordered mesoporous carbons for catalytic applications

    Nitz, Jörg Joachim

    2009-01-01

    Mesoporöses Siliziumdioxid (SBA-15 und KIT-6) wird verwandt um mit Hilfe des "Nanocasting"-Verfahrens geordnete mesoporöse Kohlereplikastrukturen der CMK-Familie zu synthetisieren. Die Struktur, Topologie, sowie Oberflächenmodifikationen solcher Materialien wurden detailliert untersucht. So lässt sich durch schrittweise Oberflächenfunktionalisierung das innere Porensystem einer CMK-5 Kohle mit bimodaler Porenstruktur selektiv modifizieren. Solche Kohlereplikastrukturen eignen sich...

  14. Characterization and adsorptive application of ordered mesoporous silicas

    Rockmann, Rico [Wilhelm Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, 2 Linnestrasse, D-04103 Leipzig (Germany); Kalies, Grit [Wilhelm Ostwald Institute of Physical and Theoretical Chemistry, University of Leipzig, 2 Linnestrasse, D-04103 Leipzig (Germany)]. E-mail: kalies@uni-leipzig.de

    2007-04-30

    The adsorption behaviour of the n-octane/ethanol binary liquid mixture has been studied on ordered mesoporous silica materials. Adsorption excesses on SBA-15, SBA-16 and MCM-48 solids are measured and described by mathematical functions. The experimental adsorption excess isotherms are presented and discussed. The mesoporous silicas used for liquid-adsorption experiments are characterized by nitrogen adsorption before and after liquid adsorption by the powder X-ray diffraction (XRD) and by the sample controlled thermal analysis (SCTA)

  15. Adsorption and Diffusion of Xylene Isomers on Mesoporous Beta Zeolite

    Aixia Song; Jinghong Ma; Duo Xu; Ruifeng Li

    2015-01-01

    A systematic and detailed analysis of adsorption and diffusion properties of xylene isomers over Beta zeolites with different mesoporosity was conducted. Adsorption isotherms of xylene isomers over microporous and mesoporous Beta zeolites through gravimetric methods were applied to investigate the impact of mesopores inside Beta zeolites on the adsorption properties of xylene isomers in the pressure range of lower 20 mbar. It is seen that the adsorption isotherms of three xylene isomers over ...

  16. Synthesis of self-assembled photosensitive molecules in mesoporous silicates

    Honma, Itaru; Zhou, H.-S.

    1997-02-01

    Self-assembled functional molecules in mesoporous materials are synthesized directly either by co-assembly of dye-bound surfactant of ferrocenyl TMA with silicate or Pc (phthalocyanine) molecules doped in the C16TMA micelles with oxides framework such as V2O5, MoO3, WO3 and SiO2. The process provides well-organized molecular doped mesoporous structure by direct and simple procedure.

  17. Curing kinetics of alkyd/melamine resin mixtures

    Jovičić Mirjana C.; Radičević Radmila Ž.

    2009-01-01

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

  18. Gold Loading on Ion Exchange Resins in Non-Ammoniacal Resin-Solution Systems

    Abrar Muslim

    2010-12-01

    Full Text Available The loading of gold using strong base anion exchange resin in non-ammoniac resin-solution (NARS systems has been studied. The loading of gold onto ion exchange resins is affected by polythionate concentration, and trithionate can be used as the baseline in the system. The results also show that resin capacity on gold loading increases due to the increase in the equilibrium thiosulfate concentration in the NARS system. Gold loading performances show the need of optimization the equilibrium concentrations of thiosulfate in the NARS system. Keywords: equilibrium, gold loading, resin capacity, thiosulfate, trithionate

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

    Furuse, Adilson Yoshio; da Cunha, Leonardo Fernandes; Benetti, Ana Raquel; Mondelli, José

    2007-01-01

    The purpose of this study was to investigate the effect of different surface treatments on shear bond strength of saliva-contaminated resin-resin interfaces. Flat resin surfaces were fabricated. In the control group, no contamination or surface treatment was performed. The resin surfaces of the...... experimental groups were contaminated with saliva and air-dried, and then submitted to: (G1) rinsing with water and drying; (G2) application of an adhesive system; (G3) rinsing and drying, abrasion with finishing disks, etching and application of adhesive system; (G4) rinsing and drying, etching, application......-resin interfaces with saliva significantly reduced shear strength, especially after prolonged storage (p...

  20. CHARACTERIZATION OF GLUED LAMINATED PANELS PRODUCED WITH STRIPS OF BAMBOO (Guadua magna) NATIVE FROM THE BRAZILIAN CERRADO

    Teixeira, Divino Eterno; Bastos, Rodrigo Pinheiro; Almeida, Sergio Alberto de Oliveira

    2015-01-01

    Panels were produced with strips of bamboo (Guadua magna) in layers crossed at angles of 90° and bonded with phenol-formaldehyde or PVA based resin, glued in three and five plies. The panels were tested and the physical and mechanical properties determined. The tests were primarily related to the...

  1. CHARACTERIZATION OF GLUED LAMINATED PANELS PRODUCED WITH STRIPS OF BRAZILIAN NATIVE BAMBOO (Guadua magna) FROM CERRADO

    Teixeira, Divino Eterno; Bastos, Rodrigo Pinheiro; de Oliveira, Srgio Alberto

    2015-01-01

    Plywood panels were produced with strips of bamboo (Guadua magna) and bonded with phenol-formaldehyde and PVA based resins, glued in three and five plies. The panels characterization was based on physical and mechanical tests. The tests primarily related to commercial adhesives used in the manuf...

  2. Properties of the Carboxylate ion exchange resins; Karboxylatjonbytarmassans egenskaper

    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

    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)

  3. 21 CFR 177.2500 - Polyphenylene sulfone resins.

    2010-04-01

    ... consist of basic resin produced by reacting polyphenylene sulfide with peracetic acid such that the... optional adjuvant substances required in the production of such basic resins. These optional...

  4. Silicone modified resins for graphite fiber laminates

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

    1980-01-01

    Six silicone modified resins were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 6-63%. The highest flexural values measured for the laminates were a strength of 1,220 MPa and a modulus of 105 GPa. The highest interlaminar shear strength was 72 MPa.

  5. Ion exchange resins for uranium recovery

    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

  6. Novel silica-based ion exchange resin

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

  7. Epoxidation of linseed oil-Alkyd resins

    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

  8. Polyisoprenylated benzophenones from Clusia floral resins.

    Porto, A L; Machado, S M; de Oliveira, C M; Bittrich, V; Amaral, M C; Marsaioli, A J

    2000-12-01

    From the floral resins of various Clusia species, seven polyisoprenylated benzophenones were isolated. HPLC allowed their quantification in all resins, revealing a distribution of benzophenone derivatives distinct from each other. In some species the staminal oils were collected and oleic, stearic and palmitic acids were the main constituents. PMID:11190392

  9. 21 CFR 177.1655 - Polysulfone resins.

    2010-04-01

    ...) of this section. N-methyl-2-pyrrolidone Not to exceed 0.01 percent (100 parts per million) as...-phenyleneisopropylidene-p-phenylene) resins (CAS Reg. No. 25154-01-2) consisting of basic resins produced when the... by osmotic pressure in monochlorobenzene; or (2) 1,1′-Sulfonylbis polymer with...

  10. Terpenoid Oligomers of Dammar Resin.

    Bonaduce, Ilaria; Di Girolamo, Francesca; Corsi, Iacopo; Degano, Ilaria; Tinè, Maria Rosaria; Colombini, Maria Perla

    2016-04-22

    Dammar is a triterpenoid resin containing a volatile fraction, a monomeric fraction, and a high-molecular weight fraction. Although the low-molecular-weight components comprising sesquiterpenoids and triterpenoids have been extensively studied, the nature of the macromolecular components is still not fully understood, and different and sometimes contradictory theories have been proposed. The aim of this paper is to clarify the nature of the macromolecular components of dammar resin. A multianalytical approach was adopted based on thermoanalytical-thermogravimetric analysis (TGA), and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TGA/FTIR)-and mass spectrometric techniques-direct exposure mass spectrometry (DE/MS), pyrolysis coupled to gas chromatography and mass spectrometry (Py/GC/MS), flow injection analysis electrospray ionization mass spectrometry (FIA/ESI/MS), and gas chromatography/mass spectrometry (GC/MS). The data indicate that the oligomeric fraction comprises triterpenoids bound through ester bonds, and that these triterpenoids are the same as those found in the free terpenoid fraction. The oligomeric fraction also includes triterpenoids containing carbonyl moieties, such as formyl groups, thus suggesting that these are involved in the esters in their corresponding enolic form. PMID:26981624

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

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

    2013-12-01

    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.

  12. Influence of spatial configurations on electromagnetic interference shielding of ordered mesoporous carbon/ordered mesoporous silica/silica composites

    Wang, Jiacheng; Zhou, Hu; Zhuang, Jiandong; Liu, Qian

    2013-01-01

    Ordered mesoporous carbons (OMCs), obtained by nanocasting using ordered mesoporous silicas (OMSs) as hard templates, exhibit unique arrangements of ordered regular nanopore/nanowire mesostructures. Here, we used nanocasting combined with hot-pressing to prepare 10 wt% OMC/OMS/SiO2 ternary composites possessing various carbon mesostructure configurations of different dimensionalities (1D isolated CS41 carbon nanowires, 2D hexagonal CMK-3 carbon, and 3D cubic CMK-1 carbon). The electric/dielec...

  13. Plutonium sorption to nanocast mesoporous carbon

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

    2014-09-01

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

  14. (129)Xe NMR of Mesoporous Silicas

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

    1999-04-23

    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.

  15. Solid superacid catalysts based on mesoporous media

    Wang, Y.; Kim, A.Y.; Wang, L.Q.; Li, S. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

    1997-12-31

    Solid acid catalysts are sought to replace homogeneous mineral acids for many industrially important reactions. Homogeneous acids present both environmental and operational problems. Novel solid acid catalysts, sulfated zirconia and supported tungstophosphoric acid, have been prepared based on mesioporous supports. The advantages of mesoporous supports include high surface area, adjustable pore size, narrow pore size distribution, and large pore volume. These characteristics allow the design and preparation of novel catalysts with improved shape selectivity and thermal stability. Synthesized catalysts were characterized by gas adsorption, TEM, DTA/TGA, XRD, solid state NMR, FTIR, and temperature programmed desorption. Activity and selectivity were tested for alkylation and isomerization reactions. Effects of pore size on acid strength and distribution, reaction kinetics, product selectivity, and coking were investigated.

  16. Embedding of reactor wastes in plastic resins

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

  17. Release and toxicity of dental resin composite.

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

    2012-09-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined. PMID:23293458

  18. Electrodialytic decontamination of spent ion exchange resins

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

  19. Structural Determination of Copolymers from the Cross-catalyzed Reactions of Phenol-formaldehyde and Polymeric Methylenediphenyl Diisocyanate

    Haupt, Robert A

    2013-01-01

    This work reports the elucidation of the structure of a copolymer generated by the cross- catalyzed reactions of PF and pMDI prepolymers.  The electronic behavior of phenolic monomers as perturbed by alkali metal hydroxides in an aqueous environment was studied with 1H and 13C NMR.  Changes in electronic structure and thus reactivity were related to solvated ionic radius, solvent dielectric constant, and their effect on ion generated electric field strength. NMR chemical shifts were used to p...

  20. Solidification of ion exchange resin wastes

    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

  1. Adsorption and release of biocides with mesoporous silica nanoparticles

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

    2012-01-01

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

  2. Enhanced retention of aqueous transition metals in mesoporous silica

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

    2013-12-01

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

  3. Gyroidal mesoporous multifunctional nanocomposites via atomic layer deposition

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

    2014-07-01

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

  4. PENGARUH STRUKTUR PORI TERHADAP KAPASITANSI ELEKTRODA SUPERKAPASITOR YANG DIBUAT DARI KARBON NANOPORI

    Teguh Ariyanto

    2012-05-01

    Full Text Available THE EFFECT OF PORE STRUCTURE ON THE ELECTRODE CAPACITANCE OF SUPERCAPACITOR PREPARED BY NANOPOROUS CARBON. Nanoporous carbons, due to high specific surface area, high pore accessibility, and relatively low cost, have been used as material electrode supercapacitors. In this work, the influence of pore structure of nanoporous carbons on the specific capacitance of supercapacitors was examined. Nanoporous carbons with several types of pore structure were prepared by carbonization of phenolic resin produced by polymeric condensation of phenolic compound with formaldehyde. Furthermore, ethylene glycol, as a filler, was added in the phenolic resin polymerization to increase the mesoporosity of nanoporous carbon. The nanoporous carbons produced were characterized for their surface morphology, specific internal surface area (BET method, and pore structure. Samples were used as electrode material in supercapacitor and specific capacitances were characterized by galvanostatic test using 30% KOH aqueous solution as electrolyte. The capacitance test of supercapacitors exhibited that increasing mesoporosity increase specific capacitance value of supercapacitors. The highest specific capacitance of 336 F/g was obtained by using mesoporous carbon produced by carbonization of resorcinol phenol formaldehyde ethylene glycol (C-RPFEG2 as electrode material of supercapacitors.  Karbon nanopori dikarenakan memiliki luas permukaan internal yang tinggi, aksesibilitas pori yang baik, dan relatif murah telah digunakan sebagai material elektroda superkapasitor. Pada penelitian ini, pengaruh struktur pori dari karbon nanopori terhadap kapasitansi spesifik superkapasitor telah dipelajari. Karbon berpori dengan berbagai struktur pori dibuat dengan cara karbonisasi phenolic resin yang dibuat dengan cara polimerisaasi kondensasi senyawa phenolic dengan formaldehyde. Selain itu, etilen glikol sebagai filler ditambahkan pada saat polimerisasi phenolic resin untuk meningkatkan mesoporositas dari karbon nanopori. Karbon yang diperoleh dikarakterisasi berupa morfologi permukaan, luas permukaan spesifik (metode BET, dan struktur pori. Karbon tersebut kemudian digunakan sebagai material elektroda superkapasitor dan kapasitansi spesifik dikarakterisasi dengan tes galvanostatik menggunakan KOH 30% sebagai elektrolit. Uji kapasitansi superkapasitor menunjukkan bahwa meningkatnya mesoporositas karbon nanopori akan meningkatkan nilai kapasitansi spesifik. Kapasitansi spesifik tertinggi sebesar 336 F/g diperoleh jika menggunakan karbon mesopori hasil karbonisasi resorcinol phenol formaldehyde ethylene glycol (C-RPFEG2 sebagai material elektroda superkapasitor.

  5. FABRICATION AND STUDY OF LIGNOCELLULOSIC HIBISCUS SABDARIFFA FIBER REINFORCED POLYMER COMPOSITES

    Amar Singh Singha,; Vijay Kumar Thakur

    2008-01-01

    Fabrication of polymer composites reinforced with lignocellulosic materials has increased considerably during the last few years. This work reports the synthesis of natural fiber reinforced phenol-formaldehyde (PF) resin matrix based polymer composite using a compression molding technique. Initially the PF resin was prepared by varying the concentration of formaldehyde with a fixed weight of phenol. Polymeric resin of different P: F ratios were subjected for optimization of their mechanical p...

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

    Marie-Christine LAGEL; Pizzi, Antonio; Redl, Andreas

    2014-01-01

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

  7. Comparison of marginal adaptation between a monoincremental resin with sonic activation and a conventional resin.

    Javier Villa

    2015-12-01

    Full Text Available Aim: To determine differences in marginal adaptation between a conventional composite resin and a monoincremental resin with sonic activation. Materials and methods: 32 composite resin discs of 2.5mm in diameter and 2mm thick were fabricated in a propylene matrix and distributed in 2 groups of 16 samples each. Groups 1 FiltekTMZ350XT resin; Group 2 SonicFillTM resin with sonic activation. The gap generated between the resin and the matrix as a result of the polymerization shrinkage was analyzed in microns using a microscope at a magnification of 40X. The percentage of the lineal polymerization shrinkage was also calculated. To calculate differences in marginal adaptation between the two resins statistical analysis was performed using the unpaired t-test. Results: The extent of the gaps measured in microns and their respective standard deviations were SonicFillTM 9.95 ± 3.05 and FiltekTMZ350XT 10.21 ± 5.14 (p=.86. Conclusion: The use of the monoincremental resin system with sonic activation shows a marginal adaptation similar to that of conventional resin composites, with no statistically significant differences between the studied resins.

  8. Novel mesoporous composites based on natural rubber and hexagonal mesoporous silica: Synthesis and characterization

    The present study is the first report on the synthesis and characterization of mesoporous composites based on natural rubber (NR) and hexagonal mesoporous silica (HMS). A series of NR/HMS composites were prepared in tetrahydrofuran via an in situ sol–gel process using tetraethylorthosilicate as the silica precursor. The physicochemical properties of the composites were characterized by various techniques. The effects of the gel composition on the structural and textural properties of the NR/HMS composites were investigated. The Fourier-transform infrared spectroscopy (FTIR) and 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR) results revealed that the surface silanol groups of NR/HMS composites were covered with NR molecules. The powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) data indicated an expansion of the hexagonal unit cell and channel wall thickness due to the incorporation of NR molecules into the mesoporous structure. NR/HMS composites also possessed nanosized particles (∼79.4 nm) as confirmed by scanning electron microscopy (SEM) and particle size distribution analysis. From N2 adsorption–desorption measurement, the NR/HMS composites possessed a high BET surface area, large pore volume and narrow pore size distribution. Further, they were enhanced hydrophobicity confirmed by H2O adsorption–desorption measurement. In addition, the mechanistic pathway of the NR/HMS composite formation was proposed. - Highlights: • NR molecules were incorporated into hexagonal meso-structure of HMS. • NR/HMS composites exhibited an expanded unit cell and channel wall thickness. • Nanosized NR/HMS composites with a lower particle size range were obtained. • NR/HMS had high surface area, large pore volume and narrow pore size distribution. • NR/HMS composites displayed an enhanced hydrophobicity

  9. Advanced Fibre Reinforced Methyl Nadicimide Resins .

    Sarfaraz Alam

    1996-07-01

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

  10. SEM and elemental analysis of composite resins

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

  11. Immobilisation of ion exchange resins in cement

    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)

  12. Immobilisation of ion exchange resins in cement

    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)

  13. Epoxide resins for use at low temperatures

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

  14. Sorption of dissolved organics from aqueous solution by polystrene resins. I. Resin characterization and sorption equilibrium

    Cornel, P.; Sontheimer, H.

    1986-01-01

    The results of sorption equilibrium studies indicate that adsorption is only one of the three mechanisms involved in removing organics from aqueous solution by polystyrene resins. The other two mechanisms are associated with the resin's capability to incorporate organics into their polymer matrix while swelling. To describe the overall sorption behavior, it is not sufficient to characterize the resin structure by estimating pore size distribution and internal surface area of the dry polymers. The amount of swelling in different organic solvents must also be evaluated as an important structural parameter of polystyrene resins. The role of the different mechanisms depends on both the resin structure and the physical and chemical properties of the solute. The solute's affinity for the polystyrene surface can be correlated with the solute's benzene-water partition coefficient. A heuristic model is presented which relates the sorption capacity to both the resin and solute properties.

  15. Mesoporous TiO{sub 2}-based PEMFC catalyst supports

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

    2009-07-01

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

  16. DEVELOPMENT OF MESOPOROUS MEMBRANE MATERIALS FOR CO2 SEPARATION; SEMIANNUAL

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

  17. Immobilization of Lactate Oxidase Within a Hybrid Mesoporous Membrane

    HE Jiao

    2010-07-01

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

  18. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties.

    Variola, Fabio; Zalzal, Sylvia Francis; Leduc, Annie; Barbeau, Jean; Nanci, Antonio

    2014-01-01

    Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB) was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS), nanobeam electron diffraction (NBED), and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting. PMID:24872694

  19. Organized thiol functional groups in mesoporous core shell colloids

    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

    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.

  20. Near-field radiative heat transfer in mesoporous alumina

    The thermal conductivity of mesoporous material has aroused the great interest of scholars due to its wide applications such as insulation, catalyst, etc. Mesoporous alumina substrate consists of uniformly distributed, unconnected cylindrical pores. Near-field radiative heat transfer cannot be ignored, when the diameters of the pores are less than the characteristic wavelength of thermal radiation. In this paper, near-field radiation across a cylindrical pore is simulated by employing the fluctuation dissipation theorem and Green function. Such factors as the diameter of the pore, and the temperature of the material are further analyzed. The research results show that the radiative heat transfer on a mesoscale is 2∼4 orders higher than on a macroscale. The heat flux and equivalent thermal conductivity of radiation across a cylindrical pore decrease exponentially with pore diameter increasing, while increase with temperature increasing. The calculated equivalent thermal conductivity of radiation is further developed to modify the thermal conductivity of the mesoporous alumina. The combined thermal conductivity of the mesoporous alumina is obtained by using porosity weighted dilute medium and compared with the measurement. The combined thermal conductivity of mesoporous silica decreases gradually with pore diameter increasing, while increases smoothly with temperature increasing, which is in good agreement with the experimental data. The larger the porosity, the more significant the near-field effect is, which cannot be ignored. (paper)

  1. Nanostructured mesoporous tungsten oxide for gas sensor applications

    Rossinyol, Emma; Arbiol, Jordi; Marsal, Andreu; Peiro, Francesca; Cornet, Albert; Morante, Joan Ramon; Solovyov, Leonid A.; Tian, Bozhi; Tu, Bo; Zhao, Dongyuan

    2005-06-01

    Due to their simple implementation, low cost and good reliability for real-time control systems, semiconductor gas sensors offer good advantages with respect to other gas sensor devices. As gas adsorption is a surface effect, one of the most important parameter to tailor the sensitivity of the sensor material is to increase the surface area. For these propose, mesoporous oxides have been synthesized. Nanostructured mesoporous materials present a large and controllable pore size and high surface are. For the preparation of ordered nanostructure arrays, a hard template method has been used. This method presents some advantages when compared with a soft template method, especially in its specific topological stability, veracity, predictability and controllability. Moreover, with this hard template method we can obtain crystalline mesoporous oxides, with small particle size and high surface area. We have used SBA-15 (two-dimensional hexagonal structure) and KIT-6 (three-dimensional cubic structure) as a template for the synthesis of different crystalline mesoporous WO3 with a particle size about 8-10 nm and high surface area. Low angle XRD spectra show a high order mesoporous structure, without rests of silica template. TEM confirms that the silica host has been completely removed; therefore, the nanowires constitute a self-supported superlattice. HRTEM studies have been focused on the detailed structural characterization of these materials. Electrical characterization of the sensor response in front of NO2 has been performed. Some catalytic additives have been also introduced, in order to increase the sensitivity of the material.

  2. Catalytic hydrodeoxygenation of 2-methoxy phenol and dibenzofuran over Pt/mesoporous zeolites

    The hydrodeoxygenation of 2-methoxy phenol and dibenzofuran, which are representative model compounds of bio-oil, was performed using two different Pt/mesoporous zeolite catalysts, Pt/mesoporous Y and Pt/mesoporous MFI. The reforming of 2-methoxy phenol and dibenzofuran via catalytic hydrodeoxygenation was investigated using a batch reactor at 40bar and 250C. The characteristics of the catalysts were analyzed by N2 adsorption-desorption, X-ray diffraction, and NH3 temperature programmed desorption. Pt/mesoporous zeolite catalysts containing both strong acid sites and mesopores showed the higher conversion of 2-methoxy phenol than Pt/SiO2 and Pt/Si-MCM-48 with no acid sites, Pt/?-Al2O3, and a mixture of mesoporous Y and Pt/SiO2, indicating the importance of both Pt and strong acid sites for high catalytic activity. Among the two Pt/mesoporous zeolite catalysts tested, the conversion of 2-methoxy phenol to cyclohexane over Pt/mesoporous Y was much higher than that over the Pt/mesoporous MFI. This was attributed to the better textural properties, such as surface area, pore volume and micropore size, compared to those of Pt/mesoporous MFI. The catalytic conversions of dibenzofuran obtained using two Pt/mesoporous zeolite catalysts were similar and the main products were 1,1?-bicyclohexyl, cyclopentylmethyl-cyclohexane and cyclohexane. In addition, the reaction mechanisms of 2-methoxy phenol and dibenzofuran over Pt/mesoporous zeolite were suggested. - Highlights: HDO of 2-methoxy phenol and dibenzofuran was performed over Pt/mesoporous zeolites. Pt/mesoporous zeolites have mesopores and strong acid sites. Main product of HDO of 2-methoxy phenol was cyclohexane. Main products of HDO of dibenzofuran were bicyclohexyl (BCH), i-BCH, and cyclohexane

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

    Daisuke Shimamoto; Yusuke Imai, Yuji Hotta

    2014-01-01

    Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin-curing of carbon fiber/epoxy resin composite that was composed of discontinuous carbon fibers of 130 ?m or 3 mm were investigated. The mechanical properties of carbon fiber/epoxy resin composite cured by microwave irradiation for 20 min at 120C were si...

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

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

  5. 5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions

    Franco, Eduardo Batista; Benetti, Ana Raquel; Ishikiriama, Sérgio Kiyoshi; Santiago, Sérgio Lima; Lauris, José Roberto Pereira; Jorge, Mauro Fonseca Ferreira; Navarro, Maria Fidela de Lima

    2006-01-01

    To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions.......To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions....

  6. Advanced cement solidification technique for spent resins

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

  7. Epoxide resins for use at low temperatures

    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

  8. Synthesis of improved phenolic and polyester resins

    Delano, C. B.

    1980-01-01

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

  9. Method for regenerating magnetic polyamine-epichlorohydrin resin

    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

  10. Highly Loaded Mesoporous Silica/Nanoparticle Composites and Patterned Mesoporous Silica Films

    Kothari, Rohit; Hendricks, Nicholas R.; Wang, Xinyu; Watkins, James J.

    2014-03-01

    Novel approaches for the preparation of highly filled mesoporous silica/nanoparticle (MS/NP) composites and for the fabrication of patterned MS films are described. The incorporation of iron platinum NPs within the walls of MS is achieved at high NP loadings by doping amphiphilic poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (Pluronic®) copolymer templates via selective hydrogen bonding between the pre-synthesized NPs and the hydrophilic portion of the block copolymer. The MS is then synthesized by means of phase selective condensation of tetraethylorthosilicate (TEOS) within the NP loaded block copolymer templates dilated with supercritical carbon dioxide (scCO2) followed by calcination. For patterned films, microphase separated block copolymer/small molecule additive blends are patterned using UV-assisted nanoimprint lithography. Infusion and condensation of a TEOS within template films using ScCO2 as a processing medium followed by calcination yields the patterned MS films. Scanning electron microscopy is used characterize pattern fidelity and transmission electron microscopy analysis confirms the presence of the mesopores. Long range order in nanocomposites is confirmed by low angle x-ray diffraction.

  11. Cycloaliphatic epoxide resins for cationic UV - cure

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

  12. Volumetric polymerization shrinkage of contemporary composite resins

    Halim Nagem Filho

    2007-10-01

    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.

  13. Resin composites : Sandwich restorations and curing techniques

    Lindberg, Anders

    2005-01-01

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

  14. Heavy metal recovery by a chelating resin

    Adsorption on a chelating resin is a method to recover metals from waste water containing very small quantities of heavy metals. The usual regeneration of the resin consists of an acidic desorption of the metallic ion, an alkaline treatment of the resin and an electrolysis. A new recovering method of the metallic ion by strong complexing agents has been developed. In this case, the recovering agent is concentrated by reverse osmosis or ultrafiltration, electrolysed and then recycled at the beginning of the process. The resin used for our application is the Chelamine Standard (JPS-Chimie, Neuchatel, Switzerland). It is made of a polyacrylamide gel with tetraethylene pentamine chelating groups. Physical properties of this resin were measured. A thermodynamical study in a closed vessel showed that equilibrium was well represented by a Langmuir isotherm. These experiments stressed the influence of the resin conditioning on its equilibrium capacity: a resin regenerated in very alkaline conditions had a greater capacity than if the regenerating agent was slightly basic or neutral. Adsorption kinetics in a continuous stirred tank reactor were also conducted. Experiments were simulated by a global kinetic model comprising mass transfer in a liquid film around the resin particles, diffusion through the pores and reaction on the adsorption sites. Kinetics has been found limited by film mass transfer for all metals studied (Cu2+, Ni2+, Co2+ and Zn2+). The mass-transfer coefficient kL was found to be around 10-4 ms-1. Adsorption of heavy metals was then carried out at mini-pilot scale. Problems due to a decrease in average particle diameter during the adsorption prompted us to use a fluidized bed. It is also possible with this reactor to treat solutions containing suspended solids which would clog fixed beds. (author) figs., tabs., refs

  15. Composition of resin acids in different rosins

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

    1982-01-01

    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).

  16. Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure

    Suteewong, Teeraporn

    2011-01-19

    Mesoporous silica with cubic symmetry has attracted interest from researchers for some time. Here, we present the room temperature synthesis of mesoporous silica nanoparticles possessing cubic Pm3n symmetry with very high molar ratios (>50%) of 3-aminopropyl triethoxysilane. The synthesis is robust allowing, for example, co-condensation of organic dyes without loss of structure. By means of pore expander molecules, the pore size can be enlarged from 2.7 to 5 nm, while particle size decreases. Adding pore expander and co-condensing fluorescent dyes in the same synthesis reduces average particle size further down to 100 nm. After PEGylation, such fluorescent aminated mesoporous silica nanoparticles are spontaneously taken up by cells as demonstrated by fluorescence microscopy.

  17. Adsorption of vitamin E on mesoporous titania nanocrystals

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

    2010-07-15

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

  18. Aluminum-rich mesoporous MFI - type zeolite single crystals

    Kustova, Marina; Kustov, Arkadii; Christensen, Christina Hviid

    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...

  19. Synthesis of mesoporous silica microsphere from dual surfactant

    Venkatathri Narayanan

    2008-12-01

    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.

  20. Removal of anionic surfactants by sorption onto Aminated Mesoporous Carbon

    Moradi S.E.

    2013-01-01

    Full Text Available Direct and indirect releases of large quantities of surfactants to the environment may result in serious health and environmental problems. Therefore, surfactants should be removed from water before release to the environment or delivery for public use. In the present work, the removal of anionic surfactants, benzene sulfonate (BS, p-toluene sulfonate (TS and 4-octylbenzene sulfonate (OBS from water by adsorption onto Amino modified mesoporous carbon (AMC were studied. The AMC surface chemistry and textural properties was characterized by nitrogen adsorption, XRD and FT-IR analyses. Experiments were conducted in batch mode with the variables such as amount of contact time, solution pH, dose of adsorbent and temperature. Finally, the adsorption isotherms of anionic surfactants on mesoporous carbon adsorbents were in agreement with a Langmuir model. AMC has shown higher anionic surfactants adsorption capacity than the untreated mesoporous carbon, which can explain by strong interaction between anionic surfactant and cationic surface of adsorbent.

  1. Syntheses and applications of periodic mesoporous organosilica nanoparticles

    Croissant, Jonas G.; Catton, Xavier; Wong Chi Man, Michel; Durand, Jean-Olivier; Khashab, Niveen M.

    2015-12-01

    Periodic Mesoporous Organosilica (PMO) nanomaterials are envisioned to be one of the most prolific subjects of research in the next decade. Similar to mesoporous silica nanoparticles (MSN), PMO nanoparticles (NPs) prepared from organo-bridged alkoxysilanes have tunable mesopores that could be utilized for many applications such as gas and molecule adsorption, catalysis, drug and gene delivery, electronics, and sensing; but unlike MSN, the diversity in chemical nature of the pore walls of such nanomaterials is theoretically unlimited. Thus, we expect that PMO NPs will attract considerable interest over the next decade. In this review, we will present a comprehensive overview of the synthetic strategies for the preparation of nanoscaled PMO materials, and then describe their applications in catalysis and nanomedicine. The remarkable assets of the PMO structure are also detailed, and insights are provided for the preparation of more complex PMO nanoplatforms.

  2. Adsorption of vitamin E on mesoporous titania nanocrystals

    Tri-block nonionic surfactant and titanium chloride were used as starting materials for the synthesis of mesoporous titania nanocrystallite powders. The main objective of the present study was to examine the synthesis of mesoporous titania nanocrystals and the adsorption of vitamin E on those nanocrystals using X-ray diffraction (XRD), transmission electron microscopy, and nitrogen adsorption and desorption isotherms. When the calcination temperature was increased to 300 oC, the reflection peaks in the XRD pattern indicated the presence of an anatase phase. The crystallinity of the nanocrystallites increased from 80% to 98.6% with increasing calcination temperature from 465 oC to 500 oC. The N2 adsorption data and XRD data taken after vitamin E adsorption revealed that the vitamin E molecules were adsorbed in the mesopores of the titania nanocrystals.

  3. Zirconia-silica based mesoporous desulfurization adsorbents

    Palomino, Jessica M.; Tran, Dat T.; Kareh, Ana R.; Miller, Christopher A.; Gardner, Joshua M. V.; Dong, Hong; Oliver, Scott R. J.

    2015-03-01

    We report a series of mesoporous silicate sorbent materials templated by long-chain primary alkylamines that display record level of desulfurization of the jet fuel JP-8. Pure silica frameworks and those with a Si:Zr synthesis molar ratio ranging from 44:1 to 11:1 were investigated. The optimum sorbent was identified as dodecylamine-templated silica-zirconia synthesized from a gel with Si:Zr molar ratio of 15:1. With an optimized silver loading of 11 wt.%, a saturation adsorption capacity of 39.4 mgS g-1 and a silver efficiency of 1.21 molS mol Ag-1 were observed for JP-8. This sorbent displayed exceptional regenerability, maintaining 86% of its initial capacity in model fuel after solvent regeneration with diethyl ether. Low-cost, portable and reusable sorbents for the desulfurization of JP-8 jet fuel are needed to make solid oxide fuel cells (SOFCs) a reality for military power needs. SOFCs require ultra-low sulfur content fuel, which traditional desulfurization methods cannot achieve.

  4. Confined Polymerization in Highly Ordered Mesoporous Organosilicas.

    Comotti, Angiolina; Bracco, Silvia; Beretta, Mario; Perego, Jacopo; Gemmi, Mauro; Sozzani, Piero

    2015-12-01

    Hybrid mesoporous organosilica exhibiting crystal-like order in the walls provided an ideal channel reaction vessel for the confined polymerization of acrylonitrile (PAN). The resulting high-molecular-mass PAN fills the channels at high yield and forms an ordered nanostructure of polymer nanobundles enclosed into the hybrid matrix. The in situ thermal transformation of PAN into rigid polyconjugated and, eventually, into condensed polyaromatic carbon nanofibers, retains the periodic architecture. Simultaneously, the matrix evolves showing the fusion of the p-phenylene rings and the cleavage of carbonsilicon bonds: this gives rise to graphitic-carbon/silica nanocomposites containing hyper-oxydrylated silica nanophases. Interestingly, the 3D hexagonal mesostructure survives in the carbonaceous material. The exploitation of porous materials of high capacity and a hybrid nature, for polymerization in the confined state, followed by high temperature treatments, allowed us to achieve unique and precisely fabricated nanostructures, thus paving the way for the construction of fine-tuned electronic and light-harvesting materials. PMID:26559381

  5. Novel Mesoporous Carbon Supports for PEMFC Catalysts

    Dustin Banham

    2015-06-01

    Full Text Available Over the past decade; a significant amount of research has been performed on novel carbon supports for use in proton exchange membrane fuel cells (PEMFCs. Specifically, carbon nanotubes, ordered mesoporous carbon, and colloid imprinted carbons have shown great promise for improving the activity and/or stability of Pt-based nanoparticle catalysts. In this work, a brief overview of these materials is given, followed by an in-depth discussion of our recent work highlighting the importance of carbon wall thickness when designing novel carbon supports for PEMFC applications. Four colloid imprinted carbons (CICs were synthesized using a silica colloid imprinting method, with the resulting CICs having pores of 15 (CIC-15, 26 (CIC-26, 50 (CIC-50 and 80 (CIC-80 nm. These four CICs were loaded with 10 wt. % Pt and then evaluated as oxygen reduction (ORR catalysts for use in proton exchange membrane fuel cells. To gain insight into the poorer performance of Pt/CIC-26 vs. the other three Pt/CICs, TEM tomography was performed, indicating that CIC-26 had much thinner walls (03 nm than the other CICs and resulting in a higher resistance (leading to distributed potentials through the catalyst layer during operation. This explanation for the poorer performance of Pt/CIC-26 was supported by theoretical calculations, suggesting that the internal wall thickness of these nanoporous CICs is critical to the future design of porous carbon supports.

  6. Resin volume reduction by high force compaction

    The packaging, transportation, and disposal of contaminated spent ion exchange resin constitutes one of the most expensive items on the utility radwaste manager's budget. The waste volume limits and surcharges imposed by the Low-Level Radioactive Waste Policy Act Amendments of 1985 have created strong incentives for the application of high force compaction to reduce the volume of ion exchange resin shipped for disposal. Lab and full-scale test results demonstrated that the volume reduction achieved by compaction is a function of compressive force, resin type, moisture and crud content, and the container/packaging method. Simulated waste resin and actual plant-generated resin was tested using compressive forces between 600 and 6680 psi. Volume reduction factors, as compared to conventional dewatering, of 2:1 to 6:1 were measured using high force compaction. The relative simplicity of compaction technology as compared to other resin volume reduction technologies, and the availability of high force compaction equipment set the stage for a very cost effective and easily implemented volume reduction system

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

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

    2013-12-01

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

  8. Adsorption and Diffusion of Xylene Isomers on Mesoporous Beta Zeolite

    Aixia Song

    2015-12-01

    Full Text Available A systematic and detailed analysis of adsorption and diffusion properties of xylene isomers over Beta zeolites with different mesoporosity was conducted. Adsorption isotherms of xylene isomers over microporous and mesoporous Beta zeolites through gravimetric methods were applied to investigate the impact of mesopores inside Beta zeolites on the adsorption properties of xylene isomers in the pressure range of lower 20 mbar. It is seen that the adsorption isotherms of three xylene isomers over microporous and mesoporous Beta zeolites could be successfully described by the single-site Toth model and the dual-site Toth model, respectively. The enhanced adsorption capacities and decreased Henrys constants (KH and the initial heats of adsorption (Qst for the all xylene isomers are observed after the introduction of mesopores in the zeolites. For three xylene isomers, the order of Henrys constant is o-xylene > m-xylene > p-xylene, whereas the adsorption capacities of Beta zeolite samples for xylene isomers execute the following order of o-xylene > p-xylene > m-xylene, due to the comprehensive effects from the molecular configuration and electrostatic interaction. At the same time, the diffusion properties of xylene isomers in the mesoporous Beta zeolites were also studied through the desorption curves measured by the zero length column (ZLC method at 333373 K. It turned out that the effective diffusion time constant (Deff/R2 is a growing trend with the increasing mesoporosity, whereas the tendency of the activation energy is just the reverse, indicating the contribution of mesopores to facilitate molecule diffusion by shortening diffusion paths and reducing diffusion resistances. Moreover, the diffusivities of three xylene isomers in all Beta zeolites follow an order of p-xylene > m-xylene > o-xylene as opposed to KH, conforming the significant effects of adsorbate-adsorbent interaction on the diffusion.

  9. Monolithic gyroidal mesoporous mixed titanium-niobium nitrides.

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

    2014-08-26

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

  10. Monolithic Gyroidal Mesoporous Mixed Titanium–Niobium Nitrides

    2015-01-01

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

  11. Macroporous silica–alumina composites with mesoporous walls

    Gautam Gundiah

    2001-04-01

    Macroporous silica–alumina composites with mesopores have been prepared by employing polymethylmethacrylate beads as templates in the presence of the cationic surfactant, N-cetyl-N,N,N-trimethylammonium bromide. The Si/Al ratio in the composites has been varied between 4.5 and 48 and the occurrence of mesopores has been verified by X-ray diffraction. The surface areas of the samples vary between 676 and 1038 m2g–1, with the highest value in the sample with Si/Al = 48.

  12. Exploring Mass Transfer in Mesoporous Zeolites by NMRDiffusometry

    Ryong Ryoo

    2012-04-01

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

  13. Electric Field-Responsive Mesoporous Suspensions: A Review

    Seung Hyuk Kwon

    2015-12-01

    Full Text Available This paper briefly reviews the fabrication and electrorheological (ER characteristics of mesoporous materials and their nanocomposites with conducting polymers under an applied electric field when dispersed in an insulating liquid. Smart fluids of electrically-polarizable particles exhibit a reversible and tunable phase transition from a liquid-like to solid-like state in response to an external electric field of various strengths, and have potential applications in a variety of active control systems. The ER properties of these mesoporous suspensions are explained further according to their dielectric spectra in terms of the flow curve, dynamic moduli, and yield stress.

  14. Nanoindentation studies of nickel zinc ferrite embedded mesoporous silica template

    Banerjee, S.; Hajra, P.; Mada, M. R.; Bandopadhyay, S.; Chakravorty, D.

    2013-02-01

    Nickel zinc ferrite (NZF) embedded mesoporous silica KIT-6 nanocomposite (NZFMS) was synthesized via impregnation method. The microstructure of the samples was characterized by transmission electron microscopy (TEM). Nanoindentation (NI) studies were carried out on both mesoporous silica (MS) and the nanocomposite NZFMS. It was found that the young's modulus (E) and hardness (H) of the NZFMS were higher than that of the MS. From creep measurement it was observed that the creep-strain rate was greater for NZFMS compared to MS. This arose due to diffusion of Fe3+ ions from nickel zinc ferrite to the silica glass. The results indicate that the NZFMS material shows superplastic behaviour at room temperature.

  15. Shear bond strength evaluation of resin composite to resin-modified glass-ionomer cement using three different resin adhesives vs. glass-ionomer based adhesive

    Mostafa Sadeghi; Mohammad Atafat; Mehdi Abbasi

    2015-01-01

    Background: The clinical success of sandwich technique depends on the strength of resin-modified glass ionomer cement (RMGIC) bonding to both dentin and resin composite. Therefore, the shear bond strength (SBS) of resin composite bonded to RMGIC utilizing different resin adhesives versus a GIC-based adhesive was compared. Materials and methods: In this in vitro study, 84 holes (52 mm) were prepared in acrylic blocks, randomly divided into seven groups (n=12) and filled with RMGIC (Light-Cure...

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

    Adilson Yoshio Furuse

    2007-12-01

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

  17. Organosulfonic acid-functionalized mesoporous composites based on natural rubber and hexagonal mesoporous silica

    Nuntang, Sakdinun; Poompradub, Sirilux [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Butnark, Suchada [PTT Research and Technology Institute, PTT Public Company Limited, Wangnoi, Ayutthaya 13170 (Thailand); Yokoi, Toshiyuki; Tatsumi, Takashi [Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ngamcharussrivichai, Chawalit, E-mail: Chawalit.Ng@Chula.ac.th [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand)

    2014-10-15

    This study is the first report on synthesis, characterization and catalytic application of propylsulfonic acid-functionalized mesoporous composites based on natural rubber (NR) and hexagonal mesoporous silica (HMS). In comparison with propylsulfonic acid-functionalized HMS (HMS-SO{sub 3}H), a series of NR/HMS-SO{sub 3}H composites were prepared via an in situ solgel process using tetrahydrofuran as the synthesis media. Tetraethylorthosilicate as the silica source, was simultaneously condensed with 3-mercaptopropyltrimethoxysilane in a solution of NR followed by oxidation with hydrogen peroxide to achieve the mesoporous composites containing propylsulfonic acid groups. Fourier-transform infrared spectroscopy and {sup 29}Si MAS nuclear magnetic resonance spectroscopy results verified that the silica surfaces of the NR/HMS-SO{sub 3}H composites were functionalized with propylsulfonic acid groups and covered with NR molecules. After the incorporation of NR and organo-functional group into HMS, the hexagonal mesostructure remained intact concomitantly with an increased framework wall thickness and unit cell size, as evidenced by the X-ray powder diffraction analysis. Scanning electron microscopy analysis indicated a high interparticle porosity of NR/HMS-SO{sub 3}H composites. The textural properties of NR/HMS-SO{sub 3}H were affected by the amount of MPTMS loading to a smaller extent than that of HMS-SO{sub 3}H. NR/HMS-SO{sub 3}H exhibited higher hydrophobicity than HMS-SO{sub 3}H, as revealed by H{sub 2}O adsorptiondesorption measurements. Moreover, the NR/HMS-SO{sub 3}H catalysts possessed a superior specific activity to HMS-SO{sub 3}H in the esterification of lauric acid with ethanol, resulting in a higher conversion level. - Highlights: Acidic NR/HMS-SO{sub 3}H composites were prepared by in situ solgel process. Propylsulfonic acid was functionalized onto HMS surface by direct co-condensation. NR/HMS-SO{sub 3}H exhibited a hexagonal mesostructure and high mesoporosity. NR incorporated into the HMS structure improved the hydrophobicity of the composites. NR/HMS-SO{sub 3}H had a high esterification activity for lauric acid with ethanol.

  18. Selection of Unsaturated Polyester Resins for Closed Resin Transfer Moulding Processes

    Leyla Y. Jaramillo-Zapata

    2012-06-01

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

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

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

    2014-10-01

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

  20. USE OF BABAU FLOUR WITH ALTERNATIVE EXTENDER FOR PLYWOOD MANUFACTURING

    rika da Silva Ferreira

    2009-10-01

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

  1. Hot dewatering and resin encapsulation of intermediate level radioactive waste

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

  2. Device and method for separating clads of ion exchange resins

    Purpose: To contrive the facilitation of stocking spent ion exchange resin by separating and removing clad and nuclide ions of highly radioactive substances from the spent ion exchange resin and reducing the waste volume of the substances. Method: Spent particulate ion exchange resin which adsorbed clad is separated into anion exchange resin and cation exchange resin in a first tank, and clad is isolated from the separated cation exchange resin in a second tank by adding isolating liquid and applying supersonic vibration thereto. (Kamimura, M.)

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

    Nikola Ž. Knežević

    2014-06-01

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

  4. Controversies in posterior composite resin restorations.

    Wilson, E G; Mandradjieff, M; Brindock, T

    1990-01-01

    The use of posterior composites is riddled with so many controversies that the puzzled practitioner must step warily among them. This modality is a minefield, where one careless movement can bring disaster. All composite restorations are subject to three big destructive forces--moisture, polymerization shrinkage, and clinical wear--forces that can eventually produce both microleakage and deterioration of the silane coupling agent linking filler particles to resin matrix. Despite the extreme technique sensitivity of posterior composite resins, knowledge of resin technology, sound operative dentistry principles and foresight in case selection can be effective in producing durable cosmetic restorations. Posterior composite resin restorations bonded to enamel and dentin reputedly strengthen teeth in both conventional and adhesive types of preparations provided polymerization shrinkage can be controlled. It is imperative that a knowledge of occlusal contacts be used to influence cavity outline, confining the trauma or occlusal forces away from the tooth-resin interface and helping to minimize occlusal wear. With the increased use of posterior resins, the trend in cavity preparations should break away from the traditional Black preparation toward the adhesive type preparation. If the Black Class II preparation is used, it is suggested that bevels be confined to the facial and lingual margins of the proximal box. Prewedging helps to maintain a conservative Class II preparation. Shade selection must be made prior to rubber dam isolation for greater accuracy and to help prevent postinsertion discoloration. The enamel should be pumiced to present a clean substrate for acid etching. The smear layer should be removed. The type of pulp protection applied before acid etching is dependent on the material used. After etching, the enamel should be washed with a 1 per cent potassium chloride solution. It is a more universally chemically stable solution than additive-laden local water supplies. The potassium chloride solution lowers the electrostatic forces on the enamel that would interfere with the flow of enamel bonding agents. Furthermore, tests have shown that the use of potassium chloride washes increase the strength of the enamel body by 40 per cent. Because of the depth of most posterior cavities, an incremental filling technique must be used to ensure a thorough polymerization of the resin and to forestall a massive polymerization shrinkage. When finished and contoured, the margins of the restoration should be re-etched, washed, and dried and then covered with an application of unfilled resin to discourage microleakage. Traditional operative dentistry technique must become flexible enough to meet the new demands of resin technology.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2403943

  5. Mesoporous carbon microspheres with high capacitive performances for supercapacitors

    Highlights: • Small mesopores-enriched porous carbon microspheres were easily synthesized. • Small mesopores offer high ion-accessible surface area and facilitated ion diffusion. • The porous carbon exhibited a high specific capacitance and a good power property. - Abstract: Novel small-mesopores-enriched porous carbon microspheres have been synthesized from carbonaceous polysaccharide microspheres, by using the associated lithium acetate treating and heat treating strategies. X-ray diffraction, scanning electron microscope, transmission electron microscopy and nitrogen adsorption-desorption techniques have been employed to investigate the as-prepared samples. The analysis results indicate that the porous carbon microspheres has a high specific surface area of 1163 m2 g−1 and a satisfactory small mesoporous texture (2∼5 nm), with the mean pore size of 3.24 nm and the pore volume ratio of 2∼5 nm pores up to 92%. The capacitive performances of the samples in 6 mol L−1 KOH aqueous electrolyte, have been tested by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge techniques. A specific capacitance of 171.5 F/g is obtained for the porous carbon microspheres via charge-discharge at a current density of 1000 mA/g. It also displayed a very high cycle stability of 97.8%, compared with the initial capacitance, after 1000 cycles at the high current density of 1000 mA/g

  6. Mesoporous molecular sieves as supports for metathesis catalysts

    Balcar, Hynek; Čejka, Jiří

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

  7. Mesopore quality determines the lifetime of hierarchically structured zeolite catalysts

    Milina, Maria; Mitchell, Sharon; Crivelli, Paolo; Cooke, David; Pérez-Ramírez, Javier

    2014-05-01

    Deactivation due to coking limits the lifetime of zeolite catalysts in the production of chemicals and fuels. Superior performance can be achieved through hierarchically structuring the zeolite porosity, yet no relation has been established between the mesopore architecture and the catalyst lifetime. Here we introduce a top-down demetallation strategy to locate mesopores in different regions of MFI-type crystals with identical bulk porous and acidic properties. In contrast, well-established bottom-up strategies as carbon templating and seed silanization fail to yield materials with matching characteristics. Advanced characterization tools capable of accurately discriminating the mesopore size, distribution and connectivity are applied to corroborate the concept of mesopore quality. Positron annihilation lifetime spectroscopy proves powerful to quantify the global connectivity of the intracrystalline pore network, which, as demonstrated in the conversions of methanol or of propanal to hydrocarbons, is closely linked to the lifetime of zeolite catalysts. The findings emphasize the need to aptly tailor hierarchical materials for maximal catalytic advantage.

  8. Enhanced photocatalytic properties in well-ordered mesoporous WO3

    Li, Li

    2010-01-01

    We used polyisoprene-block-ethyleneoxide copolymers as structure-directing agents to synthesise well-ordered and highly-crystalline mesoporous WO 3 architectures that possess improved photocatalytic properties due to enhanced dye-adsorption in absence of diffusion limitation. © 2010 The Royal Society of Chemistry.

  9. Mesoporous molecular sieves as advanced supports for olefin metathesis catalysts

    Balcar, Hynek; Čejka, Jiří

    2013-01-01

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

  10. Preparation of mesoporous titania solid superacid and its catalytic property.

    Jiang, Tingshun; Zhao, Qian; Li, Mei; Yin, Hengbo

    2008-11-30

    Mesoporous titania (TiO(2)) was synthesized by hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as a template and using anhydrous ethanol and tetra-n-butyl titanate (TBOT) as raw materials. Mesoporous titania solid superacid and nanosized titania solid superacid catalysts were prepared by wet impregnation method. The structure and property of as-prepared samples were characterized by means of XRD, FT-IR and N(2) physical adsorption. The esterification of salicylic acid with isoamyl alcohol and the condensation of cyclohexanone with ethylene were used as model reactions to test the catalytic activities of the catalysts. On the other hand, the comparison of catalytic activities of the prepared solid superacid catalysts and the conventional liquid acid H(2)SO(4) was also carried out under the same experimental conditions. The results show that the catalytic activities of the prepared solid superacid catalysts were higher than that of the conventional liquid acid H(2)SO(4), and that the catalytic activity of mesoporous TiO(2) solid superacid is the highest among the three catalysts. Mesoporous TiO(2) solid superacid is a good catalyst for the synthesis of isoamyl salicylate or cyclohexanone ethylene ketal. PMID:18343571

  11. Pore ordering in mesoporous matrices induced by different directing agents

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

    2015-01-01

    Roč. 22, č. 2 (2015), s. 321-331. ISSN 1380-2224 Institutional support: RVO:61388980 Keywords : Mesoporous silica * MCM-41 * Dodecyl-trimethyl ammonium bromide * Hexadecyl-trimethylammonium bromide Subject RIV: CA - Inorganic Chemistry Impact factor: 1.108, year: 2014

  12. Mesoporous zeolite and zeotype single crystals synthesized in fluoride media

    Egeblad, Kresten; Kustova, Marina; Klitgaard, Søren Kegnæs; Zhu, Kake; Christensen, Claus H.

    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...

  13. Processing of exhausted resins for Trino NPP,

    Decomposition of organic compounds contained in the spent ion exchange resins is considered effective in reducing the waste volume. A system using the wet-oxidation process has been studied for the treatment of the spent resins stored at Trino Nuclear Power Plant owned by SOGIN. Compared with various processes for treating sludge and resin, the wet-oxidation system is rather simple and the process conditions are mild. Not contaminated ion exchange resin samples similar to those ones used in Trino NPP were processed by wet-oxidation and appropriate decomposition of the organic compounds was verified. After decomposition the residue can be solidified with cement for final disposal. When compared with direct solidification without decomposition, the number of waste packages can be significantly reduced. Additional measures for conditioning secondary waste products have also been studied, and their applicability to the Trino Nuclear Power Plant was verified. Some of conditions studied were specific to the Trino Nuclear Power Plant, but it is expected that the system will provide an effective solution for resin treatment at other Italian NPPs. (authors)

  14. Development of a heterogeneous laminating resin system

    Biermann, T. F.; Hopper, L. C.

    1985-01-01

    The factors which effect the impact resistance of laminating resin systems and yet retain equivalent performance with the conventional 450 K curing epoxy matrix systems in other areas were studied. Formulation work was conducted on two systems, an all-epoxy and an epoxy/bismaleimide, to gain fundamental information on the effect formulation changes have upon neat resin and composite properties. The all-epoxy work involved formulations with various amounts and combinations of eight different epoxy resins, four different hardeners, fifteen different toughening agents, a filler, and a catalyst. The epoxy/bismaleimide effort improved formulations with various amounts and combinations of nine different resins, four different hardeners, eight different toughening agents, four different catalysts, and a filler. When a formulation appeared to offer the proper combination of properties required for a laminating resin Celion 3K-70P fabric was prepregged. Initial screening tests on composites primarily involved Gardner type impact and measurement of short beam shear strengths under dry and hot/wet conditions.

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

    Knežević, Nikola Ž.; Lin, Victor S.-Y.

    2013-01-01

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

  16. Textural manipulation of mesoporous materials for hosting of metallic nanocatalysts.

    Sun, Junming; Bao, Xinhe

    2008-01-01

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

  17. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

    Variola F

    2014-05-01

    Full Text Available Fabio Variola,1,2 Sylvia Francis Zalzal,3 Annie Leduc,3 Jean Barbeau,3 Antonio Nanci31Faculty of Engineering, Department of Mechanical Engineering, 2Faculty of Science, Department of Physics, University of Ottawa, Ottawa, ON, 3Faculty of Dental Medicine, Université de Montréal, Montreal, QC, CanadaAbstract: Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS, nanobeam electron diffraction (NBED, and high-angle annular dark field (HAADF scanning transmission electron microscopy (STEM imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting.Keywords: mesoporosity, surface characterization, microorganisms, adhesion

  18. Multifunctional mesoporous silica nanocomposite nanoparticles for theranostic applications.

    Lee, Ji Eun; Lee, Nohyun; Kim, Taeho; Kim, Jaeyun; Hyeon, Taeghwan

    2011-10-18

    Clever combinations of different types of functional nanostructured materials will enable the development of multifunctional nanomedical platforms for multimodal imaging or simultaneous diagnosis and therapy. Mesoporous silica nanoparticles (MSNs) possess unique structural features such as their large surface areas, tunable nanometer-scale pore sizes, and well-defined surface properties. Therefore, they are ideal platforms for constructing multifunctional materials that incorporate a variety of functional nanostructured materials. In this Account, we discuss recent progress by our group and other researchers in the design and fabrication of multifunctional nanocomposite nanoparticles based on mesoporous silica nanostructures for applications to simultaneous diagnosis and therapy. Versatile mesoporous silica-based nanocomposite nanoparticles were fabricated using various methods. Here, we highlight two synthetic approaches: the encapsulation of functional nanoparticles within a mesoporous silica shell and the assembly of nanoparticles on the surface of silica nanostructures. Various nanoparticles were encapsulated in MSNs using surfactants as both phase transfer agents and pore-generating templates. Using MSNs as a scaffold, functional components such as magnetic nanoparticles and fluorescent dyes have been integrated within these systems to generate multifunctional nanocomposite systems that maintain their individual functional characteristics. For example, uniform mesoporous dye-doped silica nanoparticles immobilized with multiple magnetite nanocrystals on their surfaces have been fabricated for their use as a vehicle capable of simultaneous magnetic resonance (MR) and fluorescence imaging and drug delivery. The resulting nanoparticle-incorporated MSNs were then tested in mice with tumors. These in vivo experiments revealed that these multifunctional nanocomposite nanoparticles were delivered to the tumor sites via passive targeting. These nanocomposite nanoparticles served as successful multimodal imaging probes and also delivered anticancer drugs to the tumor site. With innumerable combinations of imaging modalities and drug delivery available within these vehicles, multifunctional nanocomposite nanoparticles provide new opportunities for clinical diagnostics and therapeutics. PMID:21848274

  19. Magnetic mesoporous materials for removal of environmental wastes

    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

    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.

  20. Synthesis of mesoporous zeolite single crystals with cheap porogens

    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.

  1. Mesoporous-silica films, fibers, and powders by evaporation

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

    2008-05-06

    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).

  2. Adsorption of L-phenylalanine onto mesoporous silica

    Mesoporous silica materials, such as SBA-3, SBA-15, SBA-16 and KIT-6 were synthesized using tetraethyl orthosilicate as the silica source and different surfactants as templates. The products were characterised by a number of techniques, including low-temperature nitrogen sorption, X-ray diffraction and transmission electron microscopy. Results of the studies confirmed the ordered mesoporous structures of all silica samples obtained. Adsorption of L-phenylalanine on various mesoporous adsorbents was studied from solutions with different pH (5.69.4). Maximum sorption capacity was observed at pH 5.6, which is close to the isoelectric point of L-phenylalanine (pI = 5.48). Above this pH value, the amount of adsorbed amino acid decreased. In the range of equilibrium concentration (pH 5.6), the adsorption capacities of ordered silica samples decreased in the following order: KIT-6 (420 ?mol g?1) > SBA-15 (389 ?mol g?1) > SBA-16 (357 ?mol g?1) > SBA-3 (219 ?mol g?1). The lowest sorption capacity towards L-phenylalanine was found for SBA-3 despite the fact that it showed the largest surface area, which can be explained assuming that part of the pores in SBA-3 can be inaccessible to L-phenylalanine molecules. Large pore size of KIT-6 and SBA-15 permitted the amino acid molecule to enter into the pores of these mesoporous molecular sieves. - Highlights: SBA-3, SBA-15, SBA-16, KIT-6 materials were prepared by hydrothermal method. Ordered mesoporous silicas are promising as adsorbents of L-phenylalanine. Adsorption of L-phenylalanine was studied from solutions with different pH. Sorption capacities decrease in the following order: KIT-6 > SBA-15 > SBA-16 > SBA-3. Large pore size of KIT-6 and SBA-15 permit the amino acid to enter into the pores

  3. Novel organic-inorganic hybrid mesoporous materials and nanocomposites

    Feng, Qiuwei

    Organic-inorganic hybrid mesoporous materials have been prepared successfully via the nonsurfactant templated sol-gel pathway using dibenzoyl-L-tartaric acid (DBTA) as the templating compound. Styrene and methyl methacrylate polymers have been incorporated into the mesoporous silica matrix on the molecular level. The synthetic conditions have been systematically studied and optimized. Titania based mesoporous materials have also been made using nonionic polyethylene glycol surfactant as the pore forming or structure-directing agent. In all of the above mesoporous materials, pore structures have been studied in detail by Transmission Electron Microscopy (TEM), X-ray diffraction and Brunauer-Emmett-Teller (BET) characterizations. The relationship between the template concentration and the pore parameters has been established. This nonsurfactant templated pathway possesses many advantages over the known surfactant approaches such as low cost, environment friendly and biocompatability. To overcome the drawback of nonsurfactant templated mesoporous materials that lack a well ordered pore structure, a flow induced synthesis has been attempted to orientate the sol-gel solution in order to obtain aligned pore structures. The versatility of this nonsurfactant templated pathway can even be extended to the making of organic-inorganic hybrid nanocomposite materials. On the basis of this approach, polymer-silica nanocomposite materials have been prepared using a polymerizable template. It is shown that the organic monomer such as hydroxyethyl methacrylate can act as a template in making nanoporous silica materials and then be further polymerized through a post synthesis technique. The properties and morphology of this new material have been studied by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Infrared Absorption Spectroscopy (FTIR). Electroactive organic-inorganic hybrid materials have also been synthesized via the sol-gel process. A coupling agent was used to covalently bond the organic and inorganic species. The morphology and conductivity of the products have been investigated.

  4. Adsorption of L-phenylalanine onto mesoporous silica

    Goscianska, Joanna; Olejnik, Anna; Pietrzak, Robert, E-mail: pietrob@amu.edu.pl

    2013-11-01

    Mesoporous silica materials, such as SBA-3, SBA-15, SBA-16 and KIT-6 were synthesized using tetraethyl orthosilicate as the silica source and different surfactants as templates. The products were characterised by a number of techniques, including low-temperature nitrogen sorption, X-ray diffraction and transmission electron microscopy. Results of the studies confirmed the ordered mesoporous structures of all silica samples obtained. Adsorption of L-phenylalanine on various mesoporous adsorbents was studied from solutions with different pH (5.69.4). Maximum sorption capacity was observed at pH 5.6, which is close to the isoelectric point of L-phenylalanine (pI = 5.48). Above this pH value, the amount of adsorbed amino acid decreased. In the range of equilibrium concentration (pH 5.6), the adsorption capacities of ordered silica samples decreased in the following order: KIT-6 (420 ?mol g{sup ?1}) > SBA-15 (389 ?mol g{sup ?1}) > SBA-16 (357 ?mol g{sup ?1}) > SBA-3 (219 ?mol g{sup ?1}). The lowest sorption capacity towards L-phenylalanine was found for SBA-3 despite the fact that it showed the largest surface area, which can be explained assuming that part of the pores in SBA-3 can be inaccessible to L-phenylalanine molecules. Large pore size of KIT-6 and SBA-15 permitted the amino acid molecule to enter into the pores of these mesoporous molecular sieves. - Highlights: SBA-3, SBA-15, SBA-16, KIT-6 materials were prepared by hydrothermal method. Ordered mesoporous silicas are promising as adsorbents of L-phenylalanine. Adsorption of L-phenylalanine was studied from solutions with different pH. Sorption capacities decrease in the following order: KIT-6 > SBA-15 > SBA-16 > SBA-3. Large pore size of KIT-6 and SBA-15 permit the amino acid to enter into the pores.

  5. Ponderosa pine resin defenses and growth: metrics matter.

    Hood, Sharon; Sala, Anna

    2015-11-01

    Bark beetles (Coleoptera: Curculionidae, Scolytinae) cause widespread tree mortality in coniferous forests worldwide. Constitutive and induced host defenses are important factors in an individual tree's ability to survive an attack and in bottom-up regulation of bark beetle population dynamics, yet quantifying defense levels is often difficult. For example, in Pinus spp., resin flow is important for resistance to bark beetles but is extremely variable among individuals and within a season. While resin is produced and stored in resin ducts, the specific resin duct metrics that best correlate with resin flow remain unclear. The ability and timing of some pine species to produce induced resin is also not well understood. We investigated (i) the relationships between ponderosa pine (Pinus ponderosa Lawson & C. Lawson) resin flow and axial resin duct characteristics, tree growth and physiological variables, and (ii) if mechanical wounding induces ponderosa pine resin flow and resin ducts in the absence of bark beetles. Resin flow increased later in the growing season under moderate water stress and was highest in faster growing trees. The best predictors of resin flow were nonstandardized measures of resin ducts, resin duct size and total resin duct area, both of which increased with tree growth. However, while faster growing trees tended to produce more resin, models of resin flow using only tree growth were not statistically significant. Further, the standardized measures of resin ducts, density and duct area relative to xylem area, decreased with tree growth rate, indicating that slower growing trees invested more in resin duct defenses per unit area of radial growth, despite a tendency to produce less resin overall. We also found that mechanical wounding induced ponderosa pine defenses, but this response was slow. Resin flow increased after 28 days, and resin duct production did not increase until the following year. These slow induced responses may allow unsuccessfully attacked or wounded trees to resist future bark beetle attacks. Forest management that encourages healthy, vigorously growing trees will also favor larger resin ducts, thereby conferring increased constitutive resistance to bark beetle attacks. PMID:26433021

  6. Adsorption of plant phenols by polystyrene resins

    Akiyoshi Fukushima

    2014-02-01

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

  7. Immobilisation of ion exchange resins in cement

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

  8. Pneumatic moulding sand reclamation in the linear regenerator system

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

    2007-01-01

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

  9. Immobilization of radioactive ion exchange resins in glass. Part I: Pretreatment of the resins

    Full Text: The ion exchange resins are used to retain the radionuclides that contaminate the water in primary and secondary circuits and storage pools of the Argentine nuclear reactors. Once used, this resins are an intermediate level waste. Due to the generated volume of resins during the reactor life, it is necessary to have a proper method for management and final disposal of these wastes. Up to now in National Atomic Energy Commission (CNEA), the most studied process is cementation. However, this method increases the waste volume and the final product has low compression hardness. The immobilization in glass of these wastes is attractive because of the volume reduction that could be attained and because of the well known durability of glass. In this work we prepared a mixed bed of resins, similar to those used in Argentina nuclear reactors. We use cesium as a simulant for the active elements present in the resins. Absorption of lithium and cesium was controlled by conductivity and/or ph measurements. The so charged resins were thermally decomposed. This process was studied by Dta/T G experiments. Some potentially problematic effects were founded (foam formation, particle explosion), regarding the possibility of immobilisation of the resins in glass by sintering. Finally, the calcination products were analyzed by Sem and X-ray diffraction. This analysis showed that lithium and cesium remain as sulfates. For this reason we decided to use those chemical compounds as simulant s of the calcination products in the following sintering experiments

  10. Ordered mesoporous carbon film as an effective solid-phase microextraction coating for determination of benzene series from aqueous media

    Jiang, Hui [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Geography Science, Nantong University, Nantong 226001 (China); Li, Jiansheng, E-mail: lijsh@mail.njust.edu.cn [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Jiang, Mingyue; Lu, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Wang, Lianjun, E-mail: wanglj@mail.njust.edu.cn [Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2015-08-12

    The present work reports preparation of ordered mesoporous carbon (OMC) film supported on a graphite fiber as a new type of solid-phase microextraction (SPME) fiber for determination of benzene series from aqueous media. The strategy for the supported OMC film preparation was combined dip-coating technology with solvent evaporation-induced self-assembly (EISA) approach. A graphite fiber was immersed in an ethanol solution containing phenolic resin and Pluronic triblock copolymer. Upon solvent evaporation and subsequent pyrolysis under 700 °C, the phenolic resin and the surfactant self-assembled on the surface of the graphite fiber to form smooth OMC film. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen isothermal adsorption results indicate that the resultant OMC film possesses well-ordered two dimensional hexagonal mesostructure with pore diameters of 4.5 nm and BET surfaces of 630 m{sup 2}/g. Scanning electron microscopy (SEM) studies show the supported OMC film with thickness at 8.5 μm is continuous and defect-free. The SPME efficiency of the OMC fiber was evaluated by analysis of five benzene series (benzene, toluene, ethylbenzene, p-xylene and m-xylene) from water samples by gas chromatography-flame ionization detection (GC-FID). The analysis results indicate that the prepared OMC fiber has wide linear ranges (0.5–500 μg/L), low detection limits (0.01–0.05 μg/L) and good repeatabilities (4.0–5.8% for one fiber, 2.9–8.7% for fiber-to-fiber). Compared with commercial counterparts, the OMC fiber exhibits improved extraction efficiency for benzene series and PAHs. - Highlights: • Ordered mesoporous carbon film supported on graphite fiber was first reported as solid-phase microextraction coating. • The strategy for the film preparation was combined dip-coating technology with evaporation-induced self-assembly approach. • The obtained fiber showed enhanced thermal stability and organic solvents resistance. • The fiber outperformed the commercial counterpart on extraction efficiency toward benzene series.

  11. Ordered mesoporous carbon film as an effective solid-phase microextraction coating for determination of benzene series from aqueous media

    The present work reports preparation of ordered mesoporous carbon (OMC) film supported on a graphite fiber as a new type of solid-phase microextraction (SPME) fiber for determination of benzene series from aqueous media. The strategy for the supported OMC film preparation was combined dip-coating technology with solvent evaporation-induced self-assembly (EISA) approach. A graphite fiber was immersed in an ethanol solution containing phenolic resin and Pluronic triblock copolymer. Upon solvent evaporation and subsequent pyrolysis under 700 °C, the phenolic resin and the surfactant self-assembled on the surface of the graphite fiber to form smooth OMC film. X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen isothermal adsorption results indicate that the resultant OMC film possesses well-ordered two dimensional hexagonal mesostructure with pore diameters of 4.5 nm and BET surfaces of 630 m2/g. Scanning electron microscopy (SEM) studies show the supported OMC film with thickness at 8.5 μm is continuous and defect-free. The SPME efficiency of the OMC fiber was evaluated by analysis of five benzene series (benzene, toluene, ethylbenzene, p-xylene and m-xylene) from water samples by gas chromatography-flame ionization detection (GC-FID). The analysis results indicate that the prepared OMC fiber has wide linear ranges (0.5–500 μg/L), low detection limits (0.01–0.05 μg/L) and good repeatabilities (4.0–5.8% for one fiber, 2.9–8.7% for fiber-to-fiber). Compared with commercial counterparts, the OMC fiber exhibits improved extraction efficiency for benzene series and PAHs. - Highlights: • Ordered mesoporous carbon film supported on graphite fiber was first reported as solid-phase microextraction coating. • The strategy for the film preparation was combined dip-coating technology with evaporation-induced self-assembly approach. • The obtained fiber showed enhanced thermal stability and organic solvents resistance. • The fiber outperformed the commercial counterpart on extraction efficiency toward benzene series

  12. NMR spectroscopy applied to the characterization of epoxy resins

    A methodology for fundamental characterization of epoxi resins (DGEBA) had been developed using 1H-NMR spectroscopy. The results were compared with one standard procedure. This methodology is only applicable to resins of low molecular weight. (author)

  13. Petroleum Resins: Separation, Character, and Role in Petroleum

    Andersen, Simon Ivar; Speight, James

    In petroleum science, the term resin generally implies material that has been eluted from various solid adsorbents, whereas the term maltenes (or petrolenes) indicates a mixture of the resins and oils obtained as filtrates from the asphaltene precipitation. Thus, after the asphaltenes are...... precipitated, adsorbents are added to the n-pentane solutions of the resins and oils, by which process the resins are adsorbed and subsequently recovered by the use of a more polar solvent, and the oils remain in solution. The resin fraction plays an important role in the stability of petroleum and prevents...... of the fact that the resin fraction is extremely important to the stability of petroleum, there is surprisingly little work reported on the characteristics of the resins. This article summarizes the work that has been carried out in determining the character and properties of the resin constituents...

  14. Vitrification of spent ion exchange resin from Korean NPPs

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

  15. Method of oxidative decomposition of radioactive ion exchange resin

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

  16. Treatment of liquid wastes using composite resins

    Composite ion exchange resins were prepared by coating copper ferrocyanide and hydrous manganese oxide powders on polyurethane foam. The binder used was polyvinyl acetate in alcohol/acetone medium. Studies were conducted in pilot scale using 50 L ion exchange column and treated category III radioactive liquid wastes. About 2000 to 2400 bed volumes of liquid wastes containing radioactive 137Cs and 90Sr were treated. Digestion of the resins was carried out in a 25 L column using alkaline KMnO4. The digested liquid was fixed in cement matrix and the matrices were characterized with respect to compressive strength, biological and leach resistance. (author)

  17. Radiation resistance of synthetic resin cements

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

  18. Treatment of Methaqualone overdose with resin hemoperfusion.

    Baggish, D.; S. Gray; Jatlow, P; Bia, M. J.

    1981-01-01

    We recently utilized the technique of resin hemoperfusion (employing an Amberlite XAD-4 resin cartridge) to remove drug from a patient i deep coma after an estimated ingestion of greater than 4.5 grams of methaqualone. At plasma flow rates of 204 ml/min, the mean value for plasma clearance of methaqualone was 179 ml/min. The amount of methaqualone recovered from the cartridge at the end of the 10-hour procedure was 1,565 mg measured by gas chromatography. The patient became responsive to deep...

  19. New phosphorus-containing bisimide resins

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

    1984-01-01

    Phosphorus-based flame retardants have been effectively used in a wide variety of polymeric materials. Such additives, however, may either influence the decomposition reaction in polymers or lack durability due to a tendency to be leached out by solvents. Attention is given to the synthesis, characterization, thermal stability and degradation mechanisms of bisimide resins, and an evaluation is conducted of the flammability and mechanical properties of graphite cloth-reinforced laminates fabricated from one of the six phosphorus-containing bisimide resins considered.

  20. Multitasking mesoporous nanomaterials for biorefinery applications

    Kandel, Kapil [Ames Laboratory

    2013-05-02

    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.

  1. Multitasking mesoporous nanomaterials for biorefinery applications

    Kandel, Kapil

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

  2. Evaluation of marginal leakage between a flowable composite resin and resin-modified glass ionomer cements

    lvaro VOLPATO

    2005-11-01

    Full Text Available The aim of the present study was to evaluate, in vitro, the leakage between a flowable composite resin (Fill Magic Flow and resin-modified glass ionomer cements (Vitremer. Forty extracted human premolars were selected for this study. The teeth were randomly assigned into two groups. Class cavities were prepared with margin extended apically. All teeth were subjected to thermocycling with 250 cycles. Afterwards, the teeth were submitted to a basic fuccina 0,5% to be analyzed to the infiltration degree throughout the walls of the preparation. The results showed that resin-modified glass ionomer cements present the worst results (p < 0,05.

  3. Direct coating of mesoporous titania on CTAB-capped gold nanorods

    Zhao, Junwei; Xu, Pengyu; Li, Yue; Wu, Jian; Xue, Junfei; Zhu, Qiannan; Lu, Xuxing; Ni, Weihai

    2016-03-01

    We demonstrate a CTAB-templated approach towards direct coating of mesoporous titania on gold nanorods in aqueous solutions. The formation of the mesoporous shell is found to be closely correlated with CTAB concentration and the amount of the titania precursor. This approach can be readily extended to form mesoporous titania shells on other CTAB-capped nanoparticles.We demonstrate a CTAB-templated approach towards direct coating of mesoporous titania on gold nanorods in aqueous solutions. The formation of the mesoporous shell is found to be closely correlated with CTAB concentration and the amount of the titania precursor. This approach can be readily extended to form mesoporous titania shells on other CTAB-capped nanoparticles. Electronic supplementary information (ESI) available: Experimental details including chemicals, sample preparation, and characterization methods. UV-Vis extinction spectra, SEM images, and TEM images of AuNR@mTiO2 nanostructures. See DOI: 10.1039/c5nr05692f

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

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

    2013-05-15

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

  5. Performances and improvement of copper-hydrazine complexation deoxidising resin

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

  6. Comparative Mechanical Properties of Bulk-Fill Resins

    Atabek Didem; Yal?n Gzde; zta? Nurhan

    2014-01-01

    Aim: The aim of this study was to compare the flexural and compressive strengths of a new sonicactivated bulk-fill system (Sonicfill) with other bulk-fill resins and a universal posterior composite resin. Materials and Methods: A low-stress flowable base resin material (SDR), a bulk-fill composite resin (Tetric Evo Ceram), a universal posterior composite (GC G-aenial), and the Sonicfill system were compared. The specimens were prepared for each group following ISO St...

  7. Synthesis of highly carboxylate acrylic resins for leather impregnation

    Ollé Otero, Lluís; Solé, M.M.; Shendrik, Alexander; Labastida, L.; Bacardit Dalmases, Anna

    2012-01-01

    This work describes the synthesis of new leather finishing acrylic resins. Four resins ware synthesized varying the concentration of ethyl acrylate, and metracrylic acid. Sodium lauryl sulphate was used as emulsifying system. By means of an experimental design, an optimal resin for leather impregnation was defined. The results obtained indicated that the variation of the monomer concentration influences the resin properties, the hardness of the film, and the penetration into the leather. Most...

  8. Evaluation of cure shrinkage measurement techniques for thermosetting resins

    Shah, Darshil U.; Peter J. Schubel

    2010-01-01

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

  9. Synthesis and Thermal Degradation Studies of Melamine Formaldehyde Resins

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

    2014-01-01

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

  10. A new phosphorous based resin for the extraction of uranium

    A modified macroporous bifunctional phosphinic acid resin was synthesised for the extraction of uranium from nitric acid medium by attempting to replace the P-H group by P-Et groups. The extraction of uranium from nitric acid medium by this resin has been studied. From the extraction studies it was observed that the extraction behaviour of the resin obtained by the modified synthetic route is comparable to that of the MPBPA resin. (author). 3 refs., 1 fig., 1 tab

  11. Interacting Blends of Novel Unsaturated Polyester Amide Resin with Styrene

    Patel, Hasmukh S.; Kumar K. Panchal

    2004-01-01

    Novel unsaturated poly (ester-amide) resins (UPEAs) were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenolA (DGEBA) and unsaturated aliphatic bisamic acids using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, Styrene (STY.) to produce a homogeneous resin syrup. The curing of these UPEAs-STY. resin blends was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored by using a differential scanning calorimeter ...

  12. Studies on ion-exchange resin complex of Dextromethorphan Hydrobromide

    MALLADI, MADHUSUDHAN; JUKANTI, RAJU; NAIR, RASHMI; Wagh, Sanjay; Padakanti, Harishanker

    2010-01-01

    The objective of present work was to assess ion exchange resins for taste masking of Dextromethorphan Hydrobromide (DM) - a highly bitter drug. A strong cationic exchange resin (Amberlite IRP-69) and weak cationic exchange resin (Amberlite IRP-64) were evaluated. Based on drug loading efficiency, Amberlite IRP-69 was selected for further evaluation. The effect of different methods of drug loading, drug: resin ratios and particle size on drug complexation was evaluated. The formation of a r...

  13. Synthesis of porous carbon/silica nanostructured microfiber with ultrahigh surface area

    Carbon/silica-nanostructured microfibers were synthesized via electrospinning method using phenol-formaldehyde resin and tetraethyl orthosilicate as carbon and silica precursor with triblock copolymer Pluronic P123 as soft template. The prepared samples show uniform microfiber structure with ∼1 μm in diameter and dozens of microns in length. Additionally, the mesopores in the material is about 2–6 nm. When the silica component was removed by HF, the porous carbon microfibers (PCMFs) were obtained. In addition, after the carbon/silica composites were calcined in air, the porous silica microfibers (PSiMFs) were obtained, revealing the converse porous nanostructure as PCMFs. It is a simple way to prepare PCMFs and PSiMFs with silica and carbon as the template to each other. Additionally, PCMFs possess an ultrahigh specific surface area (2,092 m2 g−1) and large pore volume. The electrochemical performance of the prepared PCMF material was investigated in 6.0 M KOH electrolyte. The PCMF electrode exhibits a high specific capacitance (252 F g−1 at 0.5 A g−1). Then, superior cycling stability (97 % retention after 4,000 cycles) mainly is due to its unique nanostructure

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

    Fleming, Garry J P

    2012-07-01

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

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

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

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

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

    2012-08-01

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

  17. Highly mesoporous metal–organic framework assembled in a switchable solvent

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

    2014-01-01

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

  18. Catalytic Behaviour of Mesoporous Cobalt-Aluminum Oxides for CO Oxidation

    Ankur Bordoloi; Miguel Sanchez; Heshmat Noei; Stefan Kaluza; Dennis Gromann; Yuemin Wang; Wolfgang Grnert; Martin Muhler

    2014-01-01

    Ordered mesoporous materials are promising catalyst supports due to their uniform pore size distribution, high specific surface area and pore volume, tunable pore sizes, and long-range ordering of the pore packing. The evaporation-induced self-assembly (EISA) process was applied to synthesize mesoporous mixed oxides, which consist of cobalt ions highly dispersed in an alumina matrix. The characterization of the mesoporous mixed cobalt-aluminum oxides with cobalt loadings in the range from 5 t...

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

    H. Kimura

    2011-12-01

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

  20. Color change of composite resins subjected to accelerated artificial aging

    Denise Cremonezzi Tornavoi

    2013-01-01

    Conclusions: All composite resins presented unacceptable color changes after 382 h of aging and different composite resins with same hue, presented different colors before being subjected to the aging process (B2 and C2 and after (B2. It was also observed color difference within a group of the same composite resin and same hue.

  1. Development of radiation-curable resin based on natural rubber

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

  2. 40 CFR 721.2673 - Aromatic epoxide resin (generic).

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic epoxide resin (generic). 721... Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic epoxide resin (PMN...

  3. 40 CFR 721.9499 - Modified silicone resin.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified silicone resin. 721.9499... Substances § 721.9499 Modified silicone resin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a modified silicone resin (PMN P-96-1649)...

  4. Solid-State Microwave Synthesis of Melamine-Formaldehyde Resin

    Subhash Bajia; Rashmi Sharma; Birbal Bajia

    2009-01-01

    An efficient synthesis of melamine-formaldehyde resin has been achieved using conventional as well as microwave irradiations (without and with solid support) in different molar ratio. Resin samples were tested for their chemical as well as physical properties. The structure of all the resin has been supported by their spectral data

  5. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Epoxy resin containing phosphorus... Specific Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance... epoxy resin containing phosphorus (PMN P-00-912) is subject to reporting under this section for...

  6. 40 CFR 721.4380 - Modified hydrocarbon resin.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified hydrocarbon resin. 721.4380... Substances § 721.4380 Modified hydrocarbon resin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a modified hydrocarbon resin (P-91-1418)...

  7. Electron sensitive resin and fabrication process of this one

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

  8. 21 CFR 872.3300 - Hydrophilic resin coating for dentures.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydrophilic resin coating for dentures. 872.3300... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3300 Hydrophilic resin coating for dentures. (a) Identification. A hydrophilic resin coating for dentures is a device that consists of a...

  9. 21 CFR 872.3310 - Coating material for resin fillings.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  10. Occupational asthma due to unheated polyvinylchloride resin dust.

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

    1989-01-01

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

  11. Magnetic nanocomposite spinel and FeCo core-shell and mesoporous systems

    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.

  12. Enhanced electrochemical performance of mesoporous carbon with increased pore size and decreased pore wall thickness

    As anode materials for Lithium-ion batteries, mesoporous materials such as mesoporous carbon can deliver high rate and stability on cycling owing to their unique mesostructure. Especially, the critical dimensions of pore size and wall thickness may highly influence the rate of intercalation. Herein a novel mesoporous carbon with increased pore size and decreased pore wall thickness is prepared by sacrificing Sn nanoparticles embedded in the carbon wall of CMK-3, and exhibits superior cycle and rate performances than normal CMK-3. Thus the structural parameters of mesoporous carbon are very important to its electrochemical performance and should be optimally controllable

  13. Synthesis and characterization of V- and Ti-substituted mesoporous materials

    Mesoporous Ti- and V-containing materials have been synthesized with different degree of loadings via incorporation of titanium (IV) isopropoxide and vanadium (V) oxide in the initial precursor gels. These mesoporous materials were compared with pure siliceous MCM-41 synthesized at the same conditions without adding metal precursors. The UV-vis and Raman measurements confirmed that the vanadium and titanium were mainly tetrahedrally coordinated and their coordination is not changing after calcinations. At high amount of Ti and V, the regular mesoporous long-range order decreases, however, the V- and Ti-mesoporous samples do not collapse upon calcinations

  14. Single-Crystal Mesoporous ZnO Thin Films Composed of Nanowalls

    Wang, Xudong

    2009-02-05

    This paper presents a controlled, large scale fabrication of mesoporous ZnO thin films. The entire ZnO mesoporous film is one piece of a single crystal, while high porosity made of nanowalls is present. The growth mechanism was proposed in comparison with the growth of ZnO nanowires. The ZnO mesoporous film was successfully applied as a gas sensor. The fabrication and growth analysis of the mesoporous ZnO thin film gi ve general guidance for the controlled growth of nanostructures. It also pro vides a unique structure with a superhigh surface-to-volume ratio for surface-related applications. © 2009 American Chemical Society.

  15. Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications

    Seong Huh

    2004-12-19

    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.

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

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

    2007-01-01

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

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

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

    2013-09-15

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

  18. 21 CFR 177.1500 - Nylon resins.

    2010-04-01

    ... approximately the size of a 1/8-inch cube in at least 25 milliliters of 4.2 normal hydrochloric acid. (4... CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and... manufactured by the condensation of hexamethylene-diamine and adipic acid. (2) Nylon 610 resins...

  19. Triterpenes from the resin of Boswellia neglecta

    Aman Dekebo

    2002-06-01

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

  20. Vapour absorption in melamine-formaldehyde resin

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

  1. Microbial treatment of ion exchange resins

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

  2. 21 CFR 177.2440 - Polyethersulfone resins.

    2010-04-01

    ...) resins (CAS Reg. No. 25667-42-9), which have a minimum number average molecular weight of 16,000. (2) 1,1... percent) (CAS Reg. No. 88285-91-0), which have a minimum number average molecular weight of 26,000. (3) In paragraphs (a)(1) and (a)(2) of this section, the minimum number average molecular weight is determined...

  3. Microbial treatment of ion exchange resins

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

    2001-07-01

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

  4. Crack propagation directions in unfilled resins.

    Baran, G; Sadeghipour, K; Jayaraman, S; Silage, D; Paul, D; Boberick, K

    1998-11-01

    Posterior composite restorative materials undergo accelerated wear in the occlusal contact area, primarily through a fatigue mechanism. To facilitate the timely development of new and improved materials, a predictive wear model is desirable. The objective of this study was to develop a finite element model enabling investigators to predict crack propagation directions in resins used as the matrix material in composites, and to verify these predictions by observing cracks formed during the pin-on-disc wear of a 60:40 BISGMA:TEGDMA resin and an EBPADMA resin. Laser confocal scanning microscopy was used to measure crack locations. Finite element studies were done by means of ABAQUS software, modeling a cylinder sliding on a material with pre-existing surface-breaking cracks. Variables included modulus, cylinder/material friction coefficient, crack face friction, and yield behavior. Experimental results were surprising, since most crack directions were opposite previously published observations. The majority of surface cracks, though initially orthogonal to the surface, changed direction to run 20 to 30 degrees from the horizontal in the direction of indenter movement. Finite element modeling established the importance of subsurface shear stresses, since calculations provided evidence that cracks propagate in the direction of maximum K(II)(theta), in the same direction as the motion of the indenter, and at an angle of approximately 20 degrees. These findings provide the foundation for a predictive model of sliding wear in unfilled glassy resins. PMID:9823724

  5. Process for preparing cured polyester resins

    A novel process for preparing cured unsaturated polyester resins is provided. The process comprises incorporating an unsaturated polyester resin with a vinyl monomer having an epoxy group, shaping the resulting mixture into a desired form (coatings, molded articles or impregnations), isolating it from the air by covering it with a polyester film (for example, a Mylar film) the surface of which has preliminarily been activated by suitable means such as corona discharge, flame treating plasma jet, gamma rays or chemical grafting agents, and then irradiating the unsaturated polyester with ionizing radiations. The process is advantageous in its simplicity of procedure and high weather and chemical resistance of the cured product. In one example, an unsaturated polyester resin was mixed with 0.1% by wt. of glycidyl methacrylate and coated a decorative laminate. Next, the coated surface was covered with a polyester film the surface of which had preliminarily been activated by means of corona discharge. The resin was irradiated with electron beams (500 keV, 10 Mrad) and then heated to 1000C for 30 min. Thus, a decorative board coated with a cured polyester layer in which the unsaturated polyester and the polyester film were unified was obtained. It was highly resistant to chloroform, acetone and alkali. (Kaichi, S.)

  6. Evaluation of resins for use in brachytherapy

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

    2011-07-01

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

  7. Pharmaceutical Applications of Ion-Exchange Resins

    Elder, David

    2005-01-01

    The historical uses of ion-exchanged resins and a summary of the basic chemical principles involved in the ion-exchanged process are discussed. Specific applications of ion-exchange are provided that include drug stabilization, pharmaceutical excipients, taste-masking agents, oral sustained-release products, topical products for local application

  8. ION EXCHANGE RESINS AND THEIR APPLICATIONS

    Vijay Sharma

    2014-07-01

    Full Text Available Ion exchange resins are cross-linked water insoluble polymer-carrying, ionisable functional groups. IER have received considerable attention from pharmaceutical scientists because of their versatile properties as drug delivery vehicles. Research over the last few years has revealed that IER are equally suitable for drug delivery technologies, including controlled release, transdermal, nasal, topical and taste masking. The major drawback of sustained release of extended release or extended release is dose dumping, resulting in increased risk of toxicity. The use of IER has occupied an important place in the development of controlled- or sustained-release systems because of their better drug-retaining properties and prevention of dose dumping. Synthetic ion exchange resins have been used in pharmacy and medicine for taste masking or controlled release of drug. Drug resin complexation converts drug to amorphous form leading to improved drug dissolution. Several studies have reported the use of IER for drug delivery at the desired site of action. Sulfonated and carboxylic resins with a polystyrene backbone are most widely used in clinical medicine.

  9. 21 CFR 177.1560 - Polyarylsulfone resins.

    2010-04-01

    ... polymer units. The copolymers have a minimum reduced viscosity of 0.40 deciliter per gram in 1-methyl-2-pyrrolidinone in accordance with ASTM method D2857-70 (Reapproved 1977), “Standard Test Method for Dilute... limitations. The finished polyarylsulfone resin when extracted for 2 hours with the following solvents at...

  10. Effect of Resin Coating and Chlorhexidine on Microleakage of Two Resin Cements after Storage

    F. Shafie; Doozandeh, M.; Alavi, A.

    2010-01-01

    Objective: Evaluating the effect of resin coating and chlorhexidine on microleakage of two resin cements after water storage.Materials and Methods: Standardized class V cavities were prepared on facial and lingual surfaces of one hundred twenty intact human molars with gingival margins placed 1mm below the cemento-enamel junction. Indirect composite inlays were fabricated and thespecimens were randomly assigned into 6 groups. In Groups 1 to 4, inlays were cemented with Panavia F2.0 cement. G1...

  11. Decomposition of Rare Earth Loaded Resin Particles

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

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

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

    2013-07-01

    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.

  13. ANALYSIS OF VENTING OF A RESIN SLURRY

    Laurinat, J.; Hensel, S.

    2012-03-27

    A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, rupture disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the rupture disk opened, though at a slower rate than prior to the rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture upon rupture of the disk. It is postulated that the maximum pressure at the end of this expansion is limited by energy minimization to approximately 1.5 times the rupture disk burst pressure. The magnitude of this pressure increase is consistent with the measured pressure transients. The results of this analysis demonstrate the need to allow for a margin between the design pressure and the rupture disk burst pressure in similar applications.

  14. Ion selectivity of the resins which were saturated with amines

    In PSR on the Kori 3,4 NPPs, the SGBD demineralizers are producing the low level spent resins because the pH control agents, amines are consumed the ion exchange resin capacity. Especially, after exchanging pH control agent to ETA from amonia, the volume of low active resin waste has been increased about 70%. So, the experiments were performed to find the change the end point of exhausting resin. The first important result is a newly ion selectivity order that are H 3 + + 4+ + + and second result is that the Na leakage is decreased in proportion to highly crossed resins at the outlet of ion exchangers

  15. Method for curing alkyd resin compositions by applying ionizing radiation

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

  16. Removal of phenol from saline water by polyamine chelating resin.

    Yamada, Arisa; Matsui, Akihiro; Tsuji, Hideyuki

    2013-01-01

    Removal of phenol from saline water was carried out with chelating resin. A polyamine chelating resin, Diaion CR-20, removed phenol compounds selectively from industrial wastewater containing 2% salt. From saline water containing 20 mg/L phenol, 70% of the phenol was removed. After treatment, phenol was eluted from the resin by aqueous NaOH, and the resin could also be regenerated by heating in air. Diaion CR-20 adsorbed phenol even in the presence of FeCl3, indicating that treatment with this resin of wastewater containing metal can remove phenol and metal cations in a single step. PMID:24185065

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

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

    2014-06-01

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

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

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

    2014-06-01

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

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

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

  20. Guest diffusion in interpenetrating networks of micro- and mesopores.

    Furtado, Filipe; Galvosas, Petrik; Gonçalves, Maraisa; Kopinke, Frank-Dieter; Naumov, Sergej; Rodríguez-Reinoso, Francisco; Roland, Ulf; Valiullin, Rustem; Kärger, Jörg

    2011-03-01

    Pulsed field gradient NMR is applied for monitoring the diffusion properties of guest molecules in hierarchical pore systems after pressure variation in the external atmosphere. Following previous studies with purely mesoporous solids, also in the material containing both micro- and mesopores (activated carbon MA2), the diffusivity of the guest molecules (cyclohexane) is found to be most decisively determined by the sample "history": at a given external pressure, diffusivities are always found to be larger if they are measured after pressure decrease (i.e., on the "desorption" branch) rather than after pressure increase (adsorption branch). Simple model consideration reproduces the order of magnitude of the measured diffusivities as well as the tendencies in their relation to each other and their concentration dependence. PMID:21299204

  1. Novel nanofluids based on mesoporous silica for enhanced heat transfer

    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.

  2. Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy

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

    2014-11-01

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

  3. Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy

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

  4. Natural dye -sensitized mesoporous ZnO solar cell

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

    2011-02-01

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

  5. Preparation of mesoporous silica films SBA-15 over different substrates

    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)

  6. Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction

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

    2012-08-01

    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.

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

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

    2011-07-01

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

  8. Extreme Light Management in Mesoporous Wood Cellulose Paper for Optoelectronics.

    Zhu, Hongli; Fang, Zhiqiang; Wang, Zhu; Dai, Jiaqi; Yao, Yonggang; Shen, Fei; Preston, Colin; Wu, Wenxin; Peng, Peng; Jang, Nathaniel; Yu, Qingkai; Yu, Zongfu; Hu, Liangbing

    2016-01-26

    Wood fibers possess natural unique hierarchical and mesoporous structures that enable a variety of new applications beyond their traditional use. We dramatically modulate the propagation of light through random network of wood fibers. A highly transparent and clear paper with transmittance >90% and haze 90% and haze >90% is also achieved. A thorough investigation of the relation between the mesoporous structure and the optical properties in transparent paper was conducted, including full-spectrum optical simulations. We demonstrate commercially competitive multitouch touch screen with clear paper as a replacement for plastic substrates, which shows excellent process compatibility and comparable device performance for commercial applications. Transparent cellulose paper with tunable optical properties is an emerging photonic material that will realize a range of much improved flexible electronics, photonics, and optoelectronics. PMID:26673796

  9. Designing advanced functional periodic mesoporous organosilicas for biomedical applications

    Dolores Esquivel

    2014-03-01

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

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

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

    2015-04-01

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

  11. Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy

    Imalka Munaweera

    2014-11-01

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

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

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

    2012-08-15

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

  13. Enhancement of two-photon absorption in anisotropic mesoporous silicon

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

  14. Voltammetric response of ferrocene-grafted mesoporous silica

    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

  15. Mesoporous Silica Nanoparticles and Films for Cargo Delivery

    Guardado Alvarez, Tania Maria

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

  16. Alendronate functionalized mesoporous hydroxyapatite nanoparticles for drug delivery

    Highlights: ► The synthesized mesoporous hydroxyapatite has nanostructure and bioactivity. ► The materials have high surface area and amino group. ► The materials show higher drug loading and slower release rate than pure HAP. - Abstract: Mesoporous nanosized hydroxyapatite (HAP) functionalized by alendronate (ALN) was synthesized using cationic surfactant CTAB as template. The structural, morphological and textural properties were fully characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and N2 adsorption/desorption. Then the obtained materials were performed as drug delivery carriers using ibuprofen (IBU) as a model drug to investigate their drug storage/release properties in simulated body fluid (SBF). The materials showed relatively slower release rate compared with HAP due to the ionic interaction between -NH3+ on the matrix and -COO−belongs to IBU. The system provides a new concept for improving the drug loading or slowing down the release rate

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

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

  18. Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis

    Jin, Zhao

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

  19. Synthesis and Characterizations of Melamine-Based Epoxy Resins

    Raffaele Cioffi

    2013-09-01

    Full Text Available A new, easy and cost-effective synthetic procedure for the preparation of thermosetting melamine-based epoxy resins is reported. By this innovative synthetic method, different kinds of resins can be obtained just by mixing the reagents in the presence of a catalyst without solvent and with mild curing conditions. Two types of resins were synthesized using melamine and a glycidyl derivative (resins I or by adding a silane derivative (resin II. The resins were characterized by means of chemical-physical and thermal techniques. Experimental results show that all the prepared resins have a good thermal stability, but differ for their mechanical properties: resin I exhibits remarkable stiffness with a storage modulus value up to 830 MPa at room temperature, while lower storage moduli were found for resin II, indicating that the presence of silane groups could enhance the flexibility of these materials. The resins show a pot life higher than 30 min, which makes these resins good candidates for practical applications. The functionalization with silane terminations can be exploited in the formulation of hybrid organic-inorganic composite materials.

  20. Monolithic Gyroidal Mesoporous Mixed Titanium–Niobium Nitrides

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

    2014-01-01

    Mesoporous transition metal nitrides are interesting materials for energy conversion and storage applications due to their conductivity and durability. We present ordered mixed titanium–niobium (8:2, 1:1) nitrides with gyroidal network structures synthesized from triblock terpolymer structure-directed mixed oxides. The materials retain both macroscopic integrity and mesoscale ordering despite heat treatment up to 600 °C, without a rigid carbon framework as a support. Furthermore, the gyroidal...

  1. Interfacial slippage of helium films on 2D mesoporous hectorite

    Hieda, M.; Suzuki, M.; Yano1, H.; Wada, N.; Torii, K.

    2000-07-01

    We measured by 10 MHz ultrasound the interfacial slippage of 3He and 4He films on a vibrating substrate of a two-dimensional mesoporous hectorite. It was found that the interfacial slippage shows a qualitative difference between the monolayer and bilayer films, irrespective of the adsorbate. The monolayer films slipped and underwent decoupling from this substrate at low temperatures. In the bilayer films, in contrast, the first layer of the films was locked on the substrate by the second layer promotion.

  2. Ordered mesoporous silica carrier system applied in nanobiothecnology

    Andreza de Sousa; Edésia Martins Barros de Sousa

    2005-01-01

    Ordered mesoporous materials like SBA15 possess a network of channels and pores of well-defined size in the nanoscale range (2-50 nm). This particular pore architecture makes them suitable candidates for hosting and delivery under appropriate conditions of a variety of molecules of pharmaceutical interest, including radiopharmaceuticals. The characteristics of SBA-15 prepared in different temperatures and the behavior of this system regarding microencapsulation of a model drug were investigat...

  3. Mesoporous silica layers with controllable porosity and pore size

    Silica layers with controllable porosity and pore size were prepared via a templating approach. The structure of these mesoporous films was examined by porosimetry via ellipsometry and transmission electron microscopy. A design of experiment (DOE) method was used to gather information about the influence of the processing parameters on the final film structure. A model was developed, allowing a precise control of the pore diameters and porosity of the silica coating.

  4. A Reversible Light-Operated Nanovalve on Mesoporous Silica Nanoparticles

    Tarn, Derrick; Ferris, Daniel P.; Barnes, Jonathan C.; Ambrogio, Michael W.; Stoddart, J. Fraser; Zink, Jeffrey I.

    2014-01-01

    Two azobenzene α-cyclodextrin based nanovalves are designed, synthesized and assembled on mesoporous silica nanoparticles. When in aqueous conditions, the cyclodextrin cap is tightly bound to the azobenzene moiety and capable of holding back loaded cargo molecules. Upon irradiation with a near-UV light laser, trans to cis- photoisomerization of azobenzene initiates a dethreading process, which causes the cyclodextrin cap to unbind followed by the release of cargo. The addition of a bulky stop...

  5. Enzyme immobilisation and catalysis in ordered mesoporous silica

    Smith, Graham Murray

    2008-01-01

    A range of mesoporous materials based on SBA-15 have been prepared and characterised. The materials were templated by neutral block copolymer P123, and typically have a hexagonal (p6mm) pore structure, with high surface areas and narrow pore size distributions. The removal of the surfactant template by calcination and solvent extraction has been investigated. The aqueous stability of this material, and the hydrolysis of the surface was studied. Organic functional groups were incorporated i...

  6. Synthesis of Novel Mesoporous Silica Materials with Hierarchical Pore Structures

    Porous materials with various pore sizes in the range of micropore ( 50 nm) are attractive due to their many emerging applications such as catalysts, separation systems, and low dielectric constant materials. The discovery of new M41S mesoporous silica families with pore sizes larger than 2 nm in diameter in 1992 extended the applications into much wider pore ranges, bringing in a new prosperous era in porous material research. The synthesis of these silica materials has been mainly accomplished through a self-assembly between surfactant molecules and inorganic species under various pH conditions. Recently, core-shell nanoparticles with a silica core and mesoporous shell under basic conditions were synthesized using the silica nanoparticles as a core, and a silica precursor (TEOS) and cationic surfactant (CTABr) as a material for the formation of the mesoporous shell. The resultant materials were very monodispersive in size and showed a narrow pore size distribution in the range of ca 2-3 nm in diameter, depending on the alkyl-chain length of the surfactants used. In this work, the mesoporous shell coated-fumed silicas (denoted as MS M-5s) were synthesized by using fumed silica instead of the silica nanoparticle as a core based on previous reports. Also, the structural properties of the MS M-5s such as the specific surface area and pore volume were easily controlled by varying the amount of the silica precursor and surfactant. The resultant materials exhibited a BET surface area of ca 279-446 m2/g and total pore volume of ca 0.64-0.74 cm3/g and showed a narrow pore size distribution (PSD) due to the removal of the organic surfactant molecules

  7. Electric Field-Responsive Mesoporous Suspensions: A Review

    Seung Hyuk Kwon; Shang Hao Piao; Hyoung Jin Choi

    2015-01-01

    This paper briefly reviews the fabrication and electrorheological (ER) characteristics of mesoporous materials and their nanocomposites with conducting polymers under an applied electric field when dispersed in an insulating liquid. Smart fluids of electrically-polarizable particles exhibit a reversible and tunable phase transition from a liquid-like to solid-like state in response to an external electric field of various strengths, and have potential applications in a variety of active contr...

  8. Tailored Jeffamine molecular tools for ordering mesoporous Silica

    May Masnou, Anna; Pasc, Andreea; Stébé, Marie José; Gutiérrez González, José María, 1953-; Porras Rodríguez, Montserrat; Blin, Jean-Luc

    2012-01-01

    Herein, we report the formation of organized mesoporous silica materials prepared from a novel nonionic gemini surfactant, myristoyl-end capped Jeffamine, synthesized from a polyoxyalkyleneamine (ED900). The behavior of the modified Jeffamine in water was first investigated. A direct micellar phase (L1) and a hexagonal (H1) liquid crystal were found. The structure of the micelles was investigated from the SAXS and the analysis by Generalized Indirect Fourier Transformation (GIFT), which show ...

  9. Synthesis of Mesoporous Material from Chrysotile-Derived Silica

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

    2013-01-01

    Mesoporous MCM-41-type molecular sieves were synthesized using calcined and leached chrysotile and cetyltrimethylammonium bromide as the silica source and structure directing agent, respectively. Powder X-ray diffraction (XRD), N2 isothermal adsorption-desorption, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were used to characterize the samples. The calcined and leached chrysotile can be employed as an inexpensive silica source for the formation of low-order MCM-4...

  10. B-TUD-1: a versatile mesoporous catalyst:

    Ranoux, A.; Djanashvili, K.; Arends, I.W.C.E.; Hanefeld, U.

    2013-01-01

    Novel amorphous mesoporous borosilicate, B-TUD-1, was prepared to test its performance for different sustainable reactions. The structure of the material, the effective incorporation of boron into the framework as well as the nature of incorporated boron were verified by N2-sorption, XRD, ICP-OES, TEM, NH3-desorption, MAS NMR and FTIR. The potential of these materials as catalysts was tested in two reactions under different conditions. They showed an apparently good activity and recycling pot...

  11. Hierarchically structured biphenylene-bridged periodic mesoporous organosilica

    Li, Yan.; Keilbach, Andreas; Kienle, Marcel; Goto, Yasutomo; Inagaki, Shinji; Knochel, Paul; Bein, Thomas

    2011-01-01

    Novel composites of highly ordered and stable biphenyl-bridged periodic mesoporous organosilica (PMO) materials confined within the pores of anodic alumina membranes (AAM) were successfully synthesized by evaporation-induced self-assembly (EISA). 4,40-Bis(triethoxysilyl)biphenyl (BTEBP) was used as a precursor in combination with the ionic surfactant cetyltrimethylammonium bromide (CTAB) or triblock-copolymer F127 as structure-directing agents. The resulting mesophases were characterized by s...

  12. Percolation Diffusion into Self-Assembled Mesoporous Silica Microfibres

    John Canning; George Huyang; Miles Ma; Alison Beavis; David Bishop; Kevin Cook; Andrew McDonagh; Dongqi Shi; Gang-Ding Peng; Crossley, Maxwell J.

    2014-01-01

    Percolation diffusion into long (11.5 cm) self-assembled, ordered mesoporous microfibres is studied using optical transmission and laser ablation inductive coupled mass spectrometry (LA-ICP-MS). Optical transmission based diffusion studies reveal rapid penetration (<5 s, D > 80 ?m2?s?1) of Rhodamine B with very little percolation of larger molecules such as zinc tetraphenylporphyrin (ZnTPP) observed under similar loading conditions. The failure of ZnTPP to enter the microfibre was confi...

  13. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

    Variola F; Zalzal SF; Leduc A; Barbeau J; Nanci A

    2014-01-01

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

  14. Magnetic Properties of Mesoporous and Nano-particulate Metal Oxides

    Adrian H. Hill

    2009-01-01

    The magnetic properties of the first row transition metal oxides are wide and varied and have been studied extensively since the 1930’s. Observations that the magnetic properties of these material types change with the dimension of the sample have stimulated many theoretical and experimental studies of the systems involved. As sample sizes decrease towards the nanoscale long range crystallographic order is no longer possible. However, the application of mesoporous silica sample...

  15. Effects of resins on asphaltene self-association and solubility

    Yarranton, H.W.; Fox, W.A.; Svrcek, W.Y. [Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering

    2007-10-15

    This paper described a method of modelling the self-association and precipitation of asphaltenes and resins. Self-association was assessed using vapor pressure osmometry (VPO) measurements of asphaltene and resin mixtures. A modified asphaltene self-association model was used to fit and interpret data. The molar mass distribution of the asphaltene-resin aggregates was characterized. Precipitation data were obtained by measuring asphaltenes and resins in solutions of asphaltenes, resins, toluene, and heptane. The molar mass distribution was then used as an input to the regular solution model. Results of the study suggested that resins participate in asphaltene self-association. It was concluded that both asphaltenes and resins are best characterized as a combined pseudo-component with a single molar mass distribution of the aggregated species. 30 refs., 4 tabs., 5 figs.

  16. Electrically conductive resinous bond and method of manufacture

    Snowden, Jr., Thomas M. (P.O. Box 4231, Clearwater, FL 33518); Wells, Barbara J. (865 N. Village Dr., Apt. 101B, St. Petersburg, FL 33702)

    1987-01-01

    A method of bonding elements together with a bond of high strength and good electrical conductivity which comprises: applying an unfilled polyimide resin between surfaces of the elements to be bonded, heat treating said unfilled polyimide resin in stages between a temperature range of about 40.degree. to 365.degree. C. to form a strong adhesive bond between said elements, applying a metal-filled polyimide resin overcoat between said elements so as to provide electrical connection therebetween, and heat treating said metal-filled polyimide resin with substantially the same temperature profile as the unfilled polyimide resin. The present invention is also concerned with an adhesive, resilient, substantially void free bonding combination for providing a high strength, electrically conductive adhesive attachment between electrically conductive elements which comprises a major amount of an unfilled polyimide resin and a minor amount of a metal-filled polyimide resin.

  17. Commercial Ion Exchange Resin Vitrification in Borosilicate Glass

    Bench-scale studies were performed to determine the feasibility of vitrification treatment of six resins representative of those used in the commercial nuclear industry. Each resin was successfully immobilized using the same proprietary borosilicate glass formulation. Waste loadings varied from 38 to 70 g of resin/100 g of glass produced depending on the particular resin, with volume reductions of 28 percent to 68 percent. The bench-scale results were used to perform a melter demonstration with one of the resins at the Clemson Environmental Technologies Laboratory (CETL). The resin used was a weakly acidic meth acrylic cation exchange resin. The vitrification process utilized represented a approximately 64 percent volume reduction. Glass characterization, radionuclide retention, offgas analyses, and system compatibility results will be discussed in this paper

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

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

  19. Comparison of Mechanical Properties of Resin Composites with Resin Modified Glass Ionomers

    Taha NA

    2015-06-01

    Full Text Available Statement of Problem: There are controversial reports regarding physical and mechanical properties of resin composites and glass ionomer cements. Some revealed higher strength and hardness for resin composites while others showed a comparable value for glass ionomer cements. Evaluation of mechanical properties of different types of resin composites in comparison with resin modified glass ionomers is not widely studied. Objectives: To measure and compare the flexural strength and Vickers hardness of three resin composites and two resins modified glass ionomer cements before and after ageing. Materials and Methods: Three resin composites, i.e. Filtek Supreme XTE (3M ESPE, Ice (SDI, Gradia (GC, and two resins modified glass ionomers, i.e. Fuji II LC (GC and Riva Light Cure (SDI, were selected. Ten barshaped specimens were prepared for each material and cured using LED curing light. After 24 hours storage in distilled water at 37oC, the specimens were randomly divided into two equal groups (n=5. The first group was tested as a baseline and the second group was restored at 37oC for another 29 days. Flexural strength was performed by four-point bending test using universal testing machine at crosshead speed of 0.5mm/min, and the maximum load at failure was recorded. The specimen’s halves were used for evaluating Vickers hardness, using a Digital Hardness Tester (300 g/15 sec and the Vickers hardness number (VHN was recorded. Data were analyzed using one-way analysis of variance (ANOVA, Tukey’s and student’s t-test. Results: After 24 hours of immersion, the highest hardness number was found for Filtek Supreme and Ice and the highest flexural strength was obtained for Gradia. After 30 days of storage, hardness of Fuji II LC and Gradia showed a significant decrease; flexural strength of Ice and Fuji II LC revealed a significant increase while Gradia and Filtek Supreme showed a significant decrease. Conclusions: Resin modified glass ionomers showed a comparable result for hardness and flexural strength with some of the tested resin composites and lower values than some others.

  20. Capacity of mesoporous bioactive glass nanoparticles to deliver therapeutic molecules

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

    2012-11-01

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

  1. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

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

    2014-03-15

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

  2. Soft-Template-Synthesized Mesoporous Carbon for Oral Drug Delivery

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

    2014-01-01

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

  3. Aerosol-spray diverse mesoporous metal oxides from metal nitrates.

    Kuai, Long; Wang, Junxin; Ming, Tian; Fang, Caihong; Sun, Zhenhua; Geng, Baoyou; Wang, Jianfang

    2015-01-01

    Transition metal oxides are widely used in solar cells, batteries, transistors, memories, transparent conductive electrodes, photocatalysts, gas sensors, supercapacitors, and smart windows. In many of these applications, large surface areas and pore volumes can enhance molecular adsorption, facilitate ion transfer, and increase interfacial areas; the formation of complex oxides (mixed, doped, multimetallic oxides and oxide-based hybrids) can alter electronic band structures, modify/enhance charge carrier concentrations/separation, and introduce desired functionalities. A general synthetic approach to diverse mesoporous metal oxides is therefore very attractive. Here we describe a powerful aerosol-spray method for synthesizing various mesoporous metal oxides from low-cost nitrate salts. During spray, thermal heating of precursor droplets drives solvent evaporation and induces surfactant-directed formation of mesostructures, nitrate decomposition and oxide cross-linking. Thirteen types of monometallic oxides and four groups of complex ones are successfully produced, with mesoporous iron oxide microspheres demonstrated for photocatalytic oxygen evolution and gas sensing with superior performances. PMID:25897988

  4. Facile synthesis of mesoporous aluminosilicates constructed with crystalline microporous frameworks

    A hierarchically micro-mesoporous structured ZSM-5 zeolite has been synthesized from assembly of aluminosilcate species with a tetra-quaternary ammonium type surfactant, in which the surfactant acts as two-level structure-directing templates for generating micropores and mesopores simultaneously. The synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption isotherms, scanning electron microscopy, transmission electron microscopy, 27Al magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy, Thermogravimetric analysis and Quantum chemical calculation. X-ray diffraction as well as nitrogen sorption analyses indicated the dual-porosity of samples, one is from intra-crystalline micropores, and the other is from mesopores. Quantum chemical calculation results showed that the inner ammonium groups of surfactant had more higher molecular degrees of freedom for the zeolite-structure-directing function. Moreover, on the basis of the same concept, this method could be extended to investigate other hierarchically structured zeolites.

  5. Facile synthesis of mesoporous aluminosilicates constructed with crystalline microporous frameworks

    Liu, Baoyu, E-mail: liubaoyu084@163.com; Ren, Yanqun; Duan, Qianqian; Chen, Fei; Xi, Hongxia, E-mail: cehxxi@scut.edu.cn; Qian, Yu

    2013-08-15

    A hierarchically micro-mesoporous structured ZSM-5 zeolite has been synthesized from assembly of aluminosilcate species with a tetra-quaternary ammonium type surfactant, in which the surfactant acts as two-level structure-directing templates for generating micropores and mesopores simultaneously. The synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N{sub 2} adsorption–desorption isotherms, scanning electron microscopy, transmission electron microscopy, {sup 27}Al magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy, Thermogravimetric analysis and Quantum chemical calculation. X-ray diffraction as well as nitrogen sorption analyses indicated the dual-porosity of samples, one is from intra-crystalline micropores, and the other is from mesopores. Quantum chemical calculation results showed that the inner ammonium groups of surfactant had more higher molecular degrees of freedom for the zeolite-structure-directing function. Moreover, on the basis of the same concept, this method could be extended to investigate other hierarchically structured zeolites.

  6. Mesoporous hydroxyapatite: Preparation, drug adsorption, and release properties

    Mesoporous hydroxyapatite (HA) was synthesized through gas–liquid chemical precipitation method at ambient temperature without any template. Structure, morphology and pore size distribution of HA were analyzed via X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution electron microscopy and N2 adsorption/desorption. The chemotherapeutic agent doxorubicin (DOX) was used to investigate the drug adsorption and release behavior of HA. The kinetics of DOX adsorption on HA followed the pseudo-second-order rate expression. Adsorption isotherms at various temperatures were obtained, and the equilibrium data fitted the Langmuir model. The values of thermodynamic parameters (Gibbs free energy, entropy, and enthalpy changes) demonstrated that the adsorption process was spontaneous and endothermic. In vitro pH-responsive (pH = 7.4, 5.8) controlled release was investigated. DOX-loaded HA showed a slow, long-term, and steady release rate. The release rate at pH5.8 was larger than that at pH7.4. Consequently, the as-prepared mesoporous HA has potential applications in controlled drug delivery systems. - Highlights: • Mesoporous HA was synthesized by a simple precipitation method without any template. • The kinetics of adsorption followed the pseudo-second-order rate expression. • Thermodynamics investigation showed that adsorption was spontaneous and endothermic. • DOX-loaded HA showed a long-term, steady, and pH-controlled release rate

  7. Selective Response of Mesoporous Silicon to Adsorbants with Nitro Groups

    McLeod, John A.; Kurmaev, Ernst Z.; Sushko, Petr V.; Boyko, Teak D.; Levitsky, Igor A.; Moewes, Alexander

    2012-01-30

    We demonstrate that the electronic structure of mesoporous silicon is affected by adsorption of nitrobased explosive molecules in a compound-selective manner. This selective response is demonstrated by probing the adsorption of two nitro-based molecular explosives (trinitrotoluene and cyclotrimethylenetrinitramine) and a nonexplosive nitro-based aromatic molecule (nitrotoluene) on mesoporous silicon using soft X-ray spectroscopy. The Si atoms strongly interact with adsorbed molecules to form Si-O and Si-N bonds, as evident from the large shifts in emission energy present in the Si L2,3 X-ray emission spectroscopy (XES) measurements. Furthermore, we find that the energy gap (band gap) of mesoporous silicon changes depending on the adsorbant, as estimated from the Si L2,3 XES and 2p X-ray absorption spectroscopy (XAS) measurements. Our ab initio molecular dynamics calculations of model compounds suggest that these changes are due to spontaneous breaking of the nitro groups upon contacting surface Si atoms. This compound-selective change in electronic structure may provide a powerful tool for the detection and identification of trace quantities of airborne explosive molecules.

  8. Cumene cracking on modified mesoporous material type MCM-41

    Ahmed Belhakem

    2006-06-01

    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.

  9. Sustained release of fungicide metalaxyl by mesoporous silica nanospheres

    Wanyika, Harrison, E-mail: hwanyika@gmail.com [Jomo Kenyatta University of Agriculture and Technology, Department of Chemistry (Kenya)

    2013-08-15

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

  10. Sustained release of fungicide metalaxyl by mesoporous silica nanospheres

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

  11. Treatment of spent ion-exchange resins for disposal

    Ion-exchange resins are used in CANDU-PHW nuclear power stations to purify heavy water in the primary heat transport (PHT) and moderator systems. Two techniques for conditioning spent ion-exchange resins for disposal have been evaluated: direct immobilization, and incineration combined with immobilization of the ash and scrubbed off-gases. When ion-exchange resins were immobilized directly, no volume reductions were obtained at the various resin-to-matrix weight ratios attempted. Volumes of bitumen and glass products were equal to the volumes of untreated resin while the volumes of cement and polyester products were two and three times larger. While incinerating the resin is an extra processing step, high reductions in volume result. Bitumen and glass product volumes were six times smaller than the volumes of untreated resin while cement and polyster product volumes were about half the volume of untreated resin. Since the releases of Cs-137 were about ten times lower for products made by direct immobilization, PHT resins, which have high concentrations of Cs-137, should be immobilized directly. Moderator resins which have high concentrations of C-14 should be incinerated and the ash- and C-14-contaminated scrubbing solutions should be immobilized. By pretreating such resins with calcium chloride, the C-14 present on resin could be released at temperatures below the ignition temperature of the resin. This technique reduces the amount of inactive carbon dioxide that must be scrubbed to trap the C-14. The releases of C-14 from immobilized barium hydroxide scrubbing solution were the same as releases from immobilized resin

  12. Uranium Adsorption on Ion-Exchange Resins - Batch Testing

    Mattigod, Shas V.; Golovich, Elizabeth C.; Wellman, Dawn M.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    The uranium adsorption performance of five resins (Dowex 1, Dowex 21K 16-30 [fresh], Dowex 21K 16-30 [regenerated], Purofine PFA600/4740, and ResinTech SIR-1200) were tested using unspiked, nitrate-spiked, and nitrate-spiked/pH adjusted source water from well 299-W19-36. These batch tests were conducted in support of a resin selection process in which the best resin to use for uranium treatment in the 200-West Area groundwater pump-and-treat system will be identified. The results from these tests are as follows: • The data from the high-nitrate (1331 mg/L) tests indicated that Dowex 1, Dowex 21K 16-30 (fresh), Purofine PFA600/4740, and ResinTech SIR-1200 all adsorbed uranium similarly well with Kd values ranging from ~15,000 to 95,000 ml/g. All four resins would be considered suitable for use in the treatment system based on uranium adsorption characteristics. • Lowering the pH of the high nitrate test conditions from 8.2 to 7.5 did not significantly change the uranium adsorption isotherms for the four tested resins. The Kd values for these four resins under high nitrate (1338 mg/L), lower pH (7.5) ranged from ~15,000 to 80,000 ml/g. • Higher nitrate concentrations greatly reduced the uranium adsorption on all four resins. Tests conducted with unspiked (no amendments; nitrate at 337 mg/L and pH at 8.2) source water yielded Kd values for Dowex 1, Dowex 21K 16-30 (fresh), Purofine PFA600/4740, and ResinTech SIR-1200 resins ranging from ~800,000 to >3,000,000 ml/g. These values are about two orders of magnitude higher than the Kd values noted from tests conducted using amended source water. • Compared to the fresh resin, the regenerated Dowex 21K 16-30 resin exhibited significantly lower uranium-adsorption performance under all test conditions. The calculated Kd values for the regenerated resin were typically an order of magnitude lower than the values calculated for the fresh resin. • Additional testing using laboratory columns is recommended to better resolve differences between the adsorption abilities of the resins and to develop estimates of uranium loading on the resins. By determining the quantity of uranium that each resin can adsorb and the time required to reach various levels of loading, resin lifetime in the treatment system can be estimated.

  13. Effect of Resin Coating and Chlorhexidine on Microleakage of Two Resin Cements after Storage

    F. Shafie

    2010-03-01

    Full Text Available Objective: Evaluating the effect of resin coating and chlorhexidine on microleakage of two resin cements after water storage.Materials and Methods: Standardized class V cavities were prepared on facial and lingual surfaces of one hundred twenty intact human molars with gingival margins placed 1mm below the cemento-enamel junction. Indirect composite inlays were fabricated and thespecimens were randomly assigned into 6 groups. In Groups 1 to 4, inlays were cemented with Panavia F2.0 cement. G1: according to the manufacturers instruction. G2: with light cured resin on the ED primer. G3: chlorhexidine application before priming. G4: withchlorhexidine application before priming and light cured resin on primer. G5: inlays were cemented with Nexus 2 resin cement. G6: chlorhexidine application after etching. Each group was divided into two subgroups based on the 24-hour and 6-month water storagetime. After preparation for microleakage test, the teeth were sectioned and evaluated at both margins under a 20stereomicroscope. Dye penetration was scored using 0-3 criteria.The data was analyzed using Kruskal-Wallis and complementary Dunn tests.Results: There was significantly less leakage in G2 and G4 than the Panavia F2.0 control group at gingival margins after 6 months (P<0.05. There was no significant differences in leakage between G1 and G3 at both margins after 24 hours and 6 months storage. After 6months, G6 revealed significantly less leakage than G5 at gingival margins (P=0.033. In general, gingival margins showed more leakage than occlusal margins.Conclusion: Additionally, resin coating in self-etch (Panavia F2.0 and chlorhexidine application in etch-rinse (Nexus resin cement reduced microleakage at gingival margins after storage.

  14. Post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin

    This study examined the post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin using a digital microhardness tester. Change in hardness of these materials over a period of 6 months was compared to that of conventional glass ionomer cements and a composite resin. With the exception of the composite resin, all materials showed a significant increase in hardness over 24 h after their initial set. Dual-cure resin-modified glass ionomer cements showed decreased hardness with increased storage time in saline at 37oC. Results suggest that the addition of resins to glass ionomer cements does not improve initial hardness and does not negate the acid-base reaction of conventional cements. Resin addition may, however, lead to increased water sorption and decreased hardness. (author)

  15. Bio-assisted synthesis of mesoporous Li3V2(PO4)3 for high performance lithium-ion batteries

    He, W.; Zhang, X.D.; Du, X.Y.; Zhang, Y.; Yue, Yuanzheng; Shen, S.J.; Li, M.

    2013-01-01

    hierarchical nanostructure, which consist of Li3V2(PO4)3crystal nanoparticles and amor-phous biocarbons network (11.5%) with hierarchical mesoporous structures (slit shape mesopores, openwormlike mesopores and plugged mesopores). This hierarchical nanostructure facilitates electron andlithium ion diffusion...

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

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

    2014-01-01

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

  17. Catalytic Activity and Photophysical Properties of Biomolecules Immobilized on Mesoporous Silica

    Ikemoto, Hideki

    harvesting complex 2 (LH2) from purple photosynthetic bacteria was immobilized on SBA-15 with hexagonally ordered cylindrical pores or on MCF-type mesoporous silica with disordered cage-like mesopores. To identify the location of LH2, spherical particles with small or large pores were tested for the...

  18. Hierarchical zeolites: progress on synthesis and characterization of mesoporous zeolite single crystal catalysts

    Kustova, Marina; Egeblad, Kresten; Christensen, Claus H.; Kustov, Arkadii; Christensen, Christina Hviid

    measurements. Additionally, the results of diffusion of n-hexadecane in conventional and mesoporous zeolites are presented. Isomerization and cracking of n-hexadecane was chosen as model test reaction for these materials. All results support that mesoporous zeolites are superior catalysts due to improved mass...

  19. A reconstruction strategy to synthesize mesoporous SAPO molecular sieve single crystals with high MTO catalytic activity.

    Wang, Chan; Yang, Miao; Li, Mingrun; Xu, Shutao; Yang, Yue; Tian, Peng; Liu, Zhongmin

    2016-05-11

    Mesoporous SAPO-34 single crystals with tunable porosity and Si content have been fast synthesized within 4 hours by a reconstruction strategy, which show excellent hydrothermal stability and MTO catalytic activity. This new strategy is further proven to be applicable to prepare other mesoporous SAPO molecular sieve single crystals. PMID:27101359

  20. Dehydrogenation of light alkanes over rhenium catalysts on conventional and mesoporous MFI supports

    Rovik, Anne Krogh; Hagen, Anke; Schmidt, I.; Dahl, Søren; Chorkendorff, Ib; Christensen, Christina Hviid

    of the catalyst appears to be slightly improved compared to conventional MFI crystals. The beneficial effect of a mesoporous MFI support is convincingly demonstrated in propane dehydrogenation, where both conversion and selectivities on the mesoporous MFI (Si/Al > 500) impregnated with Re are...... significantly higher than on Re supported on a comparable conventional MFI support....

  1. Hydroisomerization of hexane over micro-mesoporous zeolites with tailored structure and distribution of active sites

    Kaucký, Dalibor; Janošcová, J.; Tabor, Edyta; Rathouský, Jiří; Klein, P.; Sazama, Petr

    Caen : ENSICAEN, Université de Caen, 2015. s. 89-89. [International Symposium Advances Micro- and Mesoporous Materials /6./. 06.09.2015-09.09.2015, Sunset - Black Sea] R&D Projects: GA ČR GA15-12113S Institutional support: RVO:61388955 Keywords : micro- and mesoporous zeolite s * hydroisomerization * zeolite catalysts Subject RIV: CF - Physical ; Theoretical Chemistry

  2. Hydrothermal synthesis of mesoporous metal oxide arrays with enhanced properties for electrochemical energy storage

    Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2015-01-15

    Highlights: • NiO mesoporous nanowall arrays are prepared via hydrothermal method. • Mesoporous nanowall arrays are favorable for fast ion/electron transfer. • NiO mesoporous nanowall arrays show good supercapacitor performance. - Abstract: Mesoporous nanowall NiO arrays are prepared by a facile hydrothermal synthesis method with a following annealing process. The NiO nanowall shows continuous mesopores ranging from 5 to 10 nm and grows vertically on the substrate forming a porous net-like structure with macropores of 20–300 nm. A plausible mechanism is proposed for the growth of mesoporous nanowall NiO arrays. As cathode material of pseudocapacitors, the as-prepared mesoporous nanowall NiO arrays show good pseudocapacitive performances with a high capacitance of 600 F g{sup −1} at 2 A g{sup −1} and impressive high-rate capability with a specific capacitance of 338 F g{sup −1} at 40 A g{sup −1}. In addition, the mesoporous nanowall NiO arrays possess good cycling stability. After 6000 cycles at 2 A g{sup −1}, a high capacitance of 660 F g{sup −1} is attained, and no obvious degradation is observed. The good electrochemical performance is attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, leading to enhanced electrochemical properties.

  3. Micromolding in inverted polymer opals (MIPO): synthesis of hexagonal mesoporous silica opals

    Yang Sanming; Coombs, N.; Ozin, G.A. [Toronto Univ., Ont. (Canada). Materials Chemistry Research Group

    2000-12-15

    Regular arrays of hexagonal mesoporous silica spheres are crucial for a number of applications, but until now control of the diameter, dispersity, and packing of the spheres has not proved possible. These authors report a new method-micromolding in inverted polymer opals-that allows the synthesis of such hexagonal mesoporous silica opals for the first time. (orig.)

  4. Facile preparation of mesoporous carbon-silica-coated graphene for the selective enrichment of endogenous peptides.

    Zhang, Quanqing; Zhang, Qinghe; Xiong, Zhichao; Wan, Hao; Chen, Xiaoting; Li, Hongmei; Zou, Hanfa

    2016-01-01

    A sandwich-like composite composed of ordered mesoporous carbon-silica shell-coated graphene (denoted as graphene@mSiO2-C) was prepared by an in-situ carbonation strategy. A mesoporous silica shell was synthesized by a sol-gel method, and cetyltrimethyl ammonium bromide inside the mesopores were in-situ carbonized as a carbon source to obtain a carbon-silica shell. The resulting mesoporous carbon-silica material with a sandwich structure possesses a high surface area (600m(2)g(-1)), large pore volume (0.587cm(3)g(-1)), highly ordered mesoporous pore (3nm), and high carbon content (30%). This material shows not only high hydrophobicity of graphene and mesoporous carbon but also a hydrophilic silica framework that ensures excellent dispersibility in aqueous solution. The material can capture many more peptides from bovine serum albumin tryptic digests than mesoporous silica shell-coated graphene, demonstrating great enrichment efficiency for peptides. Furthermore, the prepared composite was applied to the enrichment of low-abundance endogenous peptides in human serum. Based on Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry identification, the graphene@mSiO2-C could efficiently size-exclude proteins and enriches the low-abundant peptides on the graphene and mesoporous carbon. And based on the LC-MS/MS results, 892 endogenous peptides were obtained by graphene@mSiO2-C, hinting at its great potential in peptides analysis. PMID:26695263

  5. Synthesis of morphology-controllable mesoporous Co3O4 and CeO2

    Recently, extensive works have been devoted to the morphology control of mesoporous materials with respect to their use in various applications. In this paper, we used two kinds of mesoporous silica, SBA-15 rods and spheres as hard templates to synthesize morphology-controllable mesoporous metal oxides. By carefully controlling the loading of metal precursors in the mesopores of the hard template, mesoporous Co3O4 and CeO2 with different morphologies, such as micrometer-sized rod, hollow sphere, saucer-like sphere, and solid sphere were conveniently obtained. The structural properties of these materials were characterized by XRD, BET, SEM and TEM. In addition, it is found that the differences observed in the textural properties of the two mesoporous metal oxides nanocasted from the same template can be attributed to the properties of metal precursors and the interaction between metal oxide and SiO2. Thus-obtained mesoporous metal oxides with such special morphologies may have a potential application in the field of environmental catalytic oxidation. - Graphical Abstract: Mesoporous Co3O4 and CeO2 with different morphologies, such as micrometer-sized rod, hollow sphere, saucer-like sphere, and solid sphere were synthesized by nanocasting.

  6. Pore-expansion of monodisperse mesoporous silica spheres by a novel surfactant exchange method.

    Mizutani, Mamoru; Yamada, Yuri; Yano, Kazuhisa

    2007-03-12

    By adapting a novel surfactant exchange method, in which surfactants inside mesopores are completely exchanged by surfactants with longer alkyl chain lengths, pore-expansion of monodisperse mesoporous silica spheres (MMSS) with radially ordered hexagonal regularity was attained while retaining spherical morphology and high monodispersity. PMID:17347729

  7. Silver nanoparticle growth in 3D-hexagonal mesoporous silica films.

    Besson, Sophie; Gacoin, Thierry; Ricolleau, Christian; Boilot, Jean-Pierre

    2003-02-01

    The 3D-hexagonal mesoporous films are used as templates to grow uniform silver nanoparticles. The grafting of hydrophobic groups at the pore surface, significantly slows down the silver ion diffusion, anchoring small silver clusters in micropores and leading to organized domains of silver particles in mesopores with a narrow size distribution. PMID:12613612

  8. Hydrothermal synthesis of mesoporous metal oxide arrays with enhanced properties for electrochemical energy storage

    Highlights: • NiO mesoporous nanowall arrays are prepared via hydrothermal method. • Mesoporous nanowall arrays are favorable for fast ion/electron transfer. • NiO mesoporous nanowall arrays show good supercapacitor performance. - Abstract: Mesoporous nanowall NiO arrays are prepared by a facile hydrothermal synthesis method with a following annealing process. The NiO nanowall shows continuous mesopores ranging from 5 to 10 nm and grows vertically on the substrate forming a porous net-like structure with macropores of 20–300 nm. A plausible mechanism is proposed for the growth of mesoporous nanowall NiO arrays. As cathode material of pseudocapacitors, the as-prepared mesoporous nanowall NiO arrays show good pseudocapacitive performances with a high capacitance of 600 F g−1 at 2 A g−1 and impressive high-rate capability with a specific capacitance of 338 F g−1 at 40 A g−1. In addition, the mesoporous nanowall NiO arrays possess good cycling stability. After 6000 cycles at 2 A g−1, a high capacitance of 660 F g−1 is attained, and no obvious degradation is observed. The good electrochemical performance is attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, leading to enhanced electrochemical properties

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

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

    2009-01-01

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

  10. Controllable synthesis of mesoporous Co3O4 nanoflake array and its application for supercapacitor

    Graphical abstract: Electrodeposited mesoporous Co3O4 nanoflake arrays exhibit porous structure composed of mesoporous nanoflakes and high supercapacitor performance. - Highlights: Mesoporous Co3O4 nanoflake arrays are prepared via electrodeposition method. Mesoporous nanowall arrays are favorable for fast ion/electron transfer. Mesoporous Co3O4 nanoflake arrays show excellent supercapacitor performance. - Abstract: A mesoporous Co3O4 nanoflake array grown on carbon cloth is prepared by a facile electrodeposition method with a following annealing process. The as-prepared Co3O4 nanoflake possesses a continuous mesopores ranging from 2 to 5 nm and grows tightly on the substrate forming a porous net-like structure with macropores of 20200 nm. The electrochemical performance of the mesoporous Co3O4 nanoflake arrays as pseudocapcitor electrode are investigated by cyclic voltammograms and galvanostatic charge/discharge tests in 2 M KOH. The as-prepared Co3O4 array exhibits a high discharge capacitance and excellent rate capability with 450 F g?1, 436 F g?1, 408 F g?1, 380 F g?1and 363 F g?1 at 1, 2, 4, 10, and 20 A g?1, respectively. The specific capacitance of 81% is maintained from 1 A g?1 to 20 A g?1. The electrode also shows rather good cycling stability and exhibits a specific capacitance of 414 F g?1 after 5000 cycles

  11. Flammability of Epoxy Resins Containing Phosphorus

    Hergenrother, P. M.; Thompson, C. M.; Smith, J. G.; Connell, J. W.; Hinkley, J. A.

    2005-01-01

    As part of a program to develop fire-resistant exterior composite structures for future subsonic commercial and general aviation aircraft, flame-retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured neat epoxy formulations were characterized by thermogravimetric analysis, propane torch test, elemental analysis, microscale combustion calorimetry, and fire calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness and compressive strength of several cured formulations showed no detrimental effect due to phosphorus content. The chemistry and properties of these new epoxy formulations are discussed.

  12. Treatment of spent ion-exchange resins

    PMMA was studied with the aim to evaluate its usefulness as an incorporation medium for the final containment of spent ion-exchange resins. The study of the effect of water content (ranging from 25 to 100%) of the incorporated resin into PMMA on the compression strength of the final solid products shows that with the increasing water content the compression strength of the final products decreases sharply. Hardness of the final products follows nearly the same trend of compression strength. Increasing gamma irradiation doses, up to 7.77x107 rad, PMMA shows increase in compression strength and hardness for small doses and then decreases with increasing irradiation dose due to the increase in polymerization process and the degradation of the incorporation medium

  13. Fatigue properties of acrylic denture base resins.

    Fujii, K

    1989-12-01

    Observations were made of fractured surfaces caused by flexural and tensile fatigue tests made in polymethyl methacrylate denture base resins (PMMA). In addition, the changes in dynamic viscoelastic and tensile properties of the materials along with fatigue propagation were investigated. In the tensile and flexural fatigue tests, both the fractured surfaces, which had striations on their surfaces and cracks near the fractured section, closely resembled each other in appearance. On the other hand, all of the tensile properties, such as elastic modulus, toughness and tensile strength, decreased with the increase of the number of stress cycles in the fatigue test. The storage modulus (E') of the material decreased gradually along with fatigue propagation over the whole range of temperatures tested. The loss modulus (E") and mechanical loss tangent (tan delta) increased slightly. The fatigue limit of four commercial denture base resins varied widely from one product to another. PMID:2490598

  14. Development of a Heterogeneous Laminating Resin

    Gosnell, R.

    1984-01-01

    The feasibility of toughening the common types of matrix resins such as Narmco 5208 by utilizing a heterogeneous additive was examined. Some basic concepts and principles in the toughening of matrix resins for advanced composites were studied. The following conclusions were advanced: (1) the use of damage volume as a guide for measurement of impact resistance appears to be a valid determination; (2) short beam shear is a good test to determine the effect of toughening agents on mechanical properties; (3) rubber toughening results in improved laminate impact strength, but with substantial loss in high temperature dry and wet strength; (4) in the all-epoxy systems, the polycarbonate toughening agent seemed to be the most effective, although hot-wet strength is sacrificed; ABS was not as effective; and (5) in general, the toughened all-epoxy systems showed better damage tolerance, but less hot-wet strength; toughened bismaleimides had better hot-wet strength.

  15. Further adventures in binding resins : investigations into asphaltene and binding resin interactions

    Graham, B.F.; May, E.F. [Western Australia Univ., Crawley, W.A. (Australia). School of Mechanical Engineering; Trengove, R.D. [Murdoch Univ., Murdoch, W.A. (Australia). Separation Science Laboratory

    2008-07-01

    Emulsions in crude oil pose a challenge to petroleum producers because such emulsions are often more viscous than free oil and must be broken to avoid flow blockage. Various techniques have been developed to address this issue, such as the application of heat and the injection of demulsification chemicals at the well head or the processing facility. Despite their high cost, these remedies are often used as a preemptive measure because it very difficult to predict reliably whether an emulsion will actually form in a given production system. This paper reported on a study that investigated the interactions and structures of the asphaltenes and binding resins using various techniques. Laboratory experiments revealed that binding resins, once separated from their co-precipitated asphaltenes will recombine in solution. Calorific and gravimetric methods were used to investigate the binding kinetics and to determine the stoichiometry of the binding resin-asphaltene complex. The mass distribution of the binding resins and asphaltenes was also examined before and after recombination to determine the differences in stoichiometry and binding strength. According to high temperature GC analysis of the resin/asphaltene complex, the bonding is thermally stable at temperatures higher than 350 degrees C. Thermo-gravimetric analysis will be used to investigate this further.

  16. Cellulose whisker/epoxy resin nanocomposites

    Tang, Liming; Weder, Christoph

    2010-01-01

    New nanocomposites composed of cellulose nanofibers or whiskers and an epoxy resin were prepared. Cellulose whiskers with aspect ratios of ?10 and ?84 were isolated from cotton and sea animals called tunicates, respectively. Suspensions of these whiskers in dimethylformamide were combined with an oligomeric difunctional diglycidyl ether of bisphenol A with an epoxide equivalent weight of 185?192 and a diethyl toluenediamine-based curing agent. Thin films were produced by casting these mixtu...

  17. Pulsed laser photopolymerization of dental composite resins

    Meniga, Andrej; Sutalo, Zrinka; Azinovic, Davorka; Pichler, Goran

    1993-12-01

    The aim of this investigation was to improve the quality of the cured composite resin using the pulsed laser, thus avoiding disadvantages of previously used methods. The light source consisted of the pump excimer laser (Lambda Physik LPX 100) and the dye laser (Lambda Physik 3000). It is expected that pulsed laser polymerization could improve the conversion rate, decrease a temperature rise in the sample, allowing the `cooling' of the material and reduce polymerization shrinkage.

  18. Toward homogeneous nanostructured polyaniline/resin blends.

    Jafarzadeh, Shadi; Thormann, Esben; Rönnevall, Ted; Adhikari, Arindam; Sundell, Per-Erik; Pan, Jinshan; Claesson, Per M

    2011-05-01

    The high interest in applications of conducting polymers, especially polyaniline (PANI), makes it important to overcome limitations for effective usage due to poor processability and solubility. One promising approach is to make blends of PANI in polymeric resins. However, in this approach other problems related to the difficulty of achieving a homogeneous PANI dispersion arise. The present article is focused on this general problem, and we discuss how the synthesis method, choice of dopant and solvent as well as interfacial energies influence the dispersibility. For this purpose, different synthesis methods and dopants have been employed to prepare nanostructures of polyaniline. Dynamic light scattering analysis of dispersions of the synthesized particles in several solvents was employed in order to understand how the choice of solvent affects PANI aggregation. Further information on this subject was achieved by scanning electron microscopy studies of PANI powders dried from various solutions. On the basis of these results, acetone was found to be a suitable dispersion medium for PANI. The polymer matrix used to make the blends in this work is a UV-curing solvent-free resin. Therefore, there is no low molecular weight liquid in the system to facilitate the mixing process and promote formation of homogeneous dispersions. Thus, a good compatibility of the components becomes crucial. For this reason, surface tension and contact angle measurements were utilized for characterizing the surface energy of the PANI particles and the polyester acrylate (PEA) resin, and also for calculating the interfacial energy between these two components that revealed good compatibility within the PANI/PEA blend. A novel technique, based on centrifugal sedimentation analysis, was employed in order to determine the PANI particle size in PEA resin, and high dispersion stability of the PANI/PEA blends was suggested by evaluation of the sedimentation data. PMID:21480657

  19. Triterpenes from the resin of Protium heptaphyllum.

    Susunaga, G S; Siani, A C; Pizzolatti, M G; Yunes, R A; Delle Monache, F

    2001-08-01

    From the neutral fraction of the resin of Protium heptaphyllum, a mixture of alpha- and beta-amyrin, a mixture of maniladiol and brein have been isolated as main components, and the novel 3 beta,24-dihydroxy-urs-12-ene (1), 3-oxo-20S-hydroxytaraxastane (2) and 3 beta,20S-dihydroxytaraxastane (3) as minor components. NMR data of the last three compounds are provided. PMID:11543977

  20. A Novel Antibacterial Dental Resin Composite

    Ruijie Huang; Gregory, Richard L; Dong Xie; Leah Howard; Yiming Weng; Chong, Voon J.

    2012-01-01

    This study reports the synthesis and evaluation of a novel furanone-containing antibacterial resin composite. Compres-sive strength (CS) and S. mutans viability were used to evaluate the mechanical strength and antibacterial activity of the composites. With 5% to 30% addition of the furanone derivative, the composite showed no change in CS but a significant antibacterial activity with a 16% - 68% reduction in the S. mutans viability. Further, the antibact...