WorldWideScience
 
 
1

Chemical Characterization of Phenol/Formaldehyde Resins  

Science.gov (United States)

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

Brayden, T. H.

1986-01-01

2

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 macropor...

MONIKA ŠUPOVÁ; JAROSLAVA SVÍTILOVÁ; ZDEN?K CHLUP; MARTIN ?ERNÝ; ZUZANA WEISHAUPTOVÁ; TOMÁŠ SUCHÝ; VLADIMÍR MACHOVI?; ZBYN?K SUCHARDA; MARGIT ŽALOUDKOVÁ

2012-01-01

3

Formulation of lignin phenol formaldehyde resins as a wood adhesive  

International Nuclear Information System (INIS)

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 Phenol had been replaced by lignin [that was extracted from black liquor of oil palm empty fruit bunch (EFB)] in synthesizing resin with a ratio lignin to phenol 1:1.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

4

Chromatographic zinc isotope separation by phenol formaldehyde benzo crown resin.  

Science.gov (United States)

New types of phenol formaldehyde resin having benzo crown as a functional group were synthesized and applied to zinc isotope chromatographic operation. Zinc adsorption and isotope separation capacities were dramatically improved by using phenol formaldehyde benzo-15-crown-5 resin. Zinc batch adsorption tests were performed by various dehydrated organic solvents. Separation coefficient, epsilon 8.1 x 10(-4) and height equivalent to a theoretical plate (HETP) 0.105 cm for the isotopic pair of 68Zn/64Zn in phenol formaldehyde benzo-15-crown-5 resin were obtained in the case of acetone as the solvent at 298+/-1K. PMID:16499915

Ding, Xingcheng; Nomura, Masao; Suzuki, Tatsuya; Sugiyama, Yuichi; Kaneshiki, Toshitaka; Fujii, Yasuhiko

2006-04-28

5

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

Directory of Open Access Journals (Sweden)

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

MONIKA ŠUPOVÁ

2012-03-01

6

Thermal and mechanical behavior of modified phenol formaldehyde resin  

International Nuclear Information System (INIS)

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

7

Electron beam curable phenol-formaldehyde resin  

International Nuclear Information System (INIS)

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

8

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study Eucalyptus tannin (T) was isolated from outer bark of Eucalyptus trees; as sodium phenoxide salt and used as extender or copolymer into phenol formaldehyde (PF) resin at five percent (10, 20, 30, 40 and 50)% W/W. Tan-nin-phenol formaldehyde (TPF) and tannin formaldehyde-phenol formaldehyde (TFPF) resins that synthesized in this study were evaluated as adhesive material for cellulosic fibers by study the mechanical properties of the composite sheets .The results show that the sub...

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

2011-01-01

9

Nanoparticles-based phenol-formaldehyde hybrid resins.  

Science.gov (United States)

The synthesis, characterization and corrosion properties of a novel material, produced by the reaction of silica nanoparticles with a functionalized Phenol-Formaldehyde Resin (PFR), are presented. Carboxylic groups were attached in situ to the PFR skeleton to produce a functionalized resin (PFR-SA), which is then reacted with sol-gel-prepared silica nanoparticles, yielding a novel hybrid (organic/inorganic) material (PFR-SA-nanoSiO2). This hybrid material was characterized by FT-IR, FT-Raman, TGA, DSC, SEM and corrosion tests, whose results showed significant improvement of the thermal properties in comparison with the PFR coating. In addition, the new material was efficient and durable against corrosion of metals, with the anticorrosive performance of PFR-SA and PFR-SA/nanoSiO2 coating films being superior to those of the original PFR coating. PMID:18681059

Hernández-Padrón, Genoveva; García-Garduño, Margarita; Canseco, Miguel A; Castaño, Victor M

2008-06-01

10

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

Science.gov (United States)

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

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

1992-01-01

11

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Liu Weihua; Li Yingmin; Qu Xueliang

2008-01-01

12

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

Directory of Open Access Journals (Sweden)

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

Liu Weihua

2008-05-01

13

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

International Nuclear Information System (INIS)

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

14

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

15

A novel thermal degradation mechanism of phenol-formaldehyde type resins  

International Nuclear Information System (INIS)

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

16

A novel thermal degradation mechanism of phenol-formaldehyde type resins  

Energy Technology Data Exchange (ETDEWEB)

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 {sup 13}C nuclear magnetic resonance ({sup 13}C 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.

Chen Yangfei [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen Zhiqin [Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Xiao Shaoyi [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Liu Hongbo [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)], E-mail: xiaoxiaoafei@tom.com

2008-09-30

17

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study develops a new solvent-compatible microfluidic chip based on phenol formaldehyde resin (PFR). In addition to its solvent-resistant characteristics, this microfluidic platform also features easy fabrication, organization, decomposition for cleaning, and reusability compared with conventional chips. Both solvent-dependent (e.g., polycaprolactone) and nonsolvent-dependent (e.g., chitosan) microparticles were successfully prepared. The size of emulsion droplets could be easily adjusted...

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

2013-01-01

18

One-pot hydrothermal formation of phenol formaldehyde resin/carbon nanotube composites  

Science.gov (United States)

Phenol formaldehyde resin (PFR) was coated on the surface of carbon nanotubes (CNTs) by a simple one-pot hydrothermal approach. The coating did not ruin the nanotube sidewall, and its shell thickness was finely controlled on the nanometer scale by adjusting the amount of monomer. Silver nanoparticles were attached onto the PFR@CNT composites followed by the in-situ redox of AgNO 3 and as-prepared PFR/CNTs through hydrothermal treatment.

Zhang, Yange; Li, Pinjiang; Fa, Wenjun; Gao, Yuanhao; Wong, Ka Wai; Zheng, Zhi

2011-06-01

19

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Yanhui Huang,; Benhua Fei; Yan Yu; Rongjun Zhao

2013-01-01

20

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

Science.gov (United States)

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

Young, Philip R.

1999-01-01

 
 
 
 
21

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

Directory of Open Access Journals (Sweden)

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

A.S. Hussein

2011-06-01

22

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-12-10

23

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

International Nuclear Information System (INIS)

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

24

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

Directory of Open Access Journals (Sweden)

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

Nour Eddine El Mansouri

2011-05-01

25

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-03-15

26

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

International Nuclear Information System (INIS)

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

27

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

Science.gov (United States)

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

Ottenbourgs, Benjamin Tony

28

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

Directory of Open Access Journals (Sweden)

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

Yanhui Huang

2013-02-01

29

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

Science.gov (United States)

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

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

2010-01-01

30

Characteristics of pyrolyzed phenol-formaldehyde resin as an anode for lithium-ion batteries  

Science.gov (United States)

Polyacenic semiconductor (PAS) is obtained by pyrolyzing phenol-formaldehyde resin (PFR). The properties of PFR heat-treated at different temperatures are investigated. The lithium intercalation capacity of PAS as a function of heat-treatment temperature (HTT) exhibits a maximum at around 700 °C. A knee appears at 700 °C, not only in the plot of atomic ratio [H]/[C] versus HTT, but also in the plot of conductivity versus HTT. For PAS with a HTT of 700 °C, the maximum in the ratio of the relative intensity of Raman spectra at 1360 cm -1 corresponds to nanometer graphite, and that at 1580 cm -1 to graphite. A reasonable explanation of these phenomena is the transformation of nanometer graphite to graphite.

Huang, Biying; Huang, Yuzhen; Wang, Zhaoxiang; Chen, Liquan; Xue, Rongjian; Wang, Fosong

31

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

Science.gov (United States)

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

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

2013-01-01

32

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

Science.gov (United States)

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

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

2009-07-01

33

Phenol-formaldehyde carbon with ordered/disordered bimodal mesoporous structure as high-performance electrode materials for supercapacitors  

Science.gov (United States)

A novel phenol-formaldehyde carbon with ordered/disordered bimodal mesoporous structure is synthesized by the facile evaporation induced self-assembly strategy under a basic aqueous condition with SiO2 particles as template. The prepared bimodal mesoporous carbons (BMCs) are composed of ordered mesoporous and disordered mesoporous with diameter of about 3.5 nm and 7.0 nm, respectively. They can be employed as supercapacitor electrodes in H2SO4 aqueous electrolyte after the simple acid-treatment. BMC exhibits an exceptional specific capacitance of 344 F g-1 at the current density of 0.1 A g-1, although it has a relatively low surface area of 722 m2 g-1. And the BMC electrode displays an excellent cycling stability over 10,000 cycles.

Cai, Tingwei; Zhou, Min; Han, Guangshuai; Guan, Shiyou

2013-11-01

34

Ordered SiO2 (phenolic-formaldehyde resin) in situ nanocomposites  

Science.gov (United States)

Nanocomposite materials consisting of monodisperse SiO2 particles embedded in a polymerized resin matrix were produced by the adhesion of silica globules on the surface of a chemically modified phenolic-formaldehyde resin (MPFR) substrate that incorporates carboxylic groups in its molecules. Two routes were followed to obtain SiO2 nanoparticles-MPFR materials. The first procedure consisted of the growth of an SiO2 phase concurrently with the presence of MPFR molecules. The second procedure involved the preparation of a monodisperse SiO2 sol that was subsequently mixed with an MPFR solution. The thermal curing of the MPFR resin phase at 80 °C brought about thin SiO2-MPFR flakes from samples obtained from procedure 1 whilst monolithic pieces arose from samples from procedure 2. During the curing process, silanol surface groups of the silica globules reacted with carboxylic groups of the MPFR molecules to create a reinforced SiO2-MPFR substance that displayed ester bonds across the interface. Thermal treatments of specimens prepared by procedure 2 were performed at 150, 250, 400, 600 and 800 °C to monitor the integrity of the resultant hybrid substrates. To assess the characteristics of SiO2-MPFR materials, some of the main chemical, structural and textural characteristics of several specimens have been determined via FTIR, SEM and N2 adsorption studies.

Hernández-Padrón, G.; Rojas, F.; Castaño, V. M.

2004-01-01

35

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

Scientific Electronic Library Online (English)

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

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

2014-05-01

36

Selective detection of ferric ions by blue-green photoluminescent nitrogen-doped phenol formaldehyde resin polymer.  

Science.gov (United States)

The smaller, the more fluorescent: The hydrothermal reaction of phenol with hexamethylenetetramine (HMT) leads to two morphologies of phenol formaldehyde resin (PFR), namely, bigger nanoparticles with feeble green fluorescence and smaller amorphous polymers with strong blue-green fluorescence. It reveals that both of them are doped with nitrogen, and the blue-green photoluminescent polymer is confirmed to sense ferric ion (Fe(3+) ) with high selectivity. PMID:24863556

Zhang, Jia; Yuan, Yue; Yu, Zhi-Long; Yu, Aimin; Yu, Shu-Hong

2014-09-24

37

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

Directory of Open Access Journals (Sweden)

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

2011-08-01

38

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-01-10

39

Modified Phenol-Formaldehyde Resins for C-Fiber Reinforced Composites: Chemical Characteristics of Resins, Microstructure and Mechanical Properties of their Composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work correlates the chemistry of phenol-formaldehyde (PF) resins, its functionalities with their microstructural and mechanical properties in composite materials. The main focus is put on the development of the pores in dependence on the chemical composition of the resins and their influence on the structure of the material. Chemical characteristics of the synthesized resins are analyzed and physical/mechanical properties of the matrices based on PF resins are determined. Differences...

Kim, Young Eun

2011-01-01

40

Hierarchical porous carbons prepared by an easy one-step carbonization and activation of phenol-formaldehyde resins with high performance for supercapacitors  

Energy Technology Data Exchange (ETDEWEB)

Hierarchical porous carbons are prepared by an easy one-step process of carbonization and activation derived from phenol-formaldehyde resins, in which potassium hydroxide acts as both the catalyst of polymerization and the activation reagent. The simple one-step preparation saves the cost of carbons and leads to high yield. The porous carbons have high surface areas with abundant pore structures. The plenty of micropores and small mesopores increase the capacitance and make the electrolyte ions diffuse fast into the pores. These hierarchical porous carbons show high performance for supercapacitors possessing of the optimized capacitance of 234 F g{sup -1} in aqueous electrolyte and 137 F g{sup -1} in organic electrolyte with high capacitive retention. (author)

Zheng, Zhoujun [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Graduate School, Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China); Gao, Qiuming [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Graduate School, Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Dingxi Road, Shanghai 200050 (China); School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191 (China)

2011-02-01

 
 
 
 
41

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

Science.gov (United States)

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

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

2008-04-01

42

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

Science.gov (United States)

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

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

2007-05-01

43

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

Directory of Open Access Journals (Sweden)

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

Badamkhand Sukhbaatar

2009-05-01

44

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

International Nuclear Information System (INIS)

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

45

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-05-15

46

The synthesis of multi-walled carbon nanotubes (MWNTs) by catalytic pyrolysis of the phenol-formaldehyde resins  

Science.gov (United States)

A series of carbon nanomaterials, particularly multi-walled carbon nanotubes (MWNT), are obtained as products from catalytic pyrolysis of the cross-linked phenol-formaldehyde resins with different ferrocene under inert atmosphere. The morphology and structure of the samples were evaluated by TEM and XRD techniques. CNTs morphology is dependent on the iron nanoparticles and their forms (Fe, Fe 3C) resulted from ferrocene decomposition. The amount of nanotubes increases with iron content released from ferrocene catalyst during the pyrolysis process. Fe 3C nanoparticles drive the nucleation and the growth of carbon nanotubes during the pyrolysis process. Long (up to microns) well-defined MWNTs with small defects, ropes and disordered carbon are representatives in the pyrolyzed resins composition.

Stamatin, Ioan; Morozan, Adina; Dumitru, Anca; Ciupina, V.; Prodan, G.; Niewolski, J.; Figiel, H.

2007-03-01

47

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

Science.gov (United States)

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 °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.

Wang, Jigang; Jiang, Nan; Guo, Quangui; Liu, Lang; Song, Jinren

2006-01-01

48

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

International Nuclear Information System (INIS)

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

49

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  

Science.gov (United States)

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.

Qian, Haisheng; Zhu, Enbo; Zheng, Shunji; Li, Zhengquan; Hu, Yong; Guo, Changfa; Yang, Xingyun; Li, Liangchao; Tong, Guoxiu; Guo, Huichen

2010-12-01

50

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  

Energy Technology Data Exchange (ETDEWEB)

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.

Qian Haisheng; Zhu Enbo; Zheng Shunji; Yang Xingyun; Li Liangchao; Tong Guoxiu [Department of Chemistry, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China); Li Zhengquan; Hu Yong; Guo Changfa [Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Guo Huichen, E-mail: shqian@zjnu.cn, E-mail: ghch-2004@hotmail.com [State Key Laboratory of Veterinary Etiological Biology and Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 11, Lanzhou, Gansu 730046 (China)

2010-12-10

51

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

International Nuclear Information System (INIS)

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

52

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

International Nuclear Information System (INIS)

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

53

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aimed to evaluate the bonding quality of plywood panels from Pinus taeda using low and high molecular weight phenol-formaldehyde resin and veneers from three different density classes. The experiment consisted of six treatments, each of which produced three panels (replicates). Tests were conducted to evaluate glue line strength to shear stress after two boiling cycles and after 24 hours of cold water immersion. Also determined was the percentage of defects in wood samples. Results...

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

2013-01-01

54

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

Science.gov (United States)

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

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

2014-09-12

55

Synthesis of multifunctional Ag@Au@phenol formaldehyde resin particles loaded with folic acids for photothermal therapy.  

Science.gov (United States)

Multifunctional Ag@Au@ phenol formaldehyde resin (PFR) particles loaded with folic acids (FA) have been designed for killing tumor cells through photothermy conversion under the irradiation of near-infrared (NIR) light. Possessing the virtue of good fluorescence, low toxicity, and good targeting, the nanocomposite consists of an Ag core, an Au layer, a PFR shell, and folic acids on the PFR shell. The Ag@PFR core-shell structure can be prepared with a simple hydrothermal method after preheating. We then filled the PFR shell with a layer of Au by heating and modified the shell with polyelectrolyte to change its surface charge state. To capture tumor cells actively, FA molecules were attached onto the surface of the Ag@Au@PFR particles in the presence of 1-ethyl-3-(3-dimethly aminopropyl) carbodiimide (EDAC) and N-hydroxysuccinimide (NHS). Owing to the excellent property of Au NPs and Ag NPs as photothermal conversion agents, the Ag@Au@ PFR@FA particles can be utilized to kill tumor cells when exposed to NIR light. PMID:22744779

Yang, Ping; Xu, Qi-Zhi; Jin, Sheng-Yu; Lu, Yang; Zhao, Yang; Yu, Shu-Hong

2012-07-23

56

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

International Nuclear Information System (INIS)

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

57

Influence of Nanoclay/Phenol Formaldehyde Resin on Wood Polymer Nanocomposites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

58

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

Science.gov (United States)

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

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

2014-04-16

59

Influence of Nanoclay/Phenol Formaldehyde Resin on Wood Polymer Nanocomposites  

Directory of Open Access Journals (Sweden)

Full Text Available Selected tropical wood specie was low dense soft wood and it is abundantly available in Borneo Island. This specie is not suitable for construction materials due to their law physical and mechanical properties. In order to overcome this problem the wood species were impregnate by Nanoclay/PF resin system. Raw wood specimens were then placed into an impregnation chamber, in which there was no contact between samples and they were covered completely by nanoclay/PF mixtures. The system was evacuated to 60 mmHg for 30 min. After that, compressed air was applied to the system and maintained at a pressure of 0.52 MPa for 30 min then released. The excess chemicals wiped off the samples. FT-IR spectra indicate the decrease wave number of the peak, ascribed to C-O stretch of C-O-H in starch at 1317 cm-1 and 1222 cm-1 and C-O stretch of C-O-C in starch at 1027 cm-1 confirmed the impregnation of nanoclay/PF wood sample due to the fact that plasticizer could form intense H-bonding interaction with the hydroxyl groups. The MOE and MOR of WPNC were significantly increased compared with raw wood. The Young’s modulus of Eugenia sp. was significantly different between raw wood and WPNC. The XRD patterns of WPNC indicate that the crystallinity increases at the amorphous region due the monomer loading. The SEM micrograph of WPNC clearly shows the void space was filled by the monomer and removes the waxy substance.

Md. Saiful Islam

2012-01-01

60

Liquefaction of cornstalk in hot-compressed phenol-water medium to phenolic feedstock for the synthesis of phenol-formaldehyde resin.  

Science.gov (United States)

Cornstalk powders were effectively liquefied in a hot-compressed phenol-water medium (1:4 wt/wt). The optimum liquefaction temperature was around 350 degrees C, where the liquid yield attained a maximum at about 70 wt%. The addition of sodium carbonate showed negligible effect over the Liquefaction product yields. When liquefied in phenol-water medium, essentially no phenol was combined with the liquid products, and the cornstalk-derived bio-oils were partially degraded monomeric and oligomeric products with a broad molecular distribution. Resol type bio-based phenol formaldehyde resins were readily synthesized from the cornstalk-derived bio-oils catalyzed by sodium hydroxide. PMID:19058960

Wang, Mingcun; Xu, Chunbao Charles; Leitch, Mathew

2009-04-01

 
 
 
 
61

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

International Nuclear Information System (INIS)

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

62

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

Directory of Open Access Journals (Sweden)

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

Graciela Ines Bolzon de Muniz

2013-06-01

63

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

Directory of Open Access Journals (Sweden)

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

2009-12-01

64

Phenol formaldehyde resin nanoparticles loaded with CdTe quantum dots: a fluorescence resonance energy transfer probe for optical visual detection of copper(II) ions.  

Science.gov (United States)

A novel fluorescence resonance energy transfer (FRET) system has been designed for the Cu2+ ions detection with optical visual assays. In this FRET reaction, the biocompatible, green luminescent monodisperse phenol formaldehyde resin nanoparticles (PFR NPs) synthesized by a simple hydrothermal method were used as the acceptor and the luminescent CdTe quantum dots (QDs) were selected as the donor. By the layer-by-layer method, the polyelectrolyte (PEI/PSS/PEI) were absorbed alternately on the surface of the PFR NPs. As a result, the amino groups were stably modified onto the surface of the PFR NPs. In the presence of 1-ethyl-3-(3-dimethly aminopropyl) carbodiimide (EDAC) and N-hydroxysuccinimide (NHS), the carboxyl groups coated CdTe QDs prepared by using mereaptoactetic acid (MA) as the stabilizer in water solution were coupled to the surface of amino group functionalized PFR NPs to obtain novel FRET nanocomposites. Owing to the sensitive quenching effect of Cu2+ ions on CdTe QDs and effective energy transfer from CdTe QDs to PFR NPs, the as-prepared FRET nanocomposites were utilized to monitor Cu2+ ion with optical visual detection at room temperature within 1 min. This nanoparticle-based FRET probe should promote further development of other nanocomposites for Cu2+ ion detection in the environmental field. PMID:21344860

Yang, Ping; Zhao, Yang; Lu, Yang; Xu, Qi-Zhi; Xu, Xue-Wei; Dong, Liang; Yu, Shu-Hong

2011-03-22

65

Synthesis of Fe3O4@phenol formaldehyde resin core-shell nanospheres loaded with Au nanoparticles as magnetic FRET nanoprobes for detection of thiols in living cells.  

Science.gov (United States)

A magnetic, sensitive, and selective fluorescence resonance energy transfer (FRET) probe for detection of thiols in living cells was designed and prepared. The FRET probe consists of an Fe(3)O(4) core, a green-luminescent phenol formaldehyde resin (PFR) shell, and Au nanoparticles (NPs) as FRET quenching agent on the surface of the PFR shell. The Fe(3)O(4) NPs were used as the core and coated with green-luminescent PFR nanoshells by a simple hydrothermal approach. Au NPs were then loaded onto the surface of the PFR shell by electric charge absorption between Fe(3)O(4)@PFR and Au NPs after modifying the Fe(3)O(4)@PFR nanocomposites with polymers to alter the charge of the PFR shell. Thus, a FRET probe can be designed on the basis of the quenching effect of Au NPs on the fluorescence of Fe(3)O(4)@PFR nanocomposites. This magnetic and sensitive FRET probe was used to detect three kinds of primary biological thiols (glutathione, homocysteine, and cysteine) in cells. Such a multifunctional fluorescent probe shows advantages of strong magnetism for sample separation, sensitive response for sample detection, and low toxicity without injury to cellular components. PMID:22190410

Yang, Ping; Xu, Qi-Zhi; Jin, Sheng-Yu; Zhao, Yang; Lu, Yang; Xu, Xue-Wei; Yu, Shu-Hong

2012-01-23

66

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

Scientific Electronic Library Online (English)

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

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

67

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

Scientific Electronic Library Online (English)

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

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

2012-05-01

68

Investigation of the volatility of toxic elements on the base of phenol-formaldehyde resin in neutron activation analysis  

International Nuclear Information System (INIS)

The volatility of some elements being determined in biological and environmental samples by NAA (neutron activation analysis) in case of their binding with phenolformaldehyde resin (PFR) is studied. Since the temperature is assumed to influence the volatility of elements stronger than radiation during irradiation of samples in nuclear pile the losses of Se, As, Sb, and Hg form samples on the basis of PFR after their heating at 100-300 deg C have been investigated. It is shown that the losses of Sb and As up to 300 deg C, Se up to 250 deg C, and Hg up to 150 deg C from PFR - based samples do not occur

69

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

70

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-15

71

Development and Characterization of Phenol - Formaldehyde Molding Powder  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 s...

Edoga, M. O.; Kovo, A. S.

2006-01-01

72

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

73

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

International Nuclear Information System (INIS)

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

74

A two-temperature concentration of alkali solutions on phenol-formaldehyde sorbents  

Science.gov (United States)

The new phenomenon of a two-temperature non-reagent concentration of alkali solutions on sorbents based on the phenol-formaldehyde resin Amberlit XAD 761, PFR-1.4/0.7, and sulfonated phenol-formaldehyde ionite KU-1 was investigated. It was found that during an alkali solution's passage through a column with a sorbent and a periodical change in temperature in the "cold" stage, the concentration of alkali in the filtrate appeared to decrease, while in the "hot" stage, the alkali concentration appeared to increase. It was shown that the increase in alkali concentration in a solution in contact with phenol-formaldehyde resin is determined by the ion-exchange properties of the phenol groups, and is associated with an increase in water dissociation upon a rise in temperature.

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

2010-11-01

75

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

Directory of Open Access Journals (Sweden)

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

??

2012-07-01

76

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

Science.gov (United States)

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

2010-07-01

77

21 CFR 173.25 - Ion-exchange resins.  

Science.gov (United States)

...Sulfite-modified cross-linked phenol-formaldehyde, with modification resulting...epichlorohydrin. (7) Cross-linked phenol-formaldehyde activated with one or both...tetraethylenepentamine. (8) Reaction resin of formaldehyde,...

2010-04-01

78

Development and Characterization of Phenol - Formaldehyde Molding Powder  

Directory of Open Access Journals (Sweden)

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

M .O. Edoga

2006-01-01

79

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

Science.gov (United States)

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

2010-07-01

80

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

Directory of Open Access Journals (Sweden)

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

Nor Hafizah Ab. Wahab

2012-11-01

 
 
 
 
81

Synthesis of white light emitting mesoporous carbon-silica nanocomposite  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-05-15

82

Synthesis of white light emitting mesoporous carbon-silica nanocomposite  

Science.gov (United States)

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

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

2011-05-01

83

Preparation and characterization of phenol-formaldehyde adhesives modified with enzymatic hydrolysis lignin.  

Science.gov (United States)

Phenol-formaldehyde (PF) adhesives modified with enzymatic hydrolysis lignin (EHL) were synthesized by a one-step process. The phenol component of the PF adhesives was partially substituted by EHL extracted from the residues of cornstalks used to produce bio-ethanol. The EHL-PF adhesives were used to prepare plywoods by hot-pressing. The pH value, viscosity, solid content, free phenol content, free formaldehyde content and brominable substance content of EHL-PF resins were investigated. The bonding strengths of the plywoods were determined, and the influences of the replacement percentage of phenol by EHL (a) and the NaOH content (b) on the properties of the adhesives were investigated. The results showed that the performance of the modified adhesives and the plywoods glued with them almost met the Chinese National Standard (GB/T 14732-2006) for first grade plywood when 20 wt% of the phenol was replaced by EHL. PMID:19854642

Jin, Yanqiao; Cheng, Xiansu; Zheng, Zuanbin

2010-03-01

84

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

Scientific Electronic Library Online (English)

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

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

85

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

Scientific Electronic Library Online (English)

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

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

2013-06-01

86

21 CFR 177.2260 - Filters, resin-bonded.  

Science.gov (United States)

...dioxide. (3) Resins: Acrylic polymers...monomers: Acrylic acid, acrylonitrile...Phenol-formaldehyde resins. Polyvinyl alcohol...copolymer of acrylic acid-allyl sucrose... Phosphoric acid. (5) Colorants...chapter. (e) Resin-bonded...

2010-04-01

87

Investigation of radiation curing of phenol-formaldehyde oligomers  

International Nuclear Information System (INIS)

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

88

Radiation-chemical hardening of phenol-formaldehyde oligomers  

International Nuclear Information System (INIS)

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

89

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

Science.gov (United States)

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

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

2014-10-01

90

21 CFR 177.2260 - Filters, resin-bonded.  

Science.gov (United States)

...modified with methyl alcohol. Melamine-formaldehyde...Phenol-formaldehyde resins. Polyvinyl alcohol. Polyvinyl...the copolymer of acrylic acid-allyl sucrose...than 8 percent alcohol. (m) Resin-bonded filters fabricated from acrylic polymers...

2010-04-01

91

Surface modification of a natural graphite/phenol formaldehyde composite plate with expanded graphite  

Energy Technology Data Exchange (ETDEWEB)

Natural graphite/phenol formaldehyde (NG/PF) resin composite plates modified with thin layers of expanded graphite (EG) are fabricated by mold compression to lower the contact resistance between the plates and gas diffusion layers (GDLs). The modification considerably reduces contact resistance versus bare NG/PF plates. The extent of the decrease in contact resistance is influenced by the expanded volume of EG used. A low contact resistance of 1.42 m{omega} cm{sup 2} persists for the EG (150 ml g{sup -1})-modified NG/PF plates despite the PF content, whereas that of bare plates increases from 3.62 to 17.01 m{omega} cm{sup 2} as PF content changes from 5 wt% to 30 wt%. With increasing EG thickness on the surface of NG/PF plates, contact resistance at first decreases and then approaches a constant value when the NG layer exceeds 40 {mu}m. More importantly, the total electrical resistance, as expressed by volume resistance, can be reduced by applying EG layers to NG/PF composite plates. The reduction of total resistance is more remarkable for the composite plates with high PF content because the bulk resistance of the EG layer can be well compensated by the decrease of contact resistance at a proper range of EG layer thickness. (author)

Li, Dongjie; Wang, Yuxin; Xu, Li; Lu, Jun; Wu, Qian [State Key Laboratory of Chemical Engineering, Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin 300072 (China)

2008-09-01

92

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

International Nuclear Information System (INIS)

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

93

21 CFR 175.300 - Resinous and polymeric coatings.  

Science.gov (United States)

...formed by reacting rosin (paragraph...Pentaerythritol. (c ) Rosin esters (paragraph...reaction with: Maleic anhydride. o-, m...Phenol-formaldehyde. (d ) Rosin salts: Calcium...limed rosin). Zinc resinate. ...as esters of acids listed in...

2010-04-01

94

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

Science.gov (United States)

Ordered nitrogen-containing mesoporous carbonaceous polymers have been synthesized via a direct triblock-copolymer-templating process by using soluble, low-molecular-weight urea-phenol-formaldehyde (UPF) resin as an organic precursor and amphiphilic triblock copolymer Pluronic F127 as a template. Characterization using small-angle X-ray scattering (SAXS), N(2) sorption, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TG), Fourier transform infrared (FTIR), and water adsorption techniques reveals that the obtained nitrogen-containing mesoporous polymers possess ordered structures, high surface areas (385-420 m(2)/g), large pore sizes (3.1-3.6nm) and pore volumes (0.25-0.44cm(3)/g), and high nitrogen content (2.69-2.94%). Various mesostructures, such as two-dimensional (2-D) hexagonal (space group, p6mm) and 3-D body-centered cubic (Im3 m) symmetries, can be obtained by simply adjusting the mass ratio of UPF/F127. The content of nitrogen in the mesoporous polymers can also be easy varied by changing the amount of urea and the reaction time of UPF resin precursors. Compared with the nitrogen-free mesoporous polymer, the obtained mesoporous carbonaceous polymers show a more hydrophilic nature and thus evidently higher water adsorption capacity. The presence of nitrogen groups can also significantly improve the adsorption performance of Fe(III) ions. PMID:19926096

Yang, Jianping; Zhai, Yunpu; Deng, Yonghui; Gu, Dong; Li, Qiang; Wu, Qingling; Huang, Yan; Tu, Bo; Zhao, Dongyuan

2010-02-15

95

Phenol-formaldehyde intumescent coating composition and coating prepared therefrom  

Science.gov (United States)

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

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

1986-01-01

96

Synthesis and characterization of ordered mesoporous anion-exchange inorganic/organic hybrid resins for radionuclide separation  

International Nuclear Information System (INIS)

Ordered mesoporous anion-exchange hybrid resin materials were prepared by hydrolysis synthesis using the micellar template approach. The prepared samples were characterized via infrared spectroscopy, nitrogen sorption, and small-angle X-ray scattering. The uptakes of anionic thorium nitrate complexes by the new resins in 8 N nitric acid solutions were determined. The thorium loading capacity of the hybrid mesoporous silica functionalized with N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium is greater than that of the hybrid mesoporous silica functionalized with N-trimethoxylsilypropyl-N,N,N-trimethylammonium. The mesoporous hybrid anion-exchange resins were shown to be much more selective than a popular organic commercial anion-exchange resin

97

Pore development of thermosetting phenol resin derived mesoporous carbon through a commercially nanosized template  

International Nuclear Information System (INIS)

Mesoporous carbons (MCs) with high specific surface area and pore volume were synthesized from thermosetting phenol resin (TPR) by using commercial nanosized silica particles as template. Based on the results of thermogravimetric analysis, nitrogen adsorption, mercury adsorption and high-resolution transmission electron microscopy (HRTEM), mechanism of the pore formation of MCs was proposed. Silica particles not only participated in the pore formation of MCs but also influenced the thermosetting process of the carbon precursor. The mechanism of pore formation in the MCs may be described as follows: mesopores were introduced by the removal of silica particles; small mesopores were created by the combination of aperture between TPR and silica particles and opened pores in the matrix generated by the release of small molecules in the carbon during carbonization process; macropores were produced by the aggregation of silica particles and the collapse of carbon wall

98

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

Science.gov (United States)

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

Lin, Yi-Feng; Chen, Jia-Ling

2014-04-15

99

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-22

100

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

Science.gov (United States)

Mesoporous phenol formaldehyde (PF) polymer resin and carbon films are prepared by a solution self-assembly of PF oligomers with amphiphilic triblock copolymers. After thermopolymerization of the PF to cross-link the network, the films show an ordered morphology as determined by X-ray diffraction and grazing incidence small-angle X-ray scattering (GISAXS). Our results show that the amphiphilic triblock copolymer template greatly influences the stability of the final porous mesostructures. The pyrolysis of the two-dimensional (2-D) hexagonal films with p6mm symmetry templated by Pluronic F127 yields a disordered porous structure following the template removal. Conversely, films templated by Pluronic P123 can exhibit well-ordered cylindrical pores after the template removal, but the solution composition range to yield ordered cylindrical mesopores is significantly reduced (nearly 70%) for thin films in comparison to bulk powders. We propose two dominant difficulties in fabricating well-ordered cylindrical mesopores in films: first, the stress from contraction during the pyrolysis can lead to a collapse of the mesostructure if the wall thickness is insufficient, and second, the surface wetting behavior in thin films leads to a small compositional range. PMID:20000606

Song, Lingyan; Feng, Dan; Fredin, Nathaniel J; Yager, Kevin G; Jones, Ronald L; Wu, Quanyan; Zhao, Dongyuan; Vogt, Bryan D

2010-01-26

 
 
 
 
101

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

Directory of Open Access Journals (Sweden)

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

J. Lv

2012-10-01

102

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

International Nuclear Information System (INIS)

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

103

Bicontinuous gyroidal mesoporous carbon matrix for facilitating protein electrochemical and bioelectrocatalytic performances.  

Science.gov (United States)

A strategy of protein-entrapment in bicontinuous gyroidal mesoporous carbon (BGMC) nanocomposite films is described. Herein, the quasi-reversible electron transfer of redox proteins (such as glucose oxidase and myoglobin) is probed and the associated biocatalytic activity is revealed. The apparent heterogeneous electron transfer rate constant of the immobilized glucose oxidase is up to 9.4 s(-1), much larger than those in carbon nanotubes and some conventional mesoporous carbons. The BGMC based glucose biosensor enables the determination of glucose at a potential of 0.6 V (vs. SCE). Its detection limit is 1.0×10(-5) M (signal-to-noise ratio, S/N=3), the linear response is up to 7.49 mM and the detection sensitivity is 52.5 nA mM(-1) Furthermore, a series of BGMCs with different pore sizes is designed and synthesized using sucrose or phenol formaldehyde resin to study the influences of pore sizes and carbon sources on the immobilization of redox proteins and on the heterogeneous electron transfer. PMID:21238745

You, Chunping; Yan, Xuewu; Kong, Jilie; Zhao, Dongyuan; Liu, Baohong

2011-02-15

104

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

Science.gov (United States)

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

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

2012-05-01

105

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

International Nuclear Information System (INIS)

rst an increase and eventually a decrease in total exchange capacity as the absorbed radiation dose increases. The phenolic cation resins (phenol-formaldehyde base structure) show a loss of effective cross-linking and oxidation of the polymer chain. Analyses of resins removed from EPICOR-II prefilters PF-8 and -20 over the next several years should show a further increase in degradation

106

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

Directory of Open Access Journals (Sweden)

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

Ramazan Kurt

2012-11-01

107

Thermal rearrangement of novolak resins used in microlithography  

Science.gov (United States)

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

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

1995-06-01

108

White-rot fungi demonstrate first biodegradation of phenolic resin.  

Science.gov (United States)

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

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

2006-07-01

109

Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Edoga, Mathew Obichukwu

2006-01-01

110

Isolation and identification of novel high strength phenol degrading bacterial strains from phenol-formaldehyde resin manufacturing industrial wastewater.  

Science.gov (United States)

Phenols are toxic to all types of organisms. Two bacterial strains capable of utilizing phenol as a sole carbon source were isolated from the phenol bearing industrial wastewater. Based on the biochemical test results the organisms were identified as Pseudomonas cepacia and Bacillus brevis. The organisms were very efficient in phenol degradation, the lag phase increased with increase in phenol concentration. The well-acclimatized cultures of P. cepacia and B. brevis degraded 2500 and 1750 mg l(-1) of phenol in 144 h, respectively. The organisms degrade phenol even in the presence of toxicants like thiocyanate, sulphide and cyanide. The organisms can be effectively used for treating high strength phenol containing thiocyanate, sulphide and cyanide. The P. cepacia degrades phenol with a faster rate than B. brevis. P. cepacia can be used effectively for treating high strength phenolic wastewater. PMID:16154261

Arutchelvan, V; Kanakasabai, V; Nagarajan, S; Muralikrishnan, V

2005-12-01

111

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2009-01-01

112

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

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this research project was to study the effects of hybrid adhesives of Phenol-Formaldehyde (PF and Polymeric Diphenylmethane Diisocyanate (MDI on the properties of Oriented Strand Lumber (OSL to determine the optimal ratio of both adhesives. The results showed that OSL formed by pure adhesive or hybrid adhesives (3 blends: 25:75, 50:50 and 75:25 had properties that pass the CSA O437.1 standards, such as (1 modulus of rupture, (2 modulus of elasticity, and (3 internal bond strength. However, the thickness swelling and bond durability of OSL formed by pure MDI failed to pass the standards, while those formed by pure PF or hybrid adhesives passed. Among the three blends of adhesives, the blend 75:25 (PF: MDI gave the best properties while ratio of 50:50 gave the worst properties, especially internal bond strength due to the phase separation of both adhesives. In addition, the modulus of rupture and modulus of elasticity in the "edgewise" direction were higher than those in the "flatwise" direction. In the edgewise direction, load is transferred in the direction of width of strand that is large while in the flatwise direction, load is transferred in the direction of thickness of strand which is small.

Wanchart Preechatiwong

2007-09-01

113

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

Directory of Open Access Journals (Sweden)

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

Wei-Cheng Chu

2013-11-01

114

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

115

Synthetic-resin-free wood panel adhesives from mixed low molecular mass lignin and tannin  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Mixed interior wood panel tannin adhesive formulations were developed in which lignin is in considerable proportion, 50%, of the wood panel binder and in which no “fortification” with synthetic resins, such as isocyanates and phenol-formaldehyde resins as used in the past, was necessary to obtain results satisfying relevant standards. A low molecular mass lignin obtained industrially by formic acid/acetic acid pulping of wheat straw was used. Environment-friendly, non-...

2010-01-01

116

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

International Nuclear Information System (INIS)

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

117

Efficient synthesis and sulfonation of ordered mesoporous carbon materials.  

Science.gov (United States)

Ordered mesoporous carbons (OMCs) with hexagonal structure were efficiently synthesized via cooperative self-assembly of phenol/formaldehyde resol and surfactant F127 under acidic aqueous conditions. Induced by HCl, a gel phase mainly containing phenol/formaldehyde resol and F127 was obtained within several hours. X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption isotherms indicated that the synthesized samples possess 2-D hexagonal mesostructure. The influence of the synthesis conditions, including acid concentration and mass ratio of resol to F127, was investigated. When the acid concentration was fixed in the range of 0.6-2.0 M and the mass ratio of resol to F127 in the range of 3.5-4.0, highly ordered mesoporous carbon could be synthesized. The synthesized OMCs could be easily sulfonated in concentrated sulfuric acid at elevated temperature. The results indicate that the mesostructural stability and the content of the surface sulfonic acid (SO(3)H) groups depend mainly on the pyrolysis temperature of the OMCs and the sulfonation temperature, suggesting that the combination of pyrolysis and sulfonation temperature is essential for developing OMCs with high densities of SO(3)H groups. PMID:22487231

Hou, Keke; Zhang, Anfeng; Gu, Lin; Liu, Min; Guo, Xinwen

2012-07-01

118

Composite material based on an ablative phenolic resin and carbon fibers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, a technological procedure for the production of a molding compound based on short carbon fibers and an ablative phenol–formaldehyde resin for high temperature application was optimized. The starting raw materials were characterized and molding compounds with different fiber/matrix ratios and different fiber lengths were obtained. From the different laboratory samples, molded parts were made by thermocompression. The basic mechanical and thermal properties of the composites we...

DIMKO DIMESKI; GORDANA BOGOEVA-GACEVA; VINETA SREBRENKOSKA

2009-01-01

119

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

120

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

International Nuclear Information System (INIS)

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

 
 
 
 
121

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-09-01

122

Investigation of colloid-chemical interaction of chelate-forming resins with metals during electrodeposition  

International Nuclear Information System (INIS)

Colloid-chemical interaction of chelate-forming resins with metals, including cadmium, during their electrochemical codeposition has been investigated. Phenol-formaldehyde resins modified by 0-aminobenzoic, 0-hydroxybenzoic or NN-phenyliminodiacetic acids were used as chelate-forming resins. The chelation process has been investigated using IR-spectroscopy. X-ray diffraction analysis permits to affirm that in the course of metal electrocrystallization together with polymer (oligomer), a metal crystal lattice distortion takes place. Joint electrodeposition influences the dispersion grade of the deposited metal. Change of coating structure at chelation results in changing the number of their properties, in particular, in corrosion and thermal stability increase

123

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

Science.gov (United States)

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

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

2014-01-01

124

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Crown, S. C.

2004-01-01

125

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

Science.gov (United States)

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

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

2014-08-27

126

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

Scientific Electronic Library Online (English)

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

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

2012-12-01

127

Radiation testing of organic ion exchange resins  

International Nuclear Information System (INIS)

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

128

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

International Nuclear Information System (INIS)

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

129

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

International Nuclear Information System (INIS)

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

130

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

International Nuclear Information System (INIS)

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

131

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

Science.gov (United States)

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

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

2009-07-01

132

Synthesis of a boron modified phenolic resin  

Directory of Open Access Journals (Sweden)

Full Text Available Phenolic resin has long been used as matrix for composites mainly because of its flame retardant behavior and high char yield after pyrolysis, which results in a self supporting structure. The addition of ceramic powders, such as SiC and B4C, as fillers to the phenolic resin, results in better thermo-oxidative stability, but as drawbacks, it has poor homogeneity, adhesion and processing difficulties during molding of the composites. The addition of single elements, such as boron, silicon and phosphorus in the main backbone of the thermo-set resin is a new strategy to obtain special high performance resins, which results in higher mechanical properties, avoiding the drawbacks of simply adding fillers, which results in enhanced thermo-oxidative stability compared to conventional phenol-formaldehyde resins. Therefore, the product can have several applications, including the use as ablative thermal protection for thermo-structural composites. This work describes the preparation of a boron-modified phenolic resin (BPR using salicyl alcohol and boric acid. The reaction was performed in refluxing toluene for a period of four hours, which produced a very high viscosity amber resin in 90% yield.The final structure of the compound, the boric acid double, substituted at the hydroxyl group of the aromatic ring, was determined with the help of the Infrared Spectroscopy, ¹H-NMR, TGA-DSC and boron elemental analysis. The absorption band of the group B-O at 1349 cm ?¹ can be visualized at the FT-IR spectrum. ¹H-NMR spectra showed peaks at 4.97-5.04 ppm and 3.60-3.90 ppm assigned to belong to CH2OH groups from the alcohol. The elemental analysis was also performed for boron determination.The product has also been tested in carbon and silicon fibers composite for the use in thermal structure. The results of the tests showed composites with superior mechanical properties when compared with the conventional phenolic resin.

Aparecida M. Kawamoto

2010-08-01

133

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

CERN Document Server

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

Crown, S C

2004-01-01

134

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

International Nuclear Information System (INIS)

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

135

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

Science.gov (United States)

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

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

2014-01-28

136

Ethylated Urea - Ether - Modified Urea - Formaldehyde Resins,  

Directory of Open Access Journals (Sweden)

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

Mathew Obichukwu EDOGA

2006-07-01

137

Thermosetting Resins  

Science.gov (United States)

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

Peng, W.; Riedl, B.

1995-07-01

138

Copper and boron fixation in wood by pyrolytic resins.  

Science.gov (United States)

A phenol-formaldehyde (PF)-resin designed to penetrate wood and immobilize copper and boron in wood cells for protection against decay was investigated. The phenol portion of the PF-resin was partially substituted with pyrolysis oil derived from softwood bark. The objective was to reduce the environmental impact associated with the production of petroleum-borne phenol, as well as to improve the product economics. Leaching tests were conducted with three different formulas of resins containing 50%, 75% or 85% by weight of pyrolytic oil on a total phenol basis. The leachates were analyzed for the presence of copper by atomic absorption spectroscopy while inductively coupled plasma spectroscopy was used for boron detection. Copper leaching was reduced up to 18 times when comparing the treatments with and without the resin. Preservative leaching varied between wood species as well as between the resins containing different concentrations of pyrolytic oil. The organic leachates were measured using gas chromatography and mass spectroscopy. Trace amounts of organics, mostly acetic acid, were found in the leachates. PMID:18835155

Mourant, Daniel; Yang, Dian-Qing; Lu, Xiao; Riedl, Bernard; Roy, Christian

2009-02-01

139

Pyrolysis of foundry sand resins: a determination of organic products by mass spectrometry.  

Science.gov (United States)

Pyrolysis-gas chromatography-mass spectrometry (MS) was used to identify the major organic products produced by pyrolysis of three foundry sand resins: (i) Novolac and (ii) phenolic urethane (PU) (both phenol-formaldehyde based resins) and (iii) furan (furfuryl alcohol based resin). These resins are used in the metal casting industry as a "sand binder" for making cores (used to produce cavities in molds) and molds for nonferrous castings. During the casting process, the cores and molds are subjected to intense heat from the molten metal. As a result, the organic resins undergo thermal decomposition and produce a number of complex organic compounds. In this study, the organics were tentatively identified by MS after pyrolysis of the resins at 750 degrees C. The major thermal decomposition products from the Novolac, PU, and furan resins were derivatives of phenol, benzene, and furan, respectively. Compounds identified that are of potential environmental concern were benzene, toluene, phenol, o- and p-xylene, o- and m-cresol, and polycyclic aromatic hydrocarbons. Pyrolysis of the Novolac resin resulted in the generation of the most compounds of environmental concern. Because there is interest in beneficially using foundry molding sands in manufactured soils and other agricultural products, it is necessary that organic thermal decomposition products be identified to ensure environmental protection. PMID:15991723

Dungan, Robert S; Reeves, James B

2005-01-01

140

???????????????? ??????????? ??????-?????????????????????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Methods differential-thermal and thermogravimetryque analyses investigate influence epoxy resin and polivinilpirolidone on thermal stability novolac phenol-formaldehyde resin. The comparative analysis of thermal stability of developed epoxy-novolac composition and phenol-formaldehyde resin is carried out. The sample of epoxy-novolac composition is characterized by higher thermal stability than phenol- formaldehyde resin sample.

????????????, ?. ?.; ????????, ?. ?.; ???????, ?? ?.

2008-01-01

 
 
 
 
141

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-10-15

142

24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.  

Science.gov (United States)

...coated with a surface finish containing formaldehyde, other than an exclusively phenol-formaldehyde resin system or finish, shall be certified...formaldehyde, other than an exclusively phenol-formaldehyde resin system, shall be stamped or...

2010-04-01

143

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

International Nuclear Information System (INIS)

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

144

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-08-01

145

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

International Nuclear Information System (INIS)

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

146

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

Science.gov (United States)

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

Dai, Mingzhi; Vogt, Bryan D

2012-12-01

147

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

Directory of Open Access Journals (Sweden)

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

Mohamad Jani Saad

2012-07-01

148

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

Directory of Open Access Journals (Sweden)

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

Abdul Hamid Saleh

2012-05-01

149

21 CFR 173.25 - Ion-exchange resins.  

Science.gov (United States)

...Cross-linked phenol-formaldehyde activated with one or both of the following: Triethylene...more of the following: bicarbonate, calcium, carbonate, chloride, hydrogen...subjected to treatment through a bed of activated carbon or one of the strongly...

2010-04-01

150

Mesoporous carbon materials  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-09-09

151

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

Directory of Open Access Journals (Sweden)

Full Text Available The research involves using phenol ? formaldehyde (Novolak resin as matrix for making composite material, while glass fiber type (E was used as reinforcing materials. The specimen of the composite material is reinforced with (60% ratio of glass fiber.The impregnation method is used in test sample preparation, using molding by pressure presses.All samples were exposure to (Co60 gamma rays of an average energy (2.5Mev. The total doses were (208, 312 and 728 KGy. The mechanical tests (bending, bending strength, shear force, impact strength and surface indentation were performed on un irradiated and irradiate samples.All of the mechanical properties were improved with an increase in radioactive dose of up to (312 KGy to be decreased afterwards.The topography of some physically tested specimens was studied using optical microscopy.

Muhammad Slab Hamza

2009-01-01

152

Responsive mesoporous photonic cellulose films by supramolecular cotemplating.  

Science.gov (United States)

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

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

2014-08-18

153

46 CFR Table II to Part 150 - Grouping of Cargoes  

Science.gov (United States)

...phenol sulfide mixture Nonyl phenol Octyl phenol Phenol Xylenols 22. Caprolactam Solutions Caprolactam...Toluene, Xylene mixtures Butylbenzene Butyl phenol, Formaldehyde resin in Xylene Butyl toluene Cumene Cymene...

2010-10-01

154

21 CFR 175.125 - Pressure-sensitive adhesives.  

Science.gov (United States)

...Rubber (natural latex solids or crepe, smoked or unsmoked). Terpene resins (?- and ?-pinene), homopolymers, copolymers, and condensates with phenol, formaldehyde, coumarone, and/or indene. Tetrasodium...

2010-04-01

155

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

Directory of Open Access Journals (Sweden)

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

M.T. Paridah

2011-01-01

156

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

Directory of Open Access Journals (Sweden)

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

Jheng-Guang Li

2014-06-01

157

Morphology control in mesoporous carbon films using solvent vapor annealing.  

Science.gov (United States)

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

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

2013-03-12

158

Mesoporous aluminum phosphite  

International Nuclear Information System (INIS)

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

159

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

Science.gov (United States)

Mesoporous polymer and carbon thin films are prepared by the organic-organic self-assembly of an oligomeric phenolic resin with an amphiphilic triblock copolymer template, Pluronic F127. The ratio of resin to template is selected such that a body-centered cubic (Im3m) mesostructure is formed in the bulk. However, well-ordered mesoporous films are not always obtained for thin films (FCO) structures. Ultrathick films having more than 30 layers of spheres are similar to the bulk body-centered cubic symmetry with a preferential orientation of the closest-packed (110) plane parallel to the substrate. Film thickness and initial composition of the carbonizable precursors in the template are critical factors in determining the morphology of mesoporous carbon films. These results provide insight into why difficulties have been reported in producing ultrathin ordered mesoporous carbon films using cooperative organic-organic self-assembly. PMID:21466222

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

2011-05-01

160

Mesoporous carbon materials  

Science.gov (United States)

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

Dai, Sheng; Wang, Xiqing

2013-08-20

 
 
 
 
161

Templating mesoporous zeolites  

DEFF Research Database (Denmark)

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

Egeblad, Kresten; Christensen, Christina Hviid

2008-01-01

162

Mesoporous aluminum phosphite  

Science.gov (United States)

High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S +I - surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N 2 adsorption-desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed.

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

2009-08-01

163

Mesoporous materials and electrochemistry.  

Science.gov (United States)

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

Walcarius, Alain

2013-05-01

164

Macroreticular p-(omega-sulfonic-perfluoroalkylated) polystyrene ion-exchange resins: a new type of selective solid acid catalyst.  

Science.gov (United States)

Macroreticular p-(omega-sulfonic-perfluoroalkylated) polystyrene (FPS) cation-exchange resins have been synthesized by sequential p-perfluoroalkylation of macroreticular polystyrene (PS) with omega-fluorosulfonylperfluorodiacyl peroxide 2, hydrolysis and acidification; the fluorinated mesoporous resins exhibited higher activity and selectivity than commercial Amberlyst 36 and Nafion NR50 in the cyclization of pseudoionone. PMID:16010322

Lin, Zhenghuan; Zhao, Chengxue

2005-07-28

165

21 CFR 175.105 - Adhesives.  

Science.gov (United States)

...urea-formaldehyde resin Starch, reacted with formaldehyde Stearamide...Styrenated phenol Styrene... Terpene resins (?-and...condensates with phenol, formaldehyde, coumarone...Triazine-formaldehyde resins as described... phenyl phenol For...

2010-04-01

166

21 CFR 177.2600 - Rubber articles intended for repeated use.  

Science.gov (United States)

...centipoises. Styrenated phenol. 4,4?-Thiobis...nonylphenyl) phosphite-formaldehyde resins produced when 1 mole...Petroleum hydrocarbon resin (produced by the...oil, sulfonated. Phenol-formaldehyde resin. Pine tar....

2010-04-01

167

Nano Hibrid Resin Komposit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Panto, Vincent

2011-01-01

168

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

Science.gov (United States)

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

Sridhar, Manasa

169

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

Science.gov (United States)

A soft-phase intercalating process to synthesize mesostructured plasticine by using amphiphilic triblock copolymer F127 as a structure-directing agent, reverse triblock copolymer 25R4 as an intercalating soft matter, and soluble phenolic resin as a carbon source is demonstrated. The "plasticine" has interlayer organic-organic hybrid structure, which is emplastic, sticky, and able to be easily shaped at will. After template removal at 350 degrees C and further carbonization at 600 degrees C, highly ordered mesoporous polymers and carbons can be successively obtained with the maintenance of the original shape. The self-supported, shape-controlled, ordered mesoporous carbon products possess high surface areas (495-777 m(2)/g), large pore volumes (0.32-0.47 cm(3)/g), uniform pore sizes (2.5-4.3 nm) in the nanoscale and hollow tremella-like morphology in the micronscale which may facilitate mass transportation. PMID:19406429

Qian, Xu-Fang; Wang, Zheng; Wan, Ying

2009-07-15

170

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

Science.gov (United States)

...MBK Butyl phenol, Formaldehyde resin in Xylene32...alkyl(C9)phenol sulfide, polyolefin...Magnesium nonyl phenol sulfide, see...Methacrylic resin in Ethylene dichloride...sulfonic acid-formaldehyde...

2010-10-01

171

Review: Resin Composite Filling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

172

Adsorption of alkaloids on ordered mesoporous carbon.  

Science.gov (United States)

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

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

2013-10-15

173

Simple synthesis of mesoporous carbon nanofibers with hierarchical nanostructure for ultrahigh lithium storage.  

Science.gov (United States)

In this study, a simple and reproducible synthesis strategy was developed to fabricate mesoporous carbon nanofibers (MCNFs) by using dual hard templates, a porous anodic aluminum oxide (AAO) membrane, and colloidal silica (Ludox TM-40). By using commercial templates, and removing AAO and the silica simultaneously, the synthesis procedures for MCNFs are greatly simplified without the need for separate preparation or the removal of templates in sequence. With phenol resin as a carbon precursor, the as-prepared MCNFs material reveals not only high surface area and mesoporous volume but also hierarchical nanostructure composed of hollow macrochannels derived from the AAO template, large mesopores (ca. 22 nm) from the removal of silica particles and micropores from the carbonization of phenol resin. Such unique surface and structural characteristics could provide a large quantity of active sites for Li storage and facilitate fast mass transport. Moreover, a one-dimensional (1D) carbon nanofiber (CNF) nanostructure favors fast electron transfer. The as-prepared MCNF anode demonstrates ultrahigh lithium storage capacity particularly at high rates, which is much higher than that reported for the commercial graphite and also significantly higher than other nanostructured carbon materials, such as ordered mesoporous carbon CMK-3 and ordered multimodal porous carbon (OMPC). PMID:24490802

Xing, Yalan; Wang, Yanjie; Zhou, Chungen; Zhang, Shichao; Fang, Baizeng

2014-02-26

174

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

Science.gov (United States)

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

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

2010-06-01

175

Engineered monodisperse mesoporous materials  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-08-01

176

Immobilization of spent resin with epoxy resin  

International Nuclear Information System (INIS)

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

177

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

Science.gov (United States)

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

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

2013-08-16

178

Mesoporous Silicate Materials in Sensing  

Directory of Open Access Journals (Sweden)

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

Paul T. Charles

2008-08-01

179

Single crystalline mesoporous silicon nanowires  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-08-18

180

Review: Resin Composite Filling  

Directory of Open Access Journals (Sweden)

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

Desmond Ng

2010-02-01

 
 
 
 
181

Composition for reinforcing weakly cemented productive bed  

Energy Technology Data Exchange (ETDEWEB)

A composition is proposed for reinforcing weakly cemented productive bed containing phenol formaldehyde or urea formaldehyde resin, hardener and water. It is distinguished by the fact that in order to preserve the permeability of the near-face zone of the weakly cemented productive bed, it contains the hardener of hydroxylamine hydrochloride with the following ratio of components (percent by weight): phenol formaldehyde resin or urea formaldehyde resin 45-55, hydroxylamine hydrochloride 0.03-0.5, water--the rest.

Sherstyanoy, M.L.; Belgov, A.A.; Fisenko, N.T.; Panov, B.D.; Seorozhenko, A.G.; Shved, G.M.; Yeremeyev, G.F.

1982-01-01

182

Magnetic mesoporous material for the sequestration of algae  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-09-09

183

Synthesis and characterization of mesoporous materials  

Science.gov (United States)

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

Cheng, Wei

184

Asphaltene-resin association  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-07-01

185

Surfactant-Templated Mesoporous Metal Oxide Nanowires  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We demonstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta2O5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous 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 sca...

Stacy Baber; Qianglu Lin; Hongmei Luo; Mahesh Naalla

2010-01-01

186

Resin Longevity Studies  

International Nuclear Information System (INIS)

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

187

Synthesis of non-siliceous mesoporous oxides.  

Science.gov (United States)

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

Gu, Dong; Schüth, Ferdi

2014-01-01

188

Cellular membrane trafficking of mesoporous silica nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

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

Fang, I-Ju

2012-06-21

189

Mesoporous sandwiches: towards mesoporous multilayer films of crystalline metal oxides.  

Science.gov (United States)

Alternating multilayers of ordered mesoporous films of different metal oxides were prepared with the EISA (evaporation-induced self-assembly) method, using block copolymer templates. Selecting certain metal oxides, as exemplified with TiO2 and WO3 in this work, a high mesoscopic order could be achieved and preserved during crystallization. In addition to standard characterizations, the electrochromism of the multilayer film was studied, proving good accessibility of the single layers. PMID:19421475

Ostermann, Rainer; Sallard, Sébastien; Smarsly, Bernd M

2009-05-21

190

21 CFR 175.105 - Adhesives.  

Science.gov (United States)

...Polyoxyethylene (40 moles) stearate Polyoxyethylene...Phthalic anhydride Polyethylene glycol Phenol-formaldehyde...Potassium Sodium Zinc Rosin, gasoline-insoluble...resins. Stannous stearate Starch hydrolysates...acid 4-ester with polyethylene glycol dodecyl...

2010-04-01

191

21 CFR 177.2910 - Ultra-filtration membranes.  

Science.gov (United States)

...prescribed conditions; (a)(1) Ultra-filtration membranes that consist of paper impregnated with cured phenol-formaldehyde resin, which is used as a support and is coated with a vinyl chloride-acrylonitrile copolymer. (2)...

2010-04-01

192

40 CFR 63.1381 - Definitions.  

Science.gov (United States)

...emissions. Bonded means wool fiberglass to which a phenol-formaldehyde binder has been applied. Building insulation ...and which may include a curing section where binder resin in the mat is thermally set and a cooling...

2010-07-01

193

[Utilization of organic resources in paper pulp waste liquid].  

Science.gov (United States)

In this paper, one hundred percent of condensed sulfate paper pulp waste liquid was used as the raw material of adhesive, and the activation of its lignin as well as the improving effects of phenol formaldehyde resin and polyfunctional aqueous polymer isocyanate (PAPI) were studied. The results showed that adding formaldehyde to the waste liquid could increase the reactivity of contained lignin, and adding 30% phenol formaldehyde resin or 20% PAPI could make the waste liquid in place of pure phenol formaldehyde resin for producing class I plywood. Furthermore, the cost could be reduced by 55.5% and 49.0%, respectively, in comparing with pure phenol formaldehyde resin. This approach fully used the organic resources in paper pulp waste liquid, reduced environment pollution at the same time, and had unexceptionable economic, social and ecological benefits. The feasibility of preparing adhesives from paper pulp waste liquid was also analyzed by infrared spectrum. PMID:16011170

Lin, Qiaojia; Liu, Jinghong; Yang, Guidi; Huang, Biao

2005-04-01

194

Control of ordering and structure in soft templated mesoporous carbon films by use of selective solvent additives.  

Science.gov (United States)

The structure of ordered mesoporous carbons fabricated using poly(styrene-block-N,N,-dimethyl-n-octadecylamine p-styrenesulfonate) (PS-b-PSS-DMODA) as the template and phenolic resin (resol) as the carbon source can be easily manipulated by inclusion of low concentrations of low volatility selective solvents in the casting solution. Casting from neat methyl ethyl ketone yields a disordered structure even upon thermal annealing. However, addition of both dioctyl phthalate (DOP, PS selective) and dimethyl sulfoxide (DMSO, resol and PSS-DMODA selective) at modest concentrations to this casting solution provides sufficient mobility to produce highly ordered films with cylindrical mesopores. The DOP acts to swell the hydrophobic domain and can more than double the mesopore size, while the DMSO acts to swell the resol phase. Moreover, the surface area of the mesoporous carbons increases significantly as the meosopore size increases. This is a result of the decrease in wall thickness, which can be ascertained by the constant d-spacing of the mesostructure as the pore size increases. This behavior is counter to the typical effect of pore swelling agents that increase the pore size and decrease the surface area. Moreover, with only 4 wt % DOP/DMSO in the solution (20 wt % relative to solids), the scattering profiles exhibit many orders of diffraction, even upon carbonization, which is not typically observed for soft templated films. Variation in the concentration of DOP and DMSO during casting enables facile tuning of the structure of mesoporous carbon films. PMID:23738851

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

2013-07-01

195

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-01-01

196

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

Scientific Electronic Library Online (English)

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

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

2008-08-01

197

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

Directory of Open Access Journals (Sweden)

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

Fabrício Gomes Gonçalves

2008-08-01

198

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Sua?rez Garci?a, Fabia?n; Vilaplana Ortego, Eduardo; Kunowsky, Mirko; Kimura, M.; Oya, Asao; Linares Solano, A?ngel

2009-01-01

199

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-03-30

200

Pseudomorphic synthesis of mesoporous zeolite Y crystals.  

Science.gov (United States)

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

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

2010-11-01

 
 
 
 
201

Polyvinyl chloride resin  

International Nuclear Information System (INIS)

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

202

Non-destructively shattered mesoporous silica for protein drug delivery  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-15

203

Chemical preparation of ferroelectric mesoporous barium titanate thin films: drastic enhancement of curie temperature induced by mesopore-derived strain.  

Science.gov (United States)

Mesoporous barium titanate (BT) thin films are synthesized by a surfactant-assisted sol-gel method. The obtained mesoporous BT thin films show enhanced ferroelectricity due to the effective strains induced by mesopores. The Curie temperature (Tc ) of the mesoporous BT reaches approximately 470?°C. PMID:25111152

Suzuki, Norihiro; Jiang, Xiangfen; Salunkhe, Rahul R; Osada, Minoru; Yamauchi, Yusuke

2014-09-01

204

Fabrication and analytical applications of hybrid mesoporous membranes.  

Science.gov (United States)

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

Yamaguchi, Akira; Teramae, Norio

2008-01-01

205

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

Science.gov (United States)

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

2014-01-01

206

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

Science.gov (United States)

The paper reports a novel approach to achieve self-healing surface hydrophobicity. Mesoporous silica is used as the reservoir for hydrophobic molecules, i.e., octadecylamine (ODA), that can release and refresh the surface hydrophobicity consecutively. A polymdopamine layer is used to further encapsulate silica-ODA, providing a reactive layer, governing release of the underlying ODA, and improving the dispersivity of silica nanoparticles in bulk resin. The approach arrives at self-healing (super)hydrophobicity without using any fluoro-containing compounds. PMID:22397693

Liu, Qinze; Wang, Xiaolong; Yu, Bo; Zhou, Feng; Xue, Qunji

2012-04-01

207

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

Science.gov (United States)

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

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

2014-01-01

208

Incombustible resin composition  

Science.gov (United States)

Incombustible resin compositions composed of aromatic compounds were obtained through (1) combustion polymer material and (2) bisphenol A or halogenated bisphenol A and bisphenol A diglycidl ether or halogenated bisphenol A diglycidyl ether. The aromatic compound is an adduct of bifunctional phenols and bifunctional epoxy resins.

Akima, T.

1982-01-01

209

Single crystalline mesoporous silicon nanowires  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-08-04

210

Synthesis and characterization of mesoporous zirconia and aluminated mesoporous zirconia  

Science.gov (United States)

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

Zhao, Elizabeth Sun

211

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Zhang, Li; Mohanty, Paritosh; Coombs, Neil; Fei, Yingwei; Mao, Ho-kwang; Landskron, Kai

2010-01-01

212

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

Science.gov (United States)

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

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

2013-11-01

213

Surfactant-Templated Mesoporous Metal Oxide Nanowires  

Directory of Open Access Journals (Sweden)

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

Stacy Baber

2010-01-01

214

Hydrothermal Synthesis of Loessial Mesoporous Materials  

Science.gov (United States)

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.

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

2010-11-01

215

Handedness inversion in preparing mesoporous silica nanoribbons  

International Nuclear Information System (INIS)

A new chiral cationic amphiphile has been synthesized. Sol-gel transcriptions were carried out to control mesoporous silica nanostructures using the organic self-assemblies of this amphiphile as templates. Left-handed coiled mesoporous silica nanoribbons were obtained in the mixture of 1-propanol and 2.5 wt% NH3 aq. at the ratio of 2:8 and 0 deg. C. However, right-handed coiled mesoporous silica nanoribbons were prepared in 2.5 wt% NH3 aq. at 25 deg. C. The organization of the low-molecular-weight gelators plays an important role in this handedness inversion

216

Handedness inversion in preparing mesoporous silica nanoribbons  

Energy Technology Data Exchange (ETDEWEB)

A new chiral cationic amphiphile has been synthesized. Sol-gel transcriptions were carried out to control mesoporous silica nanostructures using the organic self-assemblies of this amphiphile as templates. Left-handed coiled mesoporous silica nanoribbons were obtained in the mixture of 1-propanol and 2.5 wt% NH{sub 3} aq. at the ratio of 2:8 and 0 deg. C. However, right-handed coiled mesoporous silica nanoribbons were prepared in 2.5 wt% NH{sub 3} aq. at 25 deg. C. The organization of the low-molecular-weight gelators plays an important role in this handedness inversion.

Chen Yuanli; Guo Yongmin; Zhao Huanyu; Bi Lifeng; Pei Xianfeng; Li Baozong; Yang Yonggang [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry and Chemical Engineering, Suzhou (Soochow) University, Suzhou 215123 (China)], E-mail: libaozong@suda.edu.cn, E-mail: ygyang@suda.edu.cn

2008-09-03

217

Drug Loading of Mesoporous Silicon  

Science.gov (United States)

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

Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

2011-03-01

218

Reduction of polyester resin shrinkage by means of epoxy resin  

International Nuclear Information System (INIS)

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

219

Reduction of polyester resin shrinkage by means of epoxy resin  

International Nuclear Information System (INIS)

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

220

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-12-30

 
 
 
 
221

Location of laccase in ordered mesoporous materials  

Science.gov (United States)

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.

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

2014-11-01

222

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

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

Yu, Yanjie

2012-05-01

223

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

Science.gov (United States)

A coordination-assisted synthetic approach is reported here for the synthesis of highly active and stable gold nanoparticle catalysts in ordered mesoporous carbon materials using triblock copolymer F127 as a structure-directing agent, thiol-containing silane as a coordination agent, HAuCl4 as a gold source, and phenolic resin as a carbon source. Upon carbonization, the gold precursor becomes reduced to form monodispersed Au nanoparticles of ca. 9.0 nm, which are entrapped or confined by the "rigid" mesoporous carbonaceous framework. Nanoparticle aggregation is inhibited even at a high temperature of 600 °C. After removal of the silica component, the materials possess the ordered mesostructure, high surface area (~1800 m(2)/g), large pore volume (~1.19 cm(3)/g), and uniform bimodal mesopore size (gold nanoparticles are highly exposed because of the interpenetrated bimodal pores in the carbon framework, which exhibit excellent catalytic performance. A completely selective conversion of benzyl alcohol in water to benzoic acid can be achieved at 90 °C and 1 MPa oxygen. Benzyl alcohol can also be quantitatively converted to benzoic acid at 60 °C even under an atmospheric pressure, showing great advantages in green chemistry. The catalysts are stable, poison resistant, and reusable with little activity loss due to metal leaching. The silane coupling agent played several functions in this approach: (1) coordinating with gold species by the thiol group to benefit formation of monodispersed Au nanoparticles; (2) reacting with phenolic resins by silanol groups to form relatively "rigid" composite framework; (3) pore-forming agent to generate secondary pores in carbon pore walls, which lead to higher surface area, larger pore volumes, and higher accessibility to to the gold nanoparticles. Complete removal of the silica component proves to have little effect on the catalytic performance of entrapped Au nanoparticles. PMID:23865622

Wang, Shuai; Zhao, Qingfei; Wei, Huimin; Wang, Jian-Qiang; Cho, Minhyung; Cho, Hae Sung; Terasaki, Osamu; Wan, Ying

2013-08-14

224

HIGH-PERFORMANCE CELLULOSE NANOFIBRIL COMPOSITE FILMS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cellulose nanofibril/phenol formaldehyde (CNF/PF) composite films with high work of fracture were prepared by filtering a mixture of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized wood nanofibers and water-soluble phenol formaldehyde with resin contents ranging from 5 to 20 wt%, followed by hot pressing. The composites were characterized by tensile testing, dynamic mechanical analysis, scanning electron microscopy, atomic force microscopy, thermo-gravimetric analysis, and moisture/wate...

Yan Qing,; Ronald Sabo,; Yiqiang Wu; Zhiyong Cai,

2012-01-01

225

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

Science.gov (United States)

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

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

2011-12-15

226

Corrosion behavior of mesoporous transition metal nitrides  

International Nuclear Information System (INIS)

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

227

Corrosion behavior of mesoporous transition metal nitrides  

Energy Technology Data Exchange (ETDEWEB)

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

Yang, Minghui, E-mail: m.yang@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Allen, Amy J.; Nguyen, Minh T. [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Ralston, Walter T. [College of Chemistry, University of California, Berkeley 94720-1460, CA (United States); MacLeod, Michelle J. [Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139-4307, MA (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States)

2013-09-15

228

Method for removing contaminants from plastic resin  

Science.gov (United States)

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

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

2008-12-09

229

Mesoporous Carbon for Capacitive Deionization of Saline Water  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-01-01

230

Mesoporous carbon for capacitive deionization of saline water.  

Science.gov (United States)

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

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

2011-12-01

231

Phosphonic acid based exchange resins  

Science.gov (United States)

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

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

1995-01-01

232

Microleakage Pada Restorasi Resin Komposit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Sinulingga, Andri

2011-01-01

233

Synthesis of Polymer—Mesoporous Silica Nanocomposites  

Directory of Open Access Journals (Sweden)

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

Yafei Zhang

2010-07-01

234

Dodecagonal tiling in mesoporous silica.  

Science.gov (United States)

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

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

2012-07-19

235

Magnetic nanocomposites with mesoporous structures: synthesis and applications.  

Science.gov (United States)

Magnetic nanocomposites with well-defined mesoporous structures, shapes, and tailored properties are of immense scientific and technological interest. This review article is devoted to the progress in the synthesis and applications of magnetic mesoporous materials. The first part briefly reviews various general methods developed for producing magnetic nanoparticles (NPs). The second presents and categorizes the synthesis of magnetic nanocomposites with mesoporous structures. These nanocomposites are broadly categorized into four types: monodisperse magnetic nanocrystals embedded in mesoporous nanospheres, microspheres encapsulating magnetic cores into perpendicularly aligned mesoporous shells, ordered mesoporous materials loaded with magnetic NPs inside the porous channels or cages, and rattle-type magnetic nanocomposites. The third section reviews the potential applications of the magnetic nanocomposites with mesoporous structures in the areas of heath care, catalysis, and environmental separation. The final section offers a summary and future perspectives on the state-of-the art in this area. PMID:21246712

Liu, Jian; Qiao, Shi Zhang; Hu, Qiu Hong; Lu, Gao Qing Max

2011-02-18

236

Mesoporous Silica and Composite Nanostructures for Theranostics  

Directory of Open Access Journals (Sweden)

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

Khlebtsov B.N.

2013-09-01

237

Orientation specific deposition of mesoporous particles  

Science.gov (United States)

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

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

2014-11-01

238

Embedding in thermosetting resins  

International Nuclear Information System (INIS)

Among the techniques currently in use, the CEA has recently developed a process based on epoxy resins, which has proved to be the most attractive in terms of containment of radionuclides, especially cesium. Technicatome is in charge of the industrial commercialization of this process which is being operated since nearly two years in an industrial unit

239

Radiation curable epoxy resin  

International Nuclear Information System (INIS)

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

240

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

Science.gov (United States)

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

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

2008-11-01

 
 
 
 
241

Nontoxic Resins Advance Aerospace Manufacturing  

Science.gov (United States)

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

2009-01-01

243

Process for the manufacture of power mixtures acting as the initial material for the manufacture of artificial graphite or materials similar to graphite  

International Nuclear Information System (INIS)

Hydrochloric acid is used as catalyst in the formation of phenol formaldehyde resin. The phenolic OH groups of the resin are changed into phenolate. Fillter is then added to the alkaline binding resin solution. The filler grains encapsulated in binder are then separated from the liquid by decanting, filtering and drying. The powder mixture is suitable for the manufacture of moulded parts. (RW)

244

Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials  

Directory of Open Access Journals (Sweden)

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

Jianhua Zhang, Yufang Zhu, Jie Li, Min Zhu, Cuilian Tao and Nobutaka Hanagata

2013-01-01

245

Biocompatibility of soft-templated mesoporous carbons.  

Science.gov (United States)

Soft-templated mesoporous carbon is morphologically a non-nano type of carbon. It is a relatively newer variety of biomaterial, which has already demonstrated its successful role in drug delivery applications. To investigate the toxicity and biocompatibility, we introduced three types of mesoporous carbons with varying synthesis conditions and pore textural properties. We compared the Brunauer-Emmett-Teller (BET) surface area and pore width and performed cytotoxicity experiments with HeLa cells, cell viability studies with fibroblast cells and hemocomapatibility studies. Cytotoxicity tests reveal that two of the carbons are not cytotoxic, with cell survival over 90%. The mesoporous carbon with the highest surface area showed slight toxicity (? 70% cell survival) at the highest carbon concentration of 500 ?g/mL. Fibroblast cell viability assays suggested high and constant viability of over 98% after 3 days with no apparent relation with materials property and good visible cell-carbon compatibility. No hemolysis (serum albumin (BSA) and fibrinogen revealed a lower protein binding capacity of 0.2-0.6 mg/m(2) and 2-4 mg/m(2) for BSA and fibrinogen, respectively, with lower binding associated with an increase in surface area. The results of this study confirm the biocompatibility of soft-templated mesoporous carbons. PMID:25144129

Gencoglu, Maria F; Spurri, Amanda; Franko, Mitchell; Chen, Jihua; Hensley, Dale K; Heldt, Caryn L; Saha, Dipendu

2014-09-10

246

Embedding in thermosetting resins  

International Nuclear Information System (INIS)

Medium activity waste coming either from nuclear power plants in operation such as evaporator concentrates, spent resins, filter cartridges or the dismantling of installations are embedded in order to obtain a product suitable for long term disposal. Embedding in thermosetting resins (polyester or epoxy) is one among currently used techniques; it is being developed by the CEA (Commissariat a l'Energie Atomique) and Technicatome (subsidiary of CEA and EDF). The process is easy to operate and yields excellent results particularly as far as volume reduction and radioelement containment (cesium particularly) are concerned. The process has already been in operation in four stationary plants for several years. Extension of the process to mobile units has been completed by Technicatome in collaboration with the CEA

247

Resin composite restorative materials.  

Science.gov (United States)

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

Ilie, N; Hickel, R

2011-06-01

248

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

Science.gov (United States)

...resin groups listed below. Product groups are indicated with an asterisk (*). *Alkyd Resins Dicyanodiamide Resin *Epoxy Resins *Fumaric Acid Polyesters *Furan Resins Glyoxal-Urea Formaldehyde Textile Resin...

2010-07-01

249

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

Science.gov (United States)

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

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

2010-09-01

250

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-15

251

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

Science.gov (United States)

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

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

2014-06-15

252

System for removing contaminants from plastic resin  

Science.gov (United States)

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

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

2010-11-23

253

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery  

Science.gov (United States)

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

Gao, Lin; Sun, Jihong; Li, Yuzhen

2011-08-01

254

Highly mesoporous carbons obtained using a dynamic template method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New nanoporous carbons with extremely high mesopore volumes and surface areas were obtained using mesoporous silica with a 3-D wormhole porous framework as templates. Mesoporous silica was synthesized following the literature described methods. Polystyrene sulfonic acid-based organic salts were used as carbon precursors. To evaluate the effect of sodium on porosity development silica matrices with various thicknesses of pore walls were synthesized. Prior to carbonization, in order to increase...

Bandosz, Teresa J.; Ovi?n Ania, Mari?a Concepcio?n

2006-01-01

255

Mesoporous Molecular Sieves as Supports for Metathesis Catalysts  

Science.gov (United States)

Mesoporous molecular sieves represent a new family of inorganic oxides with regular nanostructure, large surface areas, large void volumes, and narrow pore size distribution of mesopores. These materials offer new possibilities for designing highly active and selective catalysts for olefin metathesis and metathesis polymerization. Siliceous sieves MCM-41, MCM-48, SBA-15, and organized mesoporous alumina (OMA) were used as supports for preparation of new molybdenum and rhenium oxide catalysts, as well as for heterogenization of well-defined homogeneous catalysts.

Balcar, Hynek; Cejka, Jirí

256

Biokompatibilitas Gelas Ionomer Modifikasi Resin  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Rotua Lestari M

2008-01-01

257

Dry PMR-15 Resin Powders  

Science.gov (United States)

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

Vannucci, Raymond D.; Roberts, Gary D.

1988-01-01

258

Vitrification of ion exchange resins  

Science.gov (United States)

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

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

2001-01-01

259

Powder Solidifyers of Epoxy Resins  

International Science & Technology Center (ISTC)

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

260

21 CFR 872.3140 - Resin applicator.  

Science.gov (United States)

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

2010-04-01

 
 
 
 
261

21 CFR 177.1595 - Polyetherimide resin.  

Science.gov (United States)

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

2010-04-01

262

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...hexamethylene-diamine and adipic acid. (2) Nylon 610 resins are manufactured by...4-butanediamine and adipic acid. (16) Nylon resins PA 6-3-T (CAS Registry...a 96 percent sulfuric acid solution (5 milligrams resin per...

2010-04-01

263

Recycle of silicate waste into mesoporous materials.  

Science.gov (United States)

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

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

2011-04-15

264

Diffraction analysis of mesostructured mesoporous materials.  

Science.gov (United States)

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

Solovyov, Leonid A

2013-05-01

265

Mesoporous Silica and Composite Nanostructures for Theranostics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We discus methods for fabrication of silica and composite nanoparticles, which can be used in various biomedical applications. The most promising types of such nanostructures are hollow silica nanosheres, sil-ica coated plasmon-resonant nanoparticles (gold nanorods and gold-silver nanocages) and nanorattles. Mesoporous silica shell can be doped by desirable targeting molecules. Here we present the results of for-mation of nanocomposites composed of gold nanorods and double-layer silica shell....

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

2013-01-01

266

Synthesis of Polymer—Mesoporous Silica Nanocomposites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polymer nanocomposites show unique properties combining the advantages of the inorganic nanofillers and the organic polymers. The mesoporous silica nanofillers have received much attention due to their ordered structure, high surface area and ease for functionalization of the nanopores. To accommodate macromolecules, the nanopores lead to unusually intimate interactions between the polymer and the inorganic phase, and some unusual properties can be observed, when compared with nonporous fille...

Yafei Zhang; Nantao Hu; Liangming Wei

2010-01-01

267

Investigation of mesoporous structures for thermoelectric applications  

International Nuclear Information System (INIS)

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

268

Cubic mesoporous titanium phosphonates with multifunctionality.  

Science.gov (United States)

Cubic mesoporous titanium phosphonate materials with bridged organic groups inside the framework were synthesized by means of a one-pot hydrothermal autoclaving process, with the assistance of cationic surfactant cetyltrimethylammonium bromide. 1-Hydroxyethylidene-1,1-diphosphonic acid was used as the coupling molecule. A typical cubic mesophase with surface area of 1052 m(2) g(-1) and pore size of 2.6 nm was confirmed by XRD, TEM, and N(2) sorption analysis. The organophosphonate groups were homogeneously incorporated in the network of the mesoporous solids, as revealed by FTIR and magic-angle spinning (MAS) NMR spectroscopy, and thermogravimetry and differential scanning calorimetry (TG-DSC) measurements. The synthesized hydroxyethylidene-bridged cubic mesoporous titanium phosphonates proved to be thermally stable up to 350 degrees C, with a well-preserved hybrid framework and cubic mesoporous architecture. The obtained cubic mesophase could be transformed into a hexagonal mesophase by simply adjusting the molar ratios of the added raw materials, namely, a Ti/P molar ratio of 1:4 and a CTAB/Ti molar ratio of 1.9-2.3 for the cubic phase and Ti/P molar ratio of 3:4 and CTAB/Ti molar ratio of 0.1-0.4 for the hexagonal phase. The cubic hybrid materials could be used as efficient photocatalysts for the photodegradation of rhodamine B. Moreover, they were also used for adsorption of CO(2) and heavy metal ions and exhibited a significant capture amount of around 1.0 mmol g(-1) for CO(2) molecules at 35 degrees C and high adsorption capacity of 28.5 micromol g(-1) for Cu(2+) ions with good reusability, which demonstrated their promising potential in environmental remediation. PMID:20540047

Ma, Tian-Yi; Lin, Xiu-Zhen; Yuan, Zhong-Yong

2010-07-26

269

Novel route to periodic mesoporous aminosilicas, PMAs: ammonolysis of periodic mesoporous organosilicas.  

Science.gov (United States)

A new route to periodic mesoporous aminosilicas (PMAs) that contain amine functional groups in the framework of a mesoporous network is reported. The materials are prepared via thermal ammonolysis of periodic mesoporous organosilicas (PMOs) under a flow of ammonia gas. PMOs integrate similar or even higher quantities of nitrogen-containing groups upon ammonolysis than similarly treated ordered mesoporous silicas (MCM-41). The quantity of amine groups introduced into the materials was found to depend strongly on the ammonolysis temperature. The largest loading of amine groups was obtained when a well-ordered cubic methylene PMO material without prior vacuum-drying was thermolyzed in ammonia. The ordered mesoporosity of PMOs was preserved during the ammonolysis with only a slight decrease in the mesopore size and the degree of mesostructural ordering. The extent of substitution of framework oxygen by amine and nitride groups was established by solid-state (29)Si CP-MAS, (29)Si MAS, (15)N MAS, and (13)C CP-MAS NMR spectroscopies, elemental analysis, and X-ray photoelectron spectroscopy. In some cases, methylene and methyl functional groups were also present in the PMAs along with amine functional groups, as inferred from elemental analysis and gas adsorption, particularly in cases where PMOs were subjected to ammonolysis at 400 and 550 degrees C for several hours. This resulted in new multifunctional mesoporous organoaminosilica nanomaterials with properties that could be tuned by systematically varying the relative amounts of hydrophilic amine and hydrophobic hydrocarbon pendent and framework groups. The stability upon storage was found to be much higher for PMAs obtained from PMOs than for those obtained from MCM-41 silicas under the same conditions. PMID:13129371

Asefa, Tewodros; Kruk, Michal; Coombs, Neil; Grondey, Hiltrud; MacLachlan, Mark J; Jaroniec, Mietek; Ozin, Geoffrey A

2003-09-24

270

Functionalized ordered mesoporous materials for environmental remediation  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

271

Mesoporous Silica from Rice Husk Ash  

Directory of Open Access Journals (Sweden)

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

S.A. Mandavgane

2010-12-01

272

Mesoporous metal catalysts formed by ultrasound  

Energy Technology Data Exchange (ETDEWEB)

We study the ultrasound-driven formation of mesoporous metal sponges. The collapse of acoustic cavitations leads to very high temperatures and pressures on very short scales. Therefore, structures may be formed and quenched far from equilibrium. Mechanism of metal modification by ultrasound is complex and involves a variety of aspects. We propose that modification of metal particles and formation of mesoporous inner structures can be achieved due to thermal etching of metals by ultrasound stimulated high speed jets of liquid. Simultaneously, oxidation of metal surfaces by free radicals produced in water during cavitation stabilizes developed metal structures. Duration and intensity of the ultrasonication treatment is able to control the structure and morphology of metal sponges. We expect that this approach to the formation of nanoscale composite sponges is universal and opens perspective for a whole new class of catalytic materials that can be prepared in a one-step process. The developed method makes it possible to control the sponge morphology and can be used for formation of modern types of catalysts. For example, the sonication technique allows to combine the fabrication of mesoporous support and distribution of metal (Cu, Pd, Au, Pt etc.) nanoparticles in its pores into a single step.

Schaeferhans, Jana; Pazos Perez, Nicolas; Andreeva, Daria [Physikalische Chemie II, Universitaet Bayreuth (Germany)

2010-07-01

273

Preparation, characterization, and electrochemical application of mesoporous copper oxide  

International Nuclear Information System (INIS)

Mesoporous CuO was successfully synthesized via thermal decomposition of CuC2O4 precursors. These products had ring-like morphology, which was made up of nanoparticles with the average diameter of 40 nm. The electrochemical experiments showed that the mesoporous CuO decreased the overvoltage of the electrode and increased electron transference in the measurement of dopamine.

274

Phosphorylated Mesoporous Carbon as a Solid Acid Catalyst  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-01-01

275

Aluminum-rich mesoporous MFI - type zeolite single crystals  

DEFF Research Database (Denmark)

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

Kustova, Marina; Kustov, Arkadii

2005-01-01

276

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

Science.gov (United States)

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

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

2014-06-01

277

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

Energy Technology Data Exchange (ETDEWEB)

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

Schuster, Joerg David

2011-06-07

278

Chromatography resin support  

Science.gov (United States)

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

Dobos, James G. (North Augusta, SC)

2002-01-01

279

Quality of black coal resin  

Energy Technology Data Exchange (ETDEWEB)

Reasons for a decrease in the quality of resin produced in the USSR are discussed, e.g. as a result of the introduction of new technology or a decline in the temperature conditions of coking. The results are discussed of investigations on magnetic processing, vibrofiltration, treating surface active substances and short-term settling in connection with demoisturizing and removing the heavy coal tars in resins. Method recommended in 1982 by the Coal Chemistry Research Institute for improving the preparation of resin is analyzed. This method consists in a flowsheet which feeds the resin from the initial gas cooler into a mechanized condenser. Resin samples from the Bagleiskii Coking Factory were tested for ash content to determine the relative accuracy of four methods, i.e. standard method, direct ashing of the resin sample, conversion of calculations of the ash in the alpha fraction. Variations in the resulting data are analyzed. It is concluded that the classification of black-coal resins according to ash indicator norms defined in TU 14-6-171-80 is not always applicable and more precise definition is required. 11 references.

Kulyasova, S.V.; Beschasnyi, V.G.; Sheryshova, N.G.

1984-10-01

280

Grafted methylenediphosphonate ion exchange resins  

Science.gov (United States)

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

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

1998-01-27

 
 
 
 
281

The development of chiral nematic mesoporous materials.  

Science.gov (United States)

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

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

2014-04-15

282

Bending characteristics of resin concretes  

Scientific Electronic Library Online (English)

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

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

2003-06-01

283

Bending characteristics of resin concretes  

Scientific Electronic Library Online (English)

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

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

284

Mechanical behavior of mesoporous titania thin films  

Science.gov (United States)

Nanoindentation is used to assess mechanical properties of ordered mesoporous titania thin films with pore sizes in the range of 8-16 nm. Estimates of strut properties are obtained under the standard scaling assumptions widely used in porous media. The inferred hardness and fracture toughness of individual struts are found to correspond to anatase titania, indicating the absence of obvious size effects in the nanostructured ceramic. This is in marked contrast to nanoporous metals, where size effects often play a crucial role in determining material properties at similar length scales.

Rahman, Tamanna; Liu, Ran; Ortel, Erik; Kraehnert, Ralph; Antoniou, Antonia

2014-06-01

285

Ordered mesoporous silica-based inorganic nanocomposites  

International Nuclear Information System (INIS)

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

286

The formation of helical mesoporous silica nanotubes  

Energy Technology Data Exchange (ETDEWEB)

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

Wan Xiaobing; Pei Xianfeng; Zhao Huanyu; Chen Yuanli; Guo Yongmin; Li Baozong; Yang Yonggang [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry and Chemical Engineering, Suzhou (Soochow) University, Suzhou 215123 (China); Hanabusa, Kenji [Department of Functional Polymer Science, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567 (Japan)], E-mail: ygyang@suda.edu.cn

2008-08-06

287

The formation of helical mesoporous silica nanotubes  

International Nuclear Information System (INIS)

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

288

Oil absorption in mesoporous silica particles  

Directory of Open Access Journals (Sweden)

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

Radislav Filipovi?

2010-12-01

289

Adsorption-Induced Deformation of Mesoporous Solids  

CERN Document Server

The Derjaguin - Broekhoff - de Boer theory of capillary condensation is employed to describe deformation of mesoporous solids in the course of adsorption-desorption hysteretic cycles. We suggest a thermodynamic model, which relates the mechanical stress induced by adsorbed phase with the adsorption isotherm. Analytical expressions are derived for the dependence of the solvation pressure on the vapor pressure. The proposed method provides a semi-quantitative description of non-monotonic hysteretic deformation during capillary condensation without invoking any adjustable parameters. The method is showcased drawing on the examples of literature experimental data on adsorption deformation of porous glass and SBA-15 silica.

Gor, Gennady Yu

2010-01-01

290

OIL PALM TRUNK POLYMER COMPOSITE: MORPHOLOGY, WATER ABSORPTION, AND THICKNESS SWELLING BEHAVIOURS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this research, impregnated oil palm trunks (OPT) and polymer composites were prepared from a combination of dried oil palm trunks with phenol formaldehyde (PF) and urea formaldehyde (UF) resin in different resin percentages using an impregnation method. Time of impregnation was a parameter used to control the percentage of resin content in the oil palm trunks. These studies investigated the effect of resin content and types of resin on the physical properties of impregnated OPT. Water abso...

C. K. Abdullah,; M. Jawaid,; H. P. S. Abdul Khalil,; A. Zaidon,; Hadiyane, A.

2012-01-01

291

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery  

International Nuclear Information System (INIS)

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

292

A general synthetic approach for ordered mesoporous metal sulfides.  

Science.gov (United States)

Mesoporous non-silica materials have shown unique properties in many fields such as heterogeneous catalysis and energy conversion and storage. Many studies have been devoted to the synthesis of mesoporous transition-metal-containing materials. However, the range of materials that can be made is mainly limited to oxides. In this work, we developed an oxide-to-sulfide transformation approach as a general synthetic method to prepare ordered mesoporous metal sulfides. Three first-row transition-metal sulfides, FeS2, CoS2, and NiS2, with highly ordered mesoporous structures and crystalline walls have been successfully synthesized for the first time. A preliminary investigation was performed to explore the photocatalytic properties of the newly synthesized mesoporous metal sulfides. All of the mesoporous metal sulfides exhibited higher activity than their bulk counterparts for the photocatalytic degradation of methylene blue dye under visible-light irradiation. More importantly, the preparation method introduced in this work may be extended to other mesoporous metal chalcogenides for a variety of potential applications. PMID:24904959

Yonemoto, Bryan T; Hutchings, Gregory S; Jiao, Feng

2014-06-25

293

Concrete rehabilitation using epoxy resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

294

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

Science.gov (United States)

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

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

2013-01-01

295

Purification of rare alkaline element compounds using phenol ionites  

International Nuclear Information System (INIS)

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

296

Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure  

Science.gov (United States)

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

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

1998-01-01

297

Ion exchange resin reproducing method and equipment  

International Nuclear Information System (INIS)

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

298

Functional polycyclopentadiene resins via hydroboration process  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a process for preparing a functionalized petroleum resin. It comprises dissolving a petroleum resin in a solvent to form a solution, the resin being formed by polymerizing feeds containing cyclopentadiene, dicyclopentadiene and alkyl derivatives thereof, the resin having a norbornene moiety with a double bond; adding to the solution a borane, reacting the petroleum resin with the borane compound at about room temperature for a sufficient period of time to form a derivative of the petroleum resin containing a borane group; and reacting the derivative of the petroleum resin with a chemical agent capable of replacing the borane group of the petroleum resin derivative with a functional group, thereby converting the derivative into the functionalized petroleum resin.

Chung, T.C.; Berluche, E.; Bock, J.; Kastrup, R.V.

1992-03-03

299

Dewatering and drying of wet spent resins  

International Nuclear Information System (INIS)

Dewatering and drying the radioactive spent resins generated from nuclear power plants are studied in laboratory. A simple way is filtering and heat drying the resins in vacuum. The important parameters of the process are determined. After filtering under vacuum the percentage of water in cation is about 53 ? 57%. By means of heat-drying in vacuum the water content of cation resin, anion resin and mixed bed resin can be further decreased to 46 ? 48%, 30% and 40%, respectively. The resins treated have good mobility. The operation time is about six hours

300

FB-Line resin testing final report  

Energy Technology Data Exchange (ETDEWEB)

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

Bannochie, C.J.

1992-01-23

 
 
 
 
301

Mesoporous carbon incorporated metal oxide nanomaterials as supercapacitor electrodes  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-08

302

Mesoporous zeolite single crystals for catalytic hydrocarbon conversion  

DEFF Research Database (Denmark)

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

Schmidt, I.; Christensen, C.H.

2005-01-01

303

Structure and optical properties of mesoporous tungsten oxide  

International Nuclear Information System (INIS)

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

304

Mesoporous silica magnetite nanocomposite synthesized by using a neutral surfactant  

Science.gov (United States)

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.

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

2008-05-01

305

Mesoporous silicas with tunable morphology for the immobilization of laccase.  

Science.gov (United States)

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

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

2014-01-01

306

Mesoporous Silicas with Tunable Morphology for the Immobilization of Laccase  

Directory of Open Access Journals (Sweden)

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

Victoria Gascón

2014-05-01

307

Low Melt Viscosity Resins for Resin Transfer Molding  

Science.gov (United States)

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

Harris, Frank W.

2002-01-01

308

Synthesis of self-assembled photosensitive molecules in mesoporous silicates  

Science.gov (United States)

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.

Honma, Itaru; Zhou, H.-S.

1997-02-01

309

Plasmonic Mesoporous Composites as Molecular Sieves for SERS Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Application of surface-enhanced Raman scattering (SERS) spectroscopy to the ultrasensitive analysis of small molecules in biological samples is complicated by signal contamination by ubiquitous macromolecules such as proteins, nucleic acids, or lipids. We present a proof-of-concept study of the application of composite films comprising branched gold nanoparticles embedded in mesoporous thin films, which act as molecular sieves. The inorganic mesoporous layer only allows the diffusion of sm...

Lo?pez-puente, V.; Abalde-cela, S.; Angelome?, P. C.; Alvarez-puebla, R. A.; Liz-marza?n, L. M.

2013-01-01

310

Recent Progress in Preparation of Ordered Mesoporous Film  

Directory of Open Access Journals (Sweden)

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

LU Xue-Min, LU Qing-Hua

2007-09-01

311

Detection of hetero-proteins-mesoporous silica assembly by BRET.  

Science.gov (United States)

The assembly of a hetero-protein (Renilla reniformis luciferase (Rluc) and a green fluorescence protein (sGFP)) encapsulated in folded-sheet mesoporous material with 7.1 nm pore diameter (FSM7.1), which was used for studying protein-protein interactions in pores of mesoporous silica, has been confirmed by the detection of bioluminescence resonance energy transfers (BRET). PMID:20386830

Matsuura, Shun-ichi; Tsunoda, Tatsuo; Shiomi, Toru; Sakaguchi, Kengo; Hanaoka, Takaaki; Mizukami, Fujio

2010-05-01

312

Mesoporous silica supraparticles for sustained inner-ear drug delivery.  

Science.gov (United States)

Mesoporous silica supraparticles (MS-SPs) are prepared via self-assembly of mesoporous silica nanoparticles under capillary force action in confined droplets. The MS-SPs are effective carriers for sustained drug delivery. Animal studies show that these particles are suitable for chronic intracochlear implantation, and neurotrophins released from the MS-SPs can efficiently rescue primary auditory neurons in an in vivo sensorineural hearing loss model. PMID:25099026

Wang, Yajun; Wise, Andrew K; Tan, Justin; Maina, James W; Shepherd, Robert K; Caruso, Frank

2014-11-01

313

Preparation, characterization, and electrochemical application of mesoporous copper oxide  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous CuO was successfully synthesized via thermal decomposition of CuC{sub 2}O{sub 4} precursors. These products had ring-like morphology, which was made up of nanoparticles with the average diameter of 40 nm. The electrochemical experiments showed that the mesoporous CuO decreased the overvoltage of the electrode and increased electron transference in the measurement of dopamine.

Cheng, Liang [Functional Nano and Soft Materials Laboratory (FUNSOM), Soochow University, Suzhou 215123 (China); Anhui Key Laboratory of Functional Molecular Solids, and College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Shao, Mingwang, E-mail: mwshao@suda.edu.cn [Functional Nano and Soft Materials Laboratory (FUNSOM), Soochow University, Suzhou 215123 (China); Anhui Key Laboratory of Functional Molecular Solids, and College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Chen, Dayan; Zhang, Yuzhong [Anhui Key Laboratory of Functional Molecular Solids, and College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

2010-02-15

314

Low temperature crystallisation of mesoporous TiO2  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

315

76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

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

2011-01-27

316

Mesoporous VN prepared by solid-solid phase separation  

Energy Technology Data Exchange (ETDEWEB)

We recently reported a simple route to prepare mesoporous, conducting nitrides from Zn containing ternary transition metal oxides. Those materials result from the condensation of atomic scale voids created by the loss of Zn by evaporation, the replacement of 3 oxygen anions by 2 nitrogen anions, and in most cases the loss of oxygen to form water on the reduction of the transition metal. In this report, we present a different route to prepare mesoporous VN from K containing vanadium oxides. In this case, ammonolysis results in a multiphase solid product that contains VN, and other water soluble compounds such as KOH or KNH{sub 2}. On removing the K containing products by washing with degassed water, only mesoporous VN remains. VN materials with different pore sizes (10 nm-20 nm) were synthesized at 600 Degree-Sign C by varying the reaction time, while larger pores are obtained at higher temperatures (50 nm at 800 Degree-Sign C). - Graphical Abstract: The synthesis process of mesoporous VN from solid-solid separation. Highlights: Black-Right-Pointing-Pointer Mesoporous VN has been prepared by solid-solid phase separation. Black-Right-Pointing-Pointer Mesoporous VN was characterized by Rietveld refinement of PXRD, SEM and nitrogen physisorption. Black-Right-Pointing-Pointer VN materials with different pore sizes (10 nm-50 nm) were synthesized.

Yang Minghui, E-mail: m.yang@cornell.edu [Department of Chemistry, Cornell University, Ithaca, New York 14853-1301 (United States); Ralston, Walter T. [Department of Chemistry, Cornell University, Ithaca, New York 14853-1301 (United States); Tessier, Franck [UMR CNRS 6226 ' Sciences Chimiques de Rennes' , Equipe ' Verres et Ceramiques' , Universite de Rennes 1, F-35042 Rennes cedex (France); Allen, Amy J. [Department of Chemistry, Cornell University, Ithaca, New York 14853-1301 (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.edu [Department of Chemistry, Cornell University, Ithaca, New York 14853-1301 (United States)

2013-01-15

317

Mesoporous VN prepared by solid–solid phase separation  

International Nuclear Information System (INIS)

We recently reported a simple route to prepare mesoporous, conducting nitrides from Zn containing ternary transition metal oxides. Those materials result from the condensation of atomic scale voids created by the loss of Zn by evaporation, the replacement of 3 oxygen anions by 2 nitrogen anions, and in most cases the loss of oxygen to form water on the reduction of the transition metal. In this report, we present a different route to prepare mesoporous VN from K containing vanadium oxides. In this case, ammonolysis results in a multiphase solid product that contains VN, and other water soluble compounds such as KOH or KNH2. On removing the K containing products by washing with degassed water, only mesoporous VN remains. VN materials with different pore sizes (10 nm–20 nm) were synthesized at 600 °C by varying the reaction time, while larger pores are obtained at higher temperatures (50 nm at 800 °C). - Graphical Abstract: The synthesis process of mesoporous VN from solid–solid separation. Highlights: ? Mesoporous VN has been prepared by solid–solid phase separation. ? Mesoporous VN was characterized by Rietveld refinement of PXRD, SEM and nitrogen physisorption. ? VN materials with different pore sizes (10 nm–50 nm) were synthesized.

318

Formation of ethylene-silica nanofibers with concentric circular mesopores inside and lamellar mesopores on the surfaces.  

Science.gov (United States)

Ethylene-silica nanofibers with concentric circular mesopores inside and lamellar mesopores outside were prepared using stearyltrimethylammonium bromide (STAB) as template and (S)-beta-citronellol as a co-structure-directing agent. They were formed at the (S)-beta-citronellol/STAB molar ratio range of 3:1 to 4:1. Field emission scanning electron microscopy and transmission electron microscopy images taken after different reaction times revealed a phase transition from hexagonal to lamellar phase on the surface of the organic-inorganic hybrid silica nanofibers. The nanofibers with concentric circular pore channels were proposed to be formed from spherical micelles. With increasing the (S)-beta-citronellol/STAB molar ratio from 0.5:1 to 5:1, the morphology changed from short hexagonal rod to long nanofiber, and then to shrunk multilamellar vesicle. Moreover, 1,4-phenylene-silica nanofibers and nanoparticles with concentric circular mesopores inside and lamellar mesopores outside were also prepared. PMID:23035477

Hu, Kai; Li, Baozong; Pu, Yunyue; Zhang, Chuanyong; Wang, Sibing; Li, Yi; Yang, Yonggang

2012-09-01

319

21 CFR 177.1330 - Ionomeric resins.  

Science.gov (United States)

...extractability conditions for ionomeric resins. Using table I of paragraph...a clean, tared evaporating dish (platinum or Pyrex), washing the flask three...are not applicable to the ionomeric resins that are used in food-packaging...

2010-04-01

320

21 CFR 872.3140 - Resin applicator.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Resin applicator. 872.3140 Section 872.3140 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a)...

2010-04-01

 
 
 
 
321

21 CFR 177.1550 - Perfluorocarbon resins.  

Science.gov (United States)

...2009-04-01 true Perfluorocarbon resins. 177.1550 Section 177.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION...Single and Repeated Use Food Contact Surfaces § 177.1550 Perfluorocarbon resins. Perfluorocarbon...

2010-04-01

322

Phosphonic acid based ion exchange resins  

Science.gov (United States)

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

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

1996-01-01

323

Ordered cobalt nanowires in mesoporous aluminosilicate  

International Nuclear Information System (INIS)

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

324

Plutonium sorption to nanocast mesoporous carbon  

International Nuclear Information System (INIS)

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

325

Plutonium sorption to nanocast mesoporous carbon  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-09-01

326

Synthesis of Vanadium-mesoporous Hollow Spheres  

Directory of Open Access Journals (Sweden)

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

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

2012-07-01

327

Adsorption of octadecyltrichlorosilane on mesoporous SBA-15  

International Nuclear Information System (INIS)

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

328

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

Science.gov (United States)

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

2010-04-01

329

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

Science.gov (United States)

...isopropylidenediphenol-epichlorohydrin epoxy resins. The resins identified in paragraph...conditions. (a) The resins are produced by the condensation of xylene-formaldehyde resin and 4,4?-isopropylidenediphenol-epichlorohydrin...di-, or trimethylol phenol and capryl alcohol...

2010-04-01

330

Uranium sorption by tannin resins  

International Nuclear Information System (INIS)

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

331

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

Science.gov (United States)

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

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

2001-10-21

332

Mesoporous hexagonal Co3O4 for high performance lithium ion batteries  

Science.gov (United States)

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

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

2014-10-01

333

Gyroidal mesoporous multifunctional nanocomposites via atomic layer deposition  

Science.gov (United States)

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

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

2014-07-01

334

21 CFR 177.1500 - Nylon resins.  

Science.gov (United States)

...5 14. Nylon 6/69 resins for use only as specified...3.0 15. Nylon 46 resins for use only in food-contact...more than 13 percent alcohol, under conditions of... 0.3 16. Nylon resins PA 6-3-T for repeated-use...25 weight percent of acrylic polymer with...

2010-04-01

335

Dielectric properties of dianic resin after ?-irradiation  

International Nuclear Information System (INIS)

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

336

21 CFR 172.280 - Terpene resin.  

Science.gov (United States)

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

2010-04-01

337

21 CFR 172.280 - Terpene resin.  

Science.gov (United States)

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

2010-04-01

338

21 CFR 177.1560 - Polyarylsulfone resins.  

Science.gov (United States)

...solvent in the finished basic resin. (c) Extractive limitations...The finished polyarylsulfone resin when extracted for 2 hours with...160 °F), 3 percent acetic acid in distilled water at 100 °C...finished poly-aryl-sulfone resin use a separate test sample...

2010-04-01

339

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

International Nuclear Information System (INIS)

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

340

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} Platinum, tin and indium recoveries from spent reforming catalysts. {yields} Adsorption of metal chlorocomplexes on strongly basic anion-exchange resins. {yields} Sequential desorption via elution with reducing (Pt, Sn) or complexing (In) agents. {yields} The elements were recovered in very high yields. {yields} The anion-exchange resins can be reused. - Abstract: This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al{sub 2}O{sub 3} catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl{sup -} form). The catalysts were leached with aqua regia (75 {sup o}C, 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{sup -1} HCl. Platinum was desorbed passing 1 mol L{sup -1} Na{sub 2}S{sub 2}O{sub 3} (pH 9). Tin was removed by elution with 0.1 mol L{sup -1} ascorbic acid. Indium was removed using 0.1 mol L{sup -1} EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).

Marinho, Roberta Santos; Silva, Cristiano Nunes da [Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, room A509, 21941-909, Ilha do Fundao, Rio de Janeiro (Brazil); Afonso, Julio Carlos, E-mail: julio@iq.ufrj.br [Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, room A509, 21941-909, Ilha do Fundao, Rio de Janeiro (Brazil); Cunha, Jose Waldemar Silva Dias da [Department of Chemistry and Nuclear Materials, Institute of Nuclear Engineering, Rua Helio de Almeida, 75, 21941-906, Ilha do Fundao, Rio de Janeiro, Ramos Brazil (Brazil)

2011-09-15

 
 
 
 
341

Synthesis and luminescence property of rare earth complex nanoparticles dispersed within pores of modified mesoporous silica  

International Nuclear Information System (INIS)

A rare earth complex, Eu(A)3Phen was successfully introduced into the pores of mesoporous silica, which was verified by X-ray photoelectron spectroscopy and nitrogen sorption isotherms. The rare earth complex dispersed in mesoporous silica displayed characteristic fluorescence emission of the pure rare earth complex, and the fluorescence emission was enhanced, especially for that with diamine treated mesoporous silica

342

A Method for Characterizing PMR-15 Resin  

Science.gov (United States)

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

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

1986-01-01

343

Vinylstyrylpyridine-modified bismaleimide composite resins  

Science.gov (United States)

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

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

1984-01-01

344

Hollow-structured mesoporous materials: chemical synthesis, functionalization and applications.  

Science.gov (United States)

Hollow-structured mesoporous materials (HMMs), as a kind of mesoporous material with unique morphology, have been of great interest in the past decade because of the subtle combination of the hollow architecture with the mesoporous nanostructure. Benefitting from the merits of low density, large void space, large specific surface area, and, especially, the good biocompatibility, HMMs present promising application prospects in various fields, such as adsorption and storage, confined catalysis when catalytically active species are incorporated in the core and/or shell, controlled drug release, targeted drug delivery, and simultaneous diagnosis and therapy of cancers when the surface and/or core of the HMMs are functionalized with functional ligands and/or nanoparticles, and so on. In this review, recent progress in the design, synthesis, functionalization, and applications of hollow mesoporous materials are discussed. Two main synthetic strategies, soft-templating and hard-templating routes, are broadly sorted and described in detail. Progress in the main application aspects of HMMs, such as adsorption and storage, catalysis, and biomedicine, are also discussed in detail in this article, in terms of the unique features of the combined large void space in the core and the mesoporous network in the shell. Functionalization of the core and pore/outer surfaces with functional organic groups and/or nanoparticles, and their performance, are summarized in this article. Finally, an outlook of their prospects and challenges in terms of their controlled synthesis and scaled application is presented. PMID:24687906

Li, Yongsheng; Shi, Jianlin

2014-05-28

345

Medium-range Order in Periodic Mesoporous Silica  

Science.gov (United States)

Periodic mesoporous materials contain ordered pores with diameters between 2 and 50 nm. In spite of their ordered pore structure, most periodic mesoporous materials do not possess crystalline pore walls, and the atomistic origin of the uncrystallizable pore walls has been elusive. It is believed that the medium-range structure in such materials holds the key to the answer. To understand the medium-range order in periodic mesoporous materials, we select periodic mesoporous silica as a model system for this study. SBA-15 of various pore sizes (5-15 nm) have been synthesized through a self-assembly process using triblock copolymers as the structure-directing agents. X-ray scattering was used to characterize the materials. Pore widths and pore thicknesses of SBA-15 were measured by small-angle x-ray scattering, and the medium-range structure was characterized by wide-angle x-ray scattering. Effects of periodic pore structure and temperature on the medium-range order of amorphous pore walls have been identified. Our study provides atomic insights into the origin of uncrystallizable pore walls of periodic mesoporous materials in general.

Wan, Ella; Li, Kuangmin; Chen, Gang

2009-03-01

346

Gyroidal mesoporous multifunctional nanocomposites via atomic layer deposition.  

Science.gov (United States)

We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are submitted to different thermal treatments. Results suggest that ALD can homogenously coat mesoporous templates with well defined pore sizes below 50 nm and thicknesses above 10 ?m. Structural tunability like titania shell thickness and pore size control is demonstrated. The ordered nanocomposites exhibit triple functionality; a 3D continuous conductive carbon core that is coated with a crystalline titania shell that in turn is in contact with a 3D continuous mesopore network in a compact monolithic architecture. This materials design is of interest for applications including energy conversion and storage. Gyroidal mesoporous titania monoliths can be obtained through simultaneous titania crystallization and template removal in air. PMID:24950610

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

2014-08-01

347

Organized thiol functional groups in mesoporous core shell colloids  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-03-15

348

Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties.  

Science.gov (United States)

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

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

2014-01-01

349

Preparation and Characterization of Mesoporous Iron-Oxide  

Directory of Open Access Journals (Sweden)

Full Text Available Transition metal oxides are easy to form insoluble oligomer in reaction because of complicated oxidation states, so it is difficult to obtain the desired mesoporous structure. To resolve the problem, mesoporous iron oxide was synthesized by reacting a micellar phase of sodium dodecyl sulfate (SDS with iron polymer solution which was prepared by controlling the proportion of sodium hydroxide and ferric chloride. Crystal structure and surface structure of the mesoporous iron oxide was characterized by powder X-ray diffraction (XRD, Fourier transform ª² infrared spectroscopy (FT-IR, thermogravimetric analyse(TGA, Nitrogen adsorptionª²desorption method and so on. The results show that mesoporous ¦?Fe2O3 can be obtained after calcining at 450¡?ith OH-/Fe3+ ratio of 2.0. Its surface area is 146.5m2¡¤g-1, BJH average diameter is 6.9nm, pore volume is 0.27cm3¡¤g-1. The asª²prepared mesoporous iron oxide has better thermal stability, it still has surface area of 110.2m2¡¤g-1 after calcination at 550¡?

XUE Hong-Tao,SHEN Shui-Fa,PAN Hai-Bo,XIE Chang-Huai

2009-05-01

350

Study of Novel Oligomeric Azo Dyes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Patel J. R.; Kiran Nimavat; Kartik Vyas

2012-01-01

351

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

DEFF Research Database (Denmark)

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

Holm, Martin Spangsberg; Egeblad, Kresten

2008-01-01

352

Synthesis of mesoporous silica microsphere from dual surfactant  

Scientific Electronic Library Online (English)

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

Venkatathri, Narayanan.

353

Mesoporous VN prepared by solid-solid phase separation  

Science.gov (United States)

We recently reported a simple route to prepare mesoporous, conducting nitrides from Zn containing ternary transition metal oxides. Those materials result from the condensation of atomic scale voids created by the loss of Zn by evaporation, the replacement of 3 oxygen anions by 2 nitrogen anions, and in most cases the loss of oxygen to form water on the reduction of the transition metal. In this report, we present a different route to prepare mesoporous VN from K containing vanadium oxides. In this case, ammonolysis results in a multiphase solid product that contains VN, and other water soluble compounds such as KOH or KNH2. On removing the K containing products by washing with degassed water, only mesoporous VN remains. VN materials with different pore sizes (10 nm-20 nm) were synthesized at 600 °C by varying the reaction time, while larger pores are obtained at higher temperatures (50 nm at 800 °C).

Yang, Minghui; Ralston, Walter T.; Tessier, Franck; Allen, Amy J.; DiSalvo, Francis J.

2013-01-01

354

Synthesis of mesoporous silica microsphere from dual surfactant  

Scientific Electronic Library Online (English)

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

Venkatathri, Narayanan.

2008-12-01

355

Synthesis and electrochemical capacitance of mesoporous Co(OH)2  

International Nuclear Information System (INIS)

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

356

Functionalized mesoporous silica for microgravimetric sensing of trace chemical vapors.  

Science.gov (United States)

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

Xu, Pengcheng; Yu, Haitao; Li, Xinxin

2011-05-01

357

Removal of anionic surfactants by sorption onto Aminated Mesoporous Carbon  

Directory of Open Access Journals (Sweden)

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.

Moradi S.E.

2013-01-01

358

Mesoporous NiO-Samaria doped ceria fuel cell materials.  

Science.gov (United States)

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

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

2009-02-01

359

Plutonium complexation by phosphonate-functionalized mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-10-27

360

Mesoporous silica and organosilica films templated by nanocrystalline chitin.  

Science.gov (United States)

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

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

2013-11-01

 
 
 
 
361

Adsorption of vitamin E on mesoporous titania nanocrystals  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-15

362

Ultrahigh porosity in mesoporous MOFs: promises and limitations.  

Science.gov (United States)

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

Senkovska, Irena; Kaskel, Stefan

2014-07-11

363

Synthesis of mesoporous silica microsphere from dual surfactant  

Directory of Open Access Journals (Sweden)

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

Venkatathri Narayanan

2008-12-01

364

Polymorphism of the glass former ethanol confined in mesoporous silicon  

CERN Document Server

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

Henschel, Anke; Huber, Patrick; 10.1080/09500831003766999

2010-01-01

365

Rhodium catalysts bound to functionalized mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-07-20

366

The ITQ-37 mesoporous chiral zeolite.  

Science.gov (United States)

The synthesis of crystalline molecular sieves with pore dimensions that fill the gap between microporous and mesoporous materials is a matter of fundamental and industrial interest. The preparation of zeolitic materials with extralarge pores and chiral frameworks would permit many new applications. Two important steps in this direction include the synthesis of ITQ-33, a stable zeolite with 18 x 10 x 10 ring windows, and the synthesis of SU-32, which has an intrinsically chiral zeolite structure and where each crystal exhibits only one handedness. Here we present a germanosilicate zeolite (ITQ-37) with extralarge 30-ring windows. Its structure was determined by combining selected area electron diffraction (SAED) and powder X-ray diffraction (PXRD) in a charge-flipping algorithm. The framework follows the SrSi(2) (srs) minimal net and forms two unique cavities, each of which is connected to three other cavities to form a gyroidal channel system. These cavities comprise the enantiomorphous srs net of the framework. ITQ-37 is the first chiral zeolite with one single gyroidal channel. It has the lowest framework density (10.3 T atoms per 1,000 A(3)) of all existing 4-coordinated crystalline oxide frameworks, and the pore volume of the corresponding silica polymorph would be 0.38 cm(3) g(-1). PMID:19407798

Sun, Junliang; Bonneau, Charlotte; Cantín, Angel; Corma, Avelino; Díaz-Cabañas, María J; Moliner, Manuel; Zhang, Daliang; Li, Mingrun; Zou, Xiaodong

2009-04-30

367

Mesoporous materials for clean energy technologies.  

Science.gov (United States)

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

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

2014-10-20

368

Controlled drug release from bifunctionalized mesoporous silica  

International Nuclear Information System (INIS)

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

369

75 FR 59997 - Shipping; Technical, Organizational, and Conforming Amendments  

Science.gov (United States)

...hydrocarbon mixtures (having 10% Benzene or more) 0 g. Butylbenzene, see Alky(C3-C4)benzenes 0 h. Butyl phenol, Formaldehyde resin in Xylene 0 i. Butyl toluene 0 j. Cymene 0 k. Decylbenzene, see Alkyl(C9+) benzenes 0 l....

2010-09-29

370

High quality self-assembly magnetite (Fe(3)O(4)) chain-like core-shell nanowires with luminescence synthesized by a facile one-pot hydrothermal process.  

Science.gov (United States)

Large scale synthesis of uniform self-assembly Fe(3)O(4)@phenol formaldehyde resin (PFR) core-shell nanowires with 80-100 nm in diameter and 20-30 microm in length can be realized by a one-pot hydrothermal process. The optical and magnetic properties of the as-synthesized Fe(3)O(4) nanostructures have been investigated. PMID:20376393

Gong, Junyan; Li, Shanzhong; Zhang, Dongen; Zhang, Xiaobo; Liu, Chao; Tong, Zhiwei

2010-05-28

371

A strategy for the development of macromolecular nonlinear optical materials  

Science.gov (United States)

Three convenient techniques to process second order organic nonlinear optical materials have been emphasized. Active moieties suffer from slow relaxation of the field-induced noncentrosymmetric alignment when processed with amorphous polymers or grafted to a flexible polymer backbone. Novel approaches to assemble the active molecules in preferred orientations in epoxy and phenol- formaldehyde resins are presented.

Mandal, Braja K.; Huang, Jan-Chan; Kumar, Jayant; Tripathy, Sukant

372

Method for making adhesive from biomass  

Science.gov (United States)

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

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

1985-01-01

373

Ion exchange on phenolic ion exchangers  

International Nuclear Information System (INIS)

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

374

Distillate fuel containing dehazing compositions  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to compositions which are the reaction products of phenol-formaldehyde resins, ..cap alpha..-olefins epoxides derived from ..cap alpha..-olefins of 4 or more carbons and alkylene oxides such as ethylene and propylene oxides; and to the use of these compositions as dehazers for petroleum distillates.

Bessler, D.U.; Tacchi, K.J.

1977-09-06

375

Structure and infrared emissivity of polyimide/mesoporous silica composite films  

International Nuclear Information System (INIS)

Polyimide/mesoporous silica composite films were prepared by direct mixing of polyamic acid solution and silylated mesoporous silica particles, or by condensation polymerization of dianhydride and diamine with silylated mesoporous silica particles in N,N-dimethylacetamide, followed with thermal imidization. Structure and glass transition temperatures of the composite films were measured with FTIR, SEM, EDX, XPS and DMTA. The results show that the silylated mesoporous silica particles in the composites tend to form the aggregation with a strip shape due to phase separation. The composite films exhibit higher glass transition temperature as comparing with that of pure polyimide. It is found that the composite films present lower infrared emissivity value than the pure polyimide and the magnitude of infrared emissivity value is related to the content of silylated mesoporous silica in the composite films. Inhibiting actions of silylated mesoporous silica on infrared emission of the composite films may be owing to presence of nanometer-scale pores in silylated mesoporous silica

376

Embedding waste in thermosetting resins  

International Nuclear Information System (INIS)

The process for waste embedding in thermosetting resins (polyester, epoxy) developed by the French Atomic Energy Commissariat (CEA) and TECHNICATOME is easy to operate and yields excellent results having regard to volume reduction and containment of radioisotopes (particularly Caesium). The industrial development of this process has led to the design of small versatile embedding stations quite adapted to research centres and experimental power plants. TECHNICATOME in cooperation with the CEA has extended such process to mobile units

377

Phosphorus-containing imide resins  

Science.gov (United States)

Flame-resistant reinforced bodies are disclosed which are composed of reinforcing fibers, filaments or fabrics in a cured body of bis- and tris-imide resins derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, or of addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride.

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

1984-01-01

378

Resin Diterpenes from Austrocedrus chilensis  

Directory of Open Access Journals (Sweden)

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

Verónica Rachel Olate

2011-12-01

379

Boron sorption characteristics in resins  

International Nuclear Information System (INIS)

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

380

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

Directory of Open Access Journals (Sweden)

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

Wei Gao

2012-01-01

 
 
 
 
381

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

Scientific Electronic Library Online (English)

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

Wei, Gao; Jianzhang, Li.

382

Hybrid non-silica meso-porous thin films  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-01-01

383

TEM studies of zeolites and ordered mesoporous materials.  

Science.gov (United States)

In the present manuscript we have reviewed recent results on transmission electron microscopy of beam sensitive materials such as zeolites and ordered mesoporous materials. The results of the investigation of the fine structure of different zeolite types as MFI, ITQ-7 and the presence of mixture of phases are shown. In addition, the incorporation of metals within the zeolitic framework and their different applications as precursors for metal nanowire growth are also described. The combination of HRTEM together with electron crystallography for solving new ordered mesoporous silica and associated analytical techniques shows the strength of electron microscopy for a full characterization of such materials. PMID:21227705

Diaz, Isabel; Mayoral, Alvaro

2011-07-01

384

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

Science.gov (United States)

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

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

2001-10-01

385

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

Science.gov (United States)

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

386

Reinforcement of Denture Base Resins  

Directory of Open Access Journals (Sweden)

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

T Nejatiant

2005-10-01

387

Wear rates of resin composites.  

Science.gov (United States)

SUMMARY A laboratory study was conducted to examine the wear of resin composite materials using a generalized wear simulation model. Ten specimens each of five resin composites (Esthet•X [EX], Filtek Supreme Plus [SP], Filtek Z250 [Z2], Tetric EvoCeram [EC], and Z100 Restorative [Z1]) were subjected to wear challenges of 100,000, 400,000, 800,000, and 1,200,000 cycles. The materials were placed in cylinder-shaped stainless-steel fixtures, and wear was generated using a flat stainless-steel antagonist in a slurry of polymethylmethacrylate beads. Wear (mean facet depth [?m] and volume loss [mm(3)]) was determined using a noncontact profilometer (Proscan 2000) with Proscan and ProForm software. Statistical analysis of the laboratory data using analysis of variance and Tukey's post hoc test showed a significant difference (p<0.05) for mean wear facet depth and volume loss for both the number of cycles and resin composite material. Linear regression analysis was used to develop predictive wear rates and volume loss rates. Linear wear was demonstrated with correlation coefficients (R(2)) ranging from 0.914 to 0.995. Mean wear values (mean facet depth [?m]) and standard deviations (SD) for 1200K cycles were as follows: Z1 13.9 (2.0), Z2 26.7 (2.7), SP 30.1 (4.1), EC 31.8 (2.3), and EX 67.5 (8.2). Volume loss (mm(3)) and SDs for 1200K cycles were as follows: Z1 0.248 (0.036), Z2 0.477 (0.044), SP 0.541 (0.072), EC 0.584 (0.037), and EX 1.162 (0.139). The wear rate (?m) and volume loss rate (mm(3)) per 100,000 cycles for the five resin composites were as follows: wear rate Z1 0.58, EC 1.27, Z2 1.49, SP 1.62, and EX 4.35, and volume loss rate Z1 0.009, EC 0.024, Z2 0.028, SP 0.029, and EX 0.075. The generalized wear model appears to be an excellent method for measuring relative wear of resin composite materials. PMID:22856679

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

2013-01-01

388

Treatment of spent ion-exchange resins  

International Nuclear Information System (INIS)

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

389

FB-Line resin testing final report  

Energy Technology Data Exchange (ETDEWEB)

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

Bannochie, C.J.

1992-01-23

390

Porous Ceramic Spheres from Ion Exchange Resin  

Science.gov (United States)

A commercial cation ion exchange resin, cross-linked polystyrene, has been successfully used as a template to fabricate 20 to 50 micron porous ceramic spheres. Ion exchange resins have dual template capabilities. Pore architecture of the ceramic spheres can be altered by changing the template pattern. Templating can be achieved by utilizing the internal porous structure or the external surface of the resin beads. Synthesis methods and chemical/physical characteristics of the ceramic spheres will be reported.

Dynys, Fred

2005-01-01

391

FABRICATION AND STUDY OF LIGNOCELLULOSIC HIBISCUS SABDARIFFA FIBER REINFORCED POLYMER COMPOSITES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Amar Singh Singha; Vijay Kumar Thakur

2008-01-01

392

Flexible heat resistant neutron shielding resin  

Energy Technology Data Exchange (ETDEWEB)

A flexible heat resistant neutron shielding material has been developed, which consists of polymer resin with 1 wt% boron. The neutron shielding performance of the developed resin, examined by the {sup 252}Cf neutron source, is almost the same as that of the polyethylene. The outgas of H{sub 2}, H{sub 2}O, CO and CO{sub 2} from the resin have been measured at {approx}250 deg. C environment. The resin will be applied around the port of the vacuum vessel as an additional shielding material and reduce the neutron streaming from a superconducting tokamak device such as JT-60SA.

Sukegawa, Atsuhiko M., E-mail: morioka.atsuhiko@jaea.go.jp [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka-machi, Ibaraki 311-0193 (Japan); Anayama, Yoshimasa [Neo-Tech R and D, 6-6-1, Ginza, Chuo-ku, Tokyo 104-0061 (Japan); Okuno, Koichi, E-mail: okunok@hazama.co.jp [Hazama Technical Research Institute, 515-1 Karima, Tsukuba-shi, Ibaraki 305-0822 (Japan); Sakurai, Shinji, E-mail: sakurai.shinji@jaea.go.jp [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka-machi, Ibaraki 311-0193 (Japan); Kaminaga, Atsushi, E-mail: kaminaga.atsushi@jaea.go.jp [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka-machi, Ibaraki 311-0193 (Japan)

2011-10-01

393

Flexible heat resistant neutron shielding resin  

International Nuclear Information System (INIS)

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

394

Dosemeter on the base of epoxidian resin  

International Nuclear Information System (INIS)

Dosimetric properties of epoxide-dian resin were investigated. Irradiation was conducted by the 60Co source at 20-40 Gy/s dose rates, as well as in 1.2 MeV electron beam at 1013-1014 s-1xcm-2 electron flux density (up to 104 Gy/s). Refractive index of the resin was measured by the IRF-22 refractometer with thermostatic control. Experiments showed that refractive index and average dispersion for epoxide-dian resin grows proportionally with absorbed dose. Conclusion is made about applicability of dosemeters on the base of epoxide-dian resin in radiation technology and when conducting nuclear-physical experiments

395

Graphite composites with advanced resin matrices  

Science.gov (United States)

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

Kourtides, D. A.

1980-01-01

396

Mesopore quality determines the lifetime of hierarchically structured zeolite catalysts  

Science.gov (United States)

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.

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

2014-05-01

397

Chemical vapor deposition of mesoporous graphene nanoballs for supercapacitor.  

Science.gov (United States)

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

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

2013-07-23

398

Contamination-resistant silica antireflective coating with closed ordered mesopores.  

Science.gov (United States)

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

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

2014-08-21

399

Ordered mesoporous cobalt oxide as highly efficient oxygen evolution catalyst.  

Science.gov (United States)

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

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

2013-03-20

400

Synthesis of Mesoporous Material from Chrysotile-Derived Silica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

 
 
 
 
401

Chemistry on the inside: green chemistry in mesoporous materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An overview of the rapidly expanding area of tailored mesoporous solids is presented. The synthesis of a wide range of the materials is covered, both inorganically and organically modified. Their applications, in particular those relating to green chemistry, are also highlighted. Finally, potential future directions for these materials are discussed.

Macquarrie, D. J.

2000-01-01

402

Mesoporous iron oxide nanofibers and their loading capacity of curcumin.  

Science.gov (United States)

Mesoporous iron oxide nanofibers were obtained by calcination of electrospun precursors at various temperatures. Their microstructure is influenced by the calcination temperature. As the calcination temperature is at 350 degrees C, the resultant iron oxide nanofibers largely consist of magnetic Fe3O4 and gamma-Fe2O3, with a specific surface area of about 120 m2/g and magnetization of about 66.5 Am2/kg. When the precursor calcined at 450 degrees C, the pure mesoporous alpha-Fe2O3 nanofibers with a specific surface area of about 92 m2/g are obtained and they show a high loading for curcumin. All the adjusted R-squares for the pseudo-second-order model overtop 0.99 in the initial curcumin ethanol solution concentrations of 30, 40 and 60 microg/mL, which suggests the pseudo-second-order kinetics model fit the adsorption kinetics of curcumin onto the mesoporous alpha-Fe2O3 nanofibers, and the adsorption can reach equilibrium in 60 min. While, Langmuir model (R2 = 0.9980) fits well the curcumin adsorption isotherm onto alpha-Fe2O3 mesoporous nanofibers, and the adsorption capacity is up to 12.48 mg/g at the curcumin concentration of 60 microg/mL. PMID:24734703

Wang, Qiuju; Liu, Ruijiang; Shen, Xiangqian; Zou, Lianli; Wu, Dingmei

2014-04-01

403

Alternative chemical route to mesoporous titania from a titanatrane complex  

DEFF Research Database (Denmark)

High-purity, mesoporous titania was prepared by reaction of dimethylaminotitanatrane, [NMe2–Ti(OCH2CH2)3N] in the presence of micellar aggregates as templating agents followed by thermal treatments in the temperature range 350–450 °C. The powders were characterized by nitrogen adsorption–desorption isotherms, thermogravimetry– differential thermal analysis, Fourier transform infrared, field-emission scanning electron microscopy, and x-ray diffraction. Analysis of the morphological characteristics of titanium oxide powders calcined at 350 °C for 120 h and at 450 °C for 6 h showed the presence of a mesoporous structure, with an average pore size of about 3.5 nm. Firing temperatures above 450 °C caused the collapse of the mesoporous structure. Composite Nafion-based membranes, containing 5 wt% mesoporous titania fired at 450 °C as a filler were successfully prepared. Preliminary tests in a prototype direct methanol fuel cell demonstrated that the composite membrane allowed cell operation up to 145 °C, thus showing a significant performance improvement over pure Nafion.

Trakanprapai, Chavalit; Esposito, Vincenzo

2005-01-01

404

Temperature effects on phase equilibrium and diffusion in mesopores  

Science.gov (United States)

The equilibrium and dynamic properties of fluids confined to mesoporous material have been studied using nuclear magnetic resonance (NMR) methods. Molecular diffusion of n -pentane in Vycor porous glass within closed sample tubes has been measured by means of the pulsed field gradient (PFG) NMR method for temperatures notably exceeding the boiling point of the neat liquid. It is found that the temperature dependence of the diffusivity dramatically depends on the state of the fluid surrounding the mesoporous monoliths. In an oversaturated sample, i.e., in a sample containing some amount of the liquid also outside of the porous material, the diffusivity in the mesopores followed the Arrhenius dependence. In samples with only the mesopores saturated by the liquid, i.e., without any excess fluid, with increasing temperature the diffusivity notably deviated from the Arrhenius dependence towards higher diffusivities. The analysis of the intensities of the respective NMR signals from the fluid within the porous material and in the surrounding phase has revealed that this anomaly is accompanied by the formation of a space free of liquid within the pore system. With the measured pore filling factors, the resulting overall diffusivity is estimated by a two-region approach with diffusion occurring in either the liquid phase or the free space within the pore volume. It is shown that this procedure, free of any fitting parameters, yields excellent agreement with the experimental data.

Dvoyashkin, Muslim; Valiullin, Rustem; Kärger, Jörg

2007-04-01

405

Thermal conductivity of a kind of mesoporous silica SBA-15  

Science.gov (United States)

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

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

2013-06-01

406

Thermal conductivity of a kind of mesoporous silica SBA-15  

International Nuclear Information System (INIS)

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

407

Iron nanowires embedded in mesoporous silica: Polarized neutron scattering study  

Science.gov (United States)

Magnetic iron nanowires embedded in the mesoporous silica matrix have been studied by Small Angle Polarized Neutron Scattering. Magnetic nanocomposites were prepared by a novel variant of the synthesis based on the introduction of the hydrophobic metal compound, Fe(CO) 5, into the hydrophobic part of as-prepared mesoporous silica-surfactant composite. The mesoporous silica represents a highly regular hexagonal structure of mesopores. A diffraction peak in SAPNS at qc?1.55 nm -1 is observed, which corresponds to a hexagonal structure with a periodicity of a0?4.6 nm. The scattering pattern of the pure matrix SiO 2 is well fitted by a sum of the contributions: the scattering on a powder consisting of large particles (1/ q4) and the scattering on the regular structure of pores (diffraction peak). The samples with iron inside the pores give additional scattering. This scattering depends significantly on the annealing temperature what demonstrates the different degrees of crystallization process. The latter is fitted as a scattering on the bunches of the nanowires with average radius Rb and with its spread ?R. The nuclear-magnetic interference in scattering of polarized neutrons was also studied. We observe no interference scattering on the periodical structure. Instead, a significant interference scattering is detected, which may be directly related to the bunches of the nanowires created during the crystallization process.

Grigorieva, N. A.; Grigoriev, S. V.; Okorokov, A. I.; Eckerlebe, H.; Eliseev, A. A.; Lukashin, A. V.; Napolskii, K. S.

2005-08-01

408

Hydrothermally stable ordered mesoporous titanosilicates with highly active catalytic sites.  

Science.gov (United States)

Mesoporous titanosilicates (MTS-9) are successfully prepared in strong acidic media by a two-step synthesis. MTS-9 has an ordered hexagonal structure and exhibits superior hydrothermal stability and high catalytic activity for the oxidation of the small molecules of phenol and styrene and also of the bulky molecule of trimethylphenol. PMID:11829580

Xiao, Feng-Shou; Han, Yu; Yu, Yi; Meng, Xiangju; Yang, Miao; Wu, Shuo

2002-02-13

409