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Sample records for resorcinol formaldehyde resin

  1. Hydraulic Permeability of Resorcinol-Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul Allen [ORNL

    2010-01-01

    An ion exchange process using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the Hanford Site, using large scale columns as part of the Waste Treatment Plant (WTP). The RF resin is also being evaluated for use in the proposed small column ion exchange (SCIX) system, which is an alternative treatment option at Hanford and at the Savannah River Site (SRS). A recirculating test loop with a small ion exchange column was used to measure the effect of oxygen uptake and radiation exposure on the permeability of a packed bed of the RF resin. The lab-scale column was designed to be prototypic of the proposed Hanford columns at the WTP. Although the test equipment was designed to model the Hanford ion exchange columns, the data on changes in the hydraulic permeability of the resin will also be valuable for determining potential pressure drops through the proposed SCIX system. The superficial fluid velocity in the lab-scale test (3.4-5.7 cm/s) was much higher than is planned for the full-scale Hanford columns to generate the maximum pressure drop expected in those columns (9.7 psig). The frictional drag from this high velocity produced forces on the resin in the lab-scale tests that matched the design basis of the full-scale Hanford column. Any changes in the resin caused by the radiation exposure and oxygen uptake were monitored by measuring the pressure drop through the lab-scale column and the physical properties of the resin. Three hydraulic test runs were completed, the first using fresh RF resin at 25 C, the second using irradiated resin at 25 C, and the third using irradiated resin at 45 C. A Hanford AP-101 simulant solution was recirculated through a test column containing 500 mL of Na-form RF resin. Known amounts of oxygen were introduced into the primary recirculation loop by saturating measured volumes of the simulant solution with oxygen and reintroducing

  2. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... chemical substance identified generically as resorcinol, formaldehyde substituted carbomonocycle resin (PMN...

  3. An Engineering Evaluation of Spherical Resorcinol Formaldehyde Resin

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    Birdwell Jr, Joseph F [ORNL; Lee, Denise L [ORNL; Taylor, Paul Allen [ORNL; Collins, Robert T [ORNL; Hunt, Rodney Dale [ORNL

    2010-09-01

    A small column ion exchange (SCIX) system has been proposed for removal of cesium from caustic, supernatant, and dissolved salt solutions stored or generated from high-level tank wastes at the US Department of Energy (DOE) Hanford Site and Savannah River Sites. In both instances, deployment of SCIX systems, either in-tank or near-tank, is a means of expediting waste pretreatment and dispositioning with minimal or no new infrastructure requirements. Conceptually, the treatment approach can utilize a range of ion exchange media. Previously, both crystalline silicotitanate (CST), an inorganic, nonelutable sorbent, and resorcinol-formaldehyde (RF), an organic, elutable resin, have been considered for cesium removal from tank waste. More recently, Pacific Northwest National Laboratory (PNNL) evaluated use of SuperLig{reg_sign} 644, an elutable ion exchange medium, for the subject application. Results of testing indicate hydraulic limitations of the SuperLig{reg_sign} resin, specifically a high pressure drop through packed ion exchange columns. This limitation is likely the result of swelling and shrinkage of the irregularly shaped (granular) resin during repeated conversions between sodium and hydrogen forms as the resin is first loaded then eluted. It is anticipated that a similar flow limitation would exist in columns packed with conventional, granular RF resin. However, use of spherical RF resin is a likely means of mitigating processing limitations due to excessive pressure drop. Although size changes occur as the spherical resin is cycled through loading and elution operations, the geometry of the resin is expected to effectively mitigate the close packing that leads to high pressure drops across ion exchange columns. Multiple evaluations have been performed to determine the feasibility of using spherical RF resin and to obtain data necessary for design of an SCIX process. The work performed consisted of examination of radiation effects on resin performance

  4. Chemical derivatization to enhance chemical/oxidative stability of resorcinol-formaldehyde resin

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    Hubler, T. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-10-01

    The purpose of this work is to develop modified resorcinol-formaldehyde (R-F) resin with enhanced chemical/oxidative stability in conditions typically encountered in the remediation of radioactive waste tanks. R-F resin is a regenerable organic ion-exchanger developed at Savannah River Technology Center that is being considered for use in the selective removal of radioactive cesium from alkaline waste tank supernates at both the Hanford and Savannah River sites.

  5. Lawps ion exchange column gravity drain of spherical resorcinol formaldehyde resin

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    Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Herman, D. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Restivo, M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-28

    Experiments at several different scales were performed to understand the removal of spherical resorcinol formaldehyde (sRF) ion exchange resin using a gravity drain system with a valve located above the resin screen in the ion exchange column (IXC). This is being considered as part of the design for the Low Activity Waste Pretreatment System (LAWPS) to be constructed at the DOE Hanford Site.

  6. Chemical derivatization to enhance chemical/oxidative stability of resorcinol-formaldehyde resin

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    Hubler, T.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    The goal of this task is to develop modified resorcinol-formaldehyde (R-F) resin to improve the chemical/oxidative stability of the resin. R-F resin is a regenerable organic ion-exchange resin that is selective for cesium ion in highly alkaline, high ionic-strength solutions. R-F resin tends to undergo chemical degradation, reducing its ability to remove cesium ion from waste solutions; the mechanistic details of these decomposition reactions are currently unknown. The approach used for this task is chemical modification of the resin structure, particularly the resorcinol ring unit of the polymer resin. This approach is based on prior characterization studies conducted at Pacific Northwest National Laboratory (PNNL) that indicated the facile chemical degradation of the resin is oxidation of the resorcinol ring to the para-quinone structure, with subsequent loss of ion-exchange sites for cesium ion. R-F resin represents an important alternative to current radiocesium remediation technology for tank wastes at both the Hanford and Savannah River sites, particularly if regenerable resins are needed.

  7. Concentrating cesium-137 from seawater using resorcinol-formaldehyde resin for radioecological monitoring

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    Egorin, Andrei; Tokar, Eduard; Tutov, Mikhail; Avramenko, Valentin [Institute of Chemistry FEBRAS, Vladivostok (Russian Federation); Far Eastern Federal Univ., Vladivostok (Russian Federation); Palamarchuk, Marina; Marinin, Dmitry [Institute of Chemistry FEBRAS, Vladivostok (Russian Federation)

    2017-04-01

    A method of preconcentrating cesium-137 from seawater using a resorcinol-formaldehyde resin, which enables one to optimize the ecological monitoring procedure, has been suggested. Studies of sorption of cesium-137 from seawater by resorcinol-formaldehyde resin have been performed, and it has been demonstrated that the cation exchanger is characterized by high selectivity with respect to cesium-137. It was found that the selectivity depended on the temperature of resin solidification and the seawater pH value. The maximal value of the cesium-137 distribution coefficient is equal to 4.1-4.5 x 10{sup 3} cm{sup 3} g{sup -1}. Under dynamic conditions, the ion-exchange resin capacity is 310-910 bed volumes depending on the seawater pH, whereas the efficiency of cesium removal exceeds 95%. The removal of more than 95% of cesium-137 has been attained using 1-3 M solutions of nitric acid: here, the eluate volume was 8-8.4 bed volumes. Application of 3 M solution of nitric acid results in resin degradation with the release of gaseous products.

  8. Cesium Isotherm Testing with Spherical Resorcinol-Formaldehyde Resin at High Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smoot, Margaret R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rinehart, Donald E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-04-01

    Washington River Protection Solutions (WRPS) is developing a Low-Activity Waste Pretreatment System (LAWPS) to provide low-activity waste (LAW) directly to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste Facility for immobilization. The pretreatment that will be conducted on tank waste supernate at the LAWPS facility entails filtration to remove entrained solids and cesium (Cs) ion exchange to remove Cs from the product sent to the WTP. Currently, spherical resorcinol-formaldehyde (sRF) resin (Microbeads AS, Skedsmokorset, Norway) is the Cs ion exchange resin of choice. Most work on Cs ion exchange efficacy in Hanford tank waste has been conducted at nominally 5 M sodium (Na). WRPS is examining the possibility of processing supernatant at high Na concentrations—up to 8 M Na—to maximize processing efficiency through the LAWPS. Minimal Cs ion exchange work has been conducted at 6 M and 8 M Na concentrations..

  9. Ion Exchange Modeling Of Cesium Removal From Hanford Waste Using Spherical Resorcinol-Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hamm, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2007-06-27

    This report discusses the expected performance of spherical Resorcinol-Formaldehyde (RF) ion exchange resin for the removal of cesium from alkaline Hanford radioactive waste. Predictions of full scale column performance in a carousel mode are made for the Hot Commissioning, Envelope B, and Subsequent Operations waste compositions under nominal operating conditions and for perturbations from the nominal. Only the loading phase of the process cycle is addressed in this report. Pertinent bench-scale column tests, kinetic experiments, and batch equilibrium experiments are used to estimate model parameters and to benchmark the ion-exchange model. The methodology and application presented in this report reflect the expected behavior of spherical RF resin manufactured at the intermediate-scale (i.e., approximately 100 gallon batch size; batch 5E-370/641). It is generally believed that scale-up to production-scale in resin manufacturing will result in similarly behaving resin batches whose chemical selectivity is unaffected while total capacity per gram of resin may vary some. As such, the full-scale facility predictions provided within this report should provide reasonable estimates of production-scale column performance.

  10. Evaluations of Mechanisms for Pu Uptake and Retention within Spherical Resorcinol-Formaldehyde Resin Columns

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, Calvin H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-15

    The unexpected uptake and retention of plutonium (Pu) onto columns containing spherical resorcinol-formaldehyde (sRF) resin during ion exchange testing of Cs (Cs) removal from alkaline tank waste was observed in experiments at both the Pacific Northwest National Laboratory (PNNL) and the Savannah River National Laboratory (SRNL). These observations have raised concern regarding the criticality safety of the Cs removal unit operation within the low-activity waste pretreatment system (LAWPS). Accordingly, studies have been initiated at Washington River Protection Solutions (WRPS), who manages the operations of the Hanford Site tank farms, including the LAWPS, PNNL, and elsewhere to investigate these findings. As part of these efforts, PNNL has prepared the present report to summarize the laboratory testing observations, evaluate these phenomena in light of published and unpublished technical information, and outline future laboratory testing, as deemed appropriate based on the literature studies, with the goal to elucidate the mechanisms for the observed Pu uptake and retention.

  11. Decontamination of spent ion-exchangers contaminated with cesium radionuclides using resorcinol-formaldehyde resins

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    Palamarchuk, Marina, E-mail: marina_p@ich.dvo.ru; Egorin, Andrey; Tokar, Eduard; Tutov, Mikhail; Marinin, Dmitry; Avramenko, Valentin

    2017-01-05

    Highlights: • Cesium radionuclides not removable by regeneration are bound to silicate deposits. • Application of RFR substantially increases cesium desorption from an ion-exchanger. • The radwaste volume was reduced at least 2-fold for zeolites and 10-fold for SIER. • The distribution coefficient values for RFR were high (K{sub d} > 10{sup 4}) after 6 regenerations. • The volume of secondary waste formed after regeneration of RFR was reduced 600-fold. - Abstract: The origin of the emergence of radioactive contamination not removable in the process of acid-base regeneration of ion-exchange resins used in treatment of technological media and liquid radioactive waste streams has been determined. It has been shown that a majority of cesium radionuclides not removable by regeneration are bound to inorganic deposits on the surface and inside the ion-exchange resin beads. The nature of the above inorganic inclusions has been investigated by means of the methods of electron microscopy, IR spectrometry and X-ray diffraction. The method of decontamination of spent ion-exchange resins and zeolites contaminated with cesium radionuclides employing selective resorcinol-formaldehyde resins has been suggested. Good prospects of such an approach in deep decontamination of spent ion exchangers have been demonstrated.

  12. Alternate Methods for Eluting Cesium from Spherical Resorcinol-Formaldehyde Resin

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    Taylor, Paul Allen [ORNL; Johnson, Heather Lauren [University of Tennessee, Knoxville (UTK)

    2009-02-01

    A small-column ion exchange (SCIX) system has been proposed for removing cesium from the supernate and dissolved salt solutions in the high-level-waste tanks at the Savannah River Site (SRS). The SCIX system could use either crystalline silicotitanate (CST), an inorganic, non-regenerable sorbent, or spherical resorcinol-formaldehyde (RF), a new regenerable resin, to remove cesium from the waste solutions. The baseline method for eluting the cesium from the RF resin uses 15 bed volumes (BV) of 0.5 M nitric acid (HNO{sub 3}). The nitric acid eluate, containing the radioactive cesium, would be combined with the sludge from the waste tanks and would be converted into glass at the Defense Waste Processing Facility (DWPF) at SRS. The amount of nitric acid that would be used to elute the RF resin, using the current elution protocol, exceeds the capacity of DWPF to destroy the nitrate ions and maintain the required chemical reducing environment in the glass melt. Installing a denitration evaporator at SRS is technically feasible but would add considerable cost to the project. Alternate methods for eluting the resin have been tested, including using lower concentrations of nitric acid, other acids, and changing the flow regimes. About 4 BV of 0.5 M HNO{sub 3} are required to remove the sodium (titrate the resin) and most of the cesium from the resin, so the bulk of the acid used for the baseline elution method removes a very small quantity of cesium from the resin. A summary of the elution methods that have been tested are listed.

  13. Gas Generation Testing of Spherical Resorcinol-Formaldehyde (sRF) Resin

    Energy Technology Data Exchange (ETDEWEB)

    Colburn, Heather A.; Bryan, Samuel A.; Camaioni, Donald M.; Mahoney, Lenna A.; Adami, Susan R.

    2018-01-19

    This report describes gas generation testing of the spherical resorcinol-formaldehyde (sRF) resin that was conducted to support the technology maturation of the LAWPS facility. The current safety basis for the LAWPS facility is based primarily on two studies that had limited or inconclusive data sets. The two studies indicated a 40% increase in hydrogen generation rate of water (as predicted by the Hu model) with sRF resin over water alone. However, the previous studies did not test the range of conditions (process fluids and temperatures) that are expected in the LAWPS facility. Additionally, the previous studies did not obtain replicate test results or comparable liquid-only control samples. All of the testing described in this report, conducted with water, 0.45M nitric acid, and waste simulants with and without sRF resin, returned hydrogen generation rates that are within the current safety basis for the facility of 1.4 times the Hu model output for water.

  14. REAL WASTE TESTING OF SPHERICAL RESORCINOL-FORMALDEHYDE ION EXCHANGE RESIN

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    Nash, C.; Duignan, M.

    2009-10-30

    This report presents data on batch contact and column testing tasks for spherical resorcinol-formaldehyde (sRF) resin. The testing used a non-radioactive simulant of SRS Tank 2F dissolved salt, as well as an actual radioactive waste sample of similar composition, which are both notably high in sodium (6 M). The resin was Microbeads batch 5E-370/641 which had been made on the hundred gallon scale. Equilibrium batch contact work focused on cesium at a temperature of 25 C due to the lack of such data to better benchmark existing isotherm models. Two campaigns were performed with small-scale ion exchange columns, first with Tank 2F simulant, then with actual dissolved salt in the Shielded Cells. An extrapolation of the batch contact results with radioactive waste over-predicted the cesium loaded onto the IX sRF resin bed by approximately 11%. This difference is not unexpected considering uncertainties from measurement and extrapolation and because the ion exchange that occurs when waste flows through a resin bed probably cannot reach the same level of equilibrium as when waste and resin are joined in a long term batch contact. Resin was also characterized to better understand basic chemistry issues such as holdup of trace transition metals present in the waste feed streams. The column tests involved using two beds of sRF resin in series, with the first bed referred to as the Lead column and the second bed as the Lag column. The test matrix included two complete IX cycles for both the simulant and actual waste phases. A cycle involves cesium adsorption, until the resin in the Lead column reaches saturation, and then regenerating the sRF resin, which includes eluting the cesium. Both the simulated and the actual wastes were treated with two cycles of operation, and the resin beds that were used in the Lead and Lag columns of simulant test phase were regenerated and reused in the actual waste test phase. This task is the first to demonstrate the treatment of SRS waste

  15. On-Chip Facile Preparation of Monodisperse Resorcinol Formaldehyde (RF Resin Microspheres

    Directory of Open Access Journals (Sweden)

    Jianmei Wang

    2018-01-01

    Full Text Available Monodisperse resorcinol formaldehyde resin (RF microspheres are an important polymeric material because of their rich surface functional group and uniform structural characteristics and have been increasingly applied as an electrode material, catalyst support, absorbent, and carbon microsphere precursor. The polymerization conditions, such as the gelation/solidification temperature and the residence time, can largely influence the physical properties and the formation of the 3D polymeric network of the RF microspheres as well as the carbon microspheres. However, few studies have reported on the complexity of the gelation and solidification processes of resol. In this work, we developed a new RF microsphere preparation device that contains three units: a droplet generation unit, a curing unit, and a collection unit. In this system, we controlled the gelation and solidification processes of the resol and observed its curing behavior, which helped us to uncover the curing mechanism of resol. Finally, we obtained the optimized polymerization parameters, obtaining uniform RF microspheres with a variation coefficient of 4.94%. The prepared porous RF microspheres presented a high absorption ability, reaching ~90% at 10 min. Thus, our method demonstrated the practicality of on-chip monodisperse microspheres synthesis. The product was useful in drug delivery and adsorbing large poisonous molecules.

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

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    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

    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.

  17. REMOVAL OF CESIUM FROM SAVANNAH RIVER SITE WASTE WITH SPHERICAL RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN EXPERIMENTAL TESTS

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.; Nash, C.

    2010-03-31

    A principal goal at the Savannah River Site (SRS) is to safely dispose of the large volume of liquid nuclear waste held in many storage tanks. In-tank ion exchange (IX) columns are being considered for cesium removal. The spherical form of resorcinol formaldehyde ion exchange resin (sRF) is being evaluated for decontamination of dissolved saltcake waste at SRS, which is generally lower in potassium and organic components than Hanford waste. The sRF performance with SRS waste was evaluated in two phases: resin batch contacts and IX column testing with both simulated and actual dissolved salt waste. The tests, equipment, and results are discussed.

  18. Preliminary flowsheet: Ion exchange for separation of cesium from Hanford tank waste using resorcinol-formaldehyde resin

    Energy Technology Data Exchange (ETDEWEB)

    Penwell, D.L.

    1994-12-28

    This preliminary flowsheet document describes an ion exchange process which uses resorcinol-formaldehyde (R-F) resin to remove cesium from Hanford tank waste. The flowsheet describes one possible equipment configuration, and contains mass balances based on that configuration with feeds of Neutralized Current Acid Waste, and Double Shell Slurry Feed. The flowsheet also discusses process alternatives, unresolved issues, and development needs associated with the ion exchange process. It is expected that this flowsheet will evolve as open issues are resolved and progress is made on development needs. This is part of the Tank Waste Remediation Program at Hanford. 26 refs, 6 figs, 25 tabs.

  19. Electrical Properties of Partial Carbonized Nanoporous Resin Based on Resorcinol-Formaldehyde

    Directory of Open Access Journals (Sweden)

    Imededdine NAJEH

    2014-05-01

    Full Text Available Organic xerogel compounds were prepared by sol-gel method from resorcinol- formaldehyde mixtures in acetone using picric acid as catalyst. The electrical properties of the obtained nanoporous carbon structures were explored by changing the pyrolysis temperature. In this study the electrical conductivity σ can be expressed as σ =/σ0exp(-Eσ/kT, where Eσ depends on the carbonized temperature. The dc and ac conductivities of the obtained amorphous carbon have been investigated from 80 to 300 °C and in the frequency range between 40 and 106 Hz for samples pyrolysed at different temperatures in the insulator-metal transition range. The temperature dependence of samples pyrolysed at low temperatures (Tp=600–675 °C follows a Mott law, whereas samples pyrolysed at high temperature (Tp=1000 °C show an Arrhenius dependence.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

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

  1. Precisely controlled resorcinol-formaldehyde resin coating for fabricating core-shell, hollow, and yolk-shell carbon nanostructures

    Science.gov (United States)

    Fang, Xiaoliang; Liu, Shengjie; Zang, Jun; Xu, Chaofa; Zheng, Ming-Sen; Dong, Quan-Feng; Sun, Daohua; Zheng, Nanfeng

    2013-07-01

    This work provides a facile one-step sol-gel route to synthesize high-quality resorcinol-formaldehyde (RF) resin coated nanocomposites that can be further used to fabricate desired carbon nanostructures. Colloidal particles with different morphologies and sizes can be coated with high-quality RF resin shells by the proposed cationic surfactant assisted RF resin coating strategy. The as-synthesized RF resin coated nanocomposites are ideal candidates for selective synthesis of core-shell, hollow, and yolk-shell carbon nanostructures. Based on the carboxylic functional RF resin coating, graphitic carbon nanostructures can also be synthesized by employing the graphitization catalyst. The as-synthesized carbon nanostructures show the advantageous performances in several applications. Hollow carbon spheres are potential electrode materials for lithium-sulfur batteries. Hollow graphitic spheres are promising catalyst supports for oxygen reduction reaction. And yolk-shell structured Au@HCS nanoreactors with ultrathin shells exhibit high catalytic activity and recyclability in confined catalysis.This work provides a facile one-step sol-gel route to synthesize high-quality resorcinol-formaldehyde (RF) resin coated nanocomposites that can be further used to fabricate desired carbon nanostructures. Colloidal particles with different morphologies and sizes can be coated with high-quality RF resin shells by the proposed cationic surfactant assisted RF resin coating strategy. The as-synthesized RF resin coated nanocomposites are ideal candidates for selective synthesis of core-shell, hollow, and yolk-shell carbon nanostructures. Based on the carboxylic functional RF resin coating, graphitic carbon nanostructures can also be synthesized by employing the graphitization catalyst. The as-synthesized carbon nanostructures show the advantageous performances in several applications. Hollow carbon spheres are potential electrode materials for lithium-sulfur batteries. Hollow graphitic

  2. Study of Mechanical Properties of Waste Biomass Reinforced Urea-Resorcinol-Formaldehyde Composites

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    A. S. SINGHA

    2011-01-01

    Full Text Available Natural fibers play an important role in developing high performing fully biodegradable composites which will be a key material to solve the current ecological and environmental problems. Due to enormous advantages of composites reinforced with natural fibers, a study on pine needles reinforced urea-resorcinol-formaldehyde composites has been made. Present investigation has revealed that urea-formaldehyde resin in 1.0: 2.5 ratio exhibits optimum mechanical behavior whereas in case urea-resorcinol- formaldehyde resin, the best mechanical behavior was shown by 1.0: 1.0: 2.5 ratios. However, reinforcing of this resin with pine-needles of 1 cm size and evaluation of their mechanical properties showed that mechanical properties increase with reinforcement. These results were further supported by the SEM and thermal studies.

  3. Study on efficient removal of clopyralid from water using resorcinol-formaldehyde carbon cryogel

    National Research Council Canada - National Science Library

    Momčilović Milan Z; Ranđelović Marjan S; Onjia Antonije E; Zarubica Aleksandra; Babić Biljana M; Matović Branko Z

    2014-01-01

    Resorcinol-formaldehyde carbon cryogel has been prepared, characterized and used for the removal of commonly used herbicide clopyralid from the aqueous solutions under varying experimental conditions...

  4. The Preparation and Characterization of Pyrolysis Bio-Oil-Resorcinol-Aldehyde Resin Cold-Set Adhesives for Wood Construction

    Directory of Open Access Journals (Sweden)

    Xueyong Ren

    2017-06-01

    Full Text Available Resorcinol-formaldehyde (RF resin is a kind of excellent exterior-grade wood structural adhesive, which can be conveniently cold-set for various applications. In order to decrease the production cost, pyrolysis bio-oil from renewable bioresources was used to replace resorcinol to synthesize the bio-oil-resorcinol-aldehyde (BRF resin. The effect of replacing resorcinol with bio-oil on the properties, bonding performance, and characterization of resorcinol-aldehyde resin was comparatively investigated. A higher solid content and viscosity, albeit a lower shear strength, was found when the replacement ratio of bio-oil increased. The bonding performance of BRF with 10 and 20 wt % bio-oil was close to that of the pure RF resin. However, the trends of being less cross-linked, more easily decomposed, but more porous were found when the substitution ratio of bio-oil was higher than 20 wt %. Interestingly, it was found that the wood failure values of the BRF resins with bio-oil of no more than 20 wt % were slightly higher than that of the pure RF resin. On the whole, BRF resins with 20 wt % bio-oil is recommended as a wood structural adhesive, comprehensively considering the bio-oil substitution ratio and resin properties. The results obtained here showed that pyrolysis bio-oil is a promising green raw material for the production of RF resin with lower cost.

  5. Bimodal activated carbons derived from resorcinol-formaldehyde cryogels

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    Szczurek, Andrzej; Amaral-Labat, Gisele; Fierro, Vanessa; Celzard, Alain [Institut Jean Lamour-UMR CNRS 7198, CNRS-Nancy-Universite-UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces. ENSTIB, 27 rue Philippe Seguin, BP 1041, 88051 Epinal cedex 9 (France); Pizzi, Antonio, E-mail: Alain.Celzard@enstib.uhp-nancy.fr [ENSTIB-LERMAB, Nancy-Universite, 27 rue Philippe Seguin, BP1041, 88051 Epinal cedex 9 (France)

    2011-06-15

    Resorcinol-formaldehyde cryogels prepared at different dilution ratios have been activated with phosphoric acid at 450 deg. C and compared with their carbonaceous counterparts obtained by pyrolysis at 900 deg. C. Whereas the latter were, as expected, highly mesoporous carbons, the former cryogels had very different pore textures. Highly diluted cryogels allowed preparation of microporous materials with high surface areas, but activation of initially dense cryogels led to almost non-porous carbons, with much lower surface areas than those obtained by pyrolysis. The optimal acid concentration for activation, corresponding to stoichiometry between molecules of acid and hydroxyl groups, was 2 M l{sup -1}, and the acid-cryogel contact time also had an optimal value. Such optimization allowed us to achieve surface areas and micropore volumes among the highest ever obtained by activation with H{sub 3}PO{sub 4}, close to 2200 m{sup 2} g{sup -1} and 0.7 cm{sup 3} g{sup -1}, respectively. Activation of diluted cryogels with a lower acid concentration of 1.2 M l{sup -1} led to authentic bimodal activated carbons, having a surface area as high as 1780 m{sup 2} g{sup -1} and 0.6 cm{sup 3} g{sup -1} of microporous volume easily accessible through a widely developed macroporosity.

  6. Bimodal activated carbons derived from resorcinol-formaldehyde cryogels

    Directory of Open Access Journals (Sweden)

    Andrzej Szczurek, Gisele Amaral-Labat, Vanessa Fierro, Antonio Pizzi and Alain Celzard

    2011-01-01

    Full Text Available Resorcinol-formaldehyde cryogels prepared at different dilution ratios have been activated with phosphoric acid at 450 °C and compared with their carbonaceous counterparts obtained by pyrolysis at 900 °C. Whereas the latter were, as expected, highly mesoporous carbons, the former cryogels had very different pore textures. Highly diluted cryogels allowed preparation of microporous materials with high surface areas, but activation of initially dense cryogels led to almost non-porous carbons, with much lower surface areas than those obtained by pyrolysis. The optimal acid concentration for activation, corresponding to stoichiometry between molecules of acid and hydroxyl groups, was 2 M l−1, and the acid–cryogel contact time also had an optimal value. Such optimization allowed us to achieve surface areas and micropore volumes among the highest ever obtained by activation with H3PO4, close to 2200 m2 g−1 and 0.7 cm3 g−1, respectively. Activation of diluted cryogels with a lower acid concentration of 1.2 M l−1 led to authentic bimodal activated carbons, having a surface area as high as 1780 m2 g−1 and 0.6 cm3 g−1 of microporous volume easily accessible through a widely developed macroporosity.

  7. Summary of pilot-scale activities with resorcinol ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Cicero, C.A. [Westinghouse Savannah River Company, AIKEN, SC (United States); Bickford, D.F.; Sargent, T.N.; Andrews, M.K.; Bibler, J.P.; Bibler, N.E.; Jantzen, C.M.

    1995-10-02

    The Mixed Waste Focus Area (MWFA) of the Department of Energy (DOE) is currently investigating vitrification technology for treatment of low level mixed wastes (LLMW). They have chartered the Savannah River Technology Center (SRTC) to study vitrification of the wastes through an Office of Technology Development (OTD) Technical Task Plan (TTP). SRTC`s efforts have included crucible-scale studies and pilot scale testing on simulated LLMW sludges, resins, soils, and other solid wastes. Results from the crucible-scale studies have been used as the basis for the pilot-scale demonstrations. As part of the fiscal year (FY) 1995 activities, SRTC performed crucible-scale studies with organic resins. This waste stream was selected because of the large number of DOE sites, as well as commercial industries, that use resins for treatment of liquid wastes. Pilot-scale studies were to be completed in FY 1995, but could not be due to a reduction in funding. Instead, a compilation of pilot-scale tests with organic resins performed under the guidance of SRTC was provided in this report. The studies which will be discussed used a resorcinol- formaldehyde resin loaded with non-radioactive cesium, which was fed with simulated wastewater treatment sludge feed. The first study was performed at the SRTC in the mini-melter, 1/100th scale of the Defense Waste Processing Facility (DWPF) melter, and also involved limited crucible-scale studies to determine the resin loading obtainable. The other study was performed at the DOE/Industrial Center for Vitrification Research (Center) and involved both crucible and pilot-scale testing in the Stir-Melter stirred-melter. Both studies were successful in vitrifying the resin in simulated radioactive sludge and glass additive feeds.

  8. Carbohydrate modified phenol-formaldehyde resins

    Science.gov (United States)

    Anthony H. Conner; Linda F. Lorenz

    1986-01-01

    For adhesive self-sufficiency, the wood industry needs new adhesive systems in which all or part of the petroleum-derived phenolic component is replaced by a renewable material without sacrificing high durability or ease of bonding. We tested the bonding of wood veneers, using phenolic resins in which part of the phenol-formaldehyde was replaced with carbohydrates. Our...

  9. Characterization of pure and composite resorcinol formaldehyde aerogels doped with silver

    Science.gov (United States)

    Attia, S. M.; Abdelfatah, M. S.; Mossad, M. M.

    2017-07-01

    A series of Resorcinol Formaldehyde (RF) aerogels composites with nanoparticles of sliver were prepared by the sol-gel method at different concentrations doped silver. FTIR spectra of pure and composite RF aerogels show six absorption bands attributed to -OH groups bonded to the benzene ring, stretching of -CH2- bonds and aromatic ring stretching. FTIR results ensured that sliver particles do not interact with aerogel network. UV-visible spectrum of pure silver show an absorbance peak at 420 nm attributed to the surface plasmon excitation of sliver Nano spheres. UV-visible spectral of pure and composite RF aerogels shows a steep decrease of absorption with wavelength after 500 nm, making sample’s color reddish brown. TEM and SEM images of pure and composite RF aerogels revealed that the textural arrangement of RF aerogels can be described as densely packed small nodules.

  10. Study on efficient removal of clopyralid from water using resorcinol-formaldehyde carbon cryogel

    Directory of Open Access Journals (Sweden)

    Momčilović Milan Z.

    2014-01-01

    Full Text Available Resorcinol-formaldehyde carbon cryogel has been prepared, characterized and used for the removal of commonly used herbicide clopyralid from the aqueous solutions under varying experimental conditions. Carbon has shown a relatively high specific surface area, significant mesoporosity and an amorphous structure. A set of the following isotherm models has been used to interpret the equilibrium data: Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Jovanović, Hurkins-Jura, and Helsey model. Several models have fitted well although the calculated values for qmax poorly correlate with the data obtained experimentally. The kinetic models of the pseudo-first and pseudo-second-order, the models of Elovich, Bangham and the intraparticle diffusion model have been used for fitting the kinetic data. The rate of the process is fast in the beginning while adsorption equilibrium is attained not until 24 hours. Adsorption was found to be pH dependent and favored in acidic solutions.

  11. High-Yield Synthesis of Janus Dendritic Mesoporous Silica@Resorcinol-Formaldehyde Nanoparticles: A Competing Growth Mechanism.

    Science.gov (United States)

    Qu, Lili; Hu, Huicheng; Yu, Jiaqi; Yu, Xiaoya; Liu, Jian; Xu, Yong; Zhang, Qiao

    2017-05-30

    Recently, Janus nanostructures that possess two or more different surface functions have attracted enormous attention because of their unique structures and promising applications in diverse fields. In this work, we present that Janus structured dendritic mesoporous silica@resorcinol-formaldehyde (DMS@RF) nanoparticles can be prepared through a simple one-pot colloidal method. The Janus DMS@RF nanoparticle shows a bonsai-like morphology which consists of a dendritic mesoporous silica part and a spherical RF part. After a systematic study on the growth process, we proposed a competing growth mechanism that accounts for the formation of Janus nanostructures. It is believed that suitable polymerization rate of silica and RF resin is critical. Based on the competing growth mechanism, eccentric and concentric core-shell nanostructures have been successfully prepared by tuning the polymerization rates of silica and RF, respectively. Metal-contained ternary Janus nanoparticles that might be used for catalysis have also been prepared. This research may pave the way for the practical applications of delicate nanomaterials with desired structures and properties.

  12. Heat stability of cured urea-formaldehyde resins by measuring formaldehyde emission

    Science.gov (United States)

    Shin-ichiro Tohmura; Chung-Yun Hse; Mitsuo Higuchi

    1999-01-01

    A test method for measuring formaldehyde from urea-formaldehyde (UF) resins at high tempera­tures was developed and used to assess the influence of the reaction pH at synthesis on the formaldehyde emission during cure and heat stability of the cured resins without water. Additionally, 13C-CP/MAS solid-state nuclear magnetic resonance (NMR)...

  13. and phenol–formaldehyde resin

    Indian Academy of Sciences (India)

    Thermosetting resin; magnetic properties; microstructures; heat treatment. 1. Introduction. The ideal insulating soft magnetic composite (SMC) is formed by ferromagnetic .... turns was wound for AC complex permeability measure- ment. Complex permeability spectra were measured by an impedance analyzer (HP 4194A) ...

  14. Perbandingan Sifat Mekanik Fisik Vulkanisat Sbr Dan Sbr/nr Menggunakan Bahan Pengisi Pati Termodifikasi Resorcinol Formaldehyde

    OpenAIRE

    Susanto, Tri

    2016-01-01

    Penelitian ini bertujuan untuk mengetahui perbandingan karakteristik vulkanisat komposit Styrene Butadiene Rubber (SBR) dan campuran Styrene Butadiene Rubber dan Natural Rubber (SBR/NR) yang keduanya menggunakan bahan pengisi starch (pati) termodifikasi Resorcinol Formaldehyde (SRF) sebagai bahan substituen Carbon Black (CB). Rasio CB/SRF untuk tiap vulkanisat yang digunakan berturut-turut 60/0; 55/5; 50/10; 45/15; 40/20 phr. Pengamatan dilakukan dengan menguji sifat physco-mechanic vulkanisa...

  15. Graphene oxide as an anti-shrinkage additive for resorcinol-formaldehyde composite aerogels.

    Science.gov (United States)

    Guo, Kang; Song, Huaihe; Chen, Xiaohong; Du, Xian; Zhong, Liang

    2014-06-21

    In order to strengthen the nanostructure and suppress the collapse of nanopores of resorcinol-formaldehyde (RF) aerogels during the drying process, graphene oxide (GO) was incorporated into the RF matrix to prepare GO-RF composite aerogels by sol-gel polymerization. The influences of GO content on the sol-gel process, structure, and physical properties of RF aerogels were investigated. The morphologies of composite aerogels were characterized by scanning electron microscopy and transmission electron microscopy, and it was found that GO was well dispersed in the RF matrix. In addition, GO can obviously accelerate the gelation of the RF solution and reduce both the drying shrinkage and aerogel density. As the content of GO increased from 0 to 2 wt%, both the linear shrinkage and density of composite aerogels decreased progressively from 28.3% to 2.0% and 506 to 195 kg m(-3), respectively, implying that GO is an effective additive for inhibiting the volume shrinkage of aerogels during the drying process.

  16. FABRICATION AND PROPERTIES OF OER COATED RESORCINOL-FORMALDEHYDE SHELLS FOR OMEGA EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    NIKROO,A; CZECHOWICZ,D; PAGUIO,R; GREENWOOD,A.L; TAKAGI,M

    2003-06-01

    OAK-B135 New high gain designs for direct drive ignition on NIF require foam shells. Scaled down versions of these designs are needed for near term experiments on the OMEGA laser facility at the Laboratory Laser Energetics (LLE). These shells need to be about 1 mm in diameter and 50-100 {micro}m wall thickness and densities of 100-250 mg/cc. In addition, a full density permeation seal needs to be deposited for retention of the fill gas at room temperature or the ice at cryogenic temperatures. They have fabricated such shells using Resorcinol-formaldehyde (R/F) as the selected foam material due to its transparency in the optical region. Extensive characterization of the wall uniformity of these shells has been performed. The foam shells have {approx} 5%-6% non-concentricities on the average. A full density permeation seal has been deposited on the R/F shells using two different techniques. In the first technique R/F shells are coated directly with plasma polymer to thicknesses of 3-4 {micro}m. In the second technique, R/F shells are coated with polyvinylphenol, using a chemical interfacial polymerization technique. Data on surface finish and gas retention for R/F shells coated by both methods are provided.

  17. Conduction mechanism and dielectric properties of pure and composite resorcinol formaldehyde aerogels doped with silver

    Science.gov (United States)

    Attia, S. M.; Abdelfatah, M. S.; Mossad, M. M.

    2017-07-01

    Pure and composite Resorcinol-Formaldehyde (RF) aerogel samples were prepared by sol-gel process using KOH as a catalyst and doped with silver nanoparticles at different concentrations (1.2×10-4, 2.4×10-4, 3.6×10-4, and 4.8×10-4 wt.% at catalyst ratio 0.024 wt.%). DC electrical conductivity σdc, AC electrical conductivity σ‧, and the dielectric properties of the prepared samples have been measured at different frequencies and temperatures. The results show that σ‧ increases with increasing frequency. The values of σ‧ range from ˜10-4 Ω-1m-1 to around unity at room temperature. The analysis of the results of σ‧(ω, T) reveals that the large overlapping polaron (OLP) is the most favorable mechanism to describe the conduction mechanism in these samples. The behavior of the dielectric constant with the frequency of these samples is normal, where it decreases with increasing frequency, while the behavior of dielectric loss tangent tanδ exhibits a peaking behavior at relatively higher temperature.

  18. Melamine-modified urea formaldehyde resin for bonding particleboards

    Science.gov (United States)

    Chung-Yun Hse; Feng Fu; Hui Pan

    2008-01-01

    For the development of a cost-effective melamine-modified urea formaldehyde resin (MUF), the study evaluated the effects of reaction pH and melamine content on resin properties and bond performance of the MUF resin adhesive systems. Eight resins, each with three replicates, were prepared in a factorial experiment that included two formulation variables: two reaction...

  19. Reduction of the formaldehyde content in leathers treated with formaldehyde resins by means of plant polyphenols

    OpenAIRE

    Marsal Monge, Agustín; Manich Bou, Albert M.; Cuadros Domènech, Sara; Font Vallès, Joaquim

    2017-01-01

    Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, releasing formaldehyde. Due to the carcinogenicity of formaldehyde, its presence in leather should be avoided or kept below allowable limits. The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the forma...

  20. 21 CFR 175.380 - Xylene-formaldehyde resins condensed with 4,4′-isopropylidenediphenol-epichlorohydrin epoxy resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Xylene-formaldehyde resins condensed with 4,4â²... Xylene-formaldehyde resins condensed with 4,4′-isopropylidenediphenol-epichlorohydrin epoxy resins. The...) The resins are produced by the condensation of xylene-formaldehyde resin and 4,4...

  1. Mixture Design Approach on the Physical Properties of Lignin-Resorcinol-Formaldehyde Xerogels

    Directory of Open Access Journals (Sweden)

    Chris D. Castro

    2015-01-01

    Full Text Available Organic xerogels were functionalized by incorporating sugarcane bagasse lignin from soda pulping black liquor, not used so far in this materials, with the aim of introducing new functional groups on traditional gels that could improve its adsorptive capacity. Two mixing designs were applied to identify the reactive combinations that allow a well gel formation and to adjust models that predict physical properties. The designs study five components: resorcinol (R, 0.04–0.3, lignin (L, 0.004–0.14, formaldehyde (F, 0.08–0.17, water (W, 0.45–0.8, and NaOH (C, 0.0003–0.0035. The first experimental design was an extreme vertices design and its results showed shrinkage between 4.3 and 59.7 and a bulk density from 0.54 to 1.3; a mass ratio LR/F near 1.5 was required for gel formation. In the second design a D-Optimal was used to achieve better adjusted coefficients and incorporate the largest possible amount of lignin in the gels. Bulk density varies from 0.42 to 0.9, shrinkage varies from 3.42 to 25.35, and specific surface area reaches values of 451.86 m2/g with 13% lignin and 270 m2/g with 27% lignin. High catalyst content improves lignin dissolution and increase shrinkage and bulk density of xerogels and bulk density. Lignin contributes to reducing shrinkage and specific surface area due to his compact and rigid structure.

  2. Thermal decomposition of energetic materials 85: Cryogels of nanoscale hydrazinium diperchlorate in resorcinol-formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Tappan, Bryce C.; Brill, Thomas B. [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)

    2003-04-01

    The objective of this work was to try to desensitize an energetic material by using sol-gel processing and freeze drying to incorporate the energetic material into the fuel matrix on the nano (or at least submicron) particle size scale. Hydrazinium diperchlorate ([N{sub 2}H{sub 6}][ClO{sub 4}]{sub 2} or HP{sub 2}) and resorcinol-formaldehyde (RF) were chosen as the oxidizer and fuel, respectively. Solid loading up to 88% HP{sub 2} was achieved by using the sol gel-to-cryogel method. Various weight percentages of HP{sub 2} in RF were characterized by elemental analysis, scanning electron (SEM) and optical microscopy, T-jump/FTIR spectroscopy, DSC, and drop-weight impact. SEM indicated that 20-50 nm diameter HP{sub 2} plates aggregated into porous 400-800 nm size clusters. Below 80% HP{sub 2} the cryogels are less sensitive to impact than physical mixtures having the same ratios of HP{sub 2} and RF. The decomposition temperatures of the cryogels are higher than that of pure HP{sub 2}, which is consistent with their lower impact sensitivity. The heat of decomposition as measured at a low heating rate increases with increasing percentage of HP{sub 2}. The cryogels and physical mixtures release similar amounts of energy, but the cryogels exhibit mainly a single exotherm by DSC whereas the physical mixtures showed a two-step energy release. Flash pyrolysis revealed gaseous product ratios suggestive of more energy being released from the cryogels than the physical mixtures. Cryogels also burn faster by visual observation. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  3. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Melamine-formaldehyde resins in molded articles...-formaldehyde resins in molded articles. Melamine-formaldehyde resins may be safely used as the food-contact...: (a) For the purpose of this section, melamine-formaldehyde resins are those produced when 1 mole of...

  4. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea-formaldehyde resins in molded articles. 177...-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact surface... conditions: (a) For the purpose of this section, urea-formaldehyde resins are those produced when 1 mole of...

  5. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Science.gov (United States)

    2010-07-01

    ...-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced & Cooled) A Appendix A to Subpart HHHH of Part... Appendix A to Subpart HHHH of Part 63—Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins... Development method of determining free-formaldehyde in urea-formaldehyde resins. This method applies to...

  6. Effect of different catalysts on urea-formaldehyde resin synthesis

    Science.gov (United States)

    Qi-Ning Sun; Chung-Yun Hse; Todd F. Shupe

    2014-01-01

    Four catalysts (H2SO4, HCl, H3PO4, and NaOH/NH4OH) were studied in the preparation of melamine modified urea– formaldehyde (UFM) resins. 13C-nuclear magnetic resonance spectroscopic analysis of the UFM resins at different synthesis stages revealed the...

  7. On the synthesis and structure of resorcinol-formaldehyde polymeric networks – Precursors to 3D-carbon macroassemblies

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, James P.; Fox, Christina A.; Worsley, Marcus A.

    2015-07-01

    With the new impetus towards the development of hierarchical graphene and CNT macro-assemblies for application in fields such as advanced energy storage, catalysis and electronics; there is much renewed interest in organic carbon-based sol–gel processes as a synthetically convenient and versatile means of forming three dimensional, covalently bonded organic/inorganic networks. Such matrices can act as highly effective precursors, scaffolds or molecular ‘glues’ for the assembly of a wide variety of functional carbon macro-assemblies. However, despite the utility and broad use of organic sol–gel processes – such as the ubiquitous resorcinol-formaldehyde (RF) reaction, there are details of the reaction chemistries of these important sol–gel processes that remain poorly understood at present. It is therefore both timely and necessary to examine these reactions in more detail using modern analytical techniques in order to gain a more rigorous understanding of the mechanisms by which these organic networks form. The goal of such studies is to obtain improved and rational control over the organic network structure, in order to better direct and tailor the architecture of the final inorganic carbon matrix. In this study we have investigated in detail, the mechanism of the organic sol–gel network forming reaction of resorcinol and formaldehyde from a structural and kinetic standpoint, by using a combination of real-time high field solution state nuclear magnetic resonance (NMR), low field NMR relaxometry and differential scanning calorimetry (DSC). These investigations have allowed us to track the network formation processes in real-time, gain both detailed structural information on the mechanisms of the RF sol–gel process and a quantitative assessment of the kinetics of the global network formation process. It has been shown that the mechanism, by which the RF organic network forms, proceeds via an initial exothermic step correlated to the formation of a

  8. Development of melamine modified urea formaldehyde resins based o nstrong acidic pH catalyzed urea formaldehyde polymer

    Science.gov (United States)

    Chung-Yun Hse

    2009-01-01

    To upgrade the performance of urea-formaldehyde (UF) resin bonded particleboards, melamine modified urea-formaldehyde (MUF) resins based on strong acidic pH catalyzed UF polymers were investigated. The study was conducted in a series of two experiments: 1) formulation of MUF resins based on a UF polymer catalyzed with strong acidic pH and 2) determination of the...

  9. Urea-formaldehyde resins: production, application, and testing

    Science.gov (United States)

    Nuryawan, A.; Risnasari, I.; Sucipto, T.; Heri Iswanto, A.; Rosmala Dewi, R.

    2017-07-01

    Urea-formaldehyde (UF) resin, one of the most important formaldehyde resin adhesives, is a polymeric condensation product of formaldehyde with urea, and being widely used for the manufacture of wood-based composite panels, such as plywood, particleboard, and fiberboard. In spite of its benefits such as fast curing, good performance in the panels (colorless), and lower cost; formaldehyde emission (FE) originated from either UF resin itself or composite products bonded by UF resins is considered a critical drawback as it affects human health particularly in indoor environment. In order to reduce the FE, lowering formaldehyde/urea (F/U) mole ratio in the synthesis of the UF resin was done. In this study, synthesis of UF resins was carried out following the conventional alkaline-acid two-step reaction with a second addition of urea, resulting in F/U mole ratio around 1.0, namely 0.95; 1.05, and 1.15. The UF resins produced were used as binder for particleboard making. The board was manufactured in the laboratory using shaving type particle of Gmelina wood, 8% UF resin based on oven dry particle, and 1% NH4Cl (20%wt) as hardener for the resin. The target of the thickness was 10 mm and the dimension was 25 cm x 25 cm. The resulted particleboard then was evaluated the physical and the mechanical properties by Japanese Industrial Standard (JIS) A 5908 (2003). Further, the resulted particleboard also was used for the mice cage’s wall in order to mimic the real living environment. After four weeks exposure in the cages, the mice then were evaluated their mucous organs as well as their blood. The experiment results were as follows: 1) It was possible to synthesis UF resins with low F/U mole ratio; 2) However, the particleboard bonded UF resins with low F/U mole ratio showed poor properties, particularly on the thickness swelling and modulus of elasticity; 3) There was no significant differences among the mucous organs of the mice after a month exposure FE originated from

  10. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  11. Literature Review of Spherical Resorcinol-Formaldehyde for Cesium Ion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Garrett N.

    2014-09-30

    The current report summarizes work performed throughout the scientific community and DOE complex as reported in the open literature and DOE-sponsored reports to evaluate the Cs+ ion exchange (CIX) characteristics of SRF resin. King (2007) completed a similar literature review in support of material selection for the Small Column Ion Exchange (SCIX) project. Josephson et al. (2010) and Sams et al. (2009) provided a similar brief review of SRF CIX for the near-tank Cs+ removal (NTCR) project. Thorson (2008a) documented the basis for recommending SRF over SuperLigTM 644 as the primary CIX resin in the WTP. The current review expands on previous work, summarizes additional work completed to date, and provides a broad view of the literature without focusing on a specific column system. Although the focus of the current review is the SRF resin, many cited references include multiple materials such as the non-spherical GGRF and SuperLigTM 644 organic resins and crystalline silicotitanate (CST) IONSIVTM IE-911, a non-elutable inorganic material. This report summarizes relevant information provided in the literature.

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

    OpenAIRE

    Liu Weihua; Li Yingmin; Qu Xueliang

    2008-01-01

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

  13. Synthesis of morphology-controlled carbon hollow particles by carbonization of resorcinol-formaldehyde precursor microspheres and applications in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Haijiao, E-mail: seaboyfang@163.com [Modern Manufacture Engineering Center, Heilongjiang Institute of Science and Technology, 150027 (China); Xu Huifang, E-mail: xuhf@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, 150001 (China); Zhao Can [Modern Manufacture Engineering Center, Heilongjiang Institute of Science and Technology, 150027 (China)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Resorcinol-formaldehyde hollow particles could be obtained by inverse suspension method. Black-Right-Pointing-Pointer The morphologies of RF carbon precursor particles could be controlled by adjusting the pH values of the RF precursor. Black-Right-Pointing-Pointer The prepared carbon hollow particles, which derived from resorcinol-formaldehyde, exhibited microporous properties. Black-Right-Pointing-Pointer The RF carbon microcapsules displayed excellent power property and cycle durability. - Abstract: The morphology-controlled carbon hollow particles, derived from resorcinol-formaldehyde (RF) particles, were prepared by using an (oil phase) O/(water phase) W/(oil phase) O inverse-emulsion system which was formed by adding RF precursor (water phase) to n-hexane (oil phase) with Span-80 as surfactant and the following carbonization. This simple method led to the formation of various morphologies of RF carbon precursor particles such as hollow spheres, bowl-like hollow structures, microcapsules, or solid microspheres by adjusting the pH values of the RF precursor. The synthesized carbon particles exhibited porous characters with the surface area of 659 m{sup 2} g{sup -1} and the total pore volume of 0.44 cm{sup 3} g{sup -1}. Additionally, the electrochemical behavior of the typical RF carbon particles in lithium-ion batteries revealed that the RF carbon microcapsules displayed a high initial discharge capacity of 1059 mAh g{sup -1} and stabilized at about 330 mAh g{sup -1}, indicating its excellent power property and cycle durability.

  14. Domestic Research Progress in Graphene Oxide/ Phenolic Formaldehyde Resin Composites

    Directory of Open Access Journals (Sweden)

    JIANG Li

    2017-04-01

    Full Text Available Graphene oxide(GO,an important derivative of graphene,has good compatibility with phenolic formaldehyde resin(PFthanks to the active groups such as hydroxyl,carboxyl and epoxy. Recently,graphene oxide has been applied in the research and development of PF based composites. GO/PF composites show good mechanical,electrical,thermal and frictional properties,as well as dielectric and flame retardant properties. This review reports the domestic research results in PF/GO composites in the recent five years.

  15. Characterization of novolac type liquefied wood/phenol/formaldehyde (LWPF) resin

    Science.gov (United States)

    Hui Pan; Todd F. Shupe; Chung-Yun Hse

    2009-01-01

    Novolac type liquefied wood/phenol/formaldehyde (LWPF) resins were synthesized from liquefied wood and formaldehyde. The average molecular weight of the LWPF resin made from the liquefied wood reacted in an atmospheric three neck flask increased with increasing P/W ratio. However, it decreased with increasing phenol/wood ratio when using a sealed Parr reactor. On...

  16. Differential scanning calorimetry of the effects of temperature and humidity on phenol-formaldehyde resin cure

    Science.gov (United States)

    X.-M. Wang; B. Riedl; A.W. Christiansen; R.L. Geimer

    1994-01-01

    Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31...

  17. Volatile organic compound and formaldehyde emissions from Populus davidiana wood treated with low molecular weight urea-formaldehyde resin.

    Science.gov (United States)

    Wang, Jing-Xian; Shen, Jun; Lei, Cheng-Shuai; Feng, Qi

    2014-09-01

    Populus davidiana wood was usually impregnated with low molecular weight thermosetting resins to improve its physical and mechanical properties. However, volatile organic compounds (VOCs) and formaldehyde emitted from treated wood have lead to poor indoor air quality (IAQ). The trends of VOC and formaldehyde emissions as a function of the weight percent gain (WPG) factor were mainly investigated in this work. Aldehydes and alkanes were the predominant compositions indentified in the VOC emissions, although low amount of ketones, terpenes and alcohols were also found. With the increase in WPG, VOC and formaldehyde concentrations improved. However, their concentration began to decrease when WPG was over 44.06% (VOC) and 36.35% (formaldehyde), respectively. The modulus of elasticity (MOE) of untreated and treated wood at different WPG levels was detected. It showed that treatment of wood with UF resin significantly improved the mechanical properties. Therefore, it is probably helpful to comprehensively analyze correlations among environmental performance, mechanical performance and processing costs.

  18. Preparation and Analytical Properties of 4-Hydroxybenzaldehyde, Biuret and Formaldehyde Terpolymer Resin

    OpenAIRE

    Bunian A. Shareef; Ibrahim F. Waheed; Kariem K. Jalaot

    2014-01-01

    The chelating resin was synthesized by polycondensation reaction of 4-hydroxy benzaldehyde, formaldehyde and biuret under alkaline condition. The prepared resin was characterized by IR spectroscopy and 1HNMR spectroscopy. The resin sample was cured isothermally at 1200C.The DSC scans was measured for the prepared resin. The analytical evaluation of the prepared resin toward the studied ions (Hg2+, Ni2+ and Pb2+) using the batch method. It was employed to study selectivity of metal ion...

  19. Synthetic conditions and chemical structures of urea-formaldehyde resins. I. Properties of the resins synthesized by three different procedures

    Science.gov (United States)

    Gu Ji-you; Mitsuo Higuchi; Mitsuhiro Morita; Chung-Yun Hse

    1995-01-01

    The properties and chemical structures of urea-formaldehyde (UF) resins synthesized by three different procedures were investigated. The procedures employed were: 1) methylolation under the conditions of pH 8 and a formaldehyde/urea (F/U) molar ratio of 2, followed by condensation at pH 5 and by additional incorporation of urea, 2) condensation under the conditions of...

  20. An outbreak of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener

    NARCIS (Netherlands)

    de Wit, F. S.; de Groot, A. C.; Weyland, J. W.; Bos, J. D.

    1988-01-01

    8 cases of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener are presented. Most patients had used nail lacquers containing this resin for many years without trouble, but became sensitized to the resin shortly after the introduction of this particular nail hardener. A

  1. PRODUCTION OF HIGH DENSITY PARTICLEBOARD USING MELAMINE-UREA-FORMALDEHYDE RESIN

    Directory of Open Access Journals (Sweden)

    Setsuo Iwakiri

    2005-12-01

    Full Text Available This research was developed aiming to evaluate the effects of board density and melamine-urea-formaldehyde resin onthe properties of particleboard for semi-structural applications. The boards were manufactured with nominal density of 0.65 g/cm³and 0.90 g/cm³ using urea-formaldehyde resin as control and melamine-urea-formaldehyde. The results showed a better dimensionallystability and mechanical properties of the boards manufactured with higher density and MUF resin content. The fine furnish usedfor external layer of particleboard in the industrial process, could be used for high density homogeneous board to semi-strucuturaluses, such as flooring applications.

  2. Migration of formaldehyde and melamine from melaware and other amino resin tableware in real life service.

    Science.gov (United States)

    Mannoni, Veruscka; Padula, Giorgio; Panico, Oronzo; Maggio, Antonino; Arena, Claudio; Milana, Maria-Rosaria

    2017-01-01

    The migration of formaldehyde and melamine monomers has been measured on 90 samples of plastic tableware in three different situations - new articles, already used articles and artificially aged articles - by using simulant, contact times and temperatures prescribed by Commission Regulation (EU) No. 10/2011. Formaldehyde was determined by ultraviolet spectroscopy analysis of the coloured complex obtained by reaction with chromotropic acid. Melamine was measured by an ultra high performance liquid chromatography method. Fourier Transformed - Infrared Analysis was applied to characterise the plastic. The results highlighted the presence of different amino resins based on formaldehyde-melamine, urea-formaldehyde or melamine-urea-formaldehyde with different migration behaviour. The migration of monomers was related to progressive degradation of the resins. Ageing studies demonstrated that the potential degradation of the resins and the consequent migration of the monomers may continue throughout the service life of the product. The specific migration limit (SML) of melamine was exceeded after ageing.

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

    DEFF Research Database (Denmark)

    Isaksson, M.; Ale, I.; Andersen, Klaus Ejner

    2015-01-01

    Background Contact allergy to phenol-formaldehyde resins (PFRs) based on phenol and formaldehyde is not detected by a p-tertiary-butylphenol-formaldehyde resin included in most baseline patch test series. Objective The aims of this study were to investigate the contact allergy rate to PFR-2.......2%) reacted to PFR-2. Of those 28 individuals, one had a positive reaction to formaldehyde and 2 to p-tertiary-butylphenol-formaldehyde resin. Simultaneous allergic reactions were noted to colophonium in 3, to Myroxylon pereirae in 5, and to fragrance mix I in 8. Conclusions The contact allergy frequency...

  4. 40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

    Science.gov (United States)

    2010-07-01

    ... Insulation Resins by Hydroxylamine Hydrochloride B Appendix B to Subpart NNN of Part 63 Protection of... Pollutants for Wool Fiberglass Manufacturing Pt. 63, Subpt. NNN, App. B Appendix B to Subpart NNN of Part 63—Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride 1. Scope This method was...

  5. Carbon xerogel microspheres and monoliths from resorcinol-formaldehyde mixtures with varying dilution ratios: preparation, surface characteristics, and electrochemical double-layer capacitances.

    Science.gov (United States)

    Zapata-Benabithe, Zulamita; Carrasco-Marín, Francisco; de Vicente, Juan; Moreno-Castilla, Carlos

    2013-05-21

    Carbon xerogels in the form of microspheres and monoliths were obtained from the sol-gel polymerization of resorcinol and formaldehyde in the presence of potassium carbonate as catalyst, using water as solvent and two different molar dilution ratios. The objectives of this study were as follows: to investigate the effect of the dilution ratio, polymerization reaction time, and temperature on the rheological properties of the sols used to prepare the carbon xerogel microspheres and monoliths; and to determine the influence of their preparation methods and shapes on their surface characteristics and electrochemical double-layer (EDL) capacitance. An increase in the molar dilution ratio produced a decrease in the apparent activation energy of the sol-gel transition. Carbon xerogel microspheres were steam-activated at different burnoff percentages. The morphology, surface area, porosity, and surface chemistry of samples were determined. The main difference between the carbon xerogel microspheres and monoliths was that the latter are largely mesoporous. Better electrochemical behavior was shown by carbon xerogels in monolith than in microsphere form, but higher gravimetric and volumetric capacitances were found in activated carbon xerogel microspheres than in carbon xerogel monoliths.

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

    Directory of Open Access Journals (Sweden)

    MONIKA ŠUPOVÁ

    2012-03-01

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

  7. Formaldehyde

    Science.gov (United States)

    Information on formaldehyde and the regulation of formaldehyde emissions from composite wood products under the Formaldehyde Standards for Composite Wood Products Act in the Toxic Substances Control Act (TSCA).

  8. Green Synthesis and Characterization of Thymol–guanidine–formaldehyde Terpolymer Resin

    Directory of Open Access Journals (Sweden)

    Suraj Diwakarrao Kukade

    2015-01-01

    Full Text Available This paper presents the green synthesis of a terpolymer resin by using the microwave irradiation technique.  The resin have been prepared by condensing thymol and guanidine hydrochloride with formaldehyde in 2M HCl using 1:1:2 molar proportions of the reacting monomers in 15 minutes.  The synthesized terpolymer resin was purified and then characterized by different spectral methods like 1H-NMR, FT-IR, and UV-visible to elucidate the structure of the obtained TGF resin.  

  9. Characteristics of urea-formaldehyde resins as related to glue bond quality of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Forty-five urea resins were formulated and replicated by factorial arrangement of three variables: molar ratio of formaldehyde to urea (1.5, 1.7, 1.9, 2.1, and 2.3), reactant concentration (35, 42.5, and 50%), and reaction temperature (75°, 85°, and 95°C).

  10. Accelerated cure of phenol-formaldehyde resins : studies with model compounds

    Science.gov (United States)

    Anthony H. Conner; Linda F. Lorenz; Kolby C. Hirth

    2002-01-01

    2-Hydroxymethylphenol (2-HMP) and 4-hydroxymethylphenol (4-HMP) were used as model compounds to study the reactions that occur during cure of phenol-formaldehyde (PF) resin to which cure accelerators (ethyl formate, propylene carbonate, g-butyrolactone, and triacetin) have been added. The addition of cure accelerators significantly increased the rate of condensation...

  11. Investigation of physical, mechanical properties and formaldehyde emission of medium density fiberboard manufactured from urea formaldehyde resin reinforced with nanocrystalline cellulose

    Directory of Open Access Journals (Sweden)

    Hossein Khanjanzadeh

    2017-08-01

    Full Text Available The purpose of this study was to evaluate the physico-mechanical properties and formaldehyde emission of medium density fiberboard (MDF made from modified urea formaldehyde resin. In this study, nanocrystalline cellulose (NCC (0, 0.5, 1, 1.5 and 2 percent based on the dry weight of resin was applied to modify urea formaldehyde resin. The results of mechanical properties indicated that MOR and IB of the MDF panels significantly increased as the NCC incorporated into the UF adhesive up to 1%wt. However, further increment in the NCC content (1.5 and 2 wt% decreased the MOR and IB of the panels. Water absorption and thickness swelling after 2 h were significantly increased when the NCC content increased from 1% to 2%, but no significant differences were observed between the panels after 24 h. Also, the formaldehyde emission significantly decreased with increasing the amount of nanocrystalline cellulose.

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

    Science.gov (United States)

    Young, Philip R.

    1999-01-01

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

  13. Fabrication of Glass Fiber Reinforced Composites Based on Bio-Oil Phenol Formaldehyde Resin

    Directory of Open Access Journals (Sweden)

    Yong Cui

    2016-11-01

    Full Text Available In this study, bio-oil from fast pyrolysis of renewable biomass was added by the mass of phenol to synthesize bio-oil phenol formaldehyde (BPF resins, which were used to fabricate glass fiber (GF reinforced BPF resin (GF/BPF composites. The properties of the BPF resin and the GF/BPF composites prepared were tested. The functional groups and thermal property of BPF resin were thoroughly investigated by Fourier transform infrared (FTIR spectra and dynamic thermomechanical analysis (DMA. Results indicated that the addition of 20% bio-oil exhibited favorable adaptability for enhancing the stiffness and heat resistance of phenol formaldehyde (PF resin. Besides, high-performance GF/BPF composites could be successfully prepared with the BPF resin based on hand lay-up process. The interface characteristics of GF/BPF composites were determined by the analysis of dynamic wettability (DW and scanning electron microscopy (SEM. It exhibited that GF could be well wetted and embedded in the BPF resin with the bio-oil addition of 20%.

  14. Synthesis and Characterization of Bio-Oil Phenol Formaldehyde Resin Used to Fabricate Phenolic Based Materials.

    Science.gov (United States)

    Cui, Yong; Hou, Xiaopeng; Wang, Wenliang; Chang, Jianmin

    2017-06-18

    In this study, bio-oil from the fast pyrolysis of renewable biomass was used as the raw material to synthesize bio-oil phenol formaldehyde (BPF) resin-a desirable resin for fabricating phenolic-based material. During the synthesis process, paraformaldehyde was used to achieve the requirement of high solid content and low viscosity. The properties of BPF resins were tested. Results indicated that BPF resin with the bio-oil addition of 20% had good performance on oxygen index and bending strength, indicating that adding bio-oil could modify the fire resistance and brittleness of PF resin. The thermal curing behavior and heat resistance of BPF resins were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Results showed that adding bio-oil had an impact on curing characteristics and thermal degradation process of PF resin, but the influence was insignificant when the addition was relatively low. The chemical structure and surface characteristics of BPF resins were determined by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The analysis demonstrated that adding bio-oil in the amount of 20% was able to improve the crosslinking degree and form more hydrocarbon chains in PF resin.

  15. New curing system for urea-formaldehyde resins with polyhydrazides. I. Curing with poly(methycrylol hydrazide)

    Science.gov (United States)

    Katsumasa Miyake; Bunichiro Tomita; Chung-Yun Hse; George E. Myers

    1989-01-01

    A new curing system for urea-formaldehyde (UF) resins was investigated using poly(methacryloyl hydrazide) as the curing reagent. Results were as follows: 1) Gel time and the water-soluble part of cured resins were determined as function of pH and molar ratio [hydrazide group/(free formaldehyde+methylol group)]. It was found that the reaction in this system proceeds for...

  16. Chelation Ion Exchange Properties of 2, 4-Dihydroxyacetophenone-Biuret-Formaldehyde Terpolymer Resin

    OpenAIRE

    Sanjiokumar S. Rahangdale; Anil B. Zade; Wasudeo B. Gurnule

    2009-01-01

    The terpolymer resin 2, 4-HABF has been synthesized by the condensation of 2, 4-dihydroxyacetophenone (2, 4-HA) and biuret (B) with formaldehyde (F) in 1:1:2 molar ratios in presence of 2 M hydrochloric acid as catalyst. UV-Visible, IR and proton NMR spectral studies have been carried out to elucidate the structure of the resin. A terpolymer (2, 4-HABF) proved to be a selective chelating ion exchange polymer for certain metals. Chelating ion-exchange properties of this polymer were studied fo...

  17. Synthesis and Characterization of Bio-Oil Phenol Formaldehyde Resin Used to Fabricate Phenolic Based Materials

    Directory of Open Access Journals (Sweden)

    Yong Cui

    2017-06-01

    Full Text Available In this study, bio-oil from the fast pyrolysis of renewable biomass was used as the raw material to synthesize bio-oil phenol formaldehyde (BPF resin—a desirable resin for fabricating phenolic-based material. During the synthesis process, paraformaldehyde was used to achieve the requirement of high solid content and low viscosity. The properties of BPF resins were tested. Results indicated that BPF resin with the bio-oil addition of 20% had good performance on oxygen index and bending strength, indicating that adding bio-oil could modify the fire resistance and brittleness of PF resin. The thermal curing behavior and heat resistance of BPF resins were investigated by differential scanning calorimetry (DSC and thermal gravimetric analysis (TGA. Results showed that adding bio-oil had an impact on curing characteristics and thermal degradation process of PF resin, but the influence was insignificant when the addition was relatively low. The chemical structure and surface characteristics of BPF resins were determined by Fourier transform infrared (FTIR spectroscopy and scanning electron microscopy (SEM. The analysis demonstrated that adding bio-oil in the amount of 20% was able to improve the crosslinking degree and form more hydrocarbon chains in PF resin.

  18. Optimization of tensile strength for new type acetone-urea-formaldehyde furan resin using uniform design

    Directory of Open Access Journals (Sweden)

    Lin Shengjun

    2011-02-01

    Full Text Available In this study, the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3% was investigated by uniform design optimization. Four independent variables such as acetone : formaldehyde molar ratio (mol/mol, solution pH value, reaction temperature (℃ and reaction time (min were considered in the experiments. U*13(134 uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations. The 24 h tensile strength was optimized by applying single factor experiments and stepwise non-linear regression analysis. Minitab (Minitab 15 trial version and MATLAB (R2010a trial version were used for data analysis. The t-value and p-value indicate that the major impact factors include the interaction effect of solution pH value and reaction temperature (X2X3, the linear terms of acetone : formaldehyde molar ratio (X1, reaction time (X4 followed by the square effects of acetone/formaldehyde molar ratio (X1X1. The optimized results were achieved with the acetone: formaldehyde molar ratio (mol/mol at 3:1, solution pH value at 6.0, reaction temperature at 70 ℃, and reaction time at 140 min, respectively. This method can not only significantly reduce the number and cost of the tests, but also provide a good experimental design strategy for the development of furan resin. The investigation shows that the predicted results of 24 h tensile strength are consistent well with the experimental ones.

  19. Preparation and Characterization of UV-Curable Cyclohexanone-Formaldehyde Resin and Its Cured Film Properties

    Directory of Open Access Journals (Sweden)

    Guang Yang

    2014-01-01

    Full Text Available UV-curable cyclohexanone-formaldehyde (UVCF resin was prepared with cyclohexanone-formaldehyde (CF resin, isophorone diisocyanate (IPDI, and pentaerythritol triacrylate (PETA as base substance, bridging agent, and functional monomer, respectively. The structure of UVCF was characterized by Fourier transform infrared spectroscopy (FT-IR, 1H-nuclear magnetic resonance spectroscopy (1H-NMR, and gel permeation chromatography (GPC. The viscosity and photopolymerization behavior of the UV-curable formulations were studied. The thermal stability and mechanical properties of the cured films were also investigated. The results showed that UVCF resin was successfully prepared, the number of average molecular weight was about 2010, and its molecular weight distribution index was 2.8. With the increase of UVCF resin content, the viscosity of the UV-curable formulations increased. After exposure to UV irradiation for 230 s, the photopolymerization conversion of the UV-curable formulations was above 80%. Moreover, when the UVCF content was 60%, the formulations had high photopolymerization rate, and the cured UVCF films showed good thermal stability and mechanical properties.

  20. Role of the excess monomer in the growth of urea and formaldehyde resin deposit particles.

    Science.gov (United States)

    Hao, Zhixian; Guo, Yuqing; Mansuer, Mulati; Zhu, Junfu; Zhu, Zhirong

    2014-09-15

    The role of excess monomer (i.e., Urea (U) or Formaldehyde (F)) in UF precipitation reaction was investigated at 28°C. The maximum output of the UF resin deposit was found around the U:F molar ratio 1.0:1.0 and this output decreased if excessive urea (or formaldehyde) was used in the reaction system. The excess monomer was considered to decrease the polymerization degree of UF resin deposit and increased the bonding saturation of its copolymerization monomer as well as the solubility of the UF resin deposit. The Influence of the excess monomer on the lamellar crystallinity of the resultant deposit, involving the polymerization degree and bonding saturation of the monomer, was examined. Three different dynamic regions containing excess monomers were revealed according to the behaviors of the deposit nucleation. The density and water absorption of the UF resin particles were finally demonstrated relative to the dynamic regions in their nucleation reactions. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Modeling and Optimization of Phenol Formaldehyde Resin Sand Mould System

    Directory of Open Access Journals (Sweden)

    Chate G. R.

    2017-06-01

    Full Text Available Chemical bonded resin sand mould system has high dimensional accuracy, surface finish and sand mould properties compared to green sand mould system. The mould cavity prepared under chemical bonded sand mould system must produce sufficient permeability and hardness to withstand sand drop while pouring molten metal through ladle. The demand for improved values of permeability and mould hardness depends on systematic study and analysis of influencing variables namely grain fineness number, setting time, percent of resin and hardener. Try-error experiment methods and analysis were considered impractical in actual foundry practice due to the associated cost. Experimental matrices of central composite design allow conducting minimum experiments that provide complete insight of the process. Statistical significance of influencing variables and their interaction were determined to control the process. Analysis of variance (ANOVA test was conducted to validate the model statistically. Mathematical equation was derived separately for mould hardness and permeability, which are expressed as a non-linear function of input variables based on the collected experimental input-output data. The developed model prediction accuracy for practical usefulness was tested with 10 random experimental conditions. The decision variables for higher mould hardness and permeability were determined using desirability function approach. The prediction results were found to be consistent with experimental values.

  2. Synthesis, characterization and thermal analysis of urea-formaldehyde/nanoSiO{sub 2} resins

    Energy Technology Data Exchange (ETDEWEB)

    Roumeli, E. [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Papadopoulou, E. [Chimar Hellas S.A., Sofouli 88, 55131 Thessaloniki (Greece); Pavlidou, E.; Vourlias, G. [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Bikiaris, D. [Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Paraskevopoulos, K.M. [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Chrissafis, K., E-mail: hrisafis@physics.auth.gr [Solid State Physics Dept., School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer UF/nanosilica resins have been produced using the minimum cost method. Black-Right-Pointing-Pointer The new resins had good dispersion and enhanced properties. Black-Right-Pointing-Pointer Nanosilica interacts with polymer chains as was proved by FTIR and DSC. Black-Right-Pointing-Pointer Nanosilica does not affect the resin's thermal stability but enhances its mechanical properties. - Abstract: In the present work urea-formaldehyde resins (UF) containing different amounts of SiO{sub 2} nanoparticles were synthesized and studied in depth. All the hybrids were characterized with Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffractometry (XRD), while the dispersion of nanoparticles was studied with scanning electron microscopy with associated energy dispersive X-ray spectrometer (SEM/EDS). It was found that even though silanol groups of SiO{sub 2} can interact with UF resin and form hydrogen bonds, aggregates of SiO{sub 2} nanoparticles can still be formed in UF resin. Their size increases as SiO{sub 2} content is increased. The curing reactions were examined with differential scanning calorimetry (DSC) and it was revealed that curing temperature of UF resin is slightly affected by the addition of nanoparticles. Furthermore, the activation energy of the curing reactions, for every hybrid, was calculated using the Kissinger's method, which implied the existence of interactions between the nanoparticles and the polymer chain. Thermogravimetric analysis (TGA) revealed that SiO{sub 2} nanoparticles do not have an effect in the thermal stability of the resin. From the application of the prepared UF/SiO{sub 2} resins in wood panels it was found that the mechanical properties of the panels, like the internal bond and the modulus of rapture, are enhanced with increasing nanoSiO{sub 2} concentration.

  3. Condensed tannin-resorcinol adducts in laminating adhesives

    Science.gov (United States)

    Richard W. Hemingway; Roland E. Kreibich

    1985-01-01

    A condensed tannin-resorcinol adduct made by co-reaction of an extract from southern pine bark with resorcinol at a 2 to 1 weight ratio was used to prepare a laminating resin in which the entire amount of resorcinol normally used was replaced by this adduct. The resin was formulated into a room temperature setting adhesive that meets the basic criteria of product...

  4. Thermoanalytical Study and Kinetics of New 8-Hydroxyquinoline 5-sulphonic Acid-Oxamide-Formaldehyde Terpolymer Resins

    Directory of Open Access Journals (Sweden)

    Rajesh N. Singru

    2009-01-01

    Full Text Available The terpolymer resins (8-HQ5-SAOF have been synthesized by the condensation of 8-hydroxyquinoline 5-sulphonic acid (8-HQ5-SA and oxamide (O with formaldehyde (F in the presence of acid catalyst and using varied molar proportion of the reacting monomers. The synthesized terpolymer resins have been characterized by different physico-chemical techniques. Thermogravimetric analysis of all terpolymer resins in present study have been carried out by non-isothermal thermogravimetric analysis technique in which sample is subjected to condition of continuous increase in temperature at linear rate. Thermal study of the resins was carried out to determine their mode of decomposition and relative thermal stabilities. Thermal decomposition curves were studied carefully with minute details. The Freeman-Carroll and Sharp-Wentworth methods have been used in the present investigation to calculate thermal activation energy and different kinetic parameter of the terpolymer resins. Thermal activation energy (Ea calculated with above two mentioned methods are in close agreement. The advantage of Freeman-Carroll method is to calculate both the order of reaction (n and energy of activation in one single stage by keeping heating rate constant. By using data of thermogravimetric analysis, various thermodynamic parameters like frequency factor (Z, entropy change (Δ S, free energy change (Δ F and apparent entropy (S* have been determined using Freeman-Carroll method.

  5. Using cellulose nanofiber as filler of urea formaldehyde resin in plywood manufacture

    Directory of Open Access Journals (Sweden)

    samira barzali

    2015-11-01

    Full Text Available Abstract In this study, physical and mechanical properties of poplar (Populus nigra plywood made by urea-formaldehyde resin along with nano fiber cellulose were studied. For this reason, the nanofiber cellulose as filler at five levels 0, 1, 3, 5 and 7% based on oven dry weight of resin were used. Physical and mechanical properties of the samples, including water absorption and thickness swelling after 2 and 24 hours immersion in water, bending strength and modulus of elasticity (parallel and perpendicular to surface grain and bonding shear strength were measured. The results showed that increasing the amount of nano fiber cellulose improved the dimentional stability of the boards. Also increasing the amount of nano fiber cellulose increases the bending strength and modulus of elasticity parallel to surface grain. On the other hand, increasing the amount of nano fiber cellulose increases the bonding shear strength but no significant differences observed between the different treatments.

  6. Examination of the chemical changes in cured phenol-formaldehyde resins during storage.

    Science.gov (United States)

    Strzemiecka, B; Zięba-Palus, J; Voelkel, A; Lachowicz, T; Socha, E

    2016-04-08

    Chemical changes occurring within cured phenol-formaldehyde resins (resite and novolak type) during their storage were investigated by FT-NIR, py-GCMS and inverse gas chromatography. It was shown that a mixture of resite with novolak was less stable than resite or novolak itself as regards bulk properties. This aging phenomenon is mainly due to reaction of ammonia (product of hexa decomposition) with CH2OH groups present in resite. FT-NIR technique seems to be the least sensitive method for assessment chemical changes occurring during cured resins storage. Applications of py-GCMS and IGC method made able to indicate that more significant changes were for bulk samples (py-GCMS results) than on their surface (IGC results). Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Solution-state NMR analysis of hydroxymethylated resorcinol cured in the presence of crude milled-wood lignin from Acer saccharum

    Science.gov (United States)

    Daniel J. Yelle

    2017-01-01

    Resorcinol-formaldehyde adhesives can reinforce stress fractures that appear from wood surface preparation. Researchers have found that applying the resorcinol-formaldehyde prepolymer, hydroxymethylated resorcinol is thought to plasticize lignin components and stabilize stress fractures through reactions with lignin subunits and hemicelluloses in wood. In this study, a...

  8. Reaction pH of urea-formaldehyde resins as related to strength properties of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Twelve urea-formaldehyde resins were prepared with factorial combinations of 4 alkaline and 3 acidic reaction phases; i. e., the reaction mixture was adjusted to pH 7, 8, 9, or 10 for the first hour and then made weakly acid to pH 5.8, 4.8, or 3.8.

  9. 40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method A Appendix A to Subpart DDD of Part 63 Protection... Hazardous Air Pollutants for Mineral Wool Production Pt. 63, Subpt. DDD, App. A Appendix A to Subpart DDD of...

  10. Chelation Ion Exchange Properties of 2, 4-Dihydroxyacetophenone-Biuret-Formaldehyde Terpolymer Resin

    Directory of Open Access Journals (Sweden)

    Sanjiokumar S. Rahangdale

    2009-01-01

    Full Text Available The terpolymer resin 2, 4-HABF has been synthesized by the condensation of 2, 4-dihydroxyacetophenone (2, 4-HA and biuret (B with formaldehyde (F in 1:1:2 molar ratios in presence of 2 M hydrochloric acid as catalyst. UV-Visible, IR and proton NMR spectral studies have been carried out to elucidate the structure of the resin. A terpolymer (2, 4-HABF proved to be a selective chelating ion exchange polymer for certain metals. Chelating ion-exchange properties of this polymer were studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+ and Pb2+ ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurement of the distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The polymer showed highest selectivity for Fe3+, Cu2+ ions than for Ni2+, Co2+, Zn2+, Cd2+, and Pb2+ ions. Study of distribution ratio as a formation of pH indicates that the amount of metal ion taken by resin is increases with the increasing pH of the medium.

  11. Effect of phenol formaldehyde resin as vulcanizing agent on flow behavior of HDPE/PB blend

    Directory of Open Access Journals (Sweden)

    Moayad N. Khalaf

    2014-07-01

    Full Text Available Thermoplastic elastomer (TPE based on High density polyethylene (HDPE/polybutadiene (HDPE/PB = 70/30 parts blends containing 1, 3, 5, 7 and 10 wt.% of dimethylol phenolic resin as a vulcanizing agent in the presence of SnCl2 as catalyst was prepared. The dimethylol phenolic resin was prepared in our laboratory. The blends were compounded in mixer-60 attached to a Haake rheochord meter-90. The rheological properties were measured at temperatures 140, 160, 180 and 200 °C. The linearity of the flow curve appeared for 5% of the vulcanizing agent. The shear stress and shear viscosity have increased upon increasing the shear rate over a range of loading levels of vulcanizing agent of 1%, 3%, 5%, 7% and 10%. This may be attributed to the increased vulcanization between polyethylene and the rubber blend. The flow behavior index of the system shows a pseudo plastic nature behavior (since n < 1. The consistency index (K increased with the increase in the phenol formaldehyde resin content and the temperature. Hence, the increase in the value of the consistency index (K of the polymer melts refers to more viscous materials prepared. The activation energy for the TPE blends fluctuated indicating that there is phase separation; where each polymer behaved separately. This study showed that HDPE/PB blends are characterized with good rheological properties, which can be recommended to be processed with the injection molding technique.

  12. Design of Ion-Exchange Resins Through EDTA and DTPA Modified Ligands

    Directory of Open Access Journals (Sweden)

    2014-07-01

    Catechol, resorcinol, and their admixtures with EDTA and DTPA moieties were converted into polymeric resins by alkaline polycondensation with formaldehyde. The resins were characterized by FTIR spectroscopy, elemental analysis, ion-exchange capacity, and distribution coefficient (D for heavy metal and radionuclide such as Cs and Sr. 137Cs and 90Sr constitutes a major source of heat in nuclear waste streams and in regards to recent nuclear event their remediation in complex solution – sea water - represent an important issue.

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

    Science.gov (United States)

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

    2013-01-01

    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 α-Fe nanoparticles can provide the magnetic properties of the composites.

  14. [Influence of urea formaldehyde resin on pyrolysis of biomass: a modeling study by TG-FTIR].

    Science.gov (United States)

    Li, Si-jin; Mu, Jun; Zhang, Yu

    2014-06-01

    Pyrolysis is an efficient and recycling way to utilize waste wood-based panels, in which urea-formaldehyde resin (UF) is the main difference between wood-based board and other kinds of biomass. The present paper studied the three main components (cellulose, hemicelluloses, lignin) of poplar wood, in order to effectively and environmentally utilize or dispose of waste wood-based panels with pyrolysis technique, to study the influence of urea formaldehyde resin on pyrolytic characteristic of wood during the process of the pyrolysis of waste wood-based panels, and to in-depth explore the mechanism of the effect of UF on each component of wood. Innovatively, the weight-loss character and gas evolution rule of the model (made from cellulose, xylan and lignin, based on the chemical components stud of poplar wood), the main components as well as the ones mixed with UF were analyzed by TG-FTIR (thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer). Results indicated that UF promoted the generation of water and carboxylic acid substances during the cellulose pyrolysis process. UF combined with lignin, formed some kind of unstable nitrogenous structure which produced a large amount of NH3, which took part in the low-temperature (200-300 degrees C) pyrolysis of lignin, and directly affected the production of pyrolysis products. It can be concluded that during the process of the pyrolysis of waste wood-based panels, lignin was the one that UF mainly impacted among the three main components of wood.

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

    Directory of Open Access Journals (Sweden)

    Imam Prasetyo

    2012-02-01

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

  16. Characterization of pre-curing behavior of urea-formaldehyde resin affected by different temperatures

    Science.gov (United States)

    Chen, Y. Z.; Xiao, H.

    2017-07-01

    Differential scanning calorimetry (DSC) was applied to investigate the thermal behavior of pre-curing urea-formaldehyde (UF) resin as affected by different temperatures; the activation energies (Ea) in different stages during the pre-curing course were analyzed by Kissinger method. The results indicated that the curing time was decreased with temperature increasing. Under isothermal temperature, the DSC curves of pre-curing UF resin shifted to shorter time, the conversion increased with increasing temperature. In dynamic scanning, with the pre-curing degree increasing, the DSC curves shifted to lower temperature, while both the onset and peak temperature decreased due to the cross-linking degree increased. The Ea and Z value decreased obviously firstly due to the concentration and reactivity of the reactants increased with water evaporation in the first stage, and then the increasing cross-linking degree and the formation of the network structure lead to both the Ea and Z value increasing in the second stage, indicating that the pre-curing behavior appeared.

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

    Directory of Open Access Journals (Sweden)

    Noelia Álvarez-Gutiérrez

    2016-03-01

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

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

    Science.gov (United States)

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

    2014-09-24

    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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Evaluation and comparison of SuperLig{reg_sign} 644, resorcinol-formaldehyde and CS-100 ion exchange materials for the removal of cesium from simulated alkaline supernate

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.N.; Bray, L.A.; Eloviche, R.J. [Pacific Northwest Lab., Richland, WA (United States); Bruening, R.L.; Decker, R.M. [IBC Advanced Technologies, Inc., Provo, UT (United States); Kafka, T.M.; White, L.R. [3M Co., St. Paul, MN (United States)

    1995-03-01

    PNL evaluated three polymeric materials for Cs removal efficiency from a simulated Hanford Neutralized Current Acid Waste (NCAW) supernatant liquid using 200 mL ion exchange columns. Cs loadings (mmole Cs/g resin) were 0.20, 0.18, and 0.039 for Super Lig 644, R-F, and CS-100 (0.045, 0.070, 0.011 mmole Cs/mL resin). Elution of each resin material with 0.5 M HNO{sub 3} required 3.5, 7.0, and 3.2 cv to reach 0.1 C/C{sub 0} for the respective materials, resulting in volume compressions of 27, 20, and 6.9. Peak Cs concentrations during elution was 185, 38.5, and 27.8 C/C{sub 0}. SuperLig 644 had the highest Cs loading per gram in NCAW and the greatest volume compression on aci elution. Because of high density and poor elution, R-F had the highest Cs loading per unit volume and lower volume compression. CS-100, the baseline material for Cs removal at Hanford, was inferior to both SuperLig 644 and R-F in terms of Cs loading and selectivity over sodium.

  20. Hydrophilic molecularly imprinted melamine-urea-formaldehyde monolithic resin prepared in water for selective recognition of plant growth regulators.

    Science.gov (United States)

    Cao, Jiankun; Yan, Hongyuan; Shen, Shigang; Bai, Ligai; Liu, Haiyan; Qiao, Fengxia

    2016-11-02

    New hydrophilic molecularly imprinted melamine-urea-formaldehyde monolithic resin (MIMR) is synthesized using dopamine hydrochloride as a dummy template via in-situ polymerization directly within pipette tips and it presents special molecular recognition to plant growth regulators in aqueous matrices. Hydrophilic groups (such as hydroxyl groups, imino groups, and amino groups) can be introduced into MIMR by melamine- urea-formaldehyde resin, which make MIMR materials compatible with aqueous media and show their specific molecular recognition in aqueous sample solutions. Meanwhile, monolithic structures avoid the influence of uneven filling on the extraction efficiency. Various parameters affecting the selective recognition of MIMR have been optimized, such as molar ratio of melamine to urea, molar ratio of melamine and urea to formaldehyde, the amount of template and porogen. The prepared MIMR is applied as the sorbents of solid phase extraction (SPE) for sensitive and selective recognition of three plant growth regulators (p-chlorophenoxyacetic acid, 1-naphthaleneacetic acid and 2.4-dichlorophenoxyacetic acid) in bean sprouts. Considering its excellent hydrophilicity and specificity, MIMR-SPE is promising to be a potential pretreatment strategy in biological, environmental, and clinical fields. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C.; Hang, T.; Aleman, S.

    2011-01-03

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a hypothetical spherical SuperLig{reg_sign} 644 (SL644) are evaluated for decontamination of dissolved saltcake wastes (supernates). Both SuperLig{reg_sign} and resorcinol formaldehyde resin beds can exhibit hydraulic problems in their granular (nonspherical) forms. SRS waste is generally lower in potassium and organic components than Hanford waste. Using VERSE-LC Version 7.8 along with the cesium Freundlich/Langmuir isotherms to simulate the waste decontamination in ion exchange columns, spherical SL644 was found to reduce column cycling by 50% for high-potassium supernates, but sRF performed equally well for the lowest-potassium feeds. Reduced cycling results in reduction of nitric acid (resin elution) and sodium addition (resin regeneration), therefore, significantly reducing life-cycle operational costs. These findings motivate the development of a spherical form of SL644. This work demonstrates the versatility of the ion exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. The value of a resin with increased selectivity for cesium over potassium can be assessed for further development.

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

    Science.gov (United States)

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

    2015-06-01

    Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepared by varying the carbonization temperature from 400 to 700°C. Adsorbents were characterized thoroughly by nitrogen sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), elemental (CHN) analysis, Fourier transform infrared (FTIR) spectroscopy and Boehm titration. Carbonization temperature controlled the properties of the synthesized adsorbents ranging from surface area to their nitrogen content, which play major role in their application as adsorbents for CO2 capture. The nanostructure of these materials was confirmed by XRD and TEM. Their nitrogen content decreased with an increase in carbonization temperature while other properties like surface area, pore volume, thermal stability and surface basicity increased with the carbonization temperature. These materials were evaluated for CO2 adsorption by fixed-bed column adsorption experiments. Adsorbent synthesized at 700°C was found to have the highest surface area and surface basicity along with maximum CO2 adsorption capacity among the synthesized adsorbents. Breakthrough time and CO2 equilibrium adsorption capacity were investigated from the breakthrough curves and were found to decrease with increase in adsorption temperature. Adsorption process for carbon adsorbent-CO2 system was found to be reversible with stable adsorption capacity over four consecutive adsorption-desorption cycles. From three isotherm models used to analyze the equilibrium data, Temkin isotherm model presented a nearly perfect fit implying the heterogeneous adsorbent surface. Copyright © 2015. Published by Elsevier B.V.

  3. Development of Self Fire Retardant Melamine-Animal Glue Formaldehyde (MGF) Resin for the Manufacture of BWR Ply Board

    Science.gov (United States)

    Khatua, Pijus Kanti; Dubey, Rajib Kumar; Roymahapatra, Gourisankar; Mishra, Anjan; Shahoo, Shadhu Charan; Kalawate, Aparna

    2017-10-01

    Wood is one of the most sustainable, naturally growing materials that consist mainly of combustible organic carbon compounds. Since plywood are widely used nowadays especially in buildings, furniture and cabinets. Too often the fire behavior of ply-board may be viewed as a drawback. Amino-plastic based thermosetting resin adhesives are the important and most widely used in the plywood panel industries. The fire retardant property of wood panel products by adding animal glue as an additive in the form of MGF resin and used as substitute of melamine for manufacture of plywood. Environment concerns and higher cost of petroleum based resins have resulted in the development of technologies to replace melamine partially by biomaterials for the manufacturing of resin adhesive. Natural bio-based materials such as tannin, CNSL (cardanol), lignin, soya etc. are used as partial substitution of melamine. This article presents the development of melamine-animal glue formaldehyde resin as plywood binder. About 30 % melamine was substituted by animal glue and optimized. The different physico-mechanical and fire retardant property properties tested as per IS: 1734-1983 and IS: 5509-2000 respectively are quite satisfactory. The production of adhesive from melamine with compatible natural proteinous material is cost effective, eco-friendly and enhance the fire retardant property.

  4. Reaction catalysts of urea-formaldehyde resin, as related to strength properties of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Twelve resins were formulated with factorial combinations of three alkaline catalysts (i.e., somdium hydroxide, hexamethylenetetramine, and triethanolamine) and four acidic catalysts (i.e., acetic acid, hydrochloric acid, ammonium chloride, and phosphoric acid). The resins were replicated.

  5. Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal

    Energy Technology Data Exchange (ETDEWEB)

    Hang, T.; Nash, C. A.; Aleman, S. E.

    2012-09-19

    The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig(r) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig(r) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, therefore, significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind ''cesium bleed'' is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SL644 resin.

  6. Dual protection of wood surface treated with melamine-modified urea-formaldehyde resin mixed with ammonium polyphosphate against both fire and decay

    Science.gov (United States)

    Xing-xia Ma; Grant T. Kirker; Ming-liang Jiang; Yu-zhang Wu

    2016-01-01

    Surface coatings of melamine-modified urea-formaldehyde resins (MUFs) containing ammonium polyphosphate (APP) have been shown to significantly improve the fire retardancy of wood by prolonging the ignition time and reducing the heat release rate, total heat released, and mass loss rate. Dual protection of wood against both decay and fire has been proposed for remedial...

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

    Science.gov (United States)

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

    2015-12-01

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

  8. Synthesis of a water-soluble thiourea-formaldehyde (WTF) resin and its application to immobilize the heavy metal in MSWI fly ash.

    Science.gov (United States)

    Liu, She-Jiang; Guo, Yu-Peng; Yang, Hong-Yang; Wang, Shen; Ding, Hui; Qi, Yun

    2016-11-01

    Because of the high concentrations of heavy metals, municipal solid waste incineration (MSWI) fly ash is classified as a hazardous waste, which need to be treated to avoid damaging the environment. A novel water-soluble thiourea-formaldehyde (WTF) resin was synthesized by two step reactions (hydroxymethylation reaction and condensation reaction) in the laboratory. Synthetic conditions, removal of free formaldehyde in the resin and the ability of immobilization heavy metals in the MSWI fly ash were studied. The possible molecular structure of the resin was also discussed by elemental analysis and FTIR spectra. Experimental results showed that the synthesis conditions of WTF resin were the formaldehyde/thiourea (T/F) mole ratio of 2.5:1, hydroxymethylation at pH 7.0-8.0 and 60 °C for 30min, and condensation of at pH 4.5-5.0 and 80 °C. In addition, the end point of condensation reaction was measured by turbidity point method. The result of elemental analysis and FTIR spectra indicated that thiourea functional group in the WTF resin chelated the heavy metal ions. Melamine can efficiently reduce the free formaldehyde content in the resin from 8.5% to 2%. The leaching test showed that the immobilization rates of Cr, Pb and Cd were 96.5%, 92.0% and 85.8%, respectively. Leaching concentrations of Cr, Pb and Cd in the treated fly ash were decreased to 0.08 mg/L, 2.44 mg/L and 0.23 mg/L, respectively. The MSWI fly ash treated by WTF resin has no harm to the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. 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)

    Strzemiecka, B; Voelkel, A; Zięba-Palus, J; Lachowicz, T

    2014-09-12

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Synthesis and cure kinetics of liquefied wood/phenol/formaldehyde resins

    Science.gov (United States)

    Hui Pan; Todd F. Shupe; Chung-Yun Hse

    2008-01-01

    Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three-necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture (liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac-type liquefied wood/phenol/...

  11. Selective Removal of Toxic Metals like Copper and Arsenic from Drinking Water Using Phenol-Formaldehyde Type Chelating Resins

    Directory of Open Access Journals (Sweden)

    Debasis Mohanty

    2009-01-01

    Full Text Available The concentration of different toxic metals has increased beyond environmentally and ecologically permissible levels due to the increase in industrial activity. More than 100 million people of Bangladesh and West Bengal in India are affected by drinking ground water contaminated with arsenic and some parts of India is also affected by poisoning effect of copper, cadmium and fluoride. Different methods have been evolved to reduce the arsenic concentration in drinking water to a maximum permissible level of 10 μg/L where as various methods are also available to separate copper from drinking water. Of the proven methods available today, removal of arsenic by polymeric ion exchangers has been most effective. While chelating ion exchange resins having specific chelating groups attached to a polymer have found extensive use in sorption and pre concentration of Cu2+ ions. Both the methods are coupled here to separate and preconcentrate toxic metal cation Cu2+ and metal anion arsenate(AsO4– at the same time. We have prepared a series of low-cost polymeric resins, which are very efficient in removing copper ion from drinking water and after coordinating with copper ion they act as polymeric ligand exchanger, which are efficiently removing arsenate from drinking water. For this purpose Schiff bases were prepared by condensing o-phenylenediamine with o-, m-, and p-hydroxybenzaldehydes. Condensing these phenolic Schiff bases with formaldehyde afforded the chelating resins in high yields. These resins are loaded with Cu2+, Ni2+ 2+, and Fe3+ ions. The resins and the polychelates are highly insoluble in water. In powdered form the metal ion-loaded resins are found to very efficiently remove arsenate ion from water at neutral pH. Resins loaded with optimum amount of Cu2+ ion is more effective in removing arsenate ions compared to those with Fe3+ ion, apparently because Cu2+ is a stronger Lewis acid than Fe3+. Various parameters influencing the removal of the

  12. Aqueous chlorination of resorcinol

    Science.gov (United States)

    Heasley, V.L.; Burns, M.D.; Kemalyan, N.A.; Mckee, T.C.; Schroeter, H.; Teegarden, B.R.; Whitney, S.E.; Wershaw, R. L.

    1989-01-01

    An investigation of the aqueous chlorination (NaOCl) of resorcinol is reported. The following intermediates were detected in moderate to high yield at different pH values and varying percentages of chlorination: 2-chloro-, 4-chloro-, 2,4-dichloro-, 4,6-dichloro- and 2,4,6-trichlororesorcinol. Only trace amounts of the intermediates were detected when the chlorination was conducted in the presence of phosphate buffer. This result has significant implications since resorcinol in phosphate buffer has been used as a model compound in several recent studies on the formation of chlorinated hydrocarbons during chlorination of drinking water. Relative rates of chlorination were determined for resorcinol and several of the chlorinated resorcinols. Resorcinol was found to chlorinate only three times faster than 2,4,6-trichlororesorcinol. The structure 2,4,6-trichlororesorcinol was established as a monohydrate even after sublimation. A tetrachloro or pentachloro intermediate was not detected, suggesting that the ring-opening step of such an intermediate must be rapid. ?? 1989.

  13. Ion Exchange Study of Some New Copolymer Resins Derived from 8-Hydroxyquinoline-5-sulphonic Acid, Biuret and Formaldehyde

    Directory of Open Access Journals (Sweden)

    P. A. Dhakite

    2011-01-01

    Full Text Available Copolymer resins (8-HQSABF were synthesized by the condensation of 8-hydroxyquinoline-5-sulphonic acid and biuret with formaldehyde in the presence of hydrochloric acid as catalyst, proved to be selective chelation ion exchange copolymer resins for certain metals. Chelation ion exchange properties to these polymers were studied for Cu2+, Cd2+, Co2+ and Zn2+ ions. A batch equilibrium method was employed in the study of the selectivity of the distribution of a given metal ions between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in a media of various ions strengths. The polymer showed a higher selectivity for Cu2+ ions than for Cd2+, Co2+ and Zn2+ ions. Hence on the basis of above studies these copolymer may be used as semiconductors, surface coating, ion-exchangers, materials for rechargeable battery cell in various electronic industries, plastic materials, elastomers and in boiler plants

  14. Molar-mass distribution of urea–formaldehyde resins of different degrees of polymerisation by MALDI-TOF mass spectrometry

    Directory of Open Access Journals (Sweden)

    IVANA GAVRILOVIĆ-GRMUŠA

    2010-05-01

    Full Text Available This paper describes some results obtained in an investigation of urea–formaldehyde (UF resins of different degrees of polymerisation by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF mass spectrometry (MS. MALDI-TOF MS proved to be an appropriate technique for analyzing these types of polymers, bearing in mind that the results of the analysis correspond with previous physical and chemical measurements. This technique enables a relatively swift determination of the degree of polymerrisation through the monitoring of key changes in the structure of a polymer. Thus, in the analysis of UF resins, it may be possible to monitor a decrease in the intensity of the monohydroxymethyl urea (MMU signal, which corresponds to an increase of the mass spectra values in the mass range of higher homologues, above 1000 g mol-1. A noticeable difference concerns the signal intensities in the higher mass ranges (up to 1400 g mol-1, which corresponds to more branched and longer homologues of the polymers. Especially, a significantly more intensive signal of MMU was registered. The average molecular weight (MW of the examined samples was between 936 and 1324 g mol-1, with a maximal deviation of 20 %, depending on the ratios of the reactants.

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

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available The adhesion properties, i. e. viscosity, tack and peel strength of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based pressure-sensitive adhesive was studied using phenol formaldehyde resin as the tackifying resin. Toluene was used as the solvent throughout the experiment. SBR composition in SBR/SMR L blend used was 0, 20, 40, 60, 80, 100%. Three different resin loadings, i. e. 40, 80 and 120 parts per hundred parts of rubber (phr were used in the adhesive formulation. The viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas loop tack and peel strength of paper/polyethylene terephthalate (PET film were measured using a Lloyd Adhesion Tester operating at 30 cm/min. Results indicate that the viscosity of adhesive decreases with increasing % SBR whereas loop tack passes through a maximum value at 20% SBR for all resin loadings. Except for the control sample (without resin, the peel strength shows a maximum value at 60% SBR for the three modes of peel tests. For a fixed % SBR, adhesive sample containing 40 phr phenol formaldehyde resin always exhibits the highest loop tack and peel strength, an observation which is associated to the optimum wettability of adhesive on the substrate.

  16. MRT letter: high resolution SEM imaging of nano-architecture of cured urea-formaldehyde resin using plasma coating of osmium.

    Science.gov (United States)

    Park, Byung-Dae; Singh, Adya P; Nuryawan, Arif; Hwang, Kiju

    2013-11-01

    Nanoarchitecture of cured urea-formaldehyde (UF) resins was examined with a field-emission scanning electron microscope (FE-SEM) after coating samples with osmium, which is considered to produce particles of considerably smaller size compared to other metal coatings used in SEM studies. This method enabled comparison of the nanoarchitecture of UF resins of low (1.0) and high (1.6) formaldehyde/urea (F/U) mole ratios to be made, based on imaging of extremely small size particles as part of UF resin architecture, not described before. Imaging revealed presence of relatively large globular particles (148.084-703.983 nm size range) as well as smaller substructures (28.004-39.604 nm size range) as part of the architecture of 1.0-mole UF resin. Globular particles were also present in 1.6 mole UF resin, but of considerably smaller size (14.760-50.269 nm). The work presented demonstrates usefulness of osmium coating in unraveling the intricacies of the nanostructural organization of cured UF resins, prompting wider application of this immensely useful but grossly underutilized metal coating type in high resolution SEM examination of biological and materials samples. Copyright © 2013 Wiley Periodicals, Inc.

  17. Preparation and characteristics of Aziridine-Benzoguanamine-Urea-Melanmine-Formaldehyde resins

    Science.gov (United States)

    Li, Wenhuan; Xu, Jie; He, Xingwei; Zhang, Jingjie; Zong, Enmin; Liu, Xiaohuan; Fu, Shenyuan

    2017-06-01

    In this study, the effect of Aziridine (AZ) addition on the properties of the BG-MF and BG-U-MF resin, such as the mechanical strength, tensile strength, moisture adsorption, and limited oxygen index, were studied in details. The best performance was obtained for modified resins with 2 wt. % added AZ. The structure characteristics of the modified MF resins were investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). It was found that the characteristic absorption peak of the hydroxyl group and the ring of the three triazine group was significantly reduced, which indicated that the addition of aziridine was beneficial to the curing reaction. It could be seen that the effect of the addition of aziridine on the crystallinity of BG15% modified resin was not obvious, but the crystallinity of BG15%+U20% modified resin was reduced. The tensile strength and elongation at break increased after the addition of 2% aziridine, and resistance to burning and boiling water were also improved.

  18. Simple synthesis of porous melamine-formaldehyde resins by low temperature solvothermal method and its CO2 adsorption properties

    Directory of Open Access Journals (Sweden)

    F. Yin

    2017-11-01

    Full Text Available A simple and environmentally-friendly approach for the preparation of porous melamine-formaldehyde resins (PMFRs was developed by using low-boiling-point solvents, such as water, as pore-forming agent. With using dimethyl sulfoxide (DMSO and low-boiling solvents cosolvent method, PMFRs with a high specific surface area and well-defined pore structure can be synthesized at a low reaction temperature of 140 °C for a short reaction duration in 20 hours, which can replace the conventional methods that use dimethyl sulfoxide (DMSO as reaction medium and require 3 days at 170 °C to achieve similar surface area. When loaded with polyethylenimine (PEI, the PMFR-PEI-30% showed good CO2 adsorption performance with a capacity of up to 2.89 mmol/g at 30 °C. These results bring new perspectives for the development of lowcost and environmentally-friendly synthetic methods for porous materials, which can boost their widespread applications.

  19. Nitrogen-doped carbon nanotubes based on melamine-formaldehyde resin as highly efficient catalyst for oxygen reduction reaction.

    Science.gov (United States)

    Zhang, Xin; Huang, Ying; Chen, Xuefang; Gao, Qiao; Zhang, Weichao

    2018-01-01

    The preparation of highly efficient and cheap electrocatalysts toward oxygen reduction reaction is significant for many electrochemical cells. Here we facilely synthesized nitrogen doped carbon nanotube by pyrolyzing melamine formaldehyde resin and Fe loading on MgO. There were mainly three morphologies observed, slender bamboo-like CNT, thick bamboo-like CNT, surface smooth, hollow CNT. The content of Fe loading on MgO had little influence on morphologies of CNT, however, when no MgO as support, only carbon ribbon obtained. The MgO as support was also significant for the formation of CNT. The samples with CNT formed represented better catalytic activity than control samples with no-CNT obtained, the morphology of CNT was beneficial for catalytic process. The sample C1-CNT with lowest content of Fe on support represented best catalytic activity which was competitive with 20% Pt/C in half-wave potential. The C1-CNT also showed outstanding stability and improved selectivity towards ORR, making it a promising alternative to Pt in application of fuel cells and metal-air batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Investigation on the effect of mixed rapeseed stalk residues with wood particles, and mixing of melamine and urea formaldehyde resin on properties of manufactured particleboard

    Directory of Open Access Journals (Sweden)

    Behzad Kord

    2016-09-01

    Full Text Available In this study, the possibility of using the rapeseed stalk mixed with industrial wood particles for manufacturing particleboard with target density of 0.7 gr/cm3 was considered. Variable factors such as mixing ratios of rapeseed stalk with industrial wood particles at five mixing levels of (0-100, 25-75, 50-50, 75-25 and 100-0 percent, mixing ratios of melamine resin with urea formaldehyde at three levels of 0-100, 15-85 and 30-70 percent, and kind of board at two levels of homogenate and layer were considered. 10 percent resin based on oven dried weight of particles, 2 percent catalyzer based on oven dried weight of resin, press temperature and time with 170 OC and 7 minute, press pressure and rate with 30 Kg/cm3 and 4.5 mm/min were fixed. Then, the boards were manufactured and the physical and mechanical properties including modulus of rupture, modulus of elasticity, internal bonding, water absorption and thickness swelling were measured according to EN standard. Results indicated that the modulus of rupture, modulus of elasticity, water absorption and thickness swelling of boards increased with increase rapeseed stalk loading; however, the internal bonding decreased. Also, the use of melamine urea formaldehyde resin caused to improve the mechanical strength and dimensional stability in the samples.

  1. Synthesis and structural features of resorcinol⿿formaldehyde resin chars containing nickel nanoparticles

    Science.gov (United States)

    Galaburda, M. V.; Bogatyrov, V. M.; Skubiszewska-ZiĿba, J.; Oranska, O. I.; Sternik, D.; Gun⿿ko, V. M.

    2016-01-01

    A series of meso- and microporous carbons containing magnetic Ni nanoparticles (Ni/C) with a variety of Ni loadings were synthesized by a simple one-pot procedure through carbonization of resorcinol⿿formaldehyde polymers containing various amounts of nickel(II) acetate. Such composite materials were characterized by N2 sorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscope (TEM). The XRD patterns reveal peaks corresponding to face centered cubic nickel with the average size of crystallites of 17⿿18 nm. SEM and TEM results reveal that the formation of the nanoparticles took place mainly in the carbon spheres (1⿿2 μm in size) and on the outer surface as well. The as-prepared composites are characterized by a core⿿shell structure with well-crystallized graphitic shells about 8⿿15 nm in thickness. The Raman spectra show that Ni content influences the structure of the carbon. It was also shown that the morphology (particle shape and sizes) and porosity (pore volume and pore size distribution) of the chars are strongly dependent on water and nickel contents in the blends. One of the applications of Ni/C was demonstrated as a magnetically separable adsorbent.

  2. Adsorption characteristics of polycyclic aromatic hydrocarbons from non-aqueous media using activated carbon derived from phenol formaldehyde resin: kinetics and thermodynamic study.

    Science.gov (United States)

    El-Shahawi, M S; Bashammakh, A S; Alwael, H; Alsibaai, A A; Dowaidar, A M

    2017-02-01

    Porous carbons were prepared by carbonization and activation of phenol formaldehyde resin by gasification with CO2 at 900 °C. Prepared activated carbon from phenol formaldehyde was characterized by measuring thermogravimetry (TG), differential thermal analysis (DTA), pH, surface area, porosity, and pore size distribution. The specific surface area (SSA) of these carbons ranges from 562 to 1904 m(2)/g, while their point of zero charge (pHPZC) varies from 2.6 to 8.8. The ability of the prepared activated carbon by gasification with CO2 at 900 °C from phenol formaldehyde resin (PFAC) to remove a series of polycyclic aromatic hydrocarbons (PAHs), e.g., naphthalene, fluorene, phenanthrene, pyrene, and fluoranthene, from mixtures of organic solvents with different polarities and chemical structures was tested. The adsorption capacity increases with the increasing the SSA and pHPZC of the carbons, confirming the roles of dispersive interactions. The kinetics and thermodynamics of the adsorption of phenanthrene as a model compound of PAH on PFAC in the organic solvent were studied. The adsorption capacity became notably greater with an increase in contact time and initial phenanthrene concentration.

  3. Mechanical properties of sisal fibre reinforced urea-formaldehyde resin composites

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available Alkali-treated sisal fibres were used as novel reinforcement to obtain composites with self-synthesized ureaformaldehyde resin as matrix phase. The composites were prepared by means of compression molding, and then the effects of sisal loading on mechanical properties such as impact strength, flexural strength, and wear resistance were investigated. In addition, water uptake was studied and structural features were revealed by the scanning electron microscopy (SEM. The composite with 30 wt% sisal fibres gives excellent flexural strength, water absorption, and especially the wear resistance showing that it has the most superior bonding and adhesion of all the composites. In particular, the highest value 9.42 kJ/m2 of charpy impact strength is observed in the composite with 50 wt% sisal fibre. SEM micrographs of impact fractured and worn surfaces clearly demonstrate the interfacial adhesion between fibre and matrix. This work shows the potential of sisal fibre (SF to improve the composite wear resistance and to be used in fibreboard.

  4. At-line validation of a process analytical technology approach for quality control of melamine-urea-formaldehyde resin in composite wood-panel production using near infrared spectroscopy.

    Science.gov (United States)

    Meder, Roger; Stahl, Wolfgang; Warburton, Paul; Woolley, Sam; Earnshaw, Scott; Haselhofer, Klaus; van Langenberg, Ken; Ebdon, Nick; Mulder, Roger

    2017-01-01

    The reactivity of melamine-urea-formaldehyde resins is of key importance in the manufacture of engineered wood products such as medium density fibreboard (MDF) and other wood composite products. Often the MDF manufacturing plant has little available information on the resin reactivity other than details of the resin specification at the time of batch manufacture, which often occurs off-site at a third-party resin plant. Often too, fresh resin on delivery at the MDF plant is mixed with variable volume of aged resin in storage tanks, thereby rendering any specification of the fresh resin batch obsolete. It is therefore highly desirable to develop a real-time, at-line or on-line, process analytical technology to monitor the quality of the resin prior to MDF panel manufacture. Near infrared (NIR) spectroscopy has been calibrated against standard quality methods and against 13C nuclear magnetic resonance (NMR) measures of molecular composition in order to provide at-line process analytical technology (PAT), to monitor the resin quality, particularly the formaldehyde content of the resin. At-line determination of formaldehyde content in the resin was made possible using a six-factor calibration with an R 2(cal) value of 0.973, and R 2(CV) value of 0.929 and a root-mean-square error of cross-validation of 0.01. This calibration was then used to generate control charts of formaldehyde content at regular four-hourly periods during MDF panel manufacture in a commercial MDF manufacturing plant.

  5. A New Inhibition Kinetic Spectrophotometric Method for the Determination of Resorcinol

    Directory of Open Access Journals (Sweden)

    Mohsen Keyvanfard

    2010-01-01

    Full Text Available A new, simple, inexpensive and fast kinetic spectrophotometric method was developed for the determination of trace amounts of resorcinol over the range of 0.02-0.80 μg/mL. The method is based on the inhibitory effect of resorcinol on the formaldehyde catalyzed oxidation reaction of of cresyl violet by bromate in acidic media is reported. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of cresyl violet at 596 nm with a fixed-time 0.5–2.5 min from initiation of the reaction.The detection limit is 0.017 μg/mL and relative standard deviation of 0.1 and 0.5 μg/mL resorcinol for six replicate measurements was 2.6 and 2.9 %, respectively. The method was applied to the determination of resorcinol in water samples.

  6. A Literature Review - Problem Definition Studies on Selected Toxic Chemicals. Volume 6. Occupational Health and Safety and Environmental Aspects of Urea-Formaldehyde Resins

    Science.gov (United States)

    1978-04-01

    COMPLETLNG FORMA 1REOTNUMBER jZ.GOVT ACCESSION NO. PraS TAOGSE . ie ture vieu-Problen DC- rinition - -00dCOVEon - T ected -Toxic Cýhei a s fllme6ý1ý are...or the lack of food supply in the Hygromull-rich mixture- 74 I-- X. EFFECTS ON PLAINUS Completely polymerized urea-formaldehyde resins are not toxic in...aquatic microflora into sinple compounds which are taken up by aquatic plants and animals and eventually enter into the food chain 50-55). NO reports on

  7. Improvements to hydroxymethylated resorcinol coupling agent for durable bonding to wood

    Science.gov (United States)

    Alfred W. Christiansen; E. Arnold Okkonen

    2003-01-01

    Improving the exterior quality bonding of wood to epoxy adhesive resins is important for bonding glass-fiber-reinforced vinyl ester resin laminae to glulam structural members, as well as for repairing glulam members in exterior applications on site. The coupling agent for these applications, hydroxymethylated resorcinol (HMR), was recently improved by using a novolak...

  8. 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)

    Graciela Ines Bolzon de Muniz

    2013-06-01

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

  9. Resorcinol–formaldehyde based carbon nanospheres by ...

    Indian Academy of Sciences (India)

    Carbon nanospheres were synthesized using sol–gel processing of organic and aqueous resorcinol formaldehyde (RF) sols combined with electrospraying technique. RF sol was electrosprayed to form nanodroplets which were collected on a Si wafer. After oven drying at 60°C for 12 h, RF nano-droplets were pyrolyzed at ...

  10. 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)

    2009-12-01

    Full Text Available This paper describes the curing behaviours, thermal properties and flame-resistance of a novel halogen-free epoxy hybrid thermoset, prepared by the curing reaction of hexakis (methoxymethyl melamine (HMMM, a phosphorouscontaining epoxy resin (EPN-D with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO group and phenol formaldehyde novolac (n-PF. The resultant thermosets showed high glass-transition temperatures (Tg, 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.

  11. Lignin-based Phenol-Formaldehyde Resins from Purified CO2 Precipitated Kraft lignin (PCO2KL)

    Science.gov (United States)

    Yao Chen; Charles R. Frihart; Zhiyong Cai; Linda F. Lorenz; Nicole M. Stark

    2013-01-01

    To investigate the potential for using purified CO2-precipitated Kraft lignin (PCO2KL) with phenol-formaldehyde (PF) for application as an adhesive in plywood production, two lignin replacement procedures were examined to assess lignin’s effect on bond quality. Methylolation and oxidation with hydrogen peroxide (H

  12. Problems associated with the use of urea-formaldehyde foam for residential insulation. Part I. The effects of temperature and humidity on formaldehyde release from urea-formaldehyde foam insulation

    Energy Technology Data Exchange (ETDEWEB)

    Long, K.R.; Pierson, D.A.; Brennan, S.T.; Frank, C.W.; Hahne, R.A.

    1979-09-01

    The study is concerned primarily with those properties related to formaldehyde and its application as an ingredient in urea-formaldehyde resins. In particular the effects of temperature and humidity on urea-formaldehyde foam are discussed.

  13. Poly(melamine-formaldehyde) microcapsules filled with epoxy resin: effect of M/F ratio on the shell wall stability

    Science.gov (United States)

    Sharma, Shilpi; Choudhary, Veena

    2017-07-01

    In this article, we systematically investigated the effects of process parameters such as melamine to formaldehyde (M/F) ratio taken in the initial feed on the yield percent, core content, solvent wash stability, morphology, mean particle size distribution and thermal stability of the microcapsules. Epoxy loaded poly(melamine-formaldehyde) (PMF) microcapsules were prepared by in situ polymerization using emulsion technique. Capsules core content and solvent wash stability increased as the formaldehyde content increased. Structural (FTIR and 1H-NMR), morphological (optical microscopy (OM) and scanning electron microscopy (SEM)) and thermal (thermogravimetry and differential scanning calorimetry) characterization was done to investigate the effects of M/F ratio on the synthesized microcapsules. The analysis of core material by FTIR and 1H-NMR spectra confirmed the presence of epoxy as the core material. OM and SEM micrographs showed that the prepared capsules were almost spherical with a perfect periphery, but showed the tendency to agglomerate as the ratio of M/F decreased. The mean particle size of epoxy filled PMF microcapsules decreased (from 87.1 µm to 67 µm) as the ratio of M/F increased. Thermal analysis showed that the microcapsules were thermally stable up to 373 °C. Thermal stability of microcapsules increased as the ratio of M/F increased. Such microcapsules are expected to find applications in the preparation of polymeric self-healing composites for aerospace industry.

  14. Microencapsulation of butyl stearate with melamine-formaldehyde resin: Effect of decreasing the pH value on the composition and thermal stability of microcapsules

    Directory of Open Access Journals (Sweden)

    M. Krajnc

    2012-10-01

    Full Text Available The object of this study was to investigate how different decreasing of pH regimes during microencapsulation process with melamine-formaldehyde (MF resin affects the composition, morphology and thermal stability of microcapsules containing a phase-change material (PCM. Technical butyl stearate was used as PCM. Microencapsulation was carried out at 70°C. For all experiments the starting pH value was 6.0. After one hour of microencapsulation at the starting pH value, the pH value was lowered to final pH value (5.5; 5.0; 4.5 in a stepwise or linear way. The properties of microcapsules were monitored during and after the microencapsulation process. The results showed that pH value decreasing regime was critical for the morphology and stability of microcapsules. During microencapsulations with a stepwise decrease of pH value we observed faster increase of the amount of MF resin in the microencapsulation product compared to the microencapsulations with a linear pH value decrease. However, faster deposition in the case of microencapsulations with stepwise decrease of pH value did not result in thicker MF shells. The shell thickness increased much faster when the pH value was decreased in a linear way or in several smaller steps. It was shown that for the best thermal stability of microcapsules, the pH value during microencapsulation had to be lowered in a linear way or in smaller steps to 5.0 or lower.

  15. Highly stable microwave susceptible agents via encapsulation of Ti-mineral superfine powders in urea-formaldehyde resin microcapsules for tumor hyperthermia therapy

    Science.gov (United States)

    Long, Dan; Mao, Jingsong; Liu, Tianlong; Fu, Changhui; Tan, Longfei; Ren, Xiangling; Shi, Haitang; Su, Hongying; Ren, Jun; Meng, Xianwei

    2016-05-01

    In this study, Ti-mineral superfine powders (Ti-MSP) encapsulated in urea-formaldehyde resin microcapsules (Ti-MSP@UF-MC) were successfully prepared via a one-step microemulsion method for the first time. Because of the strong confinement effects, the Ti-MSP@UF-MC possessed perfect microwave heating effects. The temperature was 9.3 °C higher than that of the saline solution, superior to UF-MC (no significant microwave heating effect, 0 °C) and Ti-MSP (5.1 °C). The Ti-MSP@UF-MC showed low toxicity and good biocompatibility via a series of studies, including a hemolysis study and the MTT assay in vitro and in vivo. When the concentration was below 1000 μg mL-1, the hemolysis rate was lower than 5% (hemolysis study). When the concentration was below 400 μg mL-1, the cell activity was higher than 80% (MTT assay). Moreover, the Ti-MSP@UF-MC exhibited an ideal CT imaging effect in vivo owing to the large molecular weight of Ti-MSP. The Ti-MSP@UF-MC showed a favorable microwave therapy effect in vivo. Using mice bearing H22 tumor cells as an animal model, the tumor suppression rate could reach 100%.

  16. Increase of porosity by combining semi-carbonization and KOH activation of formaldehyde resins to prepare high surface area carbons for supercapacitor applications

    Science.gov (United States)

    Heimböckel, Ruben; Kraas, Sebastian; Hoffmann, Frank; Fröba, Michael

    2018-01-01

    A series of porous carbon samples were prepared by combining a semi-carbonization process of acidic polymerized phenol-formaldehyde resins and a following chemical activation with KOH used in different ratios to increase specific surface area, micropore content and pore sizes of the carbons which is favourable for supercapacitor applications. Samples were characterized by nitrogen physisorption, powder X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The results show that the amount of KOH, combined with the semi-carbonization step had a remarkable effect on the specific surface area (up to SBET: 3595 m2 g-1 and SDFT: 2551 m2 g-1), pore volume (0.60-2.62 cm3 g-1) and pore sizes (up to 3.5 nm). The carbons were tested as electrode materials for electrochemical double layer capacitors (EDLC) in a two electrode setup with tetraethylammonium tetrafluoroborate in acetonitrile as electrolyte. The prepared carbon material with the largest surface area, pore volume and pore sizes exhibits a high specific capacitance of 145.1 F g-1 at a current density of 1 A g-1. With a high specific energy of 31 W h kg-1 at a power density of 33028 W kg-1 and a short time relaxation constant of 0.29 s, the carbon showed high power capability as an EDLC electrode material.

  17. In Situ Carbon Coated LiNi0.5Mn1.5O4 Cathode Material Prepared by Prepolymer of Melamine Formaldehyde Resin Assisted Method

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2016-01-01

    Full Text Available Carbon coated spinel LiNi0.5Mn1.5O4 were prepared by spray-drying using prepolymer of melamine formaldehyde resin (PMF as carbon source of carbon coating layer. The PMF carbon coated LiNi0.5Mn1.5O4 was characterized by XRD, SEM, and other electrochemical measurements. The as-prepared lithium nickel manganese oxide has the cubic face-centered spinel structure with a space group of Fd3m. It showed good electrochemical performance as a cathode material for lithium ion battery. After 100 discharge and charge cycles at 0.5 C rate, the specific discharge capacity of carbon coated LiNi0.5Mn1.5O4 was 130 mAh·g−1, and the corresponding capacity retention was 98.8%. The 100th cycle specific discharge capacity at 10 C rate of carbon coated LiNi0.5Mn1.5O4 was 105.4 mAh·g−1, and even the corresponding capacity retention was 95.2%.

  18. Analysis of cocondensation of melamine and urea through formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Bunichiro Tomita; Chung-Yun Hse

    1995-01-01

    The 13C-NMR (carbon 13 nuclear magnetic resonance) spectra of urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins synthesized under various conditions were taken with a frequency of 75 MHz. The main purpose was to investigate whether or not the occurrences of cocondensation...

  19. Comparative Enactment of Formaldehyde-free and Formaldehyde-based Cross-linkers on Cotton Woven Fabrics

    Directory of Open Access Journals (Sweden)

    Nawshin Farzana

    2017-04-01

    Full Text Available The performances of formaldehyde-based and non-formaldehyde cross-linkers on pretreated cotton woven fabric were assessed and compared in this research. Fixapret CL was considered as the formaldehyde-based resin and Fixapret NF as the formaldehyde-free resin. Dry cross-linking method was adopted for the application of cross-linkers. Different properties of resin treated fabrics investigated and compared were as follows: DP (durable press rating, wrinkle recovery, stiff ness, tensile strength, tear strength, shrinkage, skewness, hydrophobicity, whiteness and yellowness index. Marginally low performances in smoothness appearance and dimensional stability on fabric were exhibited with formaldehyde-free cross-linkers although indicating lower amount of the strength loss percentage. The formaldehyde-based compounds imparted more yellowing tendency to the treated fabric. The formaldehyde-free resins may be a good choice of replacements considering the overall eff ectiveness on fabric

  20. Resorcinol?triethyl?enediamine (1/1)

    OpenAIRE

    Gao, Yi-hong

    2011-01-01

    The title co-crystal, C6H12N2?C6H6O2, is composed of neutral resorcinol and triethyl?enediamine mol?ecules in which the resorcinol mol?ecules came from the in situ deca?rboxylation of 2,4-dihy?droxy?benzoic acid. In the crystal, the components are connected by O?H?N hydrogen bonds, forming a chain in the b-axis direction.

  1. Analysis of cocondensation of melamine and urea through carbon 13 enriched formaldehyde with C-13 nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Bunichiro Tomita; Chung-Yun Hse

    1995-01-01

    The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-ureaformaldehyde (MUF) cocondensed resins were synthesized using the labeling method with 13C enriched formaldehyde under neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field...

  2. Single-step conversion of synthesis gas into formaldehyde

    OpenAIRE

    Bahmanpour, Alimohammad

    2017-01-01

    Formaldehyde is known as the building block in many industries including resins, polymers, paints and adhesives. It is widely used in furniture and wood processing. The annual production rate of formaldehyde is in the range of 30 million tons globally and the demand of formaldehyde has grown by 2-3 % per year over the past two decades. Industrially, formaldehyde is produced via methanol partial oxidation. Methanol in turn is produced from synthesis gas which is produced via steam reforming of...

  3. Vitrification of cesium-contaminated organic ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Sargent, Jr., Thomas N. [Clemson Univ., SC (United States)

    1994-08-01

    Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass.

  4. Wettability of southern pine veneer by phenol formaldehyde wood adhesives

    Science.gov (United States)

    Chung-Yun Hse

    1972-01-01

    Wettability of southern pine veneers was judged by measuring the contact angles made by 36 phenol formaldehyde resins. Formulation of the resins was by factorial design, the molar ratios of sodium hydroxide to phenol being 0.4, 0.7, and 1.0, the levels of resin solids content in the reaction mixture 37, 40, and 43 percent, and the molar ratios of formaldehyde to phenol...

  5. (2-PYRIDYLAZO)RESORCINOL FOR FLOTATION

    African Journals Online (AJOL)

    4-(2-Pyridylazo)resorcinol (PAR) is one of the most popular analytical reagents. It forms colored complexes with many metal ions and can be used for their spectrophotometric determination. A well-known disadvantage of this reagent is its insufficient selectivity [1]. Commonly used approaches for increasing the selectivity ...

  6. INFLUÊNCIA DO CATALISADOR EM SOLUÇÕES POLIMÉRICAS PARA O PREPARO DE GÉIS ORGÂNICOS DE RESORCINOL-FORMALDEÍDO

    Directory of Open Access Journals (Sweden)

    Thalita S. Taiariol

    2015-11-01

    Full Text Available Resorcinol-formaldehyde (RF organic gels have been extensively used to produce carbon aerogels. The organic gel synthesis parameters greatly affect the structure of the resulting aerogel. In this study, the influence of the catalyst quantity on the polymeric solution sol-gel process was investigated. Sodium carbonate was used as a basic catalyst. RF gels were synthesized with a resorcinol to formaldehyde molar ratio of 0.5, a resorcinol to catalyst (R/C molar ratio equal to 50 or 300, and a resorcinol to solvent ratio of 0.1 g mL-1. The sol-gel process was evaluated in situ by Fourier transform infrared spectroscopy using a universal attenuated total reflectance sensor and measurements of the kinematic viscosity. The techniques showed the evolution of the sol-gel process, and the results showed that the lower catalyst quantity induced a higher gel point, with a lower viscosity at the gel point. Differential scanning calorimetry was used to investigate the thermal behavior of the RF dried gel, and results showed that the exothermic event related to the curing process was shifted to higher temperatures for solutions containing higher R/C ratios.

  7. Microwave Assisted Synthesis of Phenol-Formaldehyde Resole

    Directory of Open Access Journals (Sweden)

    Subhash Chandra Bajia

    2007-01-01

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

  8. Development of prepainted steel sheets having excellent formability, stain resistance, and hardness by control of orientation behavior of melamine-formaldehyde resin in the paint film; Kakosei, taiosensei, kodo tokusei ni sugureru precoat koban no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kanai, H.; Oka, J.; Tsutsumi, M. [Nippon Steel Corp., Tokyo (Japan)

    1994-08-01

    In the present research, the prepainted steel sheet was developed which was coated with melamine-formaldehyde resin (Rm) excelling in stain resistance and hardness. Study was made under various Res/Rm blending conditions by selecting, as a test sample, three types of polyester resin (Res), four types of Rm and two types of catalyst. The superficial structure of coated layer was analyzed by X-ray photoelectron spectroscopy. An Rm-enriched layer could be formed by combining Res of a low hydroxyl value and a strongly acidic catalyst blocked with amine. In such a formation mechanism, catalytic activity directly below the coated surface and self-condensation of Rm were observed during the backing. There exists a positive correlativity between the stain resistance and superficial Rm concentration of blended Res/Rm system. The stain resistance is judged dependent upon the self-condensation. The precoated steel sheet which excels in formability even at a room temperature of 20{degree}C was commercialized and is being sold. As compared with the conventional high-grade products, the present steel sheet is lustrous even through a 24h submergence in 5% NaOH and H2SO4. A stain resistance test in magic ink also gave a good result. 5 refs., 8 figs., 4 tabs.

  9. Development of amino resin for paint formulation: Copolymerization ...

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... Key words: Methylol urea-triethanolamine copolymer, flexibility, formaldehyde emission, copolymerization, methylol urea, esterification, tensile properties. INTRODUCTION. Amino resins are thermosetting polymers that are largely used in many industrial applications. Urea formaldehyde accounts for over ...

  10. Maximum Potential Hydrogen Gas Retention in the sRF Resin Ion Exchange Column for the LAWPS Process

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, Phillip A.; Wells, Beric E.; Bottenus, Courtney LH; Schonewill, Philip P.

    2018-01-22

    The Low-Activity Waste Pretreatment System (LAWPS) is being developed to provide treated supernatant liquid from the Hanford tank farms directly to the Low-Activity Waste (LAW) Vitrification Facility at the Hanford Tank Waste Treatment and Immobilization Plant. The design and development of the LAWPS is being conducted by Washington River Protection Solutions, LLC. A key process in LAWPS is the removal of radioactive Cs in ion exchange (IX) columns filled with spherical resorcinol-formaldehyde (sRF) resin. One accident scenario being evaluated is the loss of liquid flow through the sRF resin bed after it has been loaded with radioactive Cs and hydrogen gas is being generated by radiolysis. In normal operations, the generated hydrogen is expected to remain dissolved in the liquid and be continuously removed by liquid flow. For an accident scenario with a loss of flow, hydrogen gas can be retained within the IX column both in the sRF resin and below the bottom screen that supports the resin within the column. The purpose of this report is to summarize calculations that estimate the upper-bound volume of hydrogen gas that can be retained in the column and potentially be released to the headspace of the IX column or to process equipment connected to the IX column and, thus, pose a flammability hazard.

  11. Ion Exchange Testing with SRF Resin FY2012

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

    2013-06-11

    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.0 , which was prepared and approved in response to the Test Specification 24590 PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590 PTF TEF RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

  12. Determination of trace amounts of copper with 4-(2-pyridylazo)resorcinol by solid phase spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-de Cordova, M.L. (Dept. of Physical and Analytical Chemistry, Jaen Univ. (Spain)); Molina-Diaz, A. (Dept. of Physical and Analytical Chemistry, Jaen Univ. (Spain)); Pascual-Reguera, M.I. (Dept. of Physical and Analytical Chemistry, Jaen Univ. (Spain)); Capitan-Vallvey, L.F. (Dept. of Analytical Chemistry, Granada Univ. (Spain))

    1994-08-01

    A determination method for traces of copper by Solid-Phase Spectrophotometry (SPS) has been developed. It is based on the fixation of copper(II) as 4-(2-pyridylazo)resorcinol complex on a styrene-divinylbenzene anion-exchange resin. The resin phase absorbances at 525 and 800 nm are measured directly, and the determination of copper (with a RSD of 1.8%) is possible in the range of 0.3-4.5 [mu]g L[sup -1]. The method has been applied to the determination of copper in different samples, i.e. mushrooms, tea, drugs and waters. (orig.)

  13. 24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Formaldehyde emission controls for... Body and Frame Construction Requirements § 3280.308 Formaldehyde emission controls for certain wood products. (a) Formaldehyde emission levels. All plywood and particleboard materials bonded with a resin...

  14. Activated Carbon by Co-pyrolysis and Steam Activation from Particle Board and Melamine Formaldehyde Resin: Production, Adsorption Properties and Techno Economic Evaluation

    Directory of Open Access Journals (Sweden)

    Kenny Vanreppelen

    2013-03-01

    Full Text Available One of the top strategic objectives and research areas in Europe is recovering wood from processing and end of life products. However, there are still several "contaminated" wood products that are not or only partly reused/recycled. Particle board waste which is contaminated with aminoplasts is one of these products. In addition, a considerable amount of aminoplast waste resinis produced for the production of particle board that cannot be re-used or recycled. The chemical properties of these wastes (high nitrogen content of 5.9 wt% and 54.1 wt% for particle board and melamine formaldehyde respectively make them ideal precursors for the production of nitrogenised activated carbon. The profitability of the produced activated carbon is investigated by calculating the net present value, the minimum selling price and performing a Monte Carlo sensitivity analysis. Encouraging results for a profitable production are obtained even though the current assumptions start from a rather pessimistic scenario.

  15. Page 1 y-SUBSTITUTION IN RESORCINOL NUCLEUS Part Will ...

    Indian Academy of Sciences (India)

    ORDINARILY, resorcinol and its derivatives are known to react in the 8-posi- tion. Orcinol which is 5-methyl-resorcinol, however, manifests a marked tendency for substitution in the y-position.” Thus, while 8-substitution occurs on bromination,” Gattermann reaction” or Pechmann condensation with malic acid”; on ...

  16. Melamine–Glyoxal–Glutaraldehyde Wood Panel Adhesives without Formaldehyde

    Directory of Open Access Journals (Sweden)

    Xuedong Xi

    2017-12-01

    Full Text Available (MGG’ resin adhesives for bonding wood panels were prepared by a single step procedure, namely reacting melamine with glyoxal and simultaneously with a much smaller proportion of glutaraldehyde. No formaldehyde was used. The inherent slow hardening of this resin was overcome by the addition of N-methyl-2-pyrrolidone hydrogen sulphate ionic liquid as the adhesive hardener in the glue mix. The plywood strength results obtained were comparable with those obtained with melamine–formaldehyde resins pressed under the same conditions. Matrix assisted laser desorption ionisation time of flight (MALDI ToF and Fourier transform Infrared (FTIR analysis allowed the identification of the main oligomer species obtained and of the different types of linkages formed, as well as to indicate the multifaceted role of the ionic liquid. These resins are proposed as a suitable substitute for equivalent formaldehyde-based resins.

  17. Magnetic mesoporous thiourea-formaldehyde resin as selective adsorbent: A simple and highly-sensitive electroanalysis strategy for lead ions in drinking water and milk by solid state-based anodic stripping.

    Science.gov (United States)

    Zhao, Yanfang; Xu, Lubin; Liu, Min; Duan, Zhiqiang; Wang, Hua

    2018-01-15

    A simple and sensitive electroanalysis method has been developed for the direct determination of lead ions of nanomolar levels in real samples of drinking water and milk by employing magnetic mesoporous thiourea-formaldehyde resin (TUF@Fe 3 O 4 ) nanocomposites as the capturing absorbents. Here, the prepared TUF@Fe 3 O 4 with the large-surface-area mesoporous structure and strong Pb 2+ -binding ligands could facilitate the selective and large-scale adsorption of Pb 2+ ions from the complex sample matrices to be further magnetically separated onto the magnetic electrodes. Moreover, the Pb 2+ ions magnetically accumulated were electrochemically measured alternatively by the solid state-based anodic stripping of PbCl 2 . The detection limit was found to be 0.0070nmolL -1 . The as-developed Pb 2+ electroanalysis method with the magnetic electrodes and TUF@Fe 3 O 4 nanocomposites could avoid the complicated sample preparation and electrode modification, thus holding the great potential of applications for the Pb 2+ detection in different real samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Condensed tannin-resorcinol adducts and their use in wood-laminating adhesives: An exploratory study

    Science.gov (United States)

    Richard W. Hemingway; R.E. Kreibich

    1984-01-01

    The reaction of a tannin extract (containing about 30% carbohydrate) from loblolly pine (Pinus taeda L.) bark (two parts) and resorcinol (one part) at 120°C for 24 h with acetic acid catalyst gave a product containing predominantly oligomeric procyanidin-4-resorcinol adducts (39%), unreacted resorcinol (22%), carbohydrate (20%). the resorcinol adduct...

  19. A review of the effects of formaldehyde release from endodontic materials.

    Science.gov (United States)

    Athanassiadis, B; George, G A; Abbott, P V; Wash, L J

    2015-09-01

    Formaldehyde is present in most living cells and the environment. In dentistry, patients may be exposed to formaldehyde through the use of several endodontic materials (e.g. AH 26) and during formocresol pulpotomies. This review outlines how the human body reacts to formaldehyde exposure, how recent data has relooked at the issue of carcinogenicity and leukaemia associated with formaldehyde, and whether it is possible to quantify the amount of formaldehyde produced by endodontic cements. The review analyses the way formaldehyde is produced from epoxy resins and addresses the question of whether the amount of formaldehyde from endodontic cements is large enough to override the body's ability to deal with its own endogenous levels of formaldehyde and should the amount of formaldehyde produced be a concern. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  20. Formaldehyde exposure and patterns of concomitant contact allergy to formaldehyde and formaldehyde-releasers

    DEFF Research Database (Denmark)

    Lundov, Michael D; Johansen, Jeanne D; Carlsen, Berit C

    2010-01-01

    Formaldehyde and formaldehyde-releasers are widely used in consumer products and may often cause contact allergy.......Formaldehyde and formaldehyde-releasers are widely used in consumer products and may often cause contact allergy....

  1. Detection of formaldehyde in textiles by chromotropic acid method

    Directory of Open Access Journals (Sweden)

    Rao Sanath

    2004-11-01

    Full Text Available BACKGROUND: The common causes of textile dermatitis are formaldehyde resins and disperse dyes. There are various methods to detect the presence of formaldehyde in clothing. AIM: To detect the presence of formaldehyde in various types of textiles by the chromotropic acid method and to assess the effect of washing on the formaldehyde content. METHODS: Twenty randomly selected textiles from a local cloth store were tested for formaldehyde by the chromotropic acid method. A purple ring indicated a positive reaction. The intensity of the purple ring was graded from 1+ to 3+ and reassessed after washing the clothes. RESULTS: Eleven out of the 20 textiles tested positive for formaldehyde. The fully synthetic clothes were free from formaldehyde. After the first and second washes the majority did not show a reduction in the formaldehyde content. CONCLUSIONS: This is a simple and rapid test which can be used in the practical management of patients with textile allergy. Washing the clothes may not have an effect on the formaldehyde content.

  2. Formaldehyde: a candidate toxic air contaminant. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frye, B.; Parker, T.

    1988-03-01

    Formaldehyde (HCHO) is a gas widely used in adhesives and resins, textiles, embalming fluids, fungicides, air fresheners, and cosmetics. It is directly emitted into the ambient outdoor air from vehicular and stationary sources, and is also produced in the atmosphere from other substances by photochemical smog processes. The International Agency for Research on Cancer (IARC) has determined that there is sufficient evidence for carcinogenicity of formaldehyde to animals, and limited evidence for carcinogenicity to humans. EPA classifies formaldehyde as a probable human carcinogen with a one in a million risk concentration of 0.08 ppb.

  3. Disturb or Stabilize? A Molecular Dynamics Study of the Effects of Resorcinolic Lipids on Phospholipid Bilayers

    NARCIS (Netherlands)

    Siwko, Magdalena E.; de Vries, Alex H.; Mark, Alan E.; Kozubek, Arkadiusz; Marrink, Siewert J.

    2009-01-01

    Resorcinolic lipids, or resorcinols, are commonly found in plant membranes. They consist of a substituted benzene ring forming the hydrophilic lipid head, attached to an alkyl chain forming the hydrophobic tail. Experimental results show alternative effects of resorcinols on lipid membranes.

  4. Ion Exchange Testing with SRF Resin FY 2012

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

    2014-07-02

    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.01, which was prepared and approved in response to the Test Specification 24590-PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590-PTF-TEF-RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

  5. Microfabricated Formaldehyde Gas Sensors

    OpenAIRE

    Cheung, Karen C.; Ko, Frank K.; Jonas Flueckiger

    2009-01-01

    Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based d...

  6. The reduction of formaldehyde and VOCs emission from wood-based flooring by green adhesive using cashew nut shell liquid (CNSL).

    Science.gov (United States)

    Kim, Sumin

    2010-10-15

    To discuss the reduction of formaldehyde and volatile organic compound (VOC) emissions from engineered flooring, cashew nut shell liquid (CNSL)-formaldehyde (CF) resin and CF/PVAc resin were applied for the maple face of the veneer bonding on plywood. The CF resin was used to replace urea-formaldehyde (UF) resin in the formaldehyde-based resin system in order to reduce formaldehyde and VOC emissions from the adhesives used between the plywoods and fancy veneers. For the CF/PVAc resins, 5, 10, 20 or 30% of PVAc was added to the CF resin. The CF/PVAc resins showed better bonding than the commercial natural tannin adhesive with a higher level of wood penetration. The standard formaldehyde emission test and a VOC analyzer were used to determine the formaldehyde and VOC emissions, respectively, from the engineered floorings. The CF resin and CF/PVAc resin systems with UV coating satisfied the E(1) and E(0) grades of the Korean Standard. TVOC emission was slightly increased by the PVAc addition. 2010 Elsevier B.V. All rights reserved.

  7. Characteristics of the wood adhesion bonding mechanism using hydroxymethyl resorcinol

    Science.gov (United States)

    Douglas J. Gardner; Charles E. Frazier; Alfred W. Christiansen

    2006-01-01

    A recent collaborative effort among the U.S. Forest Products Laboratory, Virginia Tech, and the University of Maine has explored the possible bonding mechanisms contributing to durable wood adhesive bonding using hydroxymethyl resorcinol (HMR) surface treatment. Current adhesive bonding mechanisms include: mechanical interlocking, electronic or electrostatic theory,...

  8. Page 1 Acetylation of Phenols Using Acetic Acid 351 Resorcinol ...

    Indian Academy of Sciences (India)

    and 12g of glacial acetic acid, only 15g. of diacetyl resorcinol, boiling at. 278° C., was obtained. Since there was the chance for mono-acetylation also to take place, the alkaline extract from the ethereal Solution containing the reaction products was diluted with water to 200 c.c., acidified with hydrochloric acid and then.

  9. resorcinol for flotation-spectrophotometric determination of iron

    African Journals Online (AJOL)

    2-pyridylazo)resorcinol (PAR) based on a 1:2 FeII-PAR complex were found to be as follows: flotation solvent (chloroform), shaking time (2 min), pH (4.5±0.5), concentration of PAR (2.0×10–4 mol L–1), reducing agent (hydroxylamine ...

  10. Resin impregnation of cellulose nanofibril films facilitated by water swelling

    Science.gov (United States)

    Yan Qing; Ronald Sabo; Zhiyong Cai; Yiqiang Wu

    2013-01-01

    Flexible composite films were produced by impregnating aqueous phenol formaldehyde (PF) resin into water-swollen cellulose nanofibril (CNF) films. CNF films were prepared using a pressurized filtration method in combination with freeze drying. The freeze-dried films were swollen with water then impregnated with PF resin by soaking in aqueous resin solutions of varying...

  11. Effect of Fiber Treatment and Fiber Loading on Mechanical Properties of Luffa-Resorcinol Composites

    Directory of Open Access Journals (Sweden)

    Chhatrapati Parida

    2015-01-01

    Full Text Available Tensile and compressive behaviour of resorcinol-formaldehyde (RF matrix and its composites reinforced with fibers of Luffa cylindrica (LC have been studied. LC fibers were subjected to chemical treatments such as alkali activation by NaOH followed by bleaching and acid hydrolysis in order to improve fiber-matrix adhesion. Both treated and untreated LC fibers are modified with calcium phosphate. The presence of hydroxy apatite, a polymorph of calcium phosphate and a major constituent of vertebrate bone and teeth, was confirmed from XRD peak of treated LC fiber. XRD analysis of the treated LC fiber has confirmed the crystalline nature of the chemically treated LC fiber by its crystallinity index. The effects of fiber loading of chemically treated and untreated LC fiber on ultimate stress, yield strength, breaking stress, and modulus of the composites were analyzed. The tensile and compressive modulus of the composites were increased with incorporation of both treated and untreated LC fibers into the RF matrix. The modulus of composites with treated LC fiber was enhanced compared to that of the untreated fiber composites. Furthermore the values of ultimate stress, yield stress, and breaking stress were increased with the incorporation of treated LC fiber in the composites.

  12. Formaldehyde in Our Environment.

    Science.gov (United States)

    Ojanlatva, Ansa; Weeks, Charlie A.

    During the energy crisis of the early 1970s, there was a drive to conserve energy in every segment of society. Citizens were encouraged to insulate their homes and tighten them up to avoid loss of energy. One of the products to emerge from this crisis was urea formaldehyde foam insulation. (Urea formaldehyde is a well-known agent for preserving…

  13. Optical Detection of Formaldehyde

    Science.gov (United States)

    Patty, Kira D.; Gregory, Don A.

    2008-01-01

    The potential for buildup .of formaldehyde in closed space environments poses a direct health hazard to personnel. The National Aeronautic Space Agency (NASA) has established a maximum permitted concentration of 0.04 ppm for 7 to 180 days for all space craft. Early detection is critical to ensure that formaldehyde levels do not accumulate. above these limits. New sensor technologies are needed to enable real time,in situ detection in a compact and reusable form factor. Addressing this need,research into the use of reactive fluorescent dyes which reversibly bind to formaldehyde (liquid or gas) has been conducted to support the development of a formaldehyde.sensor. In the presence of formaldehyde the dyes' characteristic fluorescence peaks shift providing the basis for an optical detection. Dye responses to formaldehyde exposure were characterized; demonstrating the optical detection of formaldehyde in under 10 seconds and down to concentrations of 0.5 ppm. To .incorporate the dye .in.an optical sensor device requires. a means of containing and manipulating the dye. Multiple form factors using two dissimilar sbstrates were considered to determine a suitable configuration. A prototype sensor was demonstrated and considerations for a field able sensor were presented. This research provides a necessary first step toward the development of a compact, reusable; real time optical formaldehyde sensor suitable for use in the U.S. space program,

  14. The formaldehyde dilemma.

    Science.gov (United States)

    Salthammer, Tunga

    2015-06-01

    The IARC's 2004 classification of formaldehyde as a human carcinogen has led to intensive discussion on scientific and regulatory levels. In June 2014, the European Union followed and classified formaldehyde as a cause of cancer. This automatically triggers consequences in terms of emission minimization and the health-related assessment of building and consumer products. On the other hand, authorities are demanding and authorizing technologies and products which can release significant quantities of formaldehyde into the atmosphere. In the outdoor environment, this particularly applies to combusting fuels. The formation of formaldehyde through photochemical smog has also been a recognized problem for years. Indoors there are various processes which can contribute to increased formaldehyde concentrations. Overall, legislation faces a dilemma: primary sources are often over-regulated while a lack of consideration of secondary sources negates the regulations' effects. Copyright © 2015 Elsevier GmbH. All rights reserved.

  15. EFFECT OF WOOD SPECIES USED FOR CORE LAYER ON SOME PROPERTIES OF OKUME PLYWOOD PANELS BONDED WITH MELAMINE-UREA FORMALDEHYDE (MUF) ADHESIVE

    OpenAIRE

    Cenk Demirkır; Gürsel Çolakoğlu; İsmail Aydın; Semra Çolak

    2005-01-01

    In this study; changes in some properties of the okume plywood panels when used alder and beech veneers in their core layers were investigated. Two types of melamine-urea formaldehyde (MUF) resins having different free formaldehyde contents were used for bonding plywood panels manufactured from 2 mm thick veneers at industrial conditions. The formaldehyde emission values of plywood panels bonded with MÜF having higher free formaldehyde content were found to be higher than those of the panels ...

  16. The microcapsule-type formaldehyde scavenger: the preparation and the application in urea-formaldehyde adhesives.

    Science.gov (United States)

    Duan, Hongyun; Qiu, Teng; Guo, Longhai; Ye, Jun; Li, Xiaoyu

    2015-08-15

    The limitation and regulation of formaldehyde emissions (FE) now shows great importance in wood-based materials such as plywood and particle board manufactured for building and furnishing materials. The widely used formaldehyde-based adhesives are one of the main sources of FE from the wood products. In this work, a new kind of long-term effective formaldehyde scavenger in the microcapsule form was prepared by using an intra-liquid desiccation method. The characterizations of the capsule (UC) were performed including the morphologies, the yields, the loading efficiency as well as its sustained-release of urea in aqueous conditions. The prepared UC could be integrated in urea-formaldehyde resins by simply physical blending, and the mixtures were available to be applied as the adhesives for the manufacture of plywood. The bonding strength (BS) and the FE of the bonded plywood in both short (3h) and long (12 week) period were evaluated in detail. It was found that the FE profile of the plywood behaved following a duple exponential law within 12 week. The addition of UC in the adhesive can effectively depress the FE of the plywood not only in a short period after preparation but also in a long-term period during its practical application. The slow released urea would continuously suppress the emission of toxic formaldehyde in a sustained manner without obviously deteriorating on the BS of the adhesives. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Formaldehyde-releasers : relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

    NARCIS (Netherlands)

    de Groot, Anton C.; Flyvholm, Mari-ann; Lensen, Gerda; Menne, Torkil; Coenraads, Pieter-Jan

    2009-01-01

    This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the

  18. Occupational contact allergy to formaldehyde and formaldehyde releasers.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Kuuliala, O; Suuronen, K; Alanko, K

    2008-11-01

    Formaldehyde allergy is common and usually derives from formaldehyde-releasing biocides in cosmetic and other products. To analyse patterns of patch test reactions to formaldehyde and formaldehyde-releasing compounds and the sources of sensitization. At the Finnish Institute of Occupational Health, we screened the patch test files for allergic reactions to formaldehyde and 12 formaldehyde-releasing compounds. All patients with contact allergy to any of the substances were included, and their records were reviewed. Between January 2001 and May 2007, we had patch tested 81 patients with formaldehyde allergy and 18 with independent allergy to some formaldehyde releaser. Of the formaldehyde allergies, 60 were new sensitizations, 25 of which were considered to be occupational. The most common source of occupational sensitization was metalworking fluids followed by creams and related products. Exposure to formaldehyde-releasing preservatives in liquid soaps and other rinse-off products was common in both occupational and non-occupational cases. Reactions to formaldehyde-releasing compounds were seen in 79% of the formaldehyde-allergic patients. Occupational formaldehyde allergy was common and occurred in metalworkers, hairdressers, masseurs, and workers using protective creams, detergents, and liquid soaps. When compared with studies on general dermatological patients, contact allergy to formaldehyde releasers without formaldehyde allergy was rare.

  19. Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

    DEFF Research Database (Denmark)

    de Groot, Anton C; Flyvholm, Mari-Ann; Lensen, Gerda

    2009-01-01

    This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the liter...... reactions is often challenging. What concentration of formaldehyde is safe for sensitive patients remains unknown. Levels of 200-300 p.p.m. free formaldehyde in cosmetic products have been shown to induce dermatitis from short-term use on normal skin.......This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed...

  20. Membrane perturbing properties of natural phenolic and resorcinolic lipids.

    Science.gov (United States)

    Stasiuk, Maria; Kozubek, Arkadiusz

    2008-10-29

    The effects induced by natural phenolic and resorcinolic lipids on membrane permeability were investigated. All of the compounds tested perturbed the phospholipid bilayer and stabilized erythrocytes against hypoosmotically induced hemolysis. Dipalmitoylphosphatidylcholine liposomes with two preincorporated fluorescent dyes (1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatrien p-toluenesulfonate (TMA-DPH) and N-(-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoetanolamine triethylammonium salt (NBD-PE)) were used to determine the effects of tested compounds on the core and surface of the bilayer. Resorcinolic lipids from rye and cardol increased the polarization of TMA-DPH fluorescence more than that of NBD-PE, but anacardic acid, methylocardol, and alkylphenol increased NBD-PE dye fluorescence.

  1. New curing system of urea-formaldehyde resind with polyhydrazides. I. Curing with dihydrazie compounds

    Science.gov (United States)

    Bunichiro Tomita; Hideaki Osawa; Chung-Yun Hse; George E. Myers

    1989-01-01

    A nonconventional curing system was developed using a simple mixing of urea-formaldehyde (UF) resins with polyfunctional hydrazide compounds under neutral contition. Several kinds of low molecular-weight dihydrazide compounds were investigated as hardners of the UF resins. Results were as follows: 1) As the minimum gelation times were observed in the range of molar...

  2. Accelerated cure of phenol-formaldehyde by the addition of cure accelerators : studies with model compounds

    Science.gov (United States)

    Linda F. Lorenz; Anthony C. Conner

    2000-01-01

    Fast curing phenol-formaldehyde (PF) resins could potentially allow wood to be bonded at higher moisture contents and at lower press temperatures than those currently used commercially. Recent reports in the literature have shown that the addition of esters, lactones, or organic carbonates increased the curing rate of PF resins. Several mechanisms have been proposed to...

  3. Predicting the reactivity of phenolic compounds with formaldehyde. II, continuation of an ab initio study.

    Science.gov (United States)

    Tohru Mitsunaga; Anthony H. Conner; Charles G. Jr. Hill

    2002-01-01

    Phenol–formaldehyde resins are important adhesives used by the forest products industry. The phenolic compounds in these resins are derived primarily from petrochemical sources. Alternate sources of phenolic compounds include tannins, lignins, biomass pyrolysis products, and coal gasification products. Because of variations in their chemical structures, the...

  4. Potential application of resin extracts of Anogeissus leiocarpus plant ...

    African Journals Online (AJOL)

    The ploy condensation of tannin with formaldehyde produced a thermosetting resin with useful properties; formaldehyde (10.5 ml), tannin (2.5 g), glycerol (0.6 ml), hexamine (5.5 g), pH ... Absorption behaviour of the films from the thermosetting material formulated under aqueous, acid and basic conditions were investigated.

  5. Formaldehyde Workshop Agenda

    Science.gov (United States)

    This is the agenda for the Formaldehyde Workshop hosted by the Office of Research and Development's National Center for Environmental Assessments in cooperation with the IRIS Program. The workshop was held in April 2014

  6. Selenium pretreatment attenuates formaldehyde-induced genotoxicity in A549 cell lines.

    Science.gov (United States)

    Shi, Yu-Qin; Chen, Xin; Dai, Juan; Jiang, Zhong-Fa; Li, Ning; Zhang, Ben-Yan; Zhang, Zhi-Bing

    2014-11-01

    Formaldehyde is a major industrial chemical and has been extensively used in the manufacture of synthetic resins and chemicals. Numerous studies indicate that formaldehyde can induce various genotoxic effects in vitro and in vivo. A recent study indicated that formaldehyde impaired antioxidant cellular defences and enhanced lipid peroxidation. Selenium is an important antioxidant. We hypothesized that reactive oxygen species (ROS) and lipid peroxidation are involved in formaldehyde-induced genotoxicity in human lung cancer cell line, A549 cell line. To test the hypothesis, we investigated the effects of selenium on formaldehyde-induced genotoxicity in A549 cell lines. The results indicated that exposure to formaldehyde showed the induction of DNA-protein cross-links (DPCs). Formaldehyde significantly increased the malondialdehyde levels and decreased the activities of superoxide dismutase and glutathione peroxidase. In addition, the activations of necrosis factor-κB (NF-κB) and activator protein 1 (AP-1) were induced by the formaldehyde treatment. The pretreatment with selenium counteracted the formaldehyde-induced oxidative stress, ameliorated DPCs and attenuated the activation of NF-κB and AP-1 in A549 cell lines. All the results suggested that the pretreatment with selenium attenuated the formaldehyde-induced genotoxicity through its ROS scavenging and anti-DPCs effects in A549 cell lines. © The Author(s) 2012.

  7. Eerste inventarisatie alternatieven voor biociden met formaldehyde of formaldehyde releasers

    NARCIS (Netherlands)

    Wezenbeek JJ; Janssen MPM; Scheepmaker JWA; MSP; M&V

    2015-01-01

    Formaldehyde is de werkzame stof in veel desinfecteer- en conserveringsmiddelen, maar deze stof is kankerverwekkend. Daarom zal formaldehyde naar verwachting per 1 januari 2016 op Europees niveau als zodanig worden geclassificeerd (carcinogeen 1B). Dit kan betekenen dat formaldehyde-houdende

  8. Synthesis of resorcinolic lipids bearing structural similarities to cytosporone A

    Directory of Open Access Journals (Sweden)

    Edson dos Anjos dos Santos

    2009-01-01

    Full Text Available Inspired by the structure and biological activities of resorcinolic lipids and, particularly cytosporone A- a potent inhibitor of plantule germination and growth, we have performed the synthesis of the analogs 3-heptyl-3-hydroxy-5,7-dimethoxy-2-benzofuran-1(3H-one (1 and 3-heptyl-3-hydroxy-4,6-dimethoxy-2-benzofuran-1(3H-one (2. The intermediates and products were submitted to allelopathic test using Lactuca sativa L. seeds. Target compound 1 showed an inhibitory effect on germination and growth of hypocotyl and radicle in milimolar range.

  9. Synthesis of resorcinolic lipids bearing structural similarities to cytosporone A

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Edson dos Anjos dos; Beatriz, Adilson; Lima, Denis Pires de [Universidade Federal Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Centro de Ciencias Exatas e Tecnologia. Dept. de Quimica], e-mail: dlima@nin.ufms.br; Marques, Maria Rita; Leite, Carla Braga [Universidade Federal Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Centro de Ciencias Biologicas. Dept. de Morfofisiologia

    2009-07-01

    Inspired by the structure and biological activities of resorcinolic lipids and, particularly cytosporone A- a potent inhibitor of plantule germination and growth, we have performed the synthesis of the analogs 3-heptyl-3-hydroxy-5,7-dimethoxy-2-benzofuran-1(3H)-one (1) and 3-heptyl-3-hydroxy-4,6-dimethoxy-2-benzofuran-1(3H)-one (2). The intermediates and products were submitted to allelopathic test using Lactuca sativa L. seeds. Target compound 1 showed an inhibitory effect on germination and growth of hypocotyl and radicle in millimolar range. (author)

  10. Infrared spectroscopic monitoring of urea addition to oriented strandboard resins

    Science.gov (United States)

    Chi-Leung So; Thomas L. Eberhardt; Ernest Hsu; Brian K. Via; Chung Y. Hse

    2007-01-01

    One of the variables in phenol formaldehyde adhesive resin formulation is the addition of urea, which allows the resin manufacturer to manipulate both product functionality and cost. Nitrogen content can be used as a measure of the level of urea addition because most of the nitrogen present is derived from urea added at the end of the preparation process. Nitrogen...

  11. Formaldehyde oxime - nitrosomethane tautomerism

    NARCIS (Netherlands)

    Long, J.A.; Harris, N.J.; Lammertsma, K.

    2001-01-01

    Formaldehyde oxime ⇌ nitrosomethane tautomerism, isomeric nitrone, and their common cations and anions are studied with Gaussian-2 theory using MP2(full)/6-31G* geometries and with density functional theory using B3LYP/6-311+G**. Geometrical parameters, harmonic vibrational frequencies, relative

  12. Emission of formaldehyde from furniture

    DEFF Research Database (Denmark)

    Andersen, Helle Vibeke; Klinke, Helene B.; Funch, Lis Winther

    2014-01-01

    The emission of formaldehyde from a variety of furniture was measured in climate chambers. Most tests show low emission of formaldehyde; however, there are a few exceptions. One product emitted significant amounts of formaldehyde, but according to the Danish Indoor Climate Labelling Criteria...... for furniture the impact on the formaldehyde concentration was low due to a small surface area in the standard room. One product led to a high concentration of formaldehyde in the standard room since both emission and material load were high. Even with a moderate area-specific emission rate of formaldehyde......, furniture with high material load in the standard room, such as bookcases, can have a significant impact on the indoor air. The results showed that furniture on the Danish market may have an emission of formaldehyde resulting in indoor concentrations above the WHO recommended limit of 0.1 mg m-3. Therefore...

  13. Curing mechanism of furan resin modified with different agents and their thermal strength

    Directory of Open Access Journals (Sweden)

    Huang Renhe

    2011-05-01

    Full Text Available The curing mechanism of furfuryl alcohol and urea-formaldehyde furan resins was investigated using infrared spectroscopy (IR technique. The curing productions of urea-formaldehyde furan resins modified with different agents (i.e. sorbitol, polyester polyol, phenol and acetone and the productions of incomplete curing were characterized by differential thermal analysis (DTA and thermal gravity analysis (TG. The results indicate that except for polyester polyol, the other modifiers have little effect on the thermal strength of urea-formaldehyde furan resin. Furthermore, the thermal strength can be improved at a temperature of higher than 550℃.

  14. 1H and 13C-NMR studies on phenol-formaldehyde prepolymers for tannin-based adhesives

    Science.gov (United States)

    Gerald W. McGraw; Lawerence L. Lanucci; Seiji Ohara; Richard W. Hemingway

    1989-01-01

    The number average structure and the molecular weight distribution of phenol-formaldehyde prepolymers for use in synthesis of tannin-based adhesive resins were determined with 1H and 13C-NMR spectroscopy and gel permeation chromatography of acetylated resins. These methods were used to determine differences in phenol-...

  15. Development of prepainted steel sheets having excellent formability, stain resistance and hardness by control of orientation behavior of melamine-formaldehyde resin in the paint film. Tomakuchu no melamine jushi haiko seigyo gijutsu ni yoru kakosei taiosensei kodo ni sugureta precoat koban no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kanai, H.; Oka, J.; Tsutsumi, M. (Nippon Steel Corp., Tokyo (Japan))

    1994-06-20

    Since most prepainted steel sheets are usually formed for further working, these materials must have high workability (paint film with high deformation resistance). In addition, hardness and stain resistance inherent to steel sheets must be maintained. High workability is difficult to provide for steel sheets with high hardness and stain resistance. This is one of the reasons why the applications of prepainted steel sheets have been limited. This paper describes the study of the relationships between the paint film structure and the nature of polyester (PE) and melamine-formaldehyde (MM) resin. As a result of the study, the technology of control of orientation behavior of MM in paint film was established, and, with the technology, new prepainted steel sheets were developed to solve the problem above. In this case, formability (almost decided by the elongation percentage) depends on soft PE, while hardness and stain resistance (closely related to the paint film surface structure) depend on hard MM. The compounding ratio of the material was designed so that the MM bridge formation density is higher on the surface of paint film and lower inside the paint film, taking into account the reaction mechanism. Thus, the technology of densifying the MM surface has provided the excellent and unique performance for prepainted steel sheets. 5 refs., 6 figs., 4 tabs.

  16. Formaldehyde and TVOC emission behaviors according to finishing treatment with surface materials using 20 L chamber and FLEC.

    Science.gov (United States)

    Kim, Ki-Wook; Kim, Sumin; Kim, Hyun-Joong; Park, Jin Chul

    2010-05-15

    Formaldehyde and TVOC are emitted from wood-based panels that are made using wood particles, wood fiber, wood chips and formaldehyde-based resins. This study examined the formaldehyde and TVOC emission behavior of medium density fiberboard (MDF) overlaid with three types of uncoated lignocellulosic surface materials (oak decorative veneer, low pressure melamine impregnated paper and high pressure melamine impregnated paper) and four types of coated surface materials (coated paper, two types of finishing foils, and PVC) using the Field and Laboratory Emission Cell (FLEC) method and a 20 L small chamber method. The uncoated lignocellulosic surface materials exhibited lower formaldehyde and TVOC emission levels. The coated surface materials did not show reduced TVOC emissions but the formaldehyde emission was reduced in the 20 L small chamber test. In the FLEC test, both the uncoated lignocellulosic surface materials and coated surface materials showed lower TVOC and formaldehyde emissions from MDF. Copyright (c) 2009 Elsevier B.V. All rights reserved.

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

    OpenAIRE

    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

    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 ...

  18. Preparation and Characterizations of Composite Material Based on Carbon Fiber and Two Thermoset Resins

    Directory of Open Access Journals (Sweden)

    Fouda Hany

    2017-01-01

    Full Text Available In the present investigation, we used two types of thermoset resins (epoxy resin and phenol formaldehyde resin with carbon fiber (CF to produce composite materials. CF/epoxy resin composite and CF/phenolformaldhyde resin composite were fabricated and compared between their mechanical properties as compression, tension and flexural. it was found that mechanical properties of CF/epoxy composite higher than mechanical properties of CF/phenolformaldhyde resin composite such as flexural strength of CF/epoxy resin composite increased by 30 % than flexural strength of CF/phenolformaldhyde resin composite, tensile strength of CF/epoxy resin composite increased by 11.4 % than flexural strength of CF/phenolformaldhyde resin and axial compression strength of CF/epoxy resin composite increased by 14.5 % than flexural strength of CF/phenolformaldhyde resin.

  19. Effect of resin variables on the creep behavior of high density hardwood composite panels

    Science.gov (United States)

    R.C. Tang; Jianhua Pu; C.Y Hse

    1993-01-01

    The flexural creep behavior of oriented strandboards (OSB) fabricated with mixed high, density hardwood flakes was investigated. Three types of adhesives, liquid phenolic-formaldehyde (LPF), melamine modified urea-formaldehyde (MUF), and LPF (face)/MUF (core) were chosen in this investigation. The resin contents (RC) used were 3.5 percent and 5.0 percent. The flakes...

  20. The Effect of Nanoclay on Physicochemical, Mechanical and Thermal Properties of New Urea- Glyoxal Resin

    OpenAIRE

    hamed yonesi korekhili; reza naghdi; mojtaba amiri

    2015-01-01

    In order to eliminate the harm of formaldehyde from panels bonded with UF resin to environment and human health at the source, the low volatile and nontoxic aldehyde of glyoxyal (G) was chosen to react with urea (U) to prepare the wood adhesive of urea-glyoxal (UG) resin a substitute for urea-formaldehyde (UF) resin. The urea-glyoxal (UG) resin was synthesized under weak acid conditions, and its different properties were measured. Also, the effect of nanoclay on physico-chemical, thermal and ...

  1. Emission of formaldehyde from furniture

    DEFF Research Database (Denmark)

    Andersen, Helle Vibeke; Klinke, Helene B.; Funch, Lis Winther

    The emission of formaldehyde from 20 pieces of furniture, representing a variety of types, was measured in climate chambers. Most tests show low emissions but certain scenarios of furnishing, including furniture with large surface areas in relation to room volume can emit formaldehyde resulting...

  2. The effect of pheno-formaldehyde finishing on the properties of ...

    African Journals Online (AJOL)

    This paper examined the effect of catalyst concentration, curing time and temperature on a phenolformaldehyde finished direct dyed cotton. The grey cotton fabric was desized, scoured, bleached and dyed with chlorazol D, a direct dye. Sample of the dyed cotton were subjected to resin finishing using phenol: formaldehyde.

  3. EFFECT OF WOOD SPECIES USED FOR CORE LAYER ON SOME PROPERTIES OF OKUME PLYWOOD PANELS BONDED WITH MELAMINE-UREA FORMALDEHYDE (MUF ADHESIVE

    Directory of Open Access Journals (Sweden)

    Cenk Demirkır

    2005-04-01

    Full Text Available In this study; changes in some properties of the okume plywood panels when used alder and beech veneers in their core layers were investigated. Two types of melamine-urea formaldehyde (MUF resins having different free formaldehyde contents were used for bonding plywood panels manufactured from 2 mm thick veneers at industrial conditions. The formaldehyde emission values of plywood panels bonded with MÜF having higher free formaldehyde content were found to be higher than those of the panels bonded with other resin type. The highest formaldehyde emission value was found for the panels manufactured from okume veneers in all layers while the lowest value was determined from the panels include beech veneers in the core layer. The shear and bending strength values of the panels consisted of beech veneers in the core layer were found to be higher than those of the panels consisted of okume and alder veneers in the core layers.

  4. 78 FR 34795 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-06-10

    ... June 10, 2013 Part IV Environmental Protection Agency 40 CFR Part 770 Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products; Formaldehyde Emissions... Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products...

  5. 21 CFR 573.460 - Formaldehyde.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Formaldehyde. 573.460 Section 573.460 Food and... Listing § 573.460 Formaldehyde. The food additive formaldehyde may be safely used in the manufacture of.../federal_register/code_of_federal_regulations/ibr_locations.html. (ii) Formaldehyde (37 percent solution...

  6. Modified ion exchange resins - synthesis and properties. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Doescher, F.; Klein, J.; Pohl, F.; Widdecke, H.

    1982-01-22

    Sulfomethylated resins are prepared by polymer analogous reactions, starting from macroporous poly(styrene-co-divinylbenzene) matrices. Different reaction paths are discussed and used in the synthesis. Sulfomethylation can be achieved by reaction of a chloromethylated resin with dimethyl sulfide and sodium sulfonate or alternatively by oxidation of polymer-bound thiol groups. Both methods give high conversions as shown by IR spectra and titration of the sulfonic acid groups. Poly(1-(4-hydroxysulfomethylphenyl)ethylene) (3) is obtained by reaction of poly(1-(4-hydroxyphenyl)ethylene) (2) resin with formaldehyde/sodium sulfonate. The thermal stability, catalytic activity, and ion exchange equilibria of the sulfomethylated resin are investigated.

  7. Adsorbent for resorcinol removal based on cellulose functionalized with magnetic poly(dopamine).

    Science.gov (United States)

    Ding, Chaofan; Sun, Yuanling; Wang, Yanhui; Li, Jianbo; Lin, Yanna; Sun, Weiyan; Luo, Chuannan

    2017-06-01

    A simple chemical bonding method to synthesize magnetic cellulose-poly(dopamine) (Fe3O4@CMC@PDA) was reported. The adsorption behaviors of resorcinol in aqueous solution on Fe3O4@CMC@PDA were systematically investigated. As the results shown that, with the advantage of high surface area, abundant hydroxyl and amino groups of Fe3O4@CMC@PDA, and the magnetic property of Fe3O4, the resorcinol can be easily and rapidly extracted from the water by magnetic attraction under investigation. The adsorption equilibrium of Fe3O4@CMC@PDA for resorcinol corresponded with Freundlich isotherm, and the novel adsorbent exhibited better resorcinol removal efficiency in solutions with low pH. It was found that the resorcinol adsorption performance of Fe3O4@CMC@PDA strongly depends on their surface charge concentration and specific surface area. These results provide evidences for estimating and optimizing the removal of phenols from the wastewater by using of Fe3O4@CMC@PDA composites in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Catalytic process for formaldehyde oxidation

    Science.gov (United States)

    Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)

    1996-01-01

    Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  9. Formaldehyde Gas Sensors: A Review

    Directory of Open Access Journals (Sweden)

    Chia-Yen Lee

    2013-04-01

    Full Text Available Many methods based on spectrophotometric, fluorometric, piezoresistive, amperometric or conductive measurements have been proposed for detecting the concentration of formaldehyde in air. However, conventional formaldehyde measurement systems are bulky and expensive and require the services of highly-trained operators. Accordingly, the emergence of sophisticated technologies in recent years has prompted the development of many microscale gaseous formaldehyde detection systems. Besides their compact size, such devices have many other advantages over their macroscale counterparts, including a real-time response, a more straightforward operation, lower power consumption, and the potential for low-cost batch production. This paper commences by providing a high level overview of the formaldehyde gas sensing field and then describes some of the more significant real-time sensors presented in the literature over the past 10 years or so.

  10. Protect Against Exposure on Formaldehyde

    Science.gov (United States)

    Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes.

  11. Absorption of formaldehyde in water

    NARCIS (Netherlands)

    Winkelman, Jozef Gerhardus Maria

    2003-01-01

    Deze dissertatie beschrijft theoretisch en experimenteel werk aan de absorptie van formaldehyde in water. Met resultaten hiervan zijn chemisch-technische modellen ontwikkeld voor de beschrijving en optimalisatie van industriële formaldehydeabsorbeurs. Deze samenvatting geeft eerst algemene

  12. Compact, Ultrasensitive Formaldehyde Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase I proposal seeks to develop an ultrasensitive, laser-based formaldehyde gas sensor system for airborne and ground-based...

  13. [Determination of resorcinol and salicylic acid in piyanning tincture by high performance liquid chromatography].

    Science.gov (United States)

    Guo, X; Zhou, M

    1998-11-01

    A method for the simultaneous determination of resorcinol and salicylic acid in Piyanning tincture by HPLC has been proposed. Operating conditions were Hyppersil ODS column, 4.6 mm x 200 mm, V (methanol): V(water): V(acetic acid) = 50:50:0.9 mobile phase and UV detection at 285 nm. The linear ranges of the method were 0.05-0.25 g/L(r = 1.000) for resorcinol and 0.025-0.127 g/L(r = 1.000) for salicylic acid. The limits of detection were both 0.2 mg/L at a signal-to-noise of 3. The assay method was capable to resolve resorcinol and salicylic acid from their impurities.

  14. Induction of formaldehyde contact sensitivity

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Boman, A; Vølund, A

    1985-01-01

    The sensitizing potential of aqueous formaldehyde was evaluated with the guinea pig maximization test (GPMT) in two laboratories (Copenhagen and Stockholm) using different guinea pig strains. Six intradermal (0.01%-3%), and 6 topical (0.5%-20%) concentrations were used for induction, and formalde......The sensitizing potential of aqueous formaldehyde was evaluated with the guinea pig maximization test (GPMT) in two laboratories (Copenhagen and Stockholm) using different guinea pig strains. Six intradermal (0.01%-3%), and 6 topical (0.5%-20%) concentrations were used for induction......, and formaldehyde 1% and 0.1% was used for challenge. The incidence of contact sensitivity depended on the intradermal, but not on the topical induction dose. Statistical analyses showed a non-monotonous (non-linear) dose response relationship. The estimated maximal sensitization rate in Copenhagen was 80% after...... intradermal induction with 0.65% formaldehyde; in Stockholm it was 84% after induction with 0.34%. The data from the two laboratories could be described by parallel displaced dose response curves suggesting that the guinea pig strain used in Stockholm was significantly more susceptible to formaldehyde than...

  15. Dual Studies on a Hydrogen-Deuterium Exchange of Resorcinol and the Subsequent Kinetic Isotope Effect

    Science.gov (United States)

    Giles, Richard; Kim, Iris; Chao, Weyjuin Eric; Moore, Jennifer; Jung, Kyung Woon

    2014-01-01

    An efficient laboratory experiment has been developed for undergraduate students to conduct hydrogen-deuterium (H-D) exchange of resorcinol by electrophilic aromatic substitution using D[subscript 2]O and a catalytic amount of H[subscript 2]SO[subscript 4]. The resulting labeled product is characterized by [superscript 1]H NMR. Students also…

  16. Formaldehyde - An Assessment of its Health Effects.

    Science.gov (United States)

    1980-03-01

    formaldehyde mutagenesis has not been resolved. Formaldehyde may cause mutations by reacting directly with DNA ; by forming mutagenic products on...reaction with amino groups on simple amines, amino acids, nucleic acids, or proteins; or by oxidizing to peroxides that can react directly with DNA or...species of grasshoppers , formaldehyde caused chromosomal damage (Manna and Parida, 1967). Germinating barley seeds soaked in formaldehyde solutions did not

  17. The Effect of Nanoclay on Physicochemical, Mechanical and Thermal Properties of New Urea- Glyoxal Resin

    Directory of Open Access Journals (Sweden)

    hamed yonesi korekhili

    2015-05-01

    Full Text Available In order to eliminate the harm of formaldehyde from panels bonded with UF resin to environment and human health at the source, the low volatile and nontoxic aldehyde of glyoxyal (G was chosen to react with urea (U to prepare the wood adhesive of urea-glyoxal (UG resin a substitute for urea-formaldehyde (UF resin. The urea-glyoxal (UG resin was synthesized under weak acid conditions, and its different properties were measured. Also, the effect of nanoclay on physico-chemical, thermal and mechanical properties of UG resin was investigated. For this purpose, the prepared UG resin was mixed with 1, 2 and 3 wt% nanoclay by mechanically stirring for 5 min at room temperature. The physico-chemical properties (such as SPG, viscosity, solid content and gelation time and dry shear strength of the prepared resin were measured according to standard methods. Also, the effect of nanoclay on curing temperature of UG resin was analyzed by Differential Scanning Calorimetry (DSC device. The physico-chemical test results indicated that addition of nanoclay increased SPG, viscosity and solid content of UG resin and decreased gelation time in the prepared resin. Dry shear strength test results showed that increasing nanoclay content from 1 to 3 wt% increased shear strength of UG resin; as the panels containing 3% nanoclay exhibited the highest shear strength value and wood failure percentage. Based on DSC test results, hardening rate as well as enthalpy value of the prepared UG resin was decreased by addition of nanoclay.

  18. Quantitative determination of formaldehyde by spectrophotometry ...

    African Journals Online (AJOL)

    Formaldehyde is a vastly used material in industry. Nowadays, it is proven that formaldehyde is toxic and carcinogenic. Thus providing a reliable method for its quantitative determination is very important. This study proposes a UV-Vis spectrophotometric based method for determination of formaldehyde. The method is ...

  19. short communication quantitative determination of formaldehyde

    African Journals Online (AJOL)

    Preferred Customer

    INTRODUCTION. Formaldehyde is known as a very toxic, mutant and carcinogen causing chemical which affects ... Formaldehyde has been classified as one of the major pollutants due to its toxicity. It tends to .... The laboratory of the factory declared the concentration of the formaldehyde in wastewater equal to 1 mg/L.

  20. Biodegradation of phenol-formaldehyde resins modified with commercial lignins

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, M.; Nicolau, V. V. [Universidad Tecnologica Nacional (UTN), Cordoba (Argentina); Sponon, M.; Estenoz, D.A. [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC/UNL/CONICET), Santa Fe (Argentina)

    2014-07-01

    Full text: In this work the biodegradation of partially-modified resols with 10% w/w of sodium lignosulfonate and 10 and 20 % w/w of Kraft lignin type is studied. The experimental work involved preliminary studies of biodegradation in Petri dish (clear zones), the degradation of resols by enzymatic attack of Pseudomonas aeruginosa under aerobic conditions for a period of 200 days and the characterization of the polymers before and after biodegradation by FT-IR and RMN spectroscopy, gas chromatography (GC) and scanning electron microscopy (SEM). The number of viable cells showed a significant increase during the process. However, the gravimetric analysis was not sufficient to check the biodegradation. The results indicated that endocellular enzymes could be involved. It was observed that the presence of low concentrations of toxic substances released during degradation of the material may have inhibitory effects. Resoles were synthesized in Centro S. A. San Francisco Cordoba, Argentina. (author)

  1. Formaldehyde in cosmetics in patch tested dermatitis patients with and without contact allergy to formaldehyde.

    Science.gov (United States)

    Hauksson, Inese; Pontén, Ann; Isaksson, Marléne; Hamada, Haneen; Engfeldt, Malin; Bruze, Magnus

    2016-03-01

    Formaldehyde is a well-known contact sensitizer. Formaldehyde releasers are widely used preservatives in cosmetics. To survey the release of formaldehyde in cosmetics brought by patients investigated because of suspected allergic contact dermatitis, to compare it with information given by the manufacturers on the packages, and to investigate whether formaldehyde-allergic patients are potentially exposed to more cosmetics releasing formaldehyde than dermatitis patients without contact allergy to formaldehyde. Cosmetics from 10 formaldehyde-allergic and 30 non-allergic patients (controls) matched for age and sex were investigated with the chromotropic acid spot test, which is a semiquantitative method measuring the release of formaldehyde. Formaldehyde was found in 58 of 245 (23.7%) products. Twenty-six of 126 (20.6%) leave-on products released formaldehyde, and 17 of 26 (65.4%) of these were not declared to contain formaldehyde or formaldehyde releasers. Among the rinse-off products, there were 32 of 119 (26.8%) formaldehyde-releasing products, and nine of 32 (28.0%) of these were not labelled as containing formaldehyde or formaldehyde releasers. Five of 10 formaldehyde-allergic patients brought leave-on products with ≥ 40 ppm formaldehyde, as compared with 4 of 30 in the control group (p = 0.029). Cosmetic products used by formaldehyde-allergic patients that are not declared to contain formaldehyde or formaldehyde-releasing preservatives should be analysed. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Preformed amide-containing biopolymer for improving the environmental performance of synthesized urea–formaldehyde in agro-fiber composites

    Science.gov (United States)

    Altaf H. Basta; Houssni El-Saied; Jerrold E. Winandy; Ronald Sabo

    2011-01-01

    Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches. This study examines the role of adding amide-containing biopolymers during synthesis of urea–formaldehyde (UF) on properties of adhesive produced, especially its adhesion potential. The environmental performance of UF-resin synthesized in the...

  3. Effect of urea formaldehyde viscosity on urea formaldehyde and ...

    African Journals Online (AJOL)

    The melting point, refractive index, density and formaldehyde emission were found to increase with increase in UF viscosity while the dry time, moisture uptake and elongation at break were found to decrease with increase in viscosity. UF viscosity below 10.82 mPa.s was found to produce UF/UP copolymer composite which ...

  4. Does occupational exposure to formaldehyde cause hematotoxicity and leukemia-specific chromosome changes in cultured myeloid progenitor cells?

    Science.gov (United States)

    Mundt, Kenneth A; Gallagher, Alexa E; Dell, Linda D; Natelson, Ethan A; Boffetta, Paolo; Gentry, P Robinan

    2017-08-01

    Several cross-sectional studies of a single population of workers exposed to formaldehyde at one of two factories using or producing formaldehyde-melamine resins in China have concluded that formaldehyde exposure induces damage to hematopoietic cells that originate in the bone marrow. Moreover, the investigators interpret observed differences between groups as evidence that formaldehyde induces myeloid leukemias, although the mechanisms for inducing these diseases are not obvious and recently published scientific findings do not support causation. Our objective was to evaluate hematological parameters and aneuploidy in relation to quantitative exposure measures of formaldehyde. We obtained the study data for the original study (Zhang et al. 2010 ) and performed linear regression analyses. Results showed that differences in white blood cell, granulocyte, platelet, and red blood cell counts are not exposure dependent. Among formaldehyde-exposed workers, no association was observed between individual average formaldehyde exposure estimates and frequency of aneuploidy, suggested by the original study authors to be indicators of myeloid leukemia risk.

  5. [5-Alkyl(C19-C25) resorcinols as regulators of succinate and NAD-dependent substrate oxidation by mitochondria].

    Science.gov (United States)

    Nenashev, V A; Pridachina, N N; Pronevich, L A; Batrakov, S G

    1989-05-01

    The effect of 5-n-alkyl(C19-C25) resorcinols isolated from Azotobacter chroococcum on the oxidation of succinate and NAD-dependent substrates (glutamate, alpha-ketoglutarate, malate, pyruvate) by rat liver mitochondria was studied, using the polarographic technique. With succinate, the above resorcinol lipids activated to some extent the 2,4-dinitrophenol-decoupled mitochondrial respiration, but markedly suppressed it (up to 95%) in the presence of NAD-dependent substrates. The activating and inhibiting effects correlated with the resorcinol lipid/mitochondrial proteins ratio and were observed, when the lipid concentration in the incubation mixture ranged from 2.4.10(-4) to 6.0.10(-4) M. The most striking inhibiting effect was observed with alpha-ketoglutarate as substrate. The results obtained suggest that 5-n-alkyl(C19-C25) resorcinols should be regarded as rotenone type regulators of cell respiration.

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

    Science.gov (United States)

    Chum, Helena L.; Black, Stuart K.; Diebold, James P.; Kreibich, Roland E.

    1993-01-01

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

  7. Simultaneous preconcentration of vanadium(V/IV) species with palmitoyl quinolin-8-ol bonded to amberlite XAD 2 and their separate spectrophotometric determination with 4-(2-pyridylazo)-resorcinol using CDTA as masking agent

    Energy Technology Data Exchange (ETDEWEB)

    Filik, Hayati; Berker, Kadriye Isil; Balkis, Nuray; Apak, Resat

    2004-08-02

    This paper reports the simultaneous preconcentration and separation of trace amounts of V species in synthetic solutions and seawater with palmitoyl quinolin-8-ol bonded amberlite XAD 2 copolymer resin column prior to simultaneous speciation analysis. Both V(IV) and V(V) species could be sorbed and preconcentrated by the resin. Both vanadium species were quantitatively eluted together from the resin column using HCl as stripping agent and used for speciation studies. For the speciation analysis of eluted V species, the selected route involved spectrophotometric determination of total vanadium with 4-(2-pyridylazo)-resorcinol (PAR) and vanadate estimation by masking vanadyl with 1,2 cyclohexanediaminetetraacetic acid (CDTA). The preconcentrated V species were assayed spectrophotometrically with PAR at 542 nm, and the results were compared with those of FAAS. The detection limits of V(V) with spectrophotometry and FAAS were 1.6 and 0.9 {mu}g l{sup -1}, respectively. The optimal experimental parameters such as pH, sample flow rate, desorption flow rate, redox behaviour of V(IV) and V(V) in resin and volume of eluent and sample were investigated. The values obtained for the preconcentration factor by the two methods were nearly consistent, and were in the range 150-fold. Analysis of certified reference material (IAEA-405) by the proposed method showed good agreement with the certified value. The established procedure was employed for preconcentrating the vanadium species from artificial and real seawater.

  8. Respiratory symptoms and functional impairments induced by occupational exposure to formaldehyde

    Directory of Open Access Journals (Sweden)

    AR Choobineh

    2010-07-01

    Full Text Available Background and aimsThe main purpose of this study was to assess the acute and chronic effects of occupational exposure to low levels of formaldehyde on respiratory health.MethodsThis historical cohort study was conducted at a local melamine-formaldehyde resin producing plant. The study population consisted of seventy exposed and 24 non-exposed (referent employees. In this study, a questionnaire was used to evaluate and determined the prevalence of respiratory symptoms. Atmospheric concentrations of formaldehyde were measured at different areas of the plant. Similarly, using a spirometer, the parameters of pulmonary function were measured during exposure and a few days after exposure ceased.ResultsAtmospheric concentrations of formaldehyde marginally exceeded current permissible levels. Additionally, significant decrements in some parameters of pulmonary function, both during and after exposure were noted. However, a relative recovery in lungfunctional capacity observed following temporary cessation of exposure. Furthermore, exposed workers had higher prevalencerates of regular cough, wheezing, phlegm, shortness of breath, chest tightness and episodes of chest illness associated with cold.ConclusionThe findings of this study indicate that exposure to formaldehyde may induce respiratory symptoms, acute partially reversible and chronic irreversible functional impairments of the lungs.

  9. Plastic casting resin poisoning

    Science.gov (United States)

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  10. Potato aphid salivary proteome: enhanced salivation using resorcinol and identification of aphid phosphoproteins.

    Science.gov (United States)

    Chaudhary, Ritu; Atamian, Hagop S; Shen, Zhouxin; Briggs, Steven P; Kaloshian, Isgouhi

    2015-04-03

    Aphids deliver saliva into plants and acquire plant sap for their nourishment using a specialized mouthpart or stylets. Aphid saliva is of great importance because it contains effectors that are involved in modulating host defense and metabolism. Although profiling aphid salivary glands and identifying secreted proteins have been successfully used, success in direct profiling of aphid saliva have been limited due to scarcity of saliva collected in artificial diets. Here we present the use of a neurostimulant, resorcinol, for inducing aphid salivation. Saliva of potato aphids (Macrosiphum euphorbiae), maintained on tomato, was collected in resorcinol diet. Salivary proteins were identified using mass spectrometry and compared with the existing M. euphorbiae salivary proteome collected in water. Comparative analysis was also performed with existing salivary proteomes from additional aphid species. Most of the proteins identified in the resorcinol diet were also present in the water diet and represented proteins with a plethora of functions in addition to a large number of unknowns. About half of the salivary proteins were not predicted for secretion or had canonical secretion signal peptides. We also analyzed the phosphorylation states of M. euphorbiae salivary proteins and identified three known aphid effectors, Me_WB01635/Mp1, Me10/Mp58, and Me23 that carry phosphorylation marks. In addition to insect proteins, tomato host proteins were also identified in aphid saliva. Our results indicate that aphid saliva is complex and provides a rich resource for functional characterization of effectors.

  11. Adsorptive removal of aniline by granular activated carbon from aqueous solutions with catechol and resorcinol.

    Science.gov (United States)

    Suresh, S; Srivastava, V C; Mishrab, I M

    2012-01-01

    In the present paper, the removal of aniline by adsorption process onto granular activated carbon (GAC) is reported from aqueous solutions containing catechol and resorcinol separately. The Taguchi experimental design was applied to study the effect of such parameters as the initial component concentrations (C(0,i)) of two solutes (aniline and catechol or aniline and resorcinol) in the solution, temperature (T), adsorbent dosage (m) and contact time (t). The L27 orthogonal array consisting of five parameters each with three levels was used to determine the total amount of solutes adsorbed on GAC (q(tot), mmol/g) and the signal-to-noise ratio. The analysis of variance (ANOVA) was used to determine the optimum conditions. Under these conditions, the ANOVA shows that m is the most important parameter in the adsorption process. The most favourable levels of process parameters were T = 303 K, m = 10 g/l and t = 660 min for both the systems, qtot values in the confirmation experiments carried out at optimum conditions were 0.73 and 0.95 mmol/g for aniline-catechol and aniline-resorcinol systems, respectively.

  12. Co-degradation of resorcinol and catechol in an UASB reactor.

    Science.gov (United States)

    Subramanyam, Revanuru; Mishra, I M

    2008-07-01

    Co-degradation of resorcinol and catechol was studied in a catechol acclimated up flow anaerobic sludge blanket (UASB) reactor. Synthetic binary aqueous solution having a total concentration of 1000 mg/L with the resorcinol/catechol (R/C) ratio of 1/19, 1/9, 3/17, 1/4, 1/3, 3/7, 2/3 and then 1/3 was fed at various time intervals to the UASB reactor with a fixed organic loading rate of 5.7 kg COD/m(3) d and hydraulic retention time of 8h. The reactor was operated over a period of 145 days after its acclimation with catechol bearing synthetic wastewater at a constant feed rate of 1.2 L/h. When the resorcinol concentration was increased to have a R/C ratio of 1/4, the COD removal efficiency and the biogas production increased to the maximum levels. Pseudo steady state condition for COD removal was achieved at each of the stepped-up loading condition. An increase in the R/C ratio above 1/4 in the binary feed solution led to a decrease in the COD removal efficiency and the biogas production rate.

  13. Resin composites

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  14. ALLERGIC CONTACT DERMATITIS FROM FORMALDEHYDE EXPOSURE.

    Directory of Open Access Journals (Sweden)

    Maya Lyapina

    2012-10-01

    Full Text Available Formaldehyde is a ubiquitous chemical agent, a part of our outdoor and indoor working and residential environment. Healthcare workers in difficult occupations are among the most affected by formaldehyde exposure. Formaldehyde is an ingredient of some dental materials. Formaldehyde is well-known mucous membrane irritant and a primary skin sensitizing agent associated with both contact dermatitis (Type IV allergy, and immediate, anaphylactic reactions (Type I allergy. Inhalation exposure to formaldehyde was identified as a potential cause of asthma. Quite a few investigations are available concerning health issues for dental students following formaldehyde exposure. Such studies would be beneficial for early diagnosis of hypersensitivity, adequate prophylactic, risk assessment and management of their work.

  15. An eco-friendly synthesis, characterization, morphology and ion exchange properties of terpolymer resin derived from p-hydroxybenzaldehyde

    OpenAIRE

    Patle, Deepti B.; Gurnule, Wasudeo B.

    2016-01-01

    A novel chelating terpolymer resin has been synthesized through the terpolymerization of p-hydroxybenzaldehyde and biuret with formaldehyde (p-HBBF) in 1:1:2 mol ratio using hydrochloric acid as a reaction medium by condensation technique. The synthesized terpolymer resin was characterized by elemental analysis, FTIR, 1H NMR and 13C NMR spectroscopy. On basis of the spectral studies, the structure of the terpolymer resin was proposed. The physico-chemical parameters have been evaluated for th...

  16. 78 FR 51696 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-08-21

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ44 Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products; Extension of Comment Period AGENCY: Environmental... formaldehyde standards for composite wood products. After receiving requests for an extension, EPA extended the...

  17. 78 FR 44090 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-07-23

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ44 Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products; Extension of Comment Period AGENCY: Environmental... formaldehyde standards for composite wood products. This document extends the comment period from August 9...

  18. Initial inventory of alternatives to biocidal products containing formaldehyde of formaldehyde releasers

    NARCIS (Netherlands)

    Wezenbeek JM; Janssen MPM; Scheepmaker JWA; MSP; M&V

    2015-01-01

    Formaldehyde is de werkzame stof in veel desinfecteer- en conserveringsmiddelen, maar deze stof is kankerverwekkend. Daarom zal formaldehyde naar verwachting per 1 januari 2016 op Europees niveau als zodanig worden geclassificeerd (carcinogeen 1B). Dit kan betekenen dat formaldehyde-houdende

  19. TECHNICAL COMPARISON OF CANDIDATE ION EXCHANGE MEDIA FOR SMALL COLUMN ION EXCHANGE (SCIX) APPLICATIONS IN SUPPORT OF SUPPLEMENTAL LAW PRETREATMENT

    Energy Technology Data Exchange (ETDEWEB)

    RAMSEY AA; THORSON MR

    2010-12-28

    At-tank supplemental pretreatment including both filtration and small column ion exchange is currently under evaluation to facilitate salt waste retrieval and processing in the Hanford tank farms. Spherical resorcinol formaldehyde (sRF) resin is the baseline ion exchange resin for use in the Waste Treatment and Immobilization Plant (WTP). This document provides background and technical rationale to assist in determining whether spherical resorcinol formaldehyde (sRF) is also the appropriate ion exchange resin for supplemental LAW pretreatment processes and compares sRF with crystalline silicotitanate (CST) as potential supplemental pretreatment ion exchange media.

  20. PERFORMANCE OF MUF RESINS FOR PARTICLEBOARDS BEFORE AND AFTER SPRAY-DRYING

    Directory of Open Access Journals (Sweden)

    Antonio PIZZI

    2012-12-01

    Full Text Available Melamine-urea-formaldehyde (MUF resins can be spray dried to obtain resins in powder form and indefinite shelf-life. Application as particleboard adhesives of such resins after redissolving them in water does yield resins of excellent performance as particleboard adhesives if the natural advancement caused by the heat in the spray-drier chamber is taken into account. CP MAS 13C NMR analysis of the spray-dried resin in powder form and thermomechanical analysis has shown some difference in behaviour in relation to MUF resins of the same level of water tolerance which have not been spray-dried. These small but significant differences can be ascribed to differences in resin structure.

  1. Formaldehyde-releasers in cosmetics: relationship to formaldehyde contact allergy. Part 2. Patch test relationship to formaldehyde contact allergy, experimental provocation tests, amount of formaldehyde released, and assessment of risk to consumers allergic to formaldehyde.

    Science.gov (United States)

    de Groot, Anton; White, Ian R; Flyvholm, Mari-Ann; Lensen, Gerda; Coenraads, Pieter-Jan

    2010-01-01

    This is the second part of an article on formaldehyde-releasers in cosmetics. The patch test relationship between the releasers in cosmetics to formaldehyde contact allergy is reviewed and it is assessed whether products preserved with formaldehyde-releasers may contain enough free formaldehyde to pose a threat to individuals with contact allergy to formaldehyde. There is a clear relationship between positive patch test reactions to formaldehyde-releasers and formaldehyde contact allergy: 15% of all reactions to 2-bromo-2-nitropropane-1,3-diol and 40-60% of the reactions to the other releasers are caused by a reaction to the formaldehyde in the test material. There is only fragmented data on the amount of free formaldehyde in cosmetics preserved with formaldehyde donors. However, all releasers (with the exception of 2-bromo-2-nitropropane-1,3-diol, for which adequate data are lacking) can, in the right circumstances of concentration and product composition, release >200 p.p.m. formaldehyde, which may result in allergic contact dermatitis. Whether this is actually the case in any particular product cannot be determined from the ingredient labelling. Therefore, we recommend advising patients allergic to formaldehyde to avoid leave-on cosmetics preserved with quaternium-15, diazolidinyl urea, DMDM hydantoin, or imidazolidinyl urea, acknowledging that many would tolerate some products.

  2. Formaldehyde Emissions from Urea-Formaldehyde- and no-added-formaldehyde-Bonded particleboard as Influenced by Temperature and Relative Humidity

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Timothy L. Chaffee; Kyle M. Gonner

    2012-01-01

    It is well documented that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF)–type adhesives. This work investigates the effect of temperature and humidity on newer commercial California Air Resources Board (CARB) phase II–compliant particleboard produced with UF-type adhesives. These...

  3. Measurement of formaldehyde concentrations in a subatmospheric steam-formaldehyde autoclave.

    Science.gov (United States)

    Marcos, D; Wiseman, D

    1979-01-01

    A method has been developed for measuring formaldehyde concentrations in a subatmospheric steam-formaldehyde autoclave. Data obtained using this method indicate that the concentration of formaldehyde in the chamber atmosphere is not homogeneous and that it decreases rapidly with time. The penetration of formaldehyde vapour into narrow tubes has also been investigated and was shown to be dependent on the length-to-bore ratio of the tubes. The formaldehyde concentration within the tubes could be increased by using a lower vacuum in the air removal stage at the beginning of the cycle. PMID:572833

  4. Environment-friendly adhesives for surface bonding of wood-based flooring using natural tannin to reduce formaldehyde and TVOC emission.

    Science.gov (United States)

    Kim, Sumin

    2009-01-01

    The objective of this research was to develop environment-friendly adhesives for face fancy veneer bonding of engineered flooring using the natural tannin form bark in the wood. The natural wattle tannin adhesive were used to replace UF resin in the formaldehyde-based resin system in order to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. PVAc was added to the natural tannin adhesive to increase viscosity of tannin adhesive for surface bonding. For tannin/PVAc hybrid adhesives, 5%, 10%, 20% and 30% of PVAc to the natural tannin adhesives were added. tannin/PVAc hybrid adhesives showed better bonding than the commercial natural tannin adhesive with a higher level of wood penetration. The initial adhesion strength was sufficient to be maintained within the optimum initial tack range. The standard formaldehyde emission test (desiccator method), field and laboratory emission cell (FLEC) and VOC analyzer were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with commercial the natural tannin adhesive and tannin/PVAc hybrid adhesives. By desiccator method and FLEC, the formaldehyde emission level of each adhesive showed the similar tendency. All adhesives satisfied the E(1) grade (below 1.5 mg/L) and E(0) grade (below 0.5 mg/L) with UV coating. VOC emission results by FLEC and VOC analyzer were different with the formaldehyde emission results. TVOC emission was slightly increased as adding PVAc.

  5. 7746 CONCENTRATIONS OF FORMALDEHYDE IN RAIN WATERS ...

    African Journals Online (AJOL)

    Win7Ent

    2013-06-03

    Jun 3, 2013 ... populace of the area of study. The chromotropic acid method described by the. National Institute for Occupational Safety and Health (NIOSH) was adopted for the determination of formaldehyde in the rain waters. Results indicated that the concentration range of the formaldehyde in the rain waters varied ...

  6. 29 CFR 1915.1048 - Formaldehyde.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical to...

  7. 29 CFR 1926.1148 - Formaldehyde.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148 Formaldehyde...

  8. Formaldehyde concentration in diagnostic patch testing

    DEFF Research Database (Denmark)

    Trattner, A; Johansen, J D; Menné, T

    1998-01-01

    Exposure to formaldehyde is common from both consumer products and industry. The reliability of the patch test is essential for the diagnosis of formaldehyde allergy as it is difficult to suspect from the patient's history. The recommended formaldehyde patch test concentration has been reduced over...... the last decades from 4-5% to 2% and is currently 1%. The changes have not been based upon formal studies, but driven by an intention to reduce irritancy and false-positive results. The aim of the present study was prospectively to compare the outcome of simultaneous testing with formaldehyde 1% and 2......% in consecutively patch-tested patients, with respect to frequency of positive patch test reactions, strength of patch test reactions to different formaldehyde test concentrations, irritancy and relevance. The study included 3734 consecutively patch tested patients. 121 gave a positive reaction to 1% and/or 2...

  9. Preliminary survey report: control technology for formaldehyde emissions at Hoosier Panel, New Albany, Indiana

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, V.D.

    1982-12-01

    An onsite visit was made to the Hoosier Panel Company, New Albany, Indiana to observe processes and controls in the veneering of wood panels. Most of the bonding of the veneer to the core was accomplished through use of a urea/formaldehyde resin and a hot press method. Some work was done using a cold-press process in which the glue was heated with radio-frequency radiation. Banding of the core with solid-wood edges prior to veneering also used an adhesive that may contain formaldehyde. At least five different recipes were used for panel glue, all of which involve the Perkins L-100 urea/formaldehyde resin. A canopy hood was installed over each press. There were six wall fans in the plate cooling rooms. Airflow across the glue room was also aided by auxiliary fans. Routine air sampling was not performed. A safety committee inspected the site monthly. The local exhaust ventilation hoods had an insufficient flow rate to capture vapors beyond the boundary of the canopy openings. The facility offered a unique approach to caul plate cooling which also provided a large quantity of the general ventilation airflow. The author recommends that the auxiliary fans might be better positioned to contribute more effectively to controlling exposures.

  10. Preliminary survey report: control technology for formaldehyde emissions at Jasper Laminates, Jasper, Indiana, October 19, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, V.D.

    1983-07-29

    An onsite visit was made to Jasper Laminates, Jasper, Indiana to observe the processes used in veneering wood panels by a heater platen press method, and methods of controlling formaldehyde emissions. The facility produced panels for pianos, organs, office furniture and other wood products, using primarily the hot press process along with some radiofrequency (RF) pressing of curved panels and small parts. The glue most often used was a urea/formaldehyde resin adhesive. The hot presses were located under one large ventilated enclosure, measuring about 20 by 150 feet. There were also eight ventilation fans in the ceiling and auxiliary fans used to provide additional cooling air for workers and for the caul plates. Therefore, the primary methods of controlling formaldehyde exposure were dispersion, using auxiliary fans, and area ventilation. No partial-shift-time weighted-average formaldehyde concentrations were measured at over 1 part per million (ppm). For two workers unloading different hot presses, short-term breathing-zone concentrations occasionally reached 2 ppm. The author concludes that this facility offers the opportunity to study large-scale area ventilation with passive make-up air supply, and the appropriate use of auxiliary fans.

  11. Effects of free formaldehyde emission reduction by ammonia fuming ...

    African Journals Online (AJOL)

    Particleboards made using formaldehyde adhesives cause substantial emission of free formaldehyde over time. Free formaldehyde is harmful to the user's health and it also weakens internal bonds of particleboards in use. Emissions levels of formaldehyde lie between 0.8 to 2.2 g/m3 of indoor air in particleboards ...

  12. The Effect of Formaldehyde Fixation on RNA

    Science.gov (United States)

    Evers, David L.; Fowler, Carol B.; Cunningham, Brady R.; Mason, Jeffrey T.; O'Leary, Timothy J.

    2011-01-01

    Formalin-fixed, paraffin-embedded tissues generally provide low yields of extractable RNA that exhibit both covalent modification of nucleic acid bases and strand cleavage. This frustrates efforts to perform retrospective analyses of gene expression using archival tissue specimens. A variety of conditions have been reported to demodify formaldehyde-fixed RNA in different model systems. We studied the reversal of formaldehyde fixation of RNA using a 50 base RNA oligonucleotide and total cellular RNA. Formaldehyde-adducted, native, and hydrolyzed RNA species were identified by their bioanalyzer electrophoretic migration patterns and RT–quantitative PCR. Demodification conditions included temperature, time, buffer, and pH. The reversal of formaldehyde-fixed RNA to native species without apparent RNA hydrolysis was most successfully performed in dilute Tris, phosphate, or similar buffers (pH 8) at 70°C for 30 minutes. Amines were not required for efficient formaldehyde demodification. Formaldehyde-fixed RNA was more labile than native RNA to treatment with heat and buffer, suggesting that antigen retrieval methods for proteins may impede RNA hybridization or RNA extraction. Taken together, the data indicate that reliable conditions may be used to remove formaldehyde adducts from RNA to improve the quality of RNA available for molecular studies. PMID:21497290

  13. Study of a composite from reactive blending of methylol urea resin ...

    African Journals Online (AJOL)

    GREGO

    2007-03-19

    Mar 19, 2007 ... natural rubber (NR) with starch and studied both rheo- logical and curing ... sodium hydroxide pellets and sucrose were reagent grades products ... Resin synthesis. Trimethylol urea was prepared by reacting one mole (6.0 g) of urea with three moles (24.3 ml) of 37% (w/v) formaldehyde. Sodium dihydrogen ...

  14. Study of a composite from reactive blending of methylol urea resin ...

    African Journals Online (AJOL)

    This study was designed to study some physical properties of a composite derivable from reactive blending of methylol urea resin (MUR) with natural rubber (NR). Formaldehyde emission, decreased with increase in NR concentration in the blend. Elongation at break and viscosity recorded an initial increase but gradually ...

  15. Wet air oxidation of resorcinol as a model treatment for refractory organics in wastewaters from the wood processing industry.

    Science.gov (United States)

    Weber, Bernd; Chavez, Alma; Morales-Mejia, Julio; Eichenauer, Sabrina; Stadlbauer, Ernst A; Almanza, Rafael

    2015-09-15

    Wastewater treatment systems are important tools to enhance sustainability in terms of reducing environmental impact and complying with sanitary requirements. This work addresses the wet air oxidation (WAO) process for pre-treatment of phenolic wastewater effluents. The aim was to increase biodegradability prior to a subsequent anaerobic stage. In WAO laboratory experiments using a micro-autoclave, the model compound resorcinol was degraded under different oxygen availability regims within the temperature range 150 °C-270 °C. The activation energy was determined to be 51.5 kJ/mol. Analysis of the products revealed that after 3 h of reaction at 230 °C, 97.5% degradation of resorcinol was achieved. At 250 °C and the same reaction time complete removal of resorcinol was observed. In this case the total organic carbon content was reduced down to 29%, from 118.0 mg/L down to 34.4 mg/L. Under these process conditions, the pollutant was only partially mineralized and the ratio of the biological oxygen demand relative to the chemical oxygen demand, which is 0.07 for resorcinol, was increased to a value exceeding 0.5. The main by-product acetic acid, which is a preferred compound for methanogenic bacteria, was found to account for 33% of the total organic carbon. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Artificial neural network modeling in competitive adsorption of phenol and resorcinol from water environment using some carbonaceous adsorbents.

    Science.gov (United States)

    Aghav, R M; Kumar, Sunil; Mukherjee, S N

    2011-04-15

    This paper illustrates the application of artificial neural network (ANN) for prediction of performances in competitive adsorption of phenol and resorcinol from aqueous solution by conventional and low cost carbonaceous adsorbent materials, such as activated carbon (AC), wood charcoal (WC) and rice husk ash (RHA). The three layer's feed forward neural network with back propagation algorithm in MATLAB environment was used for estimation of removal efficiencies of phenol and resorcinol in bi-solute water environment based on 29 sets of laboratory batch study results. The input parameters used for training of the neural network include amount of adsorbent (g/L), initial concentrations of phenol (mg/L) and resorcinol (mg/L), contact time (h), and pH. The removal efficiencies of phenol and resorcinol were considered as an output of the neural network. The performances of the developed ANN models were also measured using statistical parameters, such as mean error, mean square error, root mean square error, and linear regression. The comparison of the removal efficiencies of pollutants using ANN model and experimental results showed that ANN modeling in competitive adsorption of phenolic compounds reasonably corroborated with the experimental results. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Formaldehyde's Impact on Indoor Air Quality

    Science.gov (United States)

    Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes.

  18. Formaldehyde-releasers : relationship to formaldehyde contact allergy. Metalworking fluids and remainder. Part 1

    NARCIS (Netherlands)

    de Groot, A.C.; Le Coz, C.J.; Lensen, G.J.; Flyvholm, M.A.; Maibach, H.I.; Coenraads, P.J.

    2010-01-01

    This is the second part of a review article on formaldehyde-releasers used as durable press chemical finishes (DPCF) in textiles. The early finishes contained large amounts of free formaldehyde, which led to many cases of allergic contact dermatitis to clothes in the 1950s and 1960s. Currently, most

  19. Preservatives in cosmetics: reactivity of allergenic formaldehyde-releasers towards amino acids through breakdown products other than formaldehyde.

    Science.gov (United States)

    Kireche, Mustapha; Gimenez-Arnau, Elena; Lepoittevin, Jean-Pierre

    2010-10-01

    Compounds slowly releasing formaldehyde, the so-called formaldehyde-releasers, are commonly employed as preservatives in cosmetics instead of free formaldehyde, which is a strong skin sensitizer. It has been long accepted that formaldehyde-releaser sensitization is attributable to released formaldehyde. However, clinical studies show the existence of patients allergic to formaldehyde-releasers but not to formaldehyde itself. To prove that, for certain formaldehyde-releasers, reactive intermediates other than formaldehyde could be involved in the formation of the hapten-protein antigenic complex, a key step of the sensitization process, thus explaining their sensitizing potential. DMDM hydantoin, 2-bromo-2-nitropropane-1,3-diol and methenamine were synthesized, (13) C-labelled at the position(s) precursor of formaldehyde. Their reactivity towards amino acids was followed by one-dimensional and two-dimensional (13) C-nuclear magnetic resonance. Many adducts formed by reacting formaldehyde-releasers with amino acids resulted from a direct interaction of the releaser or from reaction of a breakdown product, and not from a reaction involving simply released formaldehyde. DMDM hydantoin was reactive per se, and 2-bromo-2-nitropropane-1,3-diol and methenamine decomposed in water, producing bromoethanol and diaminomethane, respectively, which were reactive towards some of the amino acids tested. The reactivity of distinctive formaldehyde-releasers towards amino acids is not limited to formaldehyde release. © 2010 John Wiley & Sons A/S.

  20. Penetration of urea-formaldehyde adhesives in wood tissue, part I: Radial penetration of UF adhesives into beech

    Directory of Open Access Journals (Sweden)

    Gavrilović-Grmuša Ivana

    2008-01-01

    Full Text Available Adhesive penetration plays an important role in wood adhesion, since wood is a porous material. The degree of penetration mostly depends on the wood factors, resin type and formulation and processing parameters. Tangentially cut 5 mm thick beech wood (Fagus moesiaca plies, 100 mm long (parallel to grain and 30 mm wide, were prepared for this study. The urea-formaldehyde (UF adhesive was applied to the surface of one ply. Two plies were assembled into sample so that the grains of two plies were parallel. Samples were pressed in a hydraulic press at 120°C and 0,7 MPa for 15 min. Microtome test-specimens were cut of each sample. 20 μm thick microtomes were cut by sliding microtome apparatus, exposing a bondline with a cross-sectional surface. The lack of more exhausting research on the penetration of urea-formaldehyde adhesives in wood is evident. Since ureaformaldehyde (UF glue resins were the most important type of adhesives in the wood industry in the last 60 years (Dunky, 2000, the objective of this research was microscopic detection of UF adhesive penetration in wood tissue. Four types of UF resins with different levels of polycondensation were used in this research. Safranin was added in resins, since epi-fluorescence microscope was used in this research for measuring the adhesive penetration.

  1. Evidence for chemical and cellular reactivities of the formaldehyde releaser bronopol, independent of formaldehyde release.

    Science.gov (United States)

    Kireche, Mustapha; Peiffer, Jean-Luc; Antonios, Diane; Fabre, Isabelle; Giménez-Arnau, Elena; Pallardy, Marc; Lepoittevin, Jean-Pierre; Ourlin, Jean-Claude

    2011-12-19

    Formaldehyde and formaldehyde releasers are widely used preservatives and represent an important group of skin sensitizers. Formaldehyde is very often suspected to be the sensitizing agent of formaldehyde-releasers; however, many reported clinical cases of contact allergy to these molecules such as bronopol (2-bromo-2-nitropropane-1,3-diol) indicate negative skin reactions to formaldehyde suggesting a more complex mechanism. The aim of this study was to compare the chemical reactivity and biological activity of formaldehyde with those of two formaldehyde releasers: 2-bromo-2-nitropropane-1,3-diol and 1,3-dimethylol-5,5-dimethylhydantoin. A key step in the sensitization to chemicals is the formation of the hapten-protein antigenic complex via covalent binding between the chemical sensitizer and amino acids in proteins. The chemical reactivity of the three compounds was thus addressed using (13)C NMR analysis of adduct formation upon incubation with a set of nucleophilic amino acids. The biological activity was measured in two in vitro models based on dendritic cells and a monocytic cell line (CD34-DC and THP-1 model) through monitoring of a panel of biomarkers. The results obtained show that 2-bromo-2-nitropropane-1,3-diol produces low amount of free formaldehyde in physiological buffers but that its degradation generates various molecules including 2-bromoethanol. In addition, 2-bromo-2-nitropropane-1,3-diol also generates adducts with amino acids, not observed with formaldehyde alone, that could be explained by the reactivity of 2-bromoethanol. In parallel, in a cellular approach using the human monocytic THP-1 cell line, 2-bromo-2-nitropropane-1,3-diol activates THP-1 cells at concentrations that are not correlated to simple formaldehyde release. This observation is confirmed in the more physiological model CD34-DC. Moreover, in the THP-1 model, the expression profiles of several biomarkers are specific to 2-bromo-2-nitropropane-1,3-diol. Finally, the use in the

  2. MD simulation analysis of resin filling into nano-sized pore formed on metal surface

    Science.gov (United States)

    Mori, Hodaka; Matubayasi, Nobuyuki

    2018-01-01

    All-atom MD simulation was conducted for the filling of epoxy resin into a nano-sized pore formed on aluminum surface. The resin species examined were polyphenol mixed with polyglycidylether of o-cresol formaldehyde novolac and their oligomers formed through ring-opening reactions. The degree of oligomerization was varied from 0.5 to 2.5 nm in terms of the radius of gyration, and the radius of the cylindrical pore was fixed at 2.5 nm. It was observed that a small resin penetrates into the pore along the wall, while larger resins move rather uniformly in the pore. The maximum density in the pore achieved with pushing was then seen to be larger when the resin is smaller. It was found that when the radius of gyration of resin is larger than half the pore radius, the resin density in the pore does not reach half the bulk density of the resin. This implies that the resin-resin interaction inhibits the filling of the nano-sized pore.

  3. Research on testing method of resin sand high temperature compressive strength

    Directory of Open Access Journals (Sweden)

    Peng Wan

    2016-09-01

    Full Text Available High temperature compressive strength is one of the most important performances of resin sand; its value directly concerns the quality of castings. In order to seek the best testing method of resin sand high temperature compressive strength, a self-developed instrument was used to carry out experiments, and the sample shape and size were designed and studied. The results show that a hollow cylinder sample can reflect the strength difference of different resin sands better than a solid cylinder sample, and its data is stable. The experiments selected フ20/5】30 mm as the size of the hollow cylinder samples. The high temperature compressive strengths of phenol-formaldehyde resin coated sand, furan resin self-setting sand, and TEA resin sand were each tested. For the resin sand used for cast steel and cast iron, 1,000 ìC was selected as the test temperature; for the resin sand used for cast non-ferrous alloy, 800 ìC was selected as the test temperature; and for all the resin sand samples, 1 min was selected as the holding time. This testing method can truthfully reflect the high temperature performance of three kinds of resin sand; it is reproducible, and the variation coefficients of test values are under 10%.

  4. In vitro study on cytotoxicity and intracellular formaldehyde concentration changes after exposure to formaldehyde and its derivatives.

    Science.gov (United States)

    Ke, Y J; Qin, X D; Zhang, Y C; Li, H; Li, R; Yuan, J L; Yang, X; Ding, S M

    2014-08-01

    HeLa cells were exposed to formaldehyde and its metabolic derivatives, methanol, formic acid, and acetaldehyde, to investigate that the toxicity of formaldehyde is not caused by the chemical group. After 1 h of treatment with formaldehyde, mitochondrial assays showed that low concentrations (e.g. 10 μmol/L) of formaldehyde promoted growth of the HeLa cells, while higher concentrations (e.g. ≥62.5 μmol/L) inhibited cell growth; while all four chemicals at a concentration of 125 μmol/L affected cell growth, formaldehyde affected the largest. Reactive oxygen species concentration increased with the concentration of the exposure chemical. The endogenous formaldehyde content increased the most in the formaldehyde group, but in other three groups, it did not increase as the exposure concentration increased. Expression of dehydrogenase (formaldehyde dehydrogenase (FDH)) in the formaldehyde (10.40) and methanol (10.60) groups increased significantly compared with the control (1), while it was similar to the control in formic acid (0.90) and acetaldehyde (1.10) groups. Our results suggest that formaldehyde could affect cell activity and even enter cells. Exposure to formaldehyde changes the endogenous formaldehyde concentration in cells within 24 h, and this induces expression of FDH for formaldehyde degradation to maintain the formaldehyde balance. The toxicity of formaldehyde is not caused by the carbon atoms in the aldehyde, hydroxyl, or carboxyl groups. Formaldehyde is hypothesized to be an important signaling molecule in the regulation of cell growth and maintenance of the endogenous formaldehyde level. © The Author(s) 2014.

  5. the histological effects of formaldehyde vapour on the lungs

    African Journals Online (AJOL)

    Uwaifoh

    2012-12-31

    Dec 31, 2012 ... lung injury, pulmonary fibrosis, bronchiolar epithelia degeneration, acute purulent bronchitis, cellular pyknosis and chronic lungs injury. Thus, 40% formaldehyde inhalation can induce lungs injury and possibly lung tumors. Keywords: Formaldehyde, Inhalation, Pulmonary histology, Lung injury.

  6. Synthesis of a boron modified phenolic resin

    Directory of Open Access Journals (Sweden)

    Aparecida M. Kawamoto

    2010-08-01

    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 ˉ¹ 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.

  7. Electrochemical Oxidation of Resorcinol in Aqueous Medium Using Boron-Doped Diamond Anode: Reaction Kinetics and Process Optimization with Response Surface Methodology.

    Science.gov (United States)

    Körbahti, Bahadır K; Demirbüken, Pelin

    2017-01-01

    Electrochemical oxidation of resorcinol in aqueous medium using boron-doped diamond anode (BDD) was investigated in a batch electrochemical reactor in the presence of Na 2 SO 4 supporting electrolyte. The effect of process parameters such as resorcinol concentration (100-500 g/L), current density (2-10 mA/cm 2 ), Na 2 SO 4 concentration (0-20 g/L), and reaction temperature (25-45°C) was analyzed on electrochemical oxidation using response surface methodology (RSM). The optimum operating conditions were determined as 300 mg/L resorcinol concentration, 8 mA/cm 2 current density, 12 g/L Na 2 SO 4 concentration, and 34°C reaction temperature. One hundred percent of resorcinol removal and 89% COD removal were obtained in 120 min reaction time at response surface optimized conditions. These results confirmed that the electrochemical mineralization of resorcinol was successfully accomplished using BDD anode depending on the process conditions, however the formation of intermediates and by-products were further oxidized at much lower rate. The reaction kinetics were evaluated at optimum conditions and the reaction order of electrochemical oxidation of resorcinol in aqueous medium using BDD anode was determined as 1 based on COD concentration with the activation energy of 5.32 kJ/mol that was supported a diffusion-controlled reaction.

  8. Porous Nickel Oxide Film Sensor for Formaldehyde

    Science.gov (United States)

    Cindemir, U.; Topalian, Z.; Österlund, L.; Granqvist, C. G.; Niklasson, G. A.

    2014-11-01

    Formaldehyde is a volatile organic compound and a harmful indoor pollutant contributing to the "sick building syndrome". We used advanced gas deposition to fabricate highly porous nickel oxide (NiO) thin films for formaldehyde sensing. The films were deposited on Al2O3 substrates with prefabricated comb-structured electrodes and a resistive heater at the opposite face. The morphology and structure of the films were investigated with scanning electron microscopy and X-ray diffraction. Porosity was determined by nitrogen adsorption isotherms with the Brunauer-Emmett-Teller method. Gas sensing measurements were performed to demonstrate the resistive response of the sensors with respect to different concentrations of formaldehyde at 150 °C.

  9. The effect of clothing care activities on textile formaldehyde content.

    Science.gov (United States)

    Novick, Rachel M; Nelson, Mindy L; McKinley, Meg A; Anderson, Grace L; Keenan, James J

    2013-01-01

    Textiles are commonly treated with formaldehyde-based residues that may potentially induce allergic contact dermatitis in sensitive individuals. This study examined the initial formaldehyde content in clothing and resulting changes due to care activities. Twenty clothing articles were examined and 17 of them did not have detectable levels of formaldehyde. One shirt contained a formaldehyde concentration of 3172 ppm, and two pairs of pants had formaldehyde concentrations of 1391 ppm and 86 ppm. The two highest results represent formaldehyde levels that are up to 40-fold greater than international textile regulations. The two items with the greatest formaldehyde content were washed and dried in a manner similar to that used by consumers, including hand and machine washing in hot or cold water followed by air or machine drying. The washing and drying procedures reduced formaldehyde levels to between 26 and 72% of untreated controls. Differences in the temperature or type of washing and drying did not result in a clear trend in the subsequent formaldehyde content. In addition, samples were hot ironed, which did not affect the formaldehyde content as significantly. Understanding the formaldehyde content in clothing and its potential reduction through care activities may be useful for manufacturers and formaldehyde-sensitive individuals.

  10. 78 FR 34820 - Formaldehyde Emissions Standards for Composite Wood Products

    Science.gov (United States)

    2013-06-10

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ92 Formaldehyde Emissions Standards for Composite Wood Products AGENCY... the Formaldehyde Standards for Composite Wood Products Act, or Title VI of the Toxic Substances Control Act (TSCA). These proposed requirements are designed to implement the statutory formaldehyde...

  11. 24 CFR 3280.309 - Health Notice on formaldehyde emissions.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Health Notice on formaldehyde... Construction Requirements § 3280.309 Health Notice on formaldehyde emissions. (a) Each manufactured home shall have a Health Notice on formaldehyde emissions prominently displayed in a temporary manner in the...

  12. Conversion and toxicity characteristics of formaldehyde in acetoclastic methanogenic sludge

    NARCIS (Netherlands)

    Gonzalez-Gil, G.; Kleerebezem, R.; Lettinga, G.

    2002-01-01

    An unadapted mixed methanogenic sludge transformed formaldehyde into methanol and formate. The methanol to formate ratio obtained was 1:1. Formaldehyde conversion proceeded without any lag phase, suggesting the constitutive character of the formaldehyde conversion enzymes involved. Because the rate

  13. Preparation of alpha-bisabolol and phenylethyl resorcinol/TiO2 hybrid composites for potential applications in cosmetics.

    Science.gov (United States)

    Leong, H J; Jang, I; Hyun, K-S; Jung, S-K; Hong, G-H; Jeong, H-A; Oh, S-G

    2016-10-01

    Bifunctional alpha-bisabolol and phenylethyl resorcinol/TiO2 hybrids were prepared to apply in cosmetic fields, particularly in anti-ageing and hyperpigmentation treatment. The synergistic effect of combined antioxidant and UV filtering properties was achieved through functionalization of TiO2 particles with skin-lightening materials such as alpha-bisabolol and phenylethyl resorcinol. TiO2 microspheres with a diameter of about 1 μm were synthesized through surfactant-assisted sol-gel method for use as supporting materials in the formation of hybrid composites. Carboxylation treatment was performed for surface modification of the TiO2 surface with carboxyl groups as chemical binders. Esterification reaction between carboxyl groups of carboxylated TiO2 and hydroxyl groups of alpha-bisabolol or phenylethyl resorcinol was performed. The hybrids were characterized using various techniques such as FE-SEM, DLS, EDS, ATR-FTIR, XPS and TGA. For application of prepared TiO2 composites in the field of cosmetics, the anti-radicular antioxidant abilities were evaluated using ABTS and DPPH colorimetric antioxidant assay. Organic/inorganic hybrid composites were successfully formed using esterification reaction between the carboxyl groups at TiO2 surface and the hydroxyl groups of the skin-lightening materials. The results demonstrate that both functionalized microspheres show scavenging ability towards the ABTS(•) and DPPH(•) radicals. Specifically, the phenylethyl resorcinol/TiO2 composites exhibited the highest antioxidant ability among the prepared samples owing to the presence of phenolic groups to scavenge free radicals. Using this strategy, it could be possible to prepare not only inorganic UV filter but also hybrid organic/inorganic materials with multifunctions and advantages which would be in a great demand for cosmetic applications. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  14. Investigation on synthesis of a low cost no-bake furan resin system with a high strength

    Directory of Open Access Journals (Sweden)

    Liu Weihua

    2014-09-01

    Full Text Available The synthesis of a low cost no-bake furan resin with a high strength was researched in this paper. Through the analysis of main factors influencing the strength of furan resin, an orthogonal experiment was conducted to optimize synthesis of urea-formaldehyde furan resin with 3% nitrogen. The critical factors and their optimal levels were confirmed, and high strength property was obtained. Subsequently, some active substitute materials, including polyols A agent, methyl alcohol, mother liquid of xylitol, polyols B agent and ethanol, were used for partly substitution of furfural alcohol, the main material component of furan resin. A good combination of the substitute materials was determined to achieve a high strength, and the overall proportion of substitute materials to the resin is 20%. In this study, the substitution mechanism on furan resin was also characterized and analyzed by IR.

  15. Contact allergy to 2-hydroxy-5-tert-butyl benzylalcohol and 2,6-bis(hydroxymethyl)-4-tert-butylphenol, components of a phenolic resin used in marking pens

    DEFF Research Database (Denmark)

    Hagdrup, H; Egsgaard, H; Carlsen, L

    1994-01-01

    2-hydroxy-5-tert-butyl benzylalcohol and 2,6-bis(hydroxymethyl)-4-tert-butylphenol were identified as contact allergens in a phenolic resin used as a tackifier in the ink of a marking pen, which, after being used directly on the skin, caused an acute contact dermatitis on the hand of a 13-year......-old boy. The patient also reacted to 4-tert-butylphenol-formaldehyde resin (BPF resin) 1% pet. included in the European standard series....

  16. Resin-Powder Dispenser

    Science.gov (United States)

    Standfield, Clarence E.

    1994-01-01

    Resin-powder dispenser used at NASA's Langley Research Center for processing of composite-material prepregs. Dispenser evenly distributes powder (resin polymer and other matrix materials in powder form) onto wet uncured prepregs. Provides versatility in distribution of solid resin in prepreg operation. Used wherever there is requirement for even, continuous distribution of small amount of powder.

  17. Systematic studies of tannin-formaldehyde aerogels: preparation and properties

    Science.gov (United States)

    Amaral-Labat, Gisele; Szczurek, Andrzej; Fierro, Vanessa; Pizzi, Antonio; Celzard, Alain

    2013-02-01

    Gelation of tannin-formaldehyde (TF) solutions was systematically investigated by changing pH and concentration of TF resin in water. In this way we constructed the TF phase diagram, from which chemical hydrogels could be described, and also synthesized thermoreversible tannin-based hydrogels. Conditions of non-gelation were also determined. Hydrogels were dried in supercritical CO2, leading to a broad range of TF aerogels. The latter were investigated for volume shrinkage, total porosity, micro-, meso- and macropore volumes, Brunauer-Emmett-Teller (BET) surface area, microscopic texture, mechanical and thermal properties. All these properties are discussed in relation to each other, leading to an accurate and self-consistent description of these bioresource-based highly porous materials. The conditions for obtaining the highest BET surface area or mesopore volume were determined and explained in relation to the preparation conditions. The highest BET surface area, 880 m2 g-1, is remarkably high for organic aerogels derived from a natural resource.

  18. Systematic studies of tannin–formaldehyde aerogels: preparation and properties

    Directory of Open Access Journals (Sweden)

    Gisele Amaral-Labat, Andrzej Szczurek, Vanessa Fierro, Antonio Pizzi and Alain Celzard

    2013-01-01

    Full Text Available Gelation of tannin–formaldehyde (TF solutions was systematically investigated by changing pH and concentration of TF resin in water. In this way we constructed the TF phase diagram, from which chemical hydrogels could be described, and also synthesized thermoreversible tannin-based hydrogels. Conditions of non-gelation were also determined. Hydrogels were dried in supercritical CO2, leading to a broad range of TF aerogels. The latter were investigated for volume shrinkage, total porosity, micro-, meso- and macropore volumes, Brunauer–Emmett–Teller (BET surface area, microscopic texture, mechanical and thermal properties. All these properties are discussed in relation to each other, leading to an accurate and self-consistent description of these bioresource-based highly porous materials. The conditions for obtaining the highest BET surface area or mesopore volume were determined and explained in relation to the preparation conditions. The highest BET surface area, 880 m2 g−1, is remarkably high for organic aerogels derived from a natural resource.

  19. Control of formaldehyde and TVOC emission from wood-based flooring composites at various manufacturing processes by surface finishing.

    Science.gov (United States)

    Kim, Sumin

    2010-04-15

    This paper assesses the reproducibility of testing formaldehyde and TVOC emission behavior from wood flooring composites bonded by urea-formaldehyde resin at various manufacturing steps for surface finishing materials. The surface adhesion step of laminate flooring for this research was divided into two steps; HDF only and HDF with LPMs. In the case of engineered flooring, the manufacturing steps were divided into three steps; plywood only, fancy veneer bonded on plywood and UV coated on fancy veneer with plywood. Formaldehyde and VOCs emission decreased at the process of final surface finishing materials; LPMs were applied on the surface of HDF for laminate flooring. Although emissions increased when fancy veneer was bonded onto plywood in the case of engineered flooring, emission was dramatically reduced up to similar level with plywood only when final surface finishing; UV-curable coating was applied on fancy veneer. This study suggests that formaldehyde and VOCs emission from floorings can be controlled at manufacturing steps for surface finishing. 2009 Elsevier B.V. All rights reserved.

  20. Electrospinning formaldehyde cross-linked zein solutions

    Science.gov (United States)

    In order to develop zein fibers with improved physical properties and solvent resistance, formaldehyde was used as the cross-linking reagent before spinning. The cross-linking reaction was carried out in either acetic acid or ethanolic-HCl where the amount of cross-linking reagent was between 1 and...

  1. MODELING AND SIMULATION OF INDUSTRIAL FORMALDEHYDE ABSORBERS

    NARCIS (Netherlands)

    WINKELMAN, JGM; SIJBRING, H; BEENACKERS, AACM; DEVRIES, ET

    1992-01-01

    The industrially important process of formaldehyde absorption in water constitutes a case of multicomponent mass transfer with multiple reactions and considerable heat effects. A stable solution algorithm is developed to simulate the performance of industrial absorbers for this process using a

  2. Spectrophotometric Determination of Gallium(III with 4-(2-Pyridylazo-resorcinol and Nitron

    Directory of Open Access Journals (Sweden)

    Petya Vassileva Racheva

    2015-07-01

    Full Text Available The formation and liquid-liquid extraction of ion-association complex between gallium(III − 4-(2-pyridylazo-resorcinol (PAR – 1,4-diphenyl-3-(phenylamino-1H-1,2,4-triazole (nitron, Nt, water and chloroform were studied. The optimum conditions for gallium(III extraction as an ion-association complex, (NtH+[Ga3+(PAR2]-, were found: pH, concentration of the reagents and shaking time. The following key constants were calculated: constant of extraction (logKex = 6.28 ± 0.07, constant of association (logβ = 4.98 ± 0.05, constant of distribution (logKD = 1.30 ± 0.02 and recovery factor (R / % = 95.17 ± 0.02. Beerʼs law is obeyed for Ga(III concentration up to 0.8 μg cm-3 with apparent molar absorptivity of (10.3 ± 0.4×104 dm-3 mol-1 cm-1 at λmax = 510 nm. Some additional characteristics, such as limit of detection (LOD = 0.072 μg cm-3, limit of quantification (LOQ = 0.24 μg cm-3 and Sandellʼs sensitivity (SS = 0.000675 ng cm-2 were estimated as well.

  3. Ethosomes of Phenylethyl Resorcinol as Vesicular Delivery System for Skin Lightening Applications

    Directory of Open Access Journals (Sweden)

    Tunyaluk Limsuwan

    2017-01-01

    Full Text Available Ethosome formulations containing phenylethyl resorcinol (PR were developed. The formulation was produced from 0.5% w/v PR, 0.5% w/v cholesterol from lanolin, 3% w/v L-α-phosphatidylcholine from soybean, 30% v/v absolute ethanol, and water up to 100% v/v. It was characterized by a vesicular size of 389 nm, low polydispersity index of 0.266, zeta potential of −34.19±0.44 mV, high PR entrapment efficiency of 71%, and good stability on storage at 4 and 30°C at 75% RH for 4 months. In vitro studies using pig skin revealed that permeation coefficient of PR from ethosomes was significantly higher than that from liposomes. In vitro retention profiles showed that PR accumulation in pig skin following application of ethosome formulations was 7.4-, 3.3-, and 1.8-fold higher than that achieved using liposomes, 20% propylene glycol solution, and 30% hydroethanolic solution, respectively. An inhibition value of around 80% was measured for antityrosinase activity of PR in pig skin. Consistently, ethosomes exhibited higher tyrosinase inhibition activity and melanin content reduction when compared to other formulations in B16 melanoma cells. Ethosomes did not cause acute dermal irritation in albino rabbits. These findings demonstrate that ethosomes are capable of delivering PR into the skin efficiently and hold promise for topical application of skin lightening products.

  4. Ethosomes of Phenylethyl Resorcinol as Vesicular Delivery System for Skin Lightening Applications.

    Science.gov (United States)

    Limsuwan, Tunyaluk; Boonme, Prapaporn; Khongkow, Pasarat; Amnuaikit, Thanaporn

    2017-01-01

    Ethosome formulations containing phenylethyl resorcinol (PR) were developed. The formulation was produced from 0.5% w/v PR, 0.5% w/v cholesterol from lanolin, 3% w/v L-α-phosphatidylcholine from soybean, 30% v/v absolute ethanol, and water up to 100% v/v. It was characterized by a vesicular size of 389 nm, low polydispersity index of 0.266, zeta potential of -34.19 ± 0.44 mV, high PR entrapment efficiency of 71%, and good stability on storage at 4 and 30°C at 75% RH for 4 months. In vitro studies using pig skin revealed that permeation coefficient of PR from ethosomes was significantly higher than that from liposomes. In vitro retention profiles showed that PR accumulation in pig skin following application of ethosome formulations was 7.4-, 3.3-, and 1.8-fold higher than that achieved using liposomes, 20% propylene glycol solution, and 30% hydroethanolic solution, respectively. An inhibition value of around 80% was measured for antityrosinase activity of PR in pig skin. Consistently, ethosomes exhibited higher tyrosinase inhibition activity and melanin content reduction when compared to other formulations in B16 melanoma cells. Ethosomes did not cause acute dermal irritation in albino rabbits. These findings demonstrate that ethosomes are capable of delivering PR into the skin efficiently and hold promise for topical application of skin lightening products.

  5. Simultaneous Determination of Hydroquinone, Catechol and Resorcinol at Graphene Doped Carbon Ionic Liquid Electrode

    Directory of Open Access Journals (Sweden)

    Li Ma

    2012-01-01

    Full Text Available A new composite electrode has been prepared with doping graphene into the paste consisting graphite and ionic liquid, n-octyl-pyridinum hexafluorophosphate (OPFP. This electrode shows an excellent electrochemical activity for the redox of hydroquinone (HQ, catechol (CC, and resorcinol (RS. In comparison with bare paste electrode, the redox peaks of three isomers of dihydroxybenzene can be obviously, simultaneously observed at graphene doping paste electrode. Under the optimized condition, the simultaneous determination of HQ, CC, and RS in their ternary mixture can be carried out with a differential pulse voltammetric technique. The peak currents are linear to the concentration of HQ, CC, and RS in the range form 1×10−5 to 4×10−4, 1×10−5 to 3×10−4, and 1×10−6 to 1.7×10−4 mol L−1, respectively. The limits of detection are 1.8×10−6 mol L−1 for HQ, 7.4×10−7 mol L−1 for CC, and 3.6×10−7 M for RS, respectively.

  6. Skincare products containing low concentrations of formaldehyde detected by the chromotropic acid method cannot be safely used in formaldehyde-allergic patients.

    Science.gov (United States)

    Hauksson, I; Pontén, A; Gruvberger, B; Isaksson, M; Engfeldt, M; Bruze, M

    2016-02-01

    Formaldehyde is a well-known contact sensitizer. Formaldehyde releasers are widely used preservatives in skincare products. It has been found that formaldehyde at concentrations allowed by the European Cosmetics Directive can cause allergic contact dermatitis. However, we still lack information on whether formaldehyde at low concentrations affects dermatitis in formaldehyde-allergic individuals. To study the effects of low concentrations of formaldehyde on irritant contact dermatitis in formaldehyde-allergic individuals. Fifteen formaldehyde-allergic individuals and a control group of 12 individuals without contact allergy to formaldehyde and formaldehyde releasers were included in the study. The individuals performed the repeated open application test (ROAT) during 4 weeks with four different moisturizers releasing formaldehyde in concentrations that had been determined as > 40, 20-40, 2·5-10 and 0 p.p.m. by the chromotropic acid (CA) spot test. Dimethyloldimethylhydantoin was used as a formaldehyde releaser in the moisturizers. The ROAT was performed on areas of experimentally induced sodium lauryl sulfate dermatitis. The study was double blind, controlled and randomized. Nine of the 15 formaldehyde-allergic individuals had reappearance or worsening of dermatitis on the areas that were treated with moisturizers containing formaldehyde. No such reactions were observed in the control group (P formaldehyde in the formaldehyde-allergic individuals (P formaldehyde often found in skincare products by the CA method are sufficient to worsen an existing dermatitis in formaldehyde-allergic individuals. © 2015 British Association of Dermatologists.

  7. Adhesives Based on Furan Resin for Structural Laminated Timber

    Directory of Open Access Journals (Sweden)

    Octavia ZELENIUC

    2013-06-01

    Full Text Available In wood laminated products manufacturing thephenol-based adhesives are especially used. Recentlyother adhesives such as polyurethanes were promotedon the market for structural applications withremarkable properties. Structural adhesives have tofulfil the requirements according to their uses, underwet or dry conditions as adhesive type I and type IIrespectively. Criteria for evaluating structuraladhesives, includes delamination resistance, shearstrength of bond and percent of wood failure. Thisstudy has the objective to evaluate the bondingperformance of furan based resin and its suitability forstructural purposes. There are some investigationsabout the possibility of incorporating the furan resin intowood adhesive formulations but their industrialexploitation is still modest. Three experimentaladhesive compositions based on furan and ureaformaldehyderesins, were used to cold-glue beechand spruce lamellas to form a structural timber likeglued laminated timber. Adhesive formulations includedmixed furan resin with furfuryl alcohol (FC2 and twomodified furan resins with urea-formaldehyde resin(UR/FC2 and UR/FC3 at 50% UR. Bond shearstrength by longitudinal tensile and resistance todelamination were performed according to SR EN302:2004. The best performance was obtained withadhesive FC2 which showed shear strength above thevalues indicated for structural adhesives in EN301:2004. FC2 adhesive performed significantly betterin delamination tests too, both in dry and wetconditions, compared to the other two adhesives,showing promise for its use in load-bearing timberstructures.

  8. Condensed tannin-sulfonate derivatives in cold-setting wood-laminating adhesives

    Science.gov (United States)

    Roland E. Kreibich; Richard W. Hemingway

    1987-01-01

    Extraction of southern pine bark with 4.0 percent sodium sulfite and 0.4-percent sodium carbonate(based on ovendry bark weight) gives epicatechin-(4β)-sulfonate and oligomeric procyanidin-4-sulfonatee that show great promise to replace about 50 percent of the phenol-resorcinol-formaldehyde resin in coldsetting wood-laminating adhesives. Bonds in Douglas-fir...

  9. Resistance of particleboard panels made of agricultural residues and bonded with synthetic resins or PVC plastic to wood-rotting fungi

    Directory of Open Access Journals (Sweden)

    Divino Eterno Teixeira

    2009-12-01

    Full Text Available This study aims to evaluate the resistance of three types of particleboard panel to biodeterioration, two of which bonded with synthetic resins and one bonded with PVC plastic. Composite panels were made using sugar cane straw particles as raw material which were bonded together with urea-formaldehyde (UF, tannin-formaldehyde (TANI and PVC plastic (PVC resins. Decay tests were performed following procedures outlined in the ASTM D2017-81/1994 standard, whereby sample specimens were subjected to attack by white rot fungus Trametes versicolor and brown rot fungus Gloeophyllum trabeum using pine (Pinus sp. and embaúba (Cecropia sp. as reference timber. Panels bonded with PVC resin were rated ‘resistant’ to attack by both fungi while those bonded with UF and TANI resins were rated ‘slightly resistant’ to their attack.

  10. Hair dyes resorcinol and lawsone reduce production of melanin in melanoma cells by tyrosinase activity inhibition and decreasing tyrosinase and microphthalmia-associated transcription factor (MITF) expression.

    Science.gov (United States)

    Lee, Shu-Mei; Chen, Yi-Shyan; Lin, Chih-Chien; Chen, Kuan-Hung

    2015-01-09

    Hair coloring products are one of the most important cosmetics for modern people; there are three major types of hair dyes, including the temporary, semi-permanent and permanent hair dyes. The selected hair dyes (such as ammonium persulfate, sodium persulfate, resorcinol and lawsone) are the important components for hair coloring products. Therefore, we analyzed the effects of these compounds on melanogenesis in B16-F10 melanoma cells. The results proved that hair dyes resorcinol and lawsone can reduce the production of melanin. The results also confirmed that resorcinol and lawsone inhibit mushroom and cellular tyrosinase activities in vitro. Resorcinol and lawsone can also downregulate the protein levels of tyrosinase and microphthalmia-associated transcription factor (MITF) in B16-F10 cells. Thus, we suggest that frequent use of hair dyes may have the risk of reducing natural melanin production in hair follicles. Moreover, resorcinol and lawsone may also be used as hypopigmenting agents to food, agricultural and cosmetic industry in the future.

  11. Hair Dyes Resorcinol and Lawsone Reduce Production of Melanin in Melanoma Cells by Tyrosinase Activity Inhibition and Decreasing Tyrosinase and Microphthalmia-Associated Transcription Factor (MITF Expression

    Directory of Open Access Journals (Sweden)

    Shu-Mei Lee

    2015-01-01

    Full Text Available Hair coloring products are one of the most important cosmetics for modern people; there are three major types of hair dyes, including the temporary, semi-permanent and permanent hair dyes. The selected hair dyes (such as ammonium persulfate, sodium persulfate, resorcinol and lawsone are the important components for hair coloring products. Therefore, we analyzed the effects of these compounds on melanogenesis in B16-F10 melanoma cells. The results proved that hair dyes resorcinol and lawsone can reduce the production of melanin. The results also confirmed that resorcinol and lawsone inhibit mushroom and cellular tyrosinase activities in vitro. Resorcinol and lawsone can also downregulate the protein levels of tyrosinase and microphthalmia-associated transcription factor (MITF in B16-F10 cells. Thus, we suggest that frequent use of hair dyes may have the risk of reducing natural melanin production in hair follicles. Moreover, resorcinol and lawsone may also be used as hypopigmenting agents to food, agricultural and cosmetic industry in the future.

  12. Investigation on formaldehyde release from preservatives in cosmetics.

    Science.gov (United States)

    Lv, C; Hou, J; Xie, W; Cheng, H

    2015-10-01

    To understand formaldehyde residue in cosmetics, an investigation on formaldehyde release from eight preservatives (methenamine - MA, paraformaldehyde - PF, poly(p-toluenesulfonamide-co-formaldehyde) -PTSAF, quaternium-15 - QU, imidazolidinyl urea - IU, diazolidinyl urea - DU, dimethyloldimethyl hydantoin - DMDM and bronopol - BP) under various conditions was performed. The concentration of released formaldehyde was determined by high-performance liquid chromatography with photodiode array detection after derivatization with 2,4-dinitrophenylhydrazine. The amounts of formaldehyde release were in the order of PF > DU > DMDM ≈ QU ≈ IU > MA > BP > PTSAF. The releasing amounts of formaldehyde were the highest in the presence of aqueous matrices for the releasers except QU and IU, and the releasing effect was also relative to pH. More formaldehyde was released with longer storage time and higher temperature. Furthermore, all preservatives in cosmetic matrices released fewer amounts of formaldehyde than in pure aqueous or organic matrices, and the formaldehyde-releasing amounts were also cosmetic specific. Formaldehyde release was dependent on the matrix, pH, time and mainly temperature, and the releasing effect was also cosmetic specific. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  13. DETERMINATION OF FORMALDEHYDE LEVELS IN 46 COFFEE SHOPS IN ANKARA

    Directory of Open Access Journals (Sweden)

    Songul Acar VAIZOÐLU

    2005-06-01

    Full Text Available This study is a descriptive research performed in order to measure formaldehyde levels in 46 random selected coffee shops in from central districts of Ankara. Formaldemeter 400 was used for formaldehyde measures. Simultaneous measures were applied in coffee shops. Mean of formaldehyde levels was 0,20 ppm. There was artificial ventilation in all of the coffee shops. It was used aspirator as ventilation device in 69,6% of the coffee shops. But in 81,0% of these, the formaldehyde levels were above 0,10 ppm. In 51,0% of the shops stoves were used for warming and 95,7% of these formaldehyde levels were above 0,10 ppm. There were statistically significant difference between warming-up method and formaldehyde levels of coffee shops ( p<0,05, chi square = 6,4. It was used liquid fuel in 51,1% of them as heating fuel. In 69,6% of them formaldehyde levels were above 0,10 ppm. There were statistically significant difference between fuel type and formaldehyde levels of coffee shops ( p<0,05, chi square = 5,7. As a result; in 91,3% of the coffee shops formaldehyde levels were above the 0,03 ppm which is permitted limit for indoors, and in 82,6% of them formaldehyde levels were above the 0,1 ppm which is symptom producing level. [TAF Prev Med Bull 2005; 4(3.000: 129-135

  14. Effectiveness of various methods of formaldehyde neutralization using monoethanolamine.

    Science.gov (United States)

    Coskey, Andrew; Gest, Thomas R

    2015-05-01

    Formaldehyde is the most commonly used fixative chemical for the preservation of human cadavers used for educational purposes in the United States. Formaldehyde is also a known carcinogenic agent whose exposure level is regulated by guidelines of the Occupational Safety and Health Administration. Various methods for formaldehyde neutralization exist, yet many donations programs do not take any steps to neutralize the formaldehyde in embalmed donor bodies. The effectiveness of monoethanolamine (MEA) in neutralizing formaldehyde is well documented when used as a final injection during embalming. The purpose of this study is to report the effectiveness of several post-embalming techniques of formaldehyde neutralization. Twenty-four donor bodies were assigned to four experimental groups of six. For the three experimental groups, the techniques tested involve delivery of a 20:1 dilution of deionized water:MEA via recannulization and gravity flow infusion, compartment injection, and alternate wetting solution containing four percent MEA. Our results indicated that spray bottle delivery was not effective in neutralization of formaldehyde compared to the control group, but that formaldehyde levels decreased when recannulization or compartment injection were used. The most effective method of formaldehyde neutralization was compartment injection of MEA solution (P < 0.01). The results of this study indicate that, in situations where MEA is not used as a final infusion during embalming, compartment injection of MEA solution is an effective method of formaldehyde neutralization. © 2015 Wiley Periodicals, Inc.

  15. MECHANICAL AND PHYSICAL PROPERTIES OF MDF PANELS OF DIFFERENT DENSITIES AND RESIN CONTENT

    Directory of Open Access Journals (Sweden)

    Jackson Roberto Eleotério

    2009-10-01

    Full Text Available MDF Panelboards of Pinus spp. fibers were prepared in laboratorial scale, within a range of densities (600 - 800 kg/m3 and urea-formaldehyde resin content (6, 8, 10, 12 and 14 wt. %, with the purpose of evaluating their mechanical and physical properties. The effect of density and resin content and their interactions were analyzed based on panel mechanical and physical properties. Mechanical properties evaluated were modulus of rupture and modulus of elasticity and internal bond, while physical properties studied were thickness swelling and water absorption. All the physical and mechanical properties of the MDF panels were significantly related to the resin content and density. Models have been proposed to evaluate the physical and mechanical variables of the MDF panels taking into account the average density and resin content.

  16. Assessment of the Harmfulness of Moulding Sands with Alkyd Resin Subjected to the High Temperature Influence

    Directory of Open Access Journals (Sweden)

    Holtzer M.

    2016-12-01

    Full Text Available Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. These resins in their initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin, under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene, and also polycyclic aromatic hydrocarbons (PAHs can be formed and released.

  17. Afgivelse af formaldehyd fra byggevarer og forbrugerprodukter

    DEFF Research Database (Denmark)

    Kolarik, Barbara; Gunnarsen, Lars; Funch, Llis Winther

    Rapporten præsenterer resultatet af en undersøgelse af formaldehydafgivelse fra 22 mulige kilder i indeklimaet. Undersøgelsen er gennemført for om muligt at finde årsagen til de høje koncentrationer af formaldehyd i indeluften, der blev fundet i enkelte danske boliger under en foregående undersøg......Rapporten præsenterer resultatet af en undersøgelse af formaldehydafgivelse fra 22 mulige kilder i indeklimaet. Undersøgelsen er gennemført for om muligt at finde årsagen til de høje koncentrationer af formaldehyd i indeluften, der blev fundet i enkelte danske boliger under en foregående...

  18. Physical and mechanical properties of bio-composites from wood particles and liquefied wood resin

    Science.gov (United States)

    Hui Pan; Todd F. Shupe; Chung-Yun Hse

    2009-01-01

    Compression molded composites were made from wood particles and a liquefied wood/phenol/formaldehyde co-condensed resin. Based on our previous research, a phenol to wood (P/W) ratio of 2/1 was chosen for this study. The two experimental variables selected were: 1) liquefaction temperature (150o and 180oC) and 2) cooking method (atmospheric and sealed). Panels were...

  19. Obtaining and characterization of composite material base on ablative phenolic resin and carbon fibers

    OpenAIRE

    Srebrenkoska, Vineta

    2002-01-01

    In this master paper is optimized a technological treatment for production of a molding compound based on short carbon fibers and ablative phenol- formaldehyde resin for high temperature application. The characterization of the starting raw materials is performed and molding compounds with different fiber/matrix ratio and different fiber length are obtained. From the different lab-samples molded parts are made by thermocompression. All physical, mechanical and thermal properties of the co...

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

    OpenAIRE

    Srebrenkoska, Vineta; Bogoeva-Gaceva, Gordana; Dimeski, Dimko

    2009-01-01

    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...

  1. Importance of formaldehyde in cloud chemistry

    Science.gov (United States)

    Adewuyi, Y. G.; Cho, S.-Y.; Tsay, R.-P.; Carmichael, G. R.

    1984-01-01

    A physical-chemical model which is an extension of that of Hong and Carmichael (1983) is used to investigate the role of formaldehyde in cloud chemistry. This model takes into account the mass transfer of SO2, O3, NH3, HNO3, H2O2, CO2, HCl, HCHO, O2, OH and HO2 into cloud droplets and their subsequent chemical reactions. The model is used to assess the importance of S(IV)-HCHO adduct formation, the reduction of H2O2 by HCHO, HCHO-free radical interactions, and the formation of HCOOH in the presence of HCHO in cloud droplets. Illustrative calculations indicate that the presence of HCHO inhibits sulfate production rate in cloud droplets. The direct inhibition of sulfate production rate in cloudwater due to nucleophilic addition of HSO3(-) to HCHO(aq) to form hydroxymethanesulfonate is generally low for concentrations of HCHO typical of ambient air. However, inhibition of sulfate production due to formaldehyde-free radical interactions in solution can be important. These formaldehyde-free radical reactions can also generate appreciable quantities of formic acid.

  2. A rapid liquid chromatography determination of free formaldehyde in cod.

    Science.gov (United States)

    Storey, Joseph M; Andersen, Wendy C; Heise, Andrea; Turnipseed, Sherri B; Lohne, Jack; Thomas, Terri; Madson, Mark

    2015-01-01

    A rapid method for the determination of free formaldehyde in cod is described. It uses a simple water extraction of formaldehyde which is then derivatised with 2,4-dinitrophenylhydrazine (DNPH) to form a sensitive and specific chromophore for high-performance liquid chromatography (HPLC) detection. Although this formaldehyde derivative has been widely used in past tissue analysis, this paper describes an improved derivatisation procedure. The formation of the DNPH formaldehyde derivative has been shortened to 2 min and a stabilising buffer has been added to the derivative to increase its stability. The average recovery of free formaldehyde in spiked cod was 63% with an RSD of 15% over the range of 25-200 mg kg(-1) (n = 48). The HPLC procedure described here was also compared to a commercial qualitative procedure - a swab test for the determination of free formaldehyde in fish. Several positive samples were compared by both methods.

  3. Problems associated with the use of urea-formaldehyde foam for residential insulation. Part II. The effects of temperature and humidity on free formaldehyde, extractable formaldehyde, formaldehyde emission, and physical characteristics of the foam

    Energy Technology Data Exchange (ETDEWEB)

    Schutte, W.C.; Cole, R.S.; Frank, C.W.; Long, K.R.

    1981-02-01

    Results of testing with two products of urea-formaldehyde based foams are described. Results of three products have previously been reported. Methods for detection and quantitative determination of formaldehyde, design of the experimental chambers, and the procedures are described. Samples of Product D were monitored for about 29 days and samples of Product E were monitored for 60 days in chambers and results are tabulated for formaldehyde emission. Additional tests performed on the two products are: extractable formaldehyde (high and low temperature conditions); free formaldehyde (high and low temperature conditions); comparison of free formaldehyde concentration; density (high and low temperature conditions); shrinkage (high and low temperature conditions). Control panels were constructed to simulate a wall in a home and observations were made and compared with results of the experimental products.

  4. Determination of lead in solution by solid phase extraction, elution, and spectrophotometric detection using 4-(2-pyridylazo)-resorcinol

    OpenAIRE

    Rahman, Ismail M. M.; Furusho, Yoshiaki; Begum, Zinnat A.; Sato, Rika; Okumura, Hiroshi; Honda, Hiroko; Hasegawa, Hiroshi

    2013-01-01

    Lead (+2) was selectively adsorbed on a solid phase extraction (SPE) gel (molecular recognition technology, MRT), quantitatively extracted, and spectrophotometrically determined as the Pb(II)-PAR (4-(2-pyridylazo)- resorcinol) complex. The linear range was 0.01 to 0.75 mg L-1 and the detection limit was 6.4 μg L-1. The MRT-SPE allows selective Pb(II) extraction from complex ion-rich matrices, which is difficult with other techniques. Interference from common matrix ions such as Fe2+, Ni2+, Cu...

  5. Pressure dependent isotopic fractionation in the photolysis of formaldehyde-d2

    DEFF Research Database (Denmark)

    Nilsson, E.J.K.; Schmidt, Johan Albrecht; Johnson, Matthew Stanley

    2014-01-01

    The isotope effects in formaldehyde photolysis are the key link between the δD of methane emissions and the δD of atmospheric in situ hydrogen production. A few recent studies have suggested that a pressure dependence in the isotopic fractionation can partly explain enrichment of deuterium...... earlier work with HDCO vs. H2CO. The UV lamps used for photolysis emit light at wavelengths that primarily dissociate formaldehyde into molecular products, CO and H2 or D2. The isotope effect k(H2CO)/k(D2CO) Combining double low line 3.16 ± 0.03 at 1000 mbar is in good agreement...... with results from previous studies. Similarly to what was previously shown for k(H2CO)/k(HDCO), the isotope effect decreased as pressure decreased. In addition, a model was constructed using RRKM theory to calculate the lifetime of excited formaldehyde on the S0 surface, to investigate its...

  6. Formaldehyde scavengers function as novel antigen retrieval agents

    Science.gov (United States)

    Vollert, Craig T.; Moree, Wilna J.; Gregory, Steven; Bark, Steven J.; Eriksen, Jason L.

    2015-01-01

    Antigen retrieval agents improve the detection of formaldehyde-fixed proteins, but how they work is not well understood. We demonstrate that formaldehyde scavenging represents a key characteristic associated with effective antigen retrieval; under controlled temperature and pH conditions, scavenging improves the typical antigen retrieval process through reversal of formaldehyde-protein adduct formation. This approach provides a rational framework for the identification and development of more effective antigen retrieval agents. PMID:26612041

  7. BLM protein mitigates formaldehyde-induced genomic instability.

    Science.gov (United States)

    Kumari, Anuradha; Owen, Nichole; Juarez, Eleonora; McCullough, Amanda K

    2015-04-01

    Formaldehyde is a reactive aldehyde that has been classified as a class I human carcinogen by the International Agency for Cancer Research. There are growing concerns over the possible adverse health effects related to the occupational and environmental human exposures to formaldehyde. Although formaldehyde-induced DNA and protein adducts have been identified, the genomic instability mechanisms and the cellular tolerance pathways associated with formaldehyde exposure are not fully characterized. This study specifically examines the role of a genome stability protein, Bloom (BLM) in limiting formaldehyde-induced cellular and genetic abnormalities. Here, we show that in the absence of BLM protein, formaldehyde-treated cells exhibited increased cellular sensitivity, an immediate cell cycle arrest, and an accumulation of chromosome radial structures. In addition, live-cell imaging experiments demonstrated that formaldehyde-treated cells are dependent on BLM for timely segregation of daughter cells. Both wild-type and BLM-deficient formaldehyde-treated cells showed an accumulation of 53BP1 and γH2AX foci indicative of DNA double-strand breaks (DSBs); however, relative to wild-type cells, the BLM-deficient cells exhibited delayed repair of formaldehyde-induced DSBs. In response to formaldehyde exposure, we observed co-localization of 53BP1 and BLM foci at the DSB repair site, where ATM-dependent accumulation of formaldehyde-induced BLM foci occurred after the recruitment of 53BP1. Together, these findings highlight the significance of functional interactions among ATM, 53BP1, and BLM proteins as responders associated with the repair and tolerance mechanisms induced by formaldehyde. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Degradation of formaldehyde in anaerobic sequencing batch biofilm reactor (ASBBR)

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, N.S. [Laboratorio de Processos Biologicos (LPB), Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos (EESC), Universidade de Sao Paulo - USP, Engenharia Ambiental, Bloco 4-F, Av. Joao Dagnone, 1100 Santa Angelina, 13.563-120 Sao Carlos, SP (Brazil); Zaiat, M. [Laboratorio de Processos Biologicos (LPB), Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos (EESC), Universidade de Sao Paulo - USP, Engenharia Ambiental, Bloco 4-F, Av. Joao Dagnone, 1100 Santa Angelina, 13.563-120 Sao Carlos, SP (Brazil)], E-mail: zaiat@sc.usp.br

    2009-04-30

    The present study evaluated the degradation of formaldehyde in a bench-scale anaerobic sequencing batch reactor, which contained biomass immobilized in polyurethane foam matrices. The reactor was operated for 212 days at 35 deg. C with 8 h sequential cycles, under different affluent formaldehyde concentrations ranging from 31.6 to 1104.4 mg/L (formaldehyde loading rates from 0.08 to 2.78 kg/m{sup 3} day). The results indicate excellent reactor stability and over 99% efficiency in formaldehyde removal, with average effluent formaldehyde concentration of 3.6 {+-} 1.7 mg/L. Formaldehyde degradation rates increased from 204.9 to 698.3 mg/L h as the initial concentration of formaldehyde was increased from around 100 to around 1100 mg/L. However, accumulation of organic matter was observed in the effluent (chemical oxygen demand (COD) values above 500 mg/L) due to the presence of non-degraded organic acids, especially acetic and propionic acids. This observation poses an important question regarding the anaerobic route of formaldehyde degradation, which might differ substantially from that reported in the literature. The anaerobic degradation pathway can be associated with the formation of long-chain oligomers from formaldehyde. Such long- or short-chain polymers are probably the precursors of organic acid formation by means of acidogenic anaerobic microorganisms.

  9. Formaldehyde Crosslinking: A Tool for the Study of Chromatin Complexes*

    Science.gov (United States)

    Hoffman, Elizabeth A.; Frey, Brian L.; Smith, Lloyd M.; Auble, David T.

    2015-01-01

    Formaldehyde has been used for decades to probe macromolecular structure and function and to trap complexes, cells, and tissues for further analysis. Formaldehyde crosslinking is routinely employed for detection and quantification of protein-DNA interactions, interactions between chromatin proteins, and interactions between distal segments of the chromatin fiber. Despite widespread use and a rich biochemical literature, important aspects of formaldehyde behavior in cells have not been well described. Here, we highlight features of formaldehyde chemistry relevant to its use in analyses of chromatin complexes, focusing on how its properties may influence studies of chromatin structure and function. PMID:26354429

  10. Formaldehyde crosslinking: a tool for the study of chromatin complexes.

    Science.gov (United States)

    Hoffman, Elizabeth A; Frey, Brian L; Smith, Lloyd M; Auble, David T

    2015-10-30

    Formaldehyde has been used for decades to probe macromolecular structure and function and to trap complexes, cells, and tissues for further analysis. Formaldehyde crosslinking is routinely employed for detection and quantification of protein-DNA interactions, interactions between chromatin proteins, and interactions between distal segments of the chromatin fiber. Despite widespread use and a rich biochemical literature, important aspects of formaldehyde behavior in cells have not been well described. Here, we highlight features of formaldehyde chemistry relevant to its use in analyses of chromatin complexes, focusing on how its properties may influence studies of chromatin structure and function. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. The TetR-Type Transcriptional Repressor RolR from Corynebacterium glutamicum Regulates Resorcinol Catabolism by Binding to a Unique Operator, rolO

    OpenAIRE

    Li, Tang; Zhao, Kexin; Huang, Yan; Li, Defeng; Jiang, Cheng-Ying; Zhou, Nan; Fan, Zheng; Liu, Shuang-Jiang

    2012-01-01

    The rol (designated for resorcinol) gene cluster rolRHMD is involved in resorcinol catabolism in Corynebacterium glutamicum, and RolR is the TetR-type regulator. In this study, we investigated how RolR regulated the transcription of the rol genes in C. glutamicum. The transcription start sites and promoters of rolR and rolHMD were identified. Quantitative reverse transcription-PCR and promoter activity analysis indicated that RolR negatively regulated the transcription of rolHMD and of its ow...

  12. PILOT STUDY OF CONTACT SENSITIZATION OF FORMALDEHYDE-RELEASERS, FORMALDEHYDE AND GLUTARALDEHYDE IN DENTAL STUDENTS

    Directory of Open Access Journals (Sweden)

    Lyapina Maya

    2016-03-01

    Full Text Available Introduction: Occupational allergic contact sensitization is common in dental personnel. Some of the most common occupational allergens in dental practice are some formaldehyde-releasers, formaldehyde and glutaraldehyde. Aim: The aim of the present study was to evaluate the rate of contact sensitization to formaldehyde, quaternium-15, imidazolidinyl urea, diazolidinyl urea, and to glutaraldehyde in students of dental medicine and dental patients. Material and methods: A total of 50 participants were included in the study: 40 students of dental medicine exposed to formaldehyde-releasers, formaldehyde and glutaraldehyde during the course of their education; 10 dental patients without occupational exposure to the latter substances served as a control group. All of them were patch-tested with the studied allergens. Results: The sensitization rate to formaldehyde was significantly higher in the group of dental patients if compared to the one of dental students (χ2=5.37; p=0.021. Positive skin patch test reactions to quaternium-15 and to imidazolidinyl urea were observed only in the group of dental students. A significantly higher rate of sensitization to diazolidinyl urea, if compared to the one to imidazolidinyl urea (χ2=5.4; p=0.02 and to quaternium-15 (χ2=6.76; p=0.009, as well as to glutaraldehyde, if compared to the one to quaternium-15 (χ2=3.96; p=0.04 for the whole studied population was established. For the whole studied population, significantly increased rate of concomitant sensitization to formaldehyde and glutaraldehyde (χ2=6.18 p=0.013, as well as to diazolidinyl urea and to glutaraldehyde was established (χ2=9.12 p=0.003. Conclusions: We consider the importance of exposure to diazolidinyl urea, quaternium-15, imidazolidinyl urea and glutaraldehyde during the course of practical education in dentistry for the onset of sensitization. The exposure to formaldehyde is ubiquitous and is difficult to distinguish the roles of

  13. Formaldehyde and LeukemiA: Epidemiology, Potential Mechanisms and Implications for Risk Assessment

    Science.gov (United States)

    Formaldehyde is widely used in the United States and other countries. Occupational and environmental exposures to formaldehyde may be associated with an increased risk of leukemia in exposed individuals. However, risk assessment of formaldehyde and leukemia has been challenging ...

  14. 78 FR 51695 - Formaldehyde Emissions Standards for Composite Wood Products; Extension of Comment Period

    Science.gov (United States)

    2013-08-21

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ92 Formaldehyde Emissions Standards for Composite Wood Products..., concerning formaldehyde emissions standards for composite wood products. After receiving requests for an... CFR Part 770 Environmental protection, Formaldehyde, Reporting and recordkeeping requirements, Toxic...

  15. Physico-mechanical comparison of urea formaldehyde bonded particle board manufactured from jute sticks and wood of Trewia nudiflora

    Directory of Open Access Journals (Sweden)

    Abu Saleh Md. Golam Kibria

    2012-12-01

    Full Text Available This study is to know the physical and mechanical properties of particle board made up of jute sticks (jutex board and wood chips (woodex board of Trewia nudiflora. Two leading particle board manufacturing industries of Bangladesh were selected first which have the same manufacturing process and adhesive composition. Boards of available thicknesses were collected randomly. From each thickness category, three replications were taken. The parameters were studied as adhesive composition,mass of a board, density, bending strength, modulus of elasticity,surface soundness, tensile strength, screw withdrawal, pressure and pressing time. Urea formaldehyde resin is used to manufacture both types of particle board. For achieving the greater efficiency of boards, some chemical compounds were mixed with the resin. Due to the change in thicknesses, boards were not always different in terms of the physical and mechanical properties. Moreover, except the modulus of elasticity (MOE, woodex boards were superior to the properties of jutex boards. 

  16. Physico-mechanical comparison of urea formaldehyde bonded particle board manufactured from jute sticks and wood of Trewia nudiflora

    Directory of Open Access Journals (Sweden)

    Abu Saleh Md. Golam Kibria

    2012-11-01

    Full Text Available This study is to know the physical and mechanical properties ofparticle board made up of jute sticks (jutex board and wood chips (woodex board of Trewia nudiflora. Two leading particle board manufacturing industries of Bangladesh were selected first which have the same manufacturing process and adhesive composition. Boards of available thicknesses were collected randomly. From each thickness category, three replications were taken. The parameters were studied as adhesive composition, mass of a board, density, bending strength, modulus of elasticity, surface soundness, tensile strength, screw withdrawal, pressure and pressing time. Urea formaldehyde resin is used to manufacture both types of particle board. For achieving the greater efficiency of boards, some chemical compounds were mixed with the resin. Due to the change in thicknesses, boards were not always different in terms of the physical and mechanical properties. Moreover, except the modulus of elasticity (MOE, woodex boards were superior to the properties of jutex boards.

  17. Preparation, Characterization, and Properties of In Situ Formed Graphene Oxide/Phenol Formaldehyde Nanocomposites

    Directory of Open Access Journals (Sweden)

    Weihua Xu

    2013-01-01

    Full Text Available Graphene oxide (GO has shown great potential to be used as fillers to develop polymer nanocomposites for important applications due to their special 2D geometrical structure as well as their outstanding mechanical, thermal, and electrical properties. In this work, GO was incorporated into phenol formaldehyde (PF resin by in situ polymerization. The morphologies and structures of GO sheets were characterized by FTIR, XRD, and AFM methods. The structure and properties of the GO/PF nanocomposites were characterized using FTIR, XRD, DSC, and TGA methods. Effects of GO content, reactive conditions, and blending methods on the structure and properties of GO/PF nanocomposites were studied. It was found that due to the well dispersion of GO sheets in polymer matrix and the strong interfacial interaction between the GO sheets and PF matrix, the thermal stability and thermal mechanical properties of the GO/PF nanocomposites were greatly enhanced.

  18. Melamine-formaldehyde microcapsules filled sappan dye modified polypropylene composites: encapsulation and thermal properties

    Science.gov (United States)

    Phanyawong, Suphitcha; Siengchin, Suchart; Parameswaranpillai, Jyotishkumar; Asawapirom, Udom; Polpanich, Duangporn

    2018-01-01

    Sappan dye, a natural dye extracted from sappan wood is widely used in cosmetics, textile dyeing and as food additives. However, it was recognized that natural dyes cannot withstand high temperature. In this study, a protective coating of melamine-formaldehyde shell material was applied over the sappan dye to improve its thermal stability. The percentage of sappan dye used in the microencapsulation was 30, 40, 50, 60 and 70 wt%. The color, shape, size, and thermal stability of sappan dye microcapsules were investigated. It was found that increasing amount of sappan dye content in the microcapsules decreased the particle size. Thermal analysis reveals that the melamine-formaldehyde resin served as an efficient protective shell for sappan dye. Besides, 30 wt% sappan dye microcapsules with different weight percent (1, 3 and 5 wt%) of sappan dye was used as modifier for polypropylene (PP). All the prepared composites are red in color which supports the thermal stability of the microcapsules. The changes in crystallinity and melting behavior of PP by the addition of microcapsules were studied in detail by differential scanning calorimetry. Thermogravimetric studies showed that the thermal stability of PP composites increased by the addition of microcapsules.

  19. Sustainable Bio-Based Phenol-Formaldehyde Resoles Using Hydrolytically Depolymerized Kraft Lignin

    Directory of Open Access Journals (Sweden)

    Homaira Siddiqui

    2017-10-01

    Full Text Available In this study bio-based bio-phenol-formaldehyde (BPF resoles were prepared using hydrolytically depolymerized Kraft lignin (DKL as bio-phenol to partially substitute phenol. The effects of phenol substitution ratio, weight-average molecular weight (Mw of DKL and formaldehyde-to-phenol (F/P ratio were also investigated to find the optimum curing temperature for BPF resoles. The results indicated that DKL with Mw ~ 1200 g/mol provides a curing temperature of less than 180 °C for any substitution level, provided that F/P ratios are controlled. Incorporation of lignin reduced the curing temperature of the resin, however, higher Mw DKL negatively affected the curing process. For any level of lignin Mw, the curing temperature was found to increase with lower F/P ratios at lower phenol substitution levels. At 25% and 50% phenol substitution, increasing the F/P ratio allows for synthesis of resoles with lower curing temperatures. Increasing the phenol substitution from 50% to 75% allows for a broader range of lignin Mw to attain low curing temperatures.

  20. Synthesis and Characterization of Pine Needles Reinforced RF Matrix Based Biocomposites

    Directory of Open Access Journals (Sweden)

    A. S. Singha

    2008-01-01

    Full Text Available Synthesis and characterization of pine needles reinforced thermosetting resin (Resorcinol-Formaldehyde which is most suitable as composite matrix has been reported. The polycondensation reaction between resorcinol and formaldehyde (RF in different molar ratios has been applied to the synthesis of RF polymer matrix. A thermosetting resin based composite, containing approximately 10, 20, 30 and 40% of natural fiber by weight, has been obtained by adding pine needles to the Resorcinol-Formaldehyde (RF resin. The mechanical properties of randomly oriented intimately mixed particle reinforced (Pine needles composites were determined. Effect of fiber loading in terms of weight % on mechanical properties such as tensile, compressive, and flexural and wear properties have also been evaluated. The reinforcing of the resin with Pine needles was accomplished in particle size of 200 micron by employing optimized resin. Present work reveals that mechanical properties of the RF resin increases to extensive extent when reinforced with Pine needles. Thermal (TGA/DTA and morphological studies (SEM of the resin, fiber and polymer composites thus synthesized have also been carried out.

  1. Concentrations of formaldehyde in rain waters harvested at the ...

    African Journals Online (AJOL)

    Formaldehyde has been recognized as one of the most important pollutants and a carcinogen that is present in the air, water, foods, soils, fabrics, cosmetics, cigarette smoke and treated wood. Related health effects and hazards are linked to formaldehyde, depending on mode of exposure which includes: weakness, ...

  2. [Effect of formaldehyde inhalation on allergic rhinitis in mice].

    Science.gov (United States)

    Xiang, Rong; Xu, Yu

    2015-08-01

    To observe the effect of formaldehyde inhalation on the allergic rhinitis mice model. Forty-eight male BALB/C mice in six experimental group were exposure to (A) saline control; (B) Der p1; (C) formaldehyde (3.0 mg/m3); (D) Derp1 + formaldehyde (1.5 mg/m3); (E) Der p1 + formaldehyde (3.0 mg/M3); (F) Der p1+ formaldehyde (6.0 mg/m3). The concentrations of IL-4, IL-10 and IFN-γ in the peripheral serum were measured by enzyme-linked immunosorbent assay(ELISA). Nasal mucosal inflammation was evaluated by HE staining. Result: Formaldehyde exposure could increase the number of allergic rhinitis mice with sneezing and rubbing nose. The levels of IL-4 and IL-10 in group B, D, E and F were higher than that ingroup A (P formaldehyde exposure allergic rhinitis groups. The study showed that formaldehyde exposure can promote Th2 cytokines and eosinophil infiltration and then aggravate the allergic rhinitis symptoms.

  3. Influence of indoor formaldehyde pollution on respiratory system ...

    African Journals Online (AJOL)

    Background The decoration of interior spaces can lead to dangerous levels of indoor formaldehyde pollution. Exposure to indoor air pollution may be responsible for nearly 2 million deaths per year in developing countries. Objectives To assess the prevalence of indoor formaldehyde pollution caused by decoration and ...

  4. Solution of Azelaic Acid (20%), Resorcinol (10%) and Phytic Acid (6%) Versus Glycolic Acid (50%) Peeling Agent in the Treatment of Female Patients with Facial Melasma.

    Science.gov (United States)

    Faghihi, Gita; Taheri, Azam; Shahmoradi, Zabihollah; Nilforoushzadeh, Mohammad Ali

    2017-01-01

    Melasma, a common acquired disorder of hyperpigmentation, especially in women, is often resistant to therapy. This study was aimed to evaluate the efficacy and safety of azelaic acid, resorcinol and phytic acid solution in chemical peeling of melasma in comparison to 50% glycolic acid. This clinical trial was performed, on 42 female patients with bilateral melasma. Severity of melasma was assessed by melasma area and severity index (MASI). Combination of (20% azelaic acid + 10% resorcinol + 6% phytic acid) was used as a new peeling agent on the right side of the face and 50% glycolic acid on the left side every 2 weeks for 6 times. Follow-up was carried out for 3 months after the last session. Any decrease in MASI score and unwanted complications following peeling were evaluated and compared during the trial. Patients showed marked improvement as calculated with MASI score before and after treatment in both sides of the face. The efficacy of combination formula (azelaic acid, resorcinol and phytic acid) was similar to glycolic acid, but with fewer complications. There was no statistically difference in improvement between two groups (P > 0.05). However, the patient's discomfort following procedures was significantly lower with azelaic acid, resorcinol and phytic compared with the glycolic acid peels (P glycolic acid peel.

  5. Aβ seeds resist inactivation by formaldehyde.

    Science.gov (United States)

    Fritschi, Sarah K; Cintron, Amarallys; Ye, Lan; Mahler, Jasmin; Bühler, Anika; Baumann, Frank; Neumann, Manuela; Nilsson, K Peter R; Hammarström, Per; Walker, Lary C; Jucker, Mathias

    2014-10-01

    Cerebral β-amyloidosis can be exogenously induced by the intracerebral injection of brain extracts containing aggregated β-amyloid (Aβ) into young, pre-depositing Aβ precursor protein- (APP) transgenic mice. Previous work has shown that the induction involves a prion-like seeding mechanism in which the seeding agent is aggregated Aβ itself. Here we report that the β-amyloid-inducing activity of Alzheimer's disease (AD) brain tissue or aged APP-transgenic mouse brain tissue is preserved, albeit with reduced efficacy, after formaldehyde fixation. Moreover, spectral analysis with amyloid conformation-sensitive luminescent conjugated oligothiophene dyes reveals that the strain-like properties of aggregated Aβ are maintained in fixed tissues. The resistance of Aβ seeds to inactivation and structural modification by formaldehyde underscores their remarkable durability, which in turn may contribute to their persistence and spread within the body. The present findings can be exploited to establish the relationship between the molecular structure of Aβ aggregates and the variable clinical features and disease progression of AD even in archived, formalin-fixed autopsy material.

  6. Effect of resin content and substrate on the emission of BTEX and carbonyls from low-VOC water-based wall paint.

    Science.gov (United States)

    Zhao, Ping; Cheng, Yu-Hsiang; Lin, Chi-Chi; Cheng, Yu-Lin

    2016-02-01

    The primary aim of this work is to explore the effect of resin content and the effect of substrate on the emission of benzene, toluene, ethylbenzene, and xylene (BTEX) and carbonyls from low-VOC water-based wall paint. Four low-volatile organic compound (VOC) paints include paints A (20% acrylic), B (30% acrylic), C (20% polyvinyl acetate), and D (30% polyvinyl acetate) were painted on stainless steel specimen for the study of resin effect. Green calcium silicate, green cement, and stainless steel were painted with paints A and C for the study of substrate effect. Concentrations of the VOCs in the chamber decreased with the elapsed time. Both resin type and resin quantity in paint had effects on VOC emissions. Paints with acrylic resin emitted less BTEX and carbonyls than paints with polyvinyl acetate resin. However, the effects of resin quantity varied with VOCs. Porous substrates were observed to interact more strongly with paints than inert substrates. Both green calcium silicate and green cement substrates have strong power of adsorption of VOCs from wall paints, namely toluene, formaldehyde, acetaldehyde, 2-butanone, methacrolein, butyraldehyde, and benzaldehyde. Some compounds like toluene, formaldehyde, and butyaldehyde were desorbed very slowly from green calcium silicate and green cement substrates.

  7. Acetylene terminated matrix resins

    Science.gov (United States)

    Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

    1985-01-01

    The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

  8. Synthesis of Helical Phenolic Resin Bundles through a Sol-Gel Transcription Method

    Directory of Open Access Journals (Sweden)

    Changzhen Shao

    2017-02-01

    Full Text Available Chiral and helical polymers possess special helical structures and optical property, and may find applications in chiral catalysis and optical devices. This work presents the preparation and formation process of helical phenolic resins through a sol-gel transcription method. A pair of bola-type chiral low-molecular-weight gelators (LMWGs derived from valine are used as templates, while 2,4-dihydroxybenzoic acid and formaldehyde are used as precursors. The electron microscopy images show that the phenolic resins are single-handed helical bundles comprised of helical ultrafine nanofibers. The diffused reflection circular dichroism spectra indicate that the helical phenolic resins exhibit optical activity. A possible formation mechanism is proposed, which shows the co-assembly of the LMWGs and the precursors.

  9. 40 CFR 80.56 - Measurement methods for formaldehyde and acetaldehyde.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Measurement methods for formaldehyde... Measurement methods for formaldehyde and acetaldehyde. (a) Formaldehyde and acetaldehyde will be measured by....140 of this chapter for formaldehyde analysis. Diluted exhaust sample volumes must be at least 15 L...

  10. INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE

    Directory of Open Access Journals (Sweden)

    C. C. Lobo

    Full Text Available Abstract In this work the aerobic degradation of phenol (PH, catechol (CA, resorcinol (RE, hydroquinone (HY and of the binary mixtures PH+CA, PH+RE, PH+HY by phenol-acclimated activated sludge was studied. Single substrate experiments show a Haldane-type dependence of the respiration rate on PH, RE and HY, while CA corresponded to the Monod model. Binary substrate experiments demonstrated that the presence of a second substrate only affected the kinetics, but not the stoichiometry of the oxidation of the compounds tested. While CA inhibited the oxidation of PH, PH inhibited the oxidation of RE and HY. A mathematical model was developed to represent the aerobic biodegradation of the phenolic compounds tested. The agreement between the proposed model and the experimental data indicates that the proposed model can be useful for predicting substrate and dissolved oxygen concentrations in bioreactors treating phenolic wastewaters.

  11. Quantification of atmospheric formaldehyde by infrared absorption spectroscopy

    Science.gov (United States)

    Hoffnagle, John; Fleck, Derek; Rella, Chris; Kim-Hak, David

    2017-04-01

    Formaldehyde is a toxic, carcinogenic compound that can contaminate ambient air as a result of combustion or outgassing of commercial products such as adhesives used to fabricate plywood and to affix indoor carpeting. Like many small molecules, formaldehyde has an infrared absorption spectrum exhibiting bands of ro-vibrational transitions that are well resolved at low pressure and therefore well suited for optical analysis of formaldehyde concentration. We describe progress in applying cavity ring-down spectroscopy of the 2v5 band (the first overtone of the asymmetric C-H stretch, origin at 1770 nm) to the quantitative analysis of formaldehyde concentration in ambient air. Preliminary results suggest that a sensitivity of 1-2 ppb in a measurement interval of a few seconds, and 0.1-0.2 ppb in a few minutes, should be achievable with a compact, robust, and field-deployable instrument. Finally, we note that recent satellites monitoring snapshots of formaldehyde columns give insights into global formaldehyde production, migration and lifetime. The ability to monitor formaldehyde with a small and portable analyzer has the potential to aid in validation of these snapshots and to provide complementary data to show vertical dispersions with high spatial accuracy.

  12. Determination of trace amounts of formaldehyde in acetone.

    Science.gov (United States)

    Huang, X H Hilda; Ip, H S Simon; Yu, Jian Zhen

    2007-12-05

    A method to quantify sub-ppm levels of formaldehyde in acetone has been developed and it is reported here. In this method, the different reactivities and stabilities of sulfite with formaldehyde and acetone are used to separate the two carbonyl compounds. Sulfite reacts with formaldehyde to form hydroxymethanesulfonate (HMS), the non-volatile and stable nature of which allows its separation from bulk acetone solvent. The resulting HMS is then converted back to formaldehyde under basic conditions, and formaldehyde is derivatized with 2,4-dinitrophenylhydrazine (DNPH) and quantified in its DNP hydrazone form using high-performance liquid chromatography-UV detection. The method detection limit at the 99% confidence level was 0.051 mg L(-1). A batch of samples can be processed within 4 h. The method has been applied to quantify the amount of formaldehyde in an analytical-grade acetone and in a commercial nail polish remover and the level of formaldehyde was found to be 0.175 and 0.184 mg L(-1), respectively.

  13. Polymerization of Phenol Formaldehyde in Solvent-Saturated Vapor and Study on the Microstructure and Mechanical Properties of Novolac Aerogel Product

    Directory of Open Access Journals (Sweden)

    I. Naseri

    2014-01-01

    Full Text Available Aerogels consist of low density open-cell foams with large void spaces of nanometer pore size and they are composed of sparsely semi-colloidal nanometer sized particles forming open porous structures. The high porosity and nanometer pores and particles of aerogels have interesting properties such as low thermal conductivity and low sound transmission. The main disadvantages of conventional method for preparation of aerogels are high cost of resorcinol, long preparation time and high cost of supercritical drying device. The previous research showed that sol-gel polymerization lower than temperature of normal boiling point of solvent, and a 50°C difference in temperature between the novolac resin synthesis and the temperature of curing novolac resin is the main reason for long sol-gel polymerization time. A low temperature polymerization is used for prevention of solvent evaporation and foam blowing process. The objectives of this research were to reduce time and cost in the production process of organic aerogels. To reduce the cost of raw materials, the reaction of a low cost commercial novolac resin and HMTA were used for preparation of the gel. To reduce gelation time, the polymerization was performed in an atmosphere of solvent saturated-vapor as a novel method to restrict sol-gel polymerization of curing novolac resin at appropriate temperature. The investigation showed that the polymerization carried out in solvent-saturated vapor did help to reduce polymerization time to 5 h from 5 days duration in conventional reactions without any visible shrinkage under ambient pressure and temperature. Furthermore, the compressive strength increased by one order of magnitude besides other achievements.Aerogels comprise class of low density open-cell foams with large void space, nanometer pore size and they are composed of sparsely semi-colloidal nanometer sized particles forming open porous structures. The high porosity and nanometer pores and

  14. THE EFFECTS OF BORON COMPOUNDS AND DIFFERENT MELAMINE CONTENTS IN MUF RESINS ON SOME PROPERTIES OF MDF PANELS

    OpenAIRE

    Derya Ustaomer; Mustafa Usta

    2011-01-01

    The objective of this study was to determine the effects of some boron compounds, which have fire retardant properties, as well as melamine-urea-formaldehyde (MUF) resins having different melamine contents (10%, 15%, and 20%) on some physical and mechanical properties of medium density fiberboard (MDF) panels. It was found that the water absorption (WA) and thickness swelling (TS) of MDF panels increased depending on types and concentrations of boron compounds. However, the WA and TS values o...

  15. Effect of Addition of Boric Acid and Borax on Fire-Retardant and Mechanical Properties of Urea Formaldehyde Saw Dust Composites

    Directory of Open Access Journals (Sweden)

    Zenat A. Nagieb

    2011-01-01

    Full Text Available Properties of the flame retardant urea formaldehyde (UF board made from saw dust fibers were investigated. Flame retardant chemicals that were evaluated include boric acid (BA and borax (BX which were incorporated with saw dust fibers to manufacture experimental panels. Three concentration levels, (0.5, 1, and 5% of fire retardants and 10% urea formaldehyde resin based on oven dry fiber weight were used to manufacture experimental panels. Physical and mechanical properties including water absorption, modulus of rupture (MOR, and modulus of elasticity (MOE were determined. The results showed that water absorption and bending strength decreased as the flame retardant increased. The highest concentration of (BA + BX enhanced the fire retardant more than the lower ones. Scanning electron microscope and FTIR of composite panels were studied.

  16. The emission structure of formaldehyde megamasers

    Science.gov (United States)

    Baan, Willem A.; An, Tao; Klöckner, Hans-Rainer; Thomasson, Peter

    2017-07-01

    The formaldehyde megamaser emission has been mapped for the three host galaxies IC 860, IRAS 15107+0724 and Arp 220. Elongated emission components are found at the nuclear centres of all galaxies with an extent ranging between 30 and 100 pc. These components are superposed on the peaks of the nuclear continuum. Additional isolated emission components are found superposed in the outskirts of the radio continuum structure. The brightness temperatures of the detected features ranges from 0.6 to 13.4 × 104 K, which confirms their masering nature. The masering scenario is interpreted as amplification of the radio continuum by foreground molecular gas that is pumped by far-infrared radiation fields in these starburst environments of the host galaxies.

  17. Thermal degradation kinetics and antimicrobial studies of terpolymer resins

    Directory of Open Access Journals (Sweden)

    Abdul R. Burkanudeen

    2016-09-01

    Full Text Available The terpolymer (ASF was synthesized by condensation of anthranilic acid and salicylic acid with formaldehyde in the presence of glacial acetic acid as a catalyst at 140 ± 2 °C for 6 h with varying proportions of reactants. The terpolymer ASF-I was characterized by elemental analysis, FTIR, 1H NMR and 13C NMR spectroscopy. The thermal decomposition behavior of ASF-I, II and III terpolymers was studied using thermogravimetric analysis (TGA in a static nitrogen atmosphere at a heating rate of 20 °C/min. Freeman–Carroll, Sharp–Wentworth and Phadnis–Deshpande methods were used to calculate the thermal activation energy (Ea the order of reaction (n, entropy change (ΔS, free energy change (ΔF, apparent entropy (S∗ and frequency factor (Z. Phadnis–Deshpande method was used to propose the thermal degradation model for the decomposition pattern of ASF-I terpolymer resin. The order of the decomposition reaction was found to be 0.901. The thermal activation energy determined with the help of these methods was in good agreement with each other. The ASF-I, II and III resins were tested for their inhibitory action against pathogenic bacteria and fungi. The resins show potent inhibitory action against bacteria, such as Escherichia coli, Klebsiella, Staphylococcus aureus and Pseudomonas aeruginosa and fungi viz. Aspergillus flavus, Aspergillus niger, Penicillium sp., Candida albicans, Cryptococcus neoformans and Mucor sp.

  18. Method for removing contaminants from plastic resin

    Science.gov (United States)

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

    2008-12-09

    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.

  19. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    Science.gov (United States)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  20. Formaldehyde Profiler Using Laser Induced Fluorescence Technique Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Formaldehyde (HCHO) is of great interest to atmospheric scientists in NASA and other research institutions. In this SBIR project, we propose to build an airborne or...

  1. Formaldehyde cross-linking and structural proteomics: Bridging the gap.

    Science.gov (United States)

    Srinivasa, Savita; Ding, Xuan; Kast, Juergen

    2015-11-01

    Proteins are dynamic entities constantly moving and altering their structures based on their functions and interactions inside and outside the cell. Formaldehyde cross-linking combined with mass spectrometry can accurately capture interactions of these rapidly changing biomolecules while maintaining their physiological surroundings. Even with its numerous established uses in biology and compatibility with mass spectrometry, formaldehyde has not yet been applied in structural proteomics. However, formaldehyde cross-linking is moving toward analyzing tertiary structure, which conventional cross-linkers have already accomplished. The purpose of this review is to describe the potential of formaldehyde cross-linking in structural proteomics by highlighting its applications, characteristics and current status in the field. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Low-power formaldehyde detector for space applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trace contamination of the International Space Station (ISS) by formaldehyde?a known carcinogen? is a significant potential threat to crew health. The spacecraft...

  3. Formaldehyde Profiler Using Laser Induced Fluorescence Technique Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Formaldehyde (HCHO) is a key trace species that is of great interest to atmospheric scientists in NASA and other research institutions. In this SBIR project, we...

  4. IRIS Toxicological Review of Formaldehyde (Inhalation) (External Review Draft 2010)

    Science.gov (United States)

    UPDATE EPA is currently revising its Integrated Risk Information System (IRIS) assessment of formaldehyde to address the 2011 NAS peer review recommendations. This assessment addresses both noncancer and cancer human health effects that are relevant to assessing ...

  5. Low-Power Formaldehyde Detector for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trace contamination of the International Space Station (ISS) by formaldehyde -- a known carcinogen -- is a significant threat to crew health. The spacecraft maximum...

  6. Proposed residential indoor air quality guidelines for formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, N.

    2005-07-01

    This paper proposed a set of revised residential indoor air quality guidelines for formaldehyde. In the earlier guidelines, target and action levels were set at 60 {mu}g/m{sup 3} and 120 {mu}g/. However, epidemiological studies on the effects of chronic formaldehyde exposure have consistently found respiratory and allergic effects at levels below 123 {mu}g/m{sup 3}. Formaldehyde levels in home have been associated with increased risk of atopy and have also been associated with the hospitalization of children. Summaries of various epidemiological studies were presented. A summary of critical effects and the derivation of the guidelines was provided. Based on clinical studies and animal experiments, the primary effects of acute exposure to formaldehyde are the irritation of the mucosa of the upper respiratory tract and the eyes. The no observable adverse effects level (NOAEL) and lowest observable adverse effects level (LOAEL) for this outcome are 615 and 1,230 {mu}g/m{sup 3}. It was noted that an association between low-level exposure to formaldehyde and the development of allergic sensitization and asthma is biologically plausible as it is consistent with observations in animals. It was concluded that short-term exposure to formaldehyde should be limited to 123{mu}g/m{sup 3}. It was recommended that long term exposure to formaldehyde be limited to 50 {mu}g/m{sup 3}. Although formaldehyde is carcinogenic to humans, the cancer risk associated with lifelong exposure at the recommended levels is estimated to be negligible. 73 refs., 9 tabs.

  7. Association between formaldehyde exposure and miscarriage in Chinese women.

    Science.gov (United States)

    Xu, Wenjing; Zhang, Weiqiang; Zhang, Xuezhen; Dong, Taowei; Zeng, Huiqian; Fan, Qiyun

    2017-06-01

    The aim of this study was to assess whether higher plasma formaldehyde concentration existed in women diagnosed with miscarriage and whether it contributed to higher risk of miscarriage in Chinese women.A case-control study was conducted in 118 women with a diagnosed miscarriage at the first trimester and 191 healthy women who delivered at term. Plasma levels of formaldehyde were measured by gas chromatography in conjunction with mass spectrometry after derivatization of the formaldehyde to the pentafluorophenylhydrazone and characteristics of the subjects including age, education level, occupation, family income, home decoration status, and exposure to second-hand smoke were recorded. Logistic regression analyses were performed to investigate the relationship between miscarriage and levels of formaldehyde.Women with miscarriage were comparable to controls in terms of age, education level, occupation, family income, and home decoration status. They were, however, more likely to be exposed to second-hand smoke. Plasma levels of formaldehyde were significantly higher in women with miscarriage (0.0944 ± 0.0105 vs. 0.0239 ± 0.0032 μg/mL, P formaldehyde (odds ratio [OR]: 8.06, 95% confidence interval [CI]: 4.96-13.09) and exposure to second-hand smoke (OR: 3.60, 95% CI: 1.58-8.20) were independently and significantly associated with higher risk of miscarriage.Plasma levels of formaldehyde were significantly higher in women who were diagnosed with miscarriage than those who delivered at term and higher levels of formaldehyde was an independent risk factor for miscarriage, with higher levels being associated with higher risk of miscarriage.

  8. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Science.gov (United States)

    Schwemmer, G.; Yakshin, M.; Prasad, C.; Hanisco, T.; Mylapore, A. R.; Hwang, I. H.; Lee, S.

    2016-01-01

    We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO) fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  9. Association between formaldehyde exposure and miscarriage in Chinese women

    Science.gov (United States)

    Xu, Wenjing; Zhang, Weiqiang; Zhang, Xuezhen; Dong, Taowei; Zeng, Huiqian; Fan, Qiyun

    2017-01-01

    Abstract The aim of this study was to assess whether higher plasma formaldehyde concentration existed in women diagnosed with miscarriage and whether it contributed to higher risk of miscarriage in Chinese women. A case-control study was conducted in 118 women with a diagnosed miscarriage at the first trimester and 191 healthy women who delivered at term. Plasma levels of formaldehyde were measured by gas chromatography in conjunction with mass spectrometry after derivatization of the formaldehyde to the pentafluorophenylhydrazone and characteristics of the subjects including age, education level, occupation, family income, home decoration status, and exposure to second-hand smoke were recorded. Logistic regression analyses were performed to investigate the relationship between miscarriage and levels of formaldehyde. Women with miscarriage were comparable to controls in terms of age, education level, occupation, family income, and home decoration status. They were, however, more likely to be exposed to second-hand smoke. Plasma levels of formaldehyde were significantly higher in women with miscarriage (0.0944 ± 0.0105 vs. 0.0239 ± 0.0032 μg/mL, P < .001). Multivariate logistic regression showed that higher level of formaldehyde (odds ratio [OR]: 8.06, 95% confidence interval [CI]: 4.96–13.09) and exposure to second-hand smoke (OR: 3.60, 95% CI: 1.58–8.20) were independently and significantly associated with higher risk of miscarriage. Plasma levels of formaldehyde were significantly higher in women who were diagnosed with miscarriage than those who delivered at term and higher levels of formaldehyde was an independent risk factor for miscarriage, with higher levels being associated with higher risk of miscarriage. PMID:28658105

  10. Common and uncommon reactions to formaldehyde-containing nail hardeners.

    Science.gov (United States)

    Norton, L A

    1991-03-01

    A spectrum of reactions to free formaldehyde containing nail hardeners is presented. These include inflammatory and noninflammatory onycholysis, paronychia, chromonychia, nail plate shedding, and pterygium inversum unguis as well as satellite reactions on the skin and mucous membranes. Primary irritants are more common than allergic reactions. Nail cosmetic products containing free formaldehyde are available to the consumer, but federal guidelines dictate their labeling, acceptable concentration, and usage.

  11. Formaldehyde emissions from ULEF- and NAF-bonded commercial hardwood plywood as influenced by temperature and relative humidity

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Michael J. Birkeland; Kyle M. Gonner

    2010-01-01

    It is well documented in the literature that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF) adhesives. This work investigates the effect of temperature and humidity on newer, ultra-low emitting formaldehyde urea formaldehyde (ULEF-UF) and no-added formaldehyde (NAF) adhesives. A...

  12. Formaldehyde-releasers in cosmetics : relationship to formaldehyde contact allergy Part 1. Characterization, frequency and relevance of sensitization, and frequency of use in cosmetics

    NARCIS (Netherlands)

    de Groot, Anton C.; White, Ian R.; Flyvholm, Mari-Ann; Lensen, Gerda; Coenraads, Pieter-Jan

    2010-01-01

    In this part of a series of review articles on formaldehyde-releasers and their relationship to formaldehyde contact allergy, formaldehyde-releasers in cosmetics are discussed. In this first part of the article, key data are presented including frequency of sensitization and of their use in

  13. Investigation of formaldehyde interaction with carbon nanotubes and quartz sand

    Science.gov (United States)

    Georgopoulou, Maria P.; Chrysikopoulos, Constantinos V.

    2017-04-01

    Assessment of the potential impact of synthetic carbon nanotubes on the fate and transport of common chemical contaminants (pesticides, pharmaceuticals, etc.) in groundwater systems is considered to be an increasingly important aspect of environmental research. This study investigates the interaction of formaldehyde with multi-walled carbon nanotubes (MWCNTs) and quartz sand under static and dynamic conditions. Due to polarity, formaldehyde, is expected to develop strong adsorptive interactions with carbon nanotubes. Several batch adsorption experiments were conducted in test tubes, under controlled conditions. Various initial formaldehyde solution concentration (2, 5, 8 ppm), contact times, and temperatures (8, 18, 25 °C) were considered. Supernatant liquid samples were collected at regular intervals, and centrifuged. Subsequently, the formaldehyde concentration in the supernatant was quantified indirectly, by derivatization with Nash reagent and subsequent measurement of the resulting complex using spectrophotometry in the visible spectral range. Experimental results suggested that formaldehyde has a low affinity for quartz sand, but an enhanced potential for adsorption onto carbon nanotubes. Formaldehyde adsorption onto both absorbents (quartz sand and MWCNTs) was more pronounced under dynamic than static conditions, probably, because agitation improves the mixing of the absorbent within the solution. Also, it was shown that the adsorption data were adequately described by the pseudo-second order kinetic model, suggesting that the primary adsorption mechanism was chemisorption, where two or more (sequential or parallel) processes (e.g. surface chemisorption, intraparticle diffusion) were taking place. Therefore, MWCNTs could be promising adsorbent materials for groundwater remediation.

  14. Formaldehyde Levels in Traditional and Portable Classrooms: A Pilot Investigation.

    Science.gov (United States)

    Ribeiro, Isabela C; Kowalski, Peter J; Callahan, David B; Noonan, Gary P; Moffett, Daphne B; Olson, David R; Malilay, Josephine

    2016-03-01

    The pilot study discussed in this article assessed formaldehyde levels in portable classrooms (PCs) and traditional classrooms the authors evaluated formaldehyde levels in day and overnight indoor air (TCs) and explored factors influencing indoor air quality (e.g., carbon dioxide, temperature, and relative humidity). In a cross-sectional design, samples from nine PCs renovated within three years previously and three TCs in a school district in metropolitan Atlanta, Georgia. Formaldehyde levels ranged from 0.0068 to 0.038 parts per million (ppm). In both types of classroom, overnight formaldehyde median levels (PCs = 0.018 ppm; TCs = 0.019 ppm) were higher than day formaldehyde median levels (PCs = 0.011 ppm; TCs = 0.016 ppm). Carbon dioxide levels measured 470-790 ppm at 7:00 a.m. and 470-1800 ppm at 4:00 p.m. Afternoon medians were higher in TCs (1,400 ppm) than in PCs (780 ppm). Consistent with previous studies, formaldehyde levels were similar among PCs and TCs. Reducing carbon dioxide levels by improving ventilation is recommended for classrooms.

  15. Aging-associated excess formaldehyde leads to spatial memory deficits

    Science.gov (United States)

    Tong, Zhiqian; Han, Chanshuai; Luo, Wenhong; Li, Hui; Luo, Hongjun; Qiang, Min; Su, Tao; Wu, Beibei; Liu, Ying; Yang, Xu; Wan, You; Cui, Dehua; He, Rongqiao

    2013-01-01

    Recent studies show that formaldehyde participates in DNA demethylation/methylation cycle. Emerging evidence identifies that neuronal activity induces global DNA demethylation and re-methylation; and DNA methylation is a critical step for memory formation. These data suggest that endogenous formaldehyde may intrinsically link learning-responsive DNA methylation status and memory formation. Here, we report that during spatial memory formation process, spatial training induces an initial global DNA demethylation and subsequent re-methylation associated with hippocampal formaldehyde elevation then decline to baseline level in Sprague Dawley rats. Scavenging this elevated formaldehyde by formaldehyde-degrading enzyme (FDH), or enhancing DNA demethylation by a DNA demethylating agent, both led to spatial memory deficits by blocking DNA re-methylation in rats. Furthermore, we found that the normal adult rats intrahippocampally injected with excess formaldehyde can imitate the aged-related spatial memory deficits and global DNA methylation decline. These findings indicate that aging-associated excess formaldheyde contributes to cognitive decline during aging. PMID:23657727

  16. The Massachusetts program for reducing the risk of formaldehyde exposure.

    Science.gov (United States)

    Walker, B; Fox, P; Li, V; Parker, G

    1987-01-01

    Urea formaldehyde foam insulation in homes has caused increasing concerns about the adverse health effects associated with residential exposure to formaldehyde emissions. These health effects cover a broad spectrum of symptoms, including neurophysiological effects, respiratory irritations, and eye and skin irritations. Recent studies have also suggested a possible correlation between exposure to formaldehyde vapors and cancer. In 1979, following hundreds of complaints of adverse health effects from occupants of dwellings insulated with urea formaldehyde foam insulation (UFFI), the Massachusetts Department of Public Health issued regulations banning the new installation of UFFI in Massachusetts. New State legislation was adopted in 1986 which reformulated UFFI policy. The law established a minimum concentration of formaldehyde of 0.1 parts per million (ppm) below which removal of the insulation is not required or encouraged. A trust fund financed by industry was established to pay for air testing and for the removal of UFFI from homes if the formaldehyde level exceeds the statutory minimum of 0.1 ppm or if an occupant experiences adverse health effects attributable to the insulation. Based on the Massachusetts experience, these requirements have been identified: the need for flexibility and midcourse corrections in the development of health policy to allow for the incorporation of new scientific information or changes in the economic or political environment, the need for close coordination with all affected parties, and the need for scientific and technical policy development to be joined with economic and political perspectives to ensure smooth implementation of health policies.

  17. Health risks from indoor formaldehyde exposures in northwest weatherized residences

    Energy Technology Data Exchange (ETDEWEB)

    Mellinger, P.J.; Sever, L.E.

    1986-10-01

    Conflicting opinions on the potential hazards associated with formaldehyde exposure triggered a national workshop to address the toxicological questions concerning the health effects of formaldehyde. Since quantitative human data are not available to derive a dose-response curve for formaldehyde risk assessment, nonhuman data are used. In the case of formaldehyde, data from animals exposed to high concentrations are used to estimate human risk at much lower concentrations. This study presents the several steps that make up a risk assessment and examines any additional data that might alter significantly the risk estimates presented in the 1984 EIS. Rat inhalation chronic bioassay data from a study sponsored by the Chemical Industry Institute of Toxicology (CIIT) have been used to develop a risk equation that was subsequently used by BPA in its EIS. The CIIT data base remains the only acceptable animal data that can support the estimation of a dose-response curve. The development of mathematical models continues with a great deal of energy, and the use of different models is largely responsible for the great variability of the formaldehyde risk estimates. While one can calculate different values for carcinogenic risk associated with formaldehyde exposure than were presented earlier in the BPA EIS, they are not likely to be any better.

  18. Extending the Millimeter-Submillimeter Spectrum of Protonated Formaldehyde

    Science.gov (United States)

    Roenitz, Kevin; Zou, Luyao; Widicus Weaver, Susanna L.

    2017-06-01

    Protonated formaldehyde has been detected in the interstellar medium, where it participates in the formation and destruction of methanol. The rotational spectrum for protonated formaldehyde has been previously recorded by Amano and coworkers from 120-385 GHz using a hollow cathode discharge source for ion production. Additionally, protonated formaldehyde was produced in a supersonic expansion discharge source by Duncan and coworkers, but it was detected using time-of-flight mass spectrometry. Higher frequency spectra would help to guide additional observational studies of protonated formaldehyde using instruments such as the ALMA and SOFIA observatories. As such, we have used a supersonic expansion discharge source to produce protonated formaldehyde, and recorded its spectrum using millimeter-submillimeter direct absorption spectroscopy. The rotational spectrum was recorded from 350-1000 GHz. Here we will present the experimental design, specifically focusing on the optimization of the source for production of organic ions. We will also present the spectroscopic results for protonated formaldehyde and a spectral analysis with associated prediction that can be extended to frequencies above 1 THz.

  19. Primary Formation Path of Formaldehyde in Hydrothermal Vents

    Science.gov (United States)

    Inaba, Satoshi

    2017-09-01

    Formaldehyde is abundant in the universe and one of the fundamental molecules for life. Hydrothermal vents produce a substantial amount of hydrogen molecules by serpentinization and promote reductive reactions of single carbon compounds. The abundance of formaldehyde is expected to be low due to the high Gibbs free energy in hydrothermal vents. We consider two competing formation pathways of formaldehyde: (1) the reduction of CO by H2 and (2) the reduction of HCOOH by H2 to form a methanediol, followed by the dehydration of the methanediol. We performed a number of quantum chemical simulations to examine the formation of formaldehyde in the gas phase as well as in aqueous solution. The energy barrier is significantly reduced by the catalytic effect of water molecules in aqueous solution and becomes lowest when a water cluster consisted of 5 water molecules catalyzes the reduction. The energy barrier to form a methanediol by the reduction of HCOOH is lower by 17.5 kcal/mol than that to form a formaldehyde by the reduction of CO. Considering the low energy barrier to dehydrate methanediol, the primary pathway to form formaldehyde in hydrothermal vents is concluded to be the reduction of HCOOH by H2, followed by the dehydration of methanediol.

  20. Formaldehyde in dentistry: a review of mutagenic and carcinogenic potential

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.B.; Chestner, S.B.

    1981-09-01

    For many years there has been controversy over the value of antimicrobial drugs for intracanal dressings in endodontics. Formocresol, a formaldehyde compound, has evolved as the preferred drug for routine endodontic procedures, as well as pediatric endodontics. The increase in the use of formaldehyde has been complicated by the introduction of paraformaldehyde pastes for filling root canals. Neither of these formulas has ever been standardized. The doses are arbitrary, and the common dose of formocresol has been shown to be many times greater than the minimum dose needed for effect. The efficacy of paraformaldehyde pastes is questionable and remains clouded by inconclusive evidence, conflicting research, inadequate terminology, and a lack of convincing statistical evidence. The clinical use and delivery of formocresol and paraformaldehyde pastes remain arbitrary and unscientific. Formaldehyde has a known toxic mutagenic and carcinogenic potential. Many investigations have been conducted to measure the risk of exposure to formaldehyde; it is clear that formaldehyde poses a carcinogenic risk in humans. There is a need to reevaluate the rationale underlying the use of formaldehyde in dentistry particularly in light of its deleterious effects.

  1. Synthesis of Disperse Dyes from Pyridone and Resorcinol Coupled to Diazotized 2-Amino-4-chloro-5-formylthiazole and Application to Polyester

    Directory of Open Access Journals (Sweden)

    Yusuf Y. Lams

    2014-01-01

    Full Text Available The aim of this study was to synthesize disperse dyes in the derivative of 2-amino-4-chloro-5-formylthiazole by conventional diazotization and couplings with pyridone and resorcinol. The dyes were characterized by visible absorption spectroscopy, IR spectral studies, and 1H and 13C NMR. The pyridone and resorcinol substituted dyes exhausted well with good depth on 100% polyester fabrics with a shade of brown and purple colours, respectively. The heteroatom and the intrinsic conjugation in the thiazole structure results in high bathochromic shifts and lead to brightness of shades. The dyed fabrics showed very good to excellent wash fastness and moderate to good light and perspiration fastness properties.

  2. Anti-inflammatory 5-(11'Z-heptadecenyl)- and 5-(8'Z,11'Z-heptadecadienyl)-resorcinols from mango (Mangifera indica L.) peels.

    Science.gov (United States)

    Knödler, Matthias; Conrad, Jürgen; Wenzig, Eva M; Bauer, Rudolf; Lacorn, Markus; Beifuss, Uwe; Carle, Reinhold; Schieber, Andreas

    2008-02-01

    Bioassay directed extraction and purification of mango peels revealed the 5-(11'Z-heptadecenyl)-resorcinol (1) and the known 5-(8'Z,11'Z-heptadecadienyl)-resorcinol (2) previously not described in Mangifera indica L. The structures of both compounds were determined by extensive 1D and 2D NMR studies and MS. Both compounds exhibited potent cyclooxygenase (COX)-1 and COX-2 inhibitory activity with IC(50) values ranging from 1.9 (2) to 3.5 microM (1) and from 3.5 (2) to 4.4 (1) microM, respectively, coming close to the IC(50) values of reference drugs. 5-Lipoxygenase (5-LOX) catalyzed leukotriene formation was only slightly inhibited. Structure-activity studies by referring to synthetic saturated homologues indicated that the degree of unsaturation in the alkyl chain plays a key role for COX inhibitory activity, whereas the influence of chain length was less significant.

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

    Directory of Open Access Journals (Sweden)

    Kubecki M.

    2012-09-01

    Full Text Available Suitability of the given binding agent for the moulding sands preparation depends on the one hand on the estimation of technological properties of the sand and the mould made of it and the obtained casting quality and on the other hand on the assessment of this sand influence on the natural and working environment. Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin (phenol-formaldehyde, urea, furfuryl, urea-furfuryl, alkyd under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene, and also polycyclic aromatic hydrocarbons (PAH can be formed and released.

  4. An eco-friendly synthesis, characterization, morphology and ion exchange properties of terpolymer resin derived from p-hydroxybenzaldehyde

    Directory of Open Access Journals (Sweden)

    Deepti B. Patle

    2016-09-01

    Full Text Available A novel chelating terpolymer resin has been synthesized through the terpolymerization of p-hydroxybenzaldehyde and biuret with formaldehyde (p-HBBF in 1:1:2 mol ratio using hydrochloric acid as a reaction medium by condensation technique. The synthesized terpolymer resin was characterized by elemental analysis, FTIR, 1H NMR and 13C NMR spectroscopy. On basis of the spectral studies, the structure of the terpolymer resin was proposed. The physico-chemical parameters have been evaluated for the terpolymer resin. Non-aqueous conductometric titration was used to determine the average molecular weight and polydispersity of the p-HBBF terpolymer resin and the intrinsic viscosity was also determined. The semicrystalline nature of the synthesized terpolymer was established by scanning electron microscopy (SEM. Terpolymer (p-HBBF synthesized is proved to be selective chelating ion exchange terpolymer resin for certain metals. Chelating ion exchange properties of this polymer was studied for Fe3+, Cu2+, Cd2+, Zn2+, Ni2+ and Pb2+ ions. A batch equilibrium method was employed in the study of the selectivity of the distribution of a given metal ions between the polymer sample and a solution containing the metal ion. The morphology of the terpolymers was studied by scanning electron microscopy, showing amorphous nature of the resins therefore can be used as a selective ion-exchanger for certain metal ions.

  5. Canadian synthetic resins industry

    Energy Technology Data Exchange (ETDEWEB)

    Margeson, J. [Industry Canada, Ottawa, ON (Canada)

    2000-06-01

    The growth of the synthetic resin industry in Canada is described. In 1999 the industry had shipments totalling $6.3 billion and employed about 9,000 people in 105 establishments. The industry is concentrated in Alberta, Ontario and Quebec. Plants in Alberta produce commodity-grade thermoplastic resins from raw materials derived mainly from natural gas, whereas plants in Ontario and Quebec produce both thermoplastic and thermoset resins using raw materials derived from both crude oil and natural gas. Sixty-four per cent of the synthetic reins produced in Canada, worth about $4.1 billion, are exported. This is offset by imports of 68 per cent of domestic consumption, (valued at $5.0 billion) reflecting rationalization and specialization of the resin industry on a continental basis. Process and product technologies used in Canada are up-to-date and licensed from parent or other foreign chemical companies. Capital investment in the Canadian resin industry is lagging behind investment in the United States, however, this is expected to change once the impact of recent investments in the industry in Alberta is reflected in the statistics. A five to seven per cent real average annual growth in world-wide consumption is predicted over the next five years. Growth in North America is projected to be in the three to four per cent range. The Alberta-based component of the industry, being relatively new, is expected to improve its ability to compete globally in commodity thermoplastics. In contrast, the plants in Ontario and Quebec suffer from the fact that they were built prior to the Free Trade Agreement and were designed to satisfy domestic requirements. They are attempting to compensate for their lack of economics of scale by developing strategies to supply niche products. 8 figs.

  6. Eco-friendly Crosslinking Agent for Acid Functional Acrylic Resin

    Directory of Open Access Journals (Sweden)

    Archana Shah

    2009-01-01

    Full Text Available Oil from J. multifida was extracted and it was first converted into N,N-bis(2-hydroxyethyl Jatropha fatty amide (HEJFA. HEJFA has been synthesized by reaction between Jatropha oil and diethanol amine in presence of zinc oxide as a catalyst. The reaction is relatively rapid and proceeded to high yield at 200±5 OC. The resulting HEJFA was used to formulate thermosetting coating compositions. Films were cured at ambient (air drying and elevated (stove drying temperatures using N, N-bis(2-hydroxyethyl Jatropha fatty amide (HEJFA as eco-friendly crosslinking agent for acrylic resin. The coating performance of the various compositions was tested by measurement of scratch hardness, impact strength and chemical resistance. The results show better performance of the HEJFA based compositions compared to butylated melamine formaldehyde (MF based compositions.

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

    Science.gov (United States)

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

    2013-08-01

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

  8. Chemical characterization of a commercial Commiphora wightii resin sample and chemical profiling to assess for authenticity.

    Science.gov (United States)

    Ahmed, Rida; Ali, Zulfiqar; Wu, Yunshan; Kulkarni, Swapnil; Avery, Mitchell A; Choudhary, Muhammed Iqbal; Khan, Ikhlas A

    2011-06-01

    The gum resin of Commiphora wightii [(Hook. ex Stocks) Engl.] is an ayurvedic medicine for the treatment of arthritis, inflammation, obesity, lipid disorders, and cardiovascular diseases and is known as guggul. Morphologically, it is not easy to distinguish guggul from closely related gum resins of other plants. Reliability of the commercially available guggul is critical due to the high risk of adulteration. To check authenticity, a commercial guggul sample was investigated for its chemical markers and 17 metabolites were identified, including three new, 20(S),21-epoxy-3-oxocholest-4-ene (1), 8 β-hydroxy-3,20-dioxopregn-4,6-diene (2), and 5-(13' Z-nonadecenyl)resorcinol (17) from the ethyl acetate soluble part. During the current study, compounds 14- 17 were identified as constituents of Mangifera indica gum, as an adulterant in the commercial guggul sample. This discovery highlighted the common malpractices in the trade of medicinal raw material in the developing world. The structures of the compounds were deduced by the spectroscopic technique and chemical methods, as well as by comparison with the reported data. The structure of 20(S),21-epoxy-3-oxocholest-4-ene (1) was also unambiguously deduced by single-crystal X-ray diffraction technique. © Georg Thieme Verlag KG Stuttgart · New York.

  9. In vitro reaction of barbiturates with formaldehyde.

    Science.gov (United States)

    Gannett, P M; Daft, J R; James, D; Rybeck, B; Knopp, J B; Tracy, T S

    2001-09-01

    Barbiturates are widely used as sedatives, hypnotics, and antiepileptics, and, when coupled with their narrow therapeutic index, the probability that their use will result in accidental or intentional death is significant. When barbiturates are implicated in a murder or suicide, analysis for their presence is often required. Under certain conditions, barbiturates are quite stable, but conditions found in vivo immediately after death or after embalming may promote barbiturate decomposition. If extensive decomposition occurs, analysis for them may be difficult or impossible. Here, the stability of three representative barbiturates, under conditions that model those likely to prevail in vivo shortly after death and after embalming, have been studied. Solutions of phenobarbital were found to slowly decompose in water over the pH range of approximately 3.5 to 9.5. More rapid decomposition occurred at higher pH, and 2-phenylbutyric acid was the main decomposition product. Formaldehyde (5-20%) accelerated the decomposition rate 3-10-fold such that phenobarbital decomposition could be complete after 30 days. In contrast, pentobarbital decomposed roughly 10 times more slowly and secobarbital did not detectably decompose under any of the conditions studied. Thus, certain barbiturates may partially or completely decompose in vivo after death, especially after embalming, and thus analysis for them may lead to false negatives. However, this work shows that analysis for the parent barbiturate or its predicted decomposition product may provide data that will reduce the likelihood of false negatives.

  10. Production and utilization of tannin from ipil-ipil (Leucaena leucocephala (lam) de wit) barks

    Energy Technology Data Exchange (ETDEWEB)

    Manas, A.E.

    1980-01-01

    The countercurrent extraction of L. leucocephala bark with H/sub 2/O at 80 degrees gave tannin extract in 68-74% yield with high Stiasny no. (84.57) for use in adhesive preparation for plywood. The tannin-H/sub 2/CO resin prepared from the spray-dried extract had glue shear strength superior to that of commercial urea resin. The addition of 10-40% formaldehyde-phenol copolymer or 5-30% formaldehyde-phenol-resorcinol copolymer improved the H/sub 2/O resistance of the tannin-based adhesive and also helped meet the requirements of US commercial standards for plywood.

  11. 40 CFR 721.10189 - Fatty acids, tall-oil, reaction products with (butoxymethyl) oxirane formaldehyde-phenol polymer...

    Science.gov (United States)

    2010-07-01

    ... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine... Substances § 721.10189 Fatty acids, tall-oil, reaction products with (butoxymethyl) oxirane formaldehyde... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine...

  12. Analysis of equilibrium data for cesium ion exchange of Hanford CC and NCAW supernatant liquid--Status report

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D.E.; Bray, L.A.; Brooks, K.P.; Carlson, C.D.; Kim, A.Y.

    1996-04-01

    This report contains the results of a partial analysis and correlation of a large amount of equilibrium data obtained for cesium ion exchange. Data from testing of organic resins, a phenolic- carboxylic acid resin, and a resorcinol-formaldehyde resin with NCAW and CC waste simulants were assessed. The isotherms that were considered for correlating the data include the Langmuir, the Freundlich, and a combination of the two. These correlations are being developed to provide equations that can be used with models for assessing column behavior and provide correlations that will allow prediction of the equilibrium performance of the two resins with wastes of different compositions.

  13. Foliar uptake and translocation of formaldehyde with Bracket plants (Chlorophytum comosum).

    Science.gov (United States)

    Su, Yuhong; Liang, Yongchao

    2015-06-30

    The foliar uptake and transport of formaldehyde into Bracket plants from air via leaves and roots to external water was investigated in an air-plant-water system. The results indicated that formaldehyde could be quickly taken up by plant tissues, and that formaldehyde accumulated in leaves could be released rapidly back into air when the formaldehyde level in air was diminished. This rapid reversible translocation of formaldehyde between plant leaves and air resulted in high formaldehyde concentrations in leaf dews, depending upon exposure levels of formaldehyde in air. Meanwhile, formaldehyde could be transported from air to plant rhizosphere solution through downward transport. The concentration of formaldehyde in rhizosphere solutions increased with exposure time and the formaldehyde level in air. The efficiency of the leaf extracts to break down formaldehyde increased, probably because of an increase in oxidative potential of the leaf extracts. Taken together, the main mechanism of formaldehyde loss in air can be attributed to the accumulation by (or breakdown in) plant tissues; the removal rate of formaldehyde from air reached 135 μg h(-1) plant(-1) in the experimental condition. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Membrane-associated quinoprotein formaldehyde dehydrogenase from Methylococcus capsulatus Bath.

    Science.gov (United States)

    Zahn, J A; Bergmann, D J; Boyd, J M; Kunz, R C; DiSpirito, A A

    2001-12-01

    A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 micromol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)(+)-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159-167, 1999; Vorholt et al., J. Bacteriol. 180:5351-5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b(559/569) complex as the physiological electron acceptor.

  15. Membrane-Associated Quinoprotein Formaldehyde Dehydrogenase from Methylococcus capsulatus Bath

    Science.gov (United States)

    Zahn, James A.; Bergmann, David J.; Boyd, Jeffery M.; Kunz, Ryan C.; DiSpirito, Alan A.

    2001-01-01

    A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 μmol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)+-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159–167, 1999; Vorholt et al., J. Bacteriol. 180:5351–5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b559/569 complex as the physiological electron acceptor. PMID:11698372

  16. Mammals divert endogenous genotoxic formaldehyde into one-carbon metabolism.

    Science.gov (United States)

    Burgos-Barragan, Guillermo; Wit, Niek; Meiser, Johannes; Dingler, Felix A; Pietzke, Matthias; Mulderrig, Lee; Pontel, Lucas B; Rosado, Ivan V; Brewer, Thomas F; Cordell, Rebecca L; Monks, Paul S; Chang, Christopher J; Vazquez, Alexei; Patel, Ketan J

    2017-08-31

    The folate-driven one-carbon (1C) cycle is a fundamental metabolic hub in cells that enables the synthesis of nucleotides and amino acids and epigenetic modifications. This cycle might also release formaldehyde, a potent protein and DNA crosslinking agent that organisms produce in substantial quantities. Here we show that supplementation with tetrahydrofolate, the essential cofactor of this cycle, and other oxidation-prone folate derivatives kills human, mouse and chicken cells that cannot detoxify formaldehyde or that lack DNA crosslink repair. Notably, formaldehyde is generated from oxidative decomposition of the folate backbone. Furthermore, we find that formaldehyde detoxification in human cells generates formate, and thereby promotes nucleotide synthesis. This supply of 1C units is sufficient to sustain the growth of cells that are unable to use serine, which is the predominant source of 1C units. These findings identify an unexpected source of formaldehyde and, more generally, indicate that the detoxification of this ubiquitous endogenous genotoxin creates a benign 1C unit that can sustain essential metabolism.

  17. Formaldehyde as a basis for residential ventilation rates

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, M.H.; Hodgson, A.T.

    2002-04-28

    Traditionally, houses in the U.S. have been ventilated by passive infiltration in combination with active window opening. However in recent years, the construction quality of residential building envelopes has been improved to reduce infiltration, and the use of windows for ventilation also may have decreased due to a number of factors. Thus, there has been increased interest in engineered ventilation systems for residences. The amount of ventilation provided by an engineered system should be set to protect occupants from unhealthy or objectionable exposures to indoor pollutants, while minimizing energy costs for conditioning incoming air. Determining the correct ventilation rate is a complex task, as there are numerous pollutants of potential concern, each having poorly characterized emission rates, and poorly defined acceptable levels of exposure. One ubiquitous pollutant in residences is formaldehyde. The sources of formaldehyde in new houses are reasonably understood, and there is a large body of literature on human health effects. This report examines the use of formaldehyde as a means of determining ventilation rates and uses existing data on emission rates of formaldehyde in new houses to derive recommended levels. Based on current, widely accepted concentration guidelines for formaldehyde, the minimum and guideline ventilation rates for most new houses are 0.28 and 0.5 air changes per hour, respectively.

  18. Flame Retardant Epoxy Resins

    Science.gov (United States)

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

    2004-01-01

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

  19. Preliminary survey report: control technology for formaldehyde emissions at Baker Furniture Company, Mocksville, North Carolina, September 2, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, V.D.

    1983-07-28

    An on-site visit was made to the Baker Furniture Company, Mocksville, North Carolina to observe the processes and associated controls for veneering wood panels using heated platen presses. The facility manufactured furniture and produced veneered panels. For flat panels, the hot-press process was used exclusively. There was some radiofrequency (RF) laminating of small parts and frames. Less than 5,000 square feet of panels were produced per day. The veneer department consisted of 35 workers, eight assigned to the hot press operation. For most applications, a urea/formaldehyde resin was used as the adhesive. There were canopy hoods over the feed-through press and the shuttle press. General ventilation was provided mainly by open doors and an extensive local exhaust ventilation for controlling sawdust. Formaldehyde concentrations ranging from less than 1 part per million (ppm) to between 1 and 2 ppm were noted around the feed-through press in the morning. Concentrations of 1 to 3 ppm were noted at the glue mixing station, loading platform, and unloading area in the afternoon. The general airflow through the space between the press and face of the canopy appeared to carry some emission into the work place. The author notes that this facility offers the opportunity to study a canopy hood over a feed-through press, but the low production rate may preclude an accurate evaluation of control-system effectiveness.

  20. A Low-Cost, Formaldehyde-Free and High Flame Retardancy Wood Adhesive from Inorganic Adhesives: Properties and Performance

    Directory of Open Access Journals (Sweden)

    Shicun Jin

    2017-10-01

    Full Text Available Wood composites used in indoor living environments often pose formaldehyde emission and fire hazard problems. In this study, magnesium oxychloride cement-based (MOC inorganic adhesives are presented as an effective and sustainable binder for plywood applications. The phase composition, microstructure, and thermal stability of the adhesives prepared with different ratios of MgO/MgCl2 were investigated. In addition, the dry and wet shear strength and the combustion behavior of the plywood were also examined. The results indicated that the limiting oxygen index (LOI values of the plywood bonded by the MOC adhesives were higher than those of the plywood bonded by urea-formaldehyde resin. The active MgO/MgCl2 molar ratio of 7 was the optimal ratio for the dry and wet shear strength of the plywood with values of 1.02 and 0.88 MPa, respectively, which meet the interior use panel (Type II plywood requirements. These improvements were ascribed to the increasing ratio of MgO/MgCl2 that facilitated the formation of an excellent microstructure. Meanwhile, the continuous hydration phase strengthened the interaction between the MOC adhesive and the wood. With these improved properties, MOC adhesive is expected to be widely used for industrial applications in plywood fabrication.

  1. Formaldehyde as hypothetical primer of biohomochirality

    Energy Technology Data Exchange (ETDEWEB)

    Goldanskii, V.I. [N. N. Semenov Institute of Chemical Physics of the Russian Academy of Sciences, Kosygin Street 4, Moscow, 117334 (Russia)

    1996-07-01

    One of the most intriguing and crucial problems of the prebiotic evolution and the origin of life is the explanation of the origin of biohomochirality. A scheme of conversions originated by formaldehyde (FA) as hypothetical primer of biohomochirality is proposed. The merit of FA as executor of this function is based -inter alia - on the distinguished role of FA as one of the earliest and simplest molecules in both warm, terrestrial and cold, extraterrestrial scenarios of the origin of life. The confirmation of the role of FA as primer of biohomochirality would support the option of an RNA world as an alternative to the protein world. The suggested hypothesis puts forward for the first time a concrete sequence of chemical reactions which can lead to biohomochirality. The spontaneous breaking of the mirror symmetry is secured by the application of the well-known Frank scheme (combination of autocatalysis and {open_quote}{open_quote}annihilation{close_quote}{close_quote} of L and D enantiomers) to the series of interactions of FA {open_quote}{open_quote}trimers{close_quote}{close_quote} (i.e. C{sub 3}H{sub 6}O{sub 3} compounds) of (aaa), (apa) and (app) types, where the monomeric groups (a) means {open_quote}{open_quote}achirons{close_quote}{close_quote} (a=CH{sub n}, n{ge}2 and C=M, M=C,O) and (p) mean {open_quote}{open_quote}prochirons{close_quote}{close_quote} (p=HC{asterisk}OM, M=H,C). {copyright} {ital 1996 American Institute of Physics.}

  2. System for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2010-11-23

    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.

  3. Paramagnetic epoxy resin

    Directory of Open Access Journals (Sweden)

    E. C. Vazquez Barreiro

    2017-01-01

    Full Text Available This work illustrates that macrocycles can be used as crosslinking agents for curing epoxy resins, provided that they have appropriate organic functionalities. As macrocycles can complex metal ions in their structure, this curing reaction allows for the introduction of that metal ion into the resin network. As a result, some characteristic physical properties of the metallomacrocycle could be transferred to the new material. The bisphenol A diglycidyl ether (BADGE, n = 0 and hemin (a protoporphyrin IX containing the Fe(III ion, and an additional chloride ligand have been chosen. The new material has been characterized by differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, Fourier Transform Infrared (FT-IR, Nuclear Magnetic Resonance (NMR, Transmission Electron Microscopy (TEM, and magnetic susceptibility measurements. Fe(III remains in the high-spin state during the curing process and, consequently, the final material exhibits the magnetic characteristics of hemin. The loss of the chlorine atom ligand during the cure of the resin allows that Fe(III can act as Lewis acid, catalyzing the crosslinking reactions. At high BADGE n = 0/hemin ratios, the formation of ether and ester bonds occurs simultaneously during the process.

  4. Engineering and analysis of a Saccharomyces cerevisiae strain that uses formaldehyde as an auxiliary substrate

    NARCIS (Netherlands)

    Baerends, Richard J. S.; de Hulster, Erik; Geertman, Jan-Maarten A.; Daran, Jean-Marc; van Maris, Antonius J. A.; Veenhuis, Marten; van der Klei, Ida J.; Pronk, Jack T.

    We demonstrated that formaldehyde can be efficiently coutilized by an engineered Saccharomyces cerevisiae strain that expresses Hansenula polymorpha genes encoding formaldehyde dehydrogenase (FLD1) and formate dehydrogenase (FMD), in contrast to wild-type strains. Initial chemostat experiments

  5. FORMALDEHYDE GAS INACTIVATION OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACE MATERIALS.

    Science.gov (United States)

    Research evaluated the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface material using formaldehyde gas. Spores were dried on seven types of indoor surfaces and exposed to 1100 ppm formaldehyde gas for 10 hr. Fo...

  6. Uranium (V I) recovery in aqueous solution by means of tannic resins; Recuperacion de Uranio (VI) en solucion acuosa por medio de resinas tanicas

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, M.; Urbina, B.; Alvarado, J.C.; Andreu, G.A. [Instituto de Investigaciones Cientificas. Universidad de Guanajuato. Cerro de la Venada s/n, Guanajuato, Gto. C.P. 36040 (Mexico)

    1998-12-01

    Results in studying UO{sub 2} {sup 2+} retention by tannic resins of mimosa with a very low water solubility are showed. The resin was synthesized through a condensation reaction from tannin and formaldehyde by acidic catalysis. Batch studies were realized in order to determine the optimum uranyl collection conditions in water solution. Effects of p H, temperature, shaking time and quantity of resin on the collection process were evaluated. The best retention was achieved with p H 4.0 at 60 Centigrade and 40 minutes. Column studies showed that tannic resin can be recovered several times by rinsing with 0.1N HCl. This technique is considered successful because it has a collection ability higher than 99% in addition to high repeatability-elution process (C.V. = 0.04% and 0.13%). (Author)

  7. A Short Review on Photocatalytic Degradation of Formaldehyde.

    Science.gov (United States)

    Tasbihi, Minoo; Bendyna, Joanna K; Notten, Peter H L; Hintzen, H T

    2015-09-01

    Nowadays, it is a great challenge to eliminate toxic and harmful organic pollutants from air and water. This paper reviews the role of TiO2 as a photocatalyst, light source and photoreactor in the particular case of removal of formaldehyde using the photocatalytic reaction by titanium dioxide (TiO2) in aqueous and gaseous systems. The reaction mechanisms of the photocatalytic oxidation of gaseous formaldehyde are given. We also present a detailed review of published articles on photocatalytic degradation of formaldehyde by modified titanium dioxide doped with foreign species such as metal and non-metal components. We point out the most prospective developments of the photocatalyst compositions for the future potential commercial applications.

  8. Studies on adsorption of formaldehyde in zirconium phosphate-glyphosates

    Science.gov (United States)

    Zhang, Yuejuan; Yi, Jianjun; Xu, Qinghong

    2011-01-01

    In our previous work [22], a kind of layered compound of zirconium phosphate-glyphosate (ZrGP) was synthesized. Its large surface area (445 m 2/g) indicates this compound has possible application in adsorptions. In this paper, adsorption to formaldehyde in ZrGP and mechanisms of the adsorption were studied carefully. Balance time of adsorption (about 6 h) and largest adsorbed amount (7.8%) were found when adsorption temperature was at 40 °C and pH value of adsorption environment was about 3.0. H-bonds were found existing between molecules of formaldehyde and ZrGP, and formaldehyde molecules could exist in ZrGP stably.

  9. The margin of exposure to formaldehyde in alcoholic beverages.

    Science.gov (United States)

    Monakhova, Yulia B; Jendral, Julien A; Lachenmeier, Dirk W

    2012-06-01

    Formaldehyde has been classified as carcinogenic to humans (WHO IARC group 1). It causes leukaemia and nasopharyngeal cancer, and was described to regularly occur in alcoholic beverages. However, its risk associated with consumption of alcohol has not been systematically studied, so this study will provide the first risk assessment of formaldehyde for consumers of alcoholic beverages.Human dietary intake of formaldehyde via alcoholic beverages in the European Union was estimated based on WHO alcohol consumption data and literature on formaldehyde contents of different beverage groups (beer, wine, spirits, and unrecorded alcohol). The risk assessment was conducted using the margin of exposure (MOE) approach with benchmark doses (BMD) for 10 % effect obtained from dose-response modelling of animal experiments.For tumours in male rats, a BMD of 30 mg kg(-1) body weight per day and a "BMD lower confidence limit" (BMDL) of 23 mg kg(-1) d(-1) were calculated from available long-term animal experiments. The average human exposure to formaldehyde from alcoholic beverages was estimated at 8·10(-5) mg kg(-1) d(-1). Comparing the human exposure with BMDL, the resulting MOE was above 200,000 for average scenarios. Even in the worst-case scenarios, the MOE was never below 10,000, which is considered to be the threshold for public health concerns.The risk assessment shows that the cancer risk from formaldehyde to the alcohol-consuming population is negligible and the priority for risk management (e.g. to reduce the contamination) is very low. The major risk in alcoholic beverages derives from ethanol and acetaldehyde.

  10. 40 CFR 721.7220 - Polymer of substituted phenol, formaldehyde, epichlorohydrin, and disubstituted benzene.

    Science.gov (United States)

    2010-07-01

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

  11. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated (PMN...

  12. Relationship between formaldehyde and quaternium-15 contact allergy. Influence of strength of patch test reactions

    NARCIS (Netherlands)

    de Groot, Anton C.; Blok, Janine; Coenraads, Pieter-Jan

    2010-01-01

    Objectives: To test our hypothesis that patients with stronger patch test reactions to formaldehyde are more likely to react to quaternium-15, attesting to the aetiological role for formaldehyde in such co-reactivity. Methods: Retrospective analysis of all patients patch tested with formaldehyde and

  13. 40 CFR 721.7046 - Formaldehyde, polymer with substituted phenols, glycidyl ether.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with substituted... New Uses for Specific Chemical Substances § 721.7046 Formaldehyde, polymer with substituted phenols... substance identified as formaldehyde, polymer with substituted phenols, glycidyl ether (PMN P-93-955) is...

  14. 75 FR 37792 - Formaldehyde Gas; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Science.gov (United States)

    2010-06-30

    ... AGENCY Formaldehyde Gas; Receipt of Application for Emergency Exemption, Solicitation of Public Comment... (OSWER) to use formaldehyde gas (CAS No. 82115-62-6) to decontaminate non-food contact surfaces to... Administrator to issue a quarantine exemption for the use of formaldehyde gas on non-food contact surfaces to...

  15. 78 FR 52567 - Formaldehyde Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2013-08-23

    ... Occupational Safety and Health Administration Formaldehyde Standard; Extension of the Office of Management and... the information collection requirements specified in the standard on Formaldehyde (29 CFR 1910.1048... effects from occupational exposure to formaldehyde, including an itchy, runny, and stuffy nose; a dry or...

  16. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with 1... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3...

  17. Effect of formaldehyde on the upper respiratory tract _ormal flora of ...

    African Journals Online (AJOL)

    Background: Formaldehyde is a chemical that is used to fix a tissue after death or removal from the body to prevent autolysis and putrefaction. Exposure to formaldehyde can occur as a result of occupation. Objective: To determine the effect of the formaldehyde on the throat and nasal flora of upper respiratory tract of rabbits ...

  18. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, condensated... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

  19. 40 CFR 721.10134 - Formaldehyde, polymer with dialkylphenylamine, dialkylphenol and trimethylhexanediamine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10134 Formaldehyde, polymer... significant new uses subject to reporting. (1) The chemical substance identified generically as formaldehyde...

  20. 75 FR 17163 - Formaldehyde Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2010-04-05

    ... Occupational Safety and Health Administration Formaldehyde Standard; Extension of the Office of Management and... specified in the Standard on Formaldehyde (29 CFR 1910.1048). The standard protects workers from the adverse health effects from occupational exposure to Formaldehyde. DATES: Comments must be submitted (postmarked...

  1. 78 FR 44089 - Formaldehyde Emissions Standards for Composite Wood Products; Extension of Comment Period

    Science.gov (United States)

    2013-07-23

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ92 Formaldehyde Emissions Standards for Composite Wood Products..., concerning formaldehyde emissions standards for composite wood products. This document extends the comment..., Formaldehyde, Reporting and recordkeeping requirements, Toxic substances, Wood. Dated: July 17, 2013. James...

  2. 40 CFR 721.3810 - Formaldehyde, polymers with substituted phenols (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymers with... New Uses for Specific Chemical Substances § 721.3810 Formaldehyde, polymers with substituted phenols... identified generically as Formaldehyde, polymers with substituted phenols (PMN P-99-0558) is subject to...

  3. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Directory of Open Access Journals (Sweden)

    Schwemmer G.

    2016-01-01

    Full Text Available We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  4. [Cognitive disorders in workers engaged into formaldehyde and methanol production].

    Science.gov (United States)

    Maliutina, N N; Taranenko, L A

    2014-01-01

    The authors studied cognitive functions state in workers engaged into chemical production under exposure to combination of factors with prevalent methanol and formaldehyde. Study covered 128 examinees of main occupations and 89 individuals of reference group. Through periodic medical examinations, state of cognitive functions was assessed by Montreal scale (MCA). Findings are increased serum levels of methanol and formaldehyde in the main group members. Moderate cognitive disorders of multifunctional type were seen. Associations of these disorders with acting agents were studied, and high degree of their correlations with occupation was revealed.

  5. Numerical analysis of the interaction between high-pressure resin spray and wood chips in a vapour stream

    Directory of Open Access Journals (Sweden)

    Massimo Milani

    2016-04-01

    Full Text Available This article investigates the interaction between the resin spray and the wood chips in a vapour stream using a multi-phase multi-component computational fluid dynamics approach. The interaction between the spray and the chips is one of the main issues in the industrial process for manufacturing medium density fibre boards. Thus, the optimization of this process can lead to important benefits, such as the reduction in the emission of formaldehyde-based toxic chemicals, the reduction in energy consumption in the blending process and energy saving in the fibreboard drying process. First step of the study is the numerical analysis of the resin injector in order to extend the experimental measurements carried out with water to the resin spray. The effects of the injector’s geometrical features on the spray formation are highlighted under different injection pressure values and needle displacements. Afterwards, the results obtained in the analysis of the single injector are used for the complete simulation of multi-injector rail where the mixing of the resin spray and wood chips takes place. The influence of the main operating conditions, such as the vapour and the wood chip flow rates, on the resin distribution is addressed in order to optimize the resination process.

  6. Development of a new instrument for measurement of high temperature mechanical properties of resin-bonded sand

    Directory of Open Access Journals (Sweden)

    Peng Wan

    2017-07-01

    Full Text Available The mechanical properties of resin-bonded sand mixtures at high temperatures significantly affect the quality of casting. However, the existing instruments for high-temperature performances testing mainly focus on inorganic binder-bonded sands no matter the test items or the atmospheric protection, while the instrumentss specially designed for resin-bonded sand are not yet available. A new instrument for testing the high-temperature performance of resin sand was designed including the confirmation of the testing parameters, loading, measurement and control systems, and the design of the frame shape and heating furnace. This instrument can test the compressive strength, heat tolerance time and restraining load of phenol-formaldehyde resin coated sand, self-hardened furan resin sand, and trimethylamine (TEA-based resin bonded sand at high temperatures. The developed instrument has a high accuracy offering smaller than 0.3% deviation at a full scale in the measurement of the high temperature compressive strength and the restraining load over the range of 0–6.8 MPa and 0–2,000 N, respectively. The high temperature heat tolerance time range is 0–300 s and its measurement accuracy is ±1 s.

  7. Novel self-healing dental resin with microcapsules of polymerizable triethylene glycol dimethacrylate and N,N-dihydroxyethyl-p-toluidine.

    Science.gov (United States)

    Wu, Junling; Weir, Michael D; Zhang, Qiang; Zhou, Chuanjian; Melo, Mary Anne S; Xu, Hockin H K

    2016-02-01

    Bulk fracture is one of the primary reasons for resin-based dental restoration failures. To date, there has been no report on the use of polymerizable dental monomers with acceptable biocompatibility to develop a resin with substantial self-healing capability. The objectives of this study were to: (1) develop a self-healing resin containing microcapsules with triethylene glycol dimethacrylate (TEGDMA)-N,N-dihydroxyethyl-p-toluidine (DHEPT) healing liquid in poly(urea-formaldehyde) (PUF) shells for the first time, and (2) determine the physical and mechanical properties, self-healing efficiency, and fibroblast cytotoxicity. Microcapsules of polymerizable TEGDMA-DHEPT in PUF were prepared via an in situ polymerization method. Microcapsules were added into a BisGMA-TEGDMA resin at microcapsule mass fractions of 0%, 5%, 10%, 15% and 20%. A flexural test was used to measure composite strength and elastic modulus. A single edge V-notched beam method was used to measure fracture toughness KIC and self-healing efficiency. Flexural strength and elastic modulus (mean±sd; n=6) of resin containing 5-15% microcapsules were similar to control without microcapsules (p>0.1). Adding microcapsules into the resin increased the virgin KIC, which was about 40% higher at 15% microcapsules than that with 0% microcapsules (pmicrocapsules. All specimens with 0-20% microcapsules had fibroblast viability similar to control without resin eluents (p>0.1). Self-healing dental resin containing microcapsules with polymerizable TEGDMA-DHEPT healing liquid in PUF shells were prepared for the first time with excellent self-healing capability. These microcapsules and self-healing resins containing them may be promising for dental restorations to heal cracks/damage and increase durability. Copyright © 2015 Academy of Dental Materials. All rights reserved.

  8. Evaluation of methods to reduce formaldehyde levels of cadavers in the dissection laboratory.

    Science.gov (United States)

    Whitehead, Mark C; Savoia, Maria C

    2008-01-01

    Dissection of conventionally embalmed cadavers exposes students, staff, and faculty to formaldehyde, a probable carcinogen. Therefore, prudent practices should seek to minimize formaldehyde exposure. In this study, we evaluated two commercially available chemicals, InfuTrace and Perfect Solution, for their effectiveness in reducing ambient formaldehyde levels. Four cadavers embalmed conventionally with formaldehyde and/or with the above agents were compared for their formaldehyde levels under conditions that strictly controlled for air circulation and for locations and methods of testing, and during activities that simulated student dissecting. For InfuTrace, one cadaver was reinfused with InfuTrace after initial standard perfusion with formaldehyde; a second cadaver had InfuTrace injected into the thoracic and abdominal body cavities after formaldehyde perfusion. For Perfect Solution, the product was used for embalming a third cadaver in lieu of formaldehyde. For a control, a fourth cadaver was embalmed with the standard formaldehyde solution. Testing of personal and ambient room air samples and of fluid obtained from the cadavers was performed and analyzed in a blinded fashion. Results indicated that both Perfect Solution, substituted for standard formaldehyde embalming, and InfuTrace infused through the vasculature after formaldehyde embalming, resulted in lower concentrations of formaldehyde than embalming with formaldehyde solution alone or in combination with body cavity injection of InfuTrace. These differences in formaldehyde concentrations are consistent across measuring methods, for example, of room air, of breathing zone air during cadaver handling and dissection, and of liquid samples obtained from the cadavers. Perfect Solution yielded suboptimum fixation and a different texture, color, and smell than the formaldehyde treatments. (c) 2007 Wiley-Liss, Inc.

  9. Development of a nanostructured lipid carrier formulation for increasing photo-stability and water solubility of Phenylethyl Resorcinol

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Hengfeng; Liu, Guoqing; Huang, Yiqing; Li, Yan; Xia, Qiang, E-mail: xiaq@seu.edu.cn

    2014-01-01

    The Phenylethyl Resorcinol loaded nanostructured lipid carrier (PR-NLC) was developed by hot high-pressure homogenization method. The freshly prepared PR-NLC showed a spherical morphology under transmission electron microscope, and the particle size was 218.3 ± 9.2 nm. The value of the zeta potential of PR-NLC decreased from −30.2 ± 1.9 mV to −64.9 ± 1.3 mV when the dilution times reach 10. The loading amount of PR encapsulated in NLC was 2.94 ± 0.03%, and the average entrapment efficiencies of PR-NLC determinated by size exclusion chromatography and ultrafiltration were 90.2 ± 0.6% and 98.3 ± 0.3%. Lyophilization was proved feasible for the storage of NLC dispersion. Fourier transform infrared spectra (FTIR) was exploited to investigate the possible drug–lipid complex formation. Advancements in water solubility of PR were demonstrated by NLC using a contact angle measurement. The hemolysis percentage of the NLC was less than 1.3% in a certain range of concentration. In 90 days’ storage, 88.6 ± 2.8% of PR remained unchanged in PR-NLC under natural daylight. In vitro release studies revealed a sustained drug release, and in vitro penetration studies showed an increase of retention amount of PR in the skin, when applying PR-NLC. Therefore, the NLC might be a potential delivery vehicle in cosmetic dermal products.

  10. Development of a nanostructured lipid carrier formulation for increasing photo-stability and water solubility of Phenylethyl Resorcinol

    Science.gov (United States)

    Fan, Hengfeng; Liu, Guoqing; Huang, Yiqing; Li, Yan; Xia, Qiang

    2014-01-01

    The Phenylethyl Resorcinol loaded nanostructured lipid carrier (PR-NLC) was developed by hot high-pressure homogenization method. The freshly prepared PR-NLC showed a spherical morphology under transmission electron microscope, and the particle size was 218.3 ± 9.2 nm. The value of the zeta potential of PR-NLC decreased from -30.2 ± 1.9 mV to -64.9 ± 1.3 mV when the dilution times reach 10. The loading amount of PR encapsulated in NLC was 2.94 ± 0.03%, and the average entrapment efficiencies of PR-NLC determinated by size exclusion chromatography and ultrafiltration were 90.2 ± 0.6% and 98.3 ± 0.3%. Lyophilization was proved feasible for the storage of NLC dispersion. Fourier transform infrared spectra (FTIR) was exploited to investigate the possible drug-lipid complex formation. Advancements in water solubility of PR were demonstrated by NLC using a contact angle measurement. The hemolysis percentage of the NLC was less than 1.3% in a certain range of concentration. In 90 days' storage, 88.6 ± 2.8% of PR remained unchanged in PR-NLC under natural daylight. In vitro release studies revealed a sustained drug release, and in vitro penetration studies showed an increase of retention amount of PR in the skin, when applying PR-NLC. Therefore, the NLC might be a potential delivery vehicle in cosmetic dermal products.

  11. Impurities of Resorcinol Bis(diphenyl phosphate) in Plastics and Dust Collected on Electric/Electronic Material.

    Science.gov (United States)

    Ballesteros-Gómez, Ana; Aragón, Álvaro; Van den Eede, Nele; de Boer, Jacob; Covaci, Adrian

    2016-02-16

    Resorcinol bis(diphenylphosphate) (RDP) is an organophosphorus flame retardant widely used in electric and electronic equipment. It has been detected in house dust of several European countries according to recent literature. Similar to other flame retardants, RDP formulations and products treated with RDP, such as plastics, can contain RDP impurities, byproducts and breakdown products. In this study, we use screening methods based on wide scope solvent extraction and high resolution time-of-flight mass spectrometry for the identification of RDP related compounds in products and in dust. We analyzed both plastics from electrical/electronic equipment that contained RDP and indoor dust collected on and around surfaces of this equipment. A variety of compounds, namely TPHP, hydroxylated TPHP and RDP (meta-HO-TPHP and meta-HO-RDP), dihydroxylated TPHP, RDP with the loss of a phenyl group (RDP-[Phe]) and RDP oligomers were detected in plastics containing high levels of RDP. Regarding dust samples collected on electronics, TPHP meta-HO-TPHP, meta-HO-RDP, RDP-[Phe] and RDP oligomers were detected. High concentrations of meta-HO-TPHP (20-14 227 ng/g), TPHP (222-50 728 ng/g) and RDP (23-29 118 ng/g) were found in many of the dust samples, so that these compounds seem to easily migrate into the environment. These RDP impurities, byproducts and breakdown products are for the first time reported in indoor dust. Meta-HO-TPHP could be relevant for future biomonitoring studies concerning flame retardants.

  12. Cure shrinkage in casting resins

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J. Brock [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    A method is described whereby the shrinkage of a casting resin can be determined. Values for the shrinkage of several resin systems in frequent use by Sandia have been measured. A discussion of possible methods for determining the stresses generated by cure shrinkage and thermal contraction is also included.

  13. [Acrylic resin removable partial dentures

    NARCIS (Netherlands)

    Baat, C. de; Witter, D.J.; Creugers, N.H.J.

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of

  14. Spectroscopic studies of micelle-enhanced ligand exchange of gallium (III)/4-(2-pyridylazo) resorcinol complex by calf thymus DNA.

    Science.gov (United States)

    Romeika, Jennifer M; Spurgeon, Charina L; Yan, Fei

    2014-01-03

    The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of gallium (III) with 4-(2-pyridylazo) resorcinol (PAR) under varying conditions has been studied spectrophotometrically. At pH 6.0, CTAB (0.05% w/v) markedly enhanced the absorption intensity of gallium (III)-PAR complex. Furthermore, the introduction of CTAB provided unique selectivity for the ligand exchange of Ga(III)-PAR by calf thymus dsDNA over calf thymus ssDNA. This phenomenon offers a novel spectrophotometric sensing strategy for direct detection of dsDNA. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Inhaled formaldehyde: Evaluation of sensory irritation in relation to carcinogenicity

    NARCIS (Netherlands)

    Arts, J.H.E.; Rennen, M.A.J.; Heer, C.de

    2006-01-01

    Objectives: The critical health effects of formaldehyde exposure include sensory irritation and the potential to induce tumours in the upper respiratory tract. In literature, a concentration as low as 0.24 ppm has been reported to be irritating to the respiratory tract in humans. Nasal

  16. Organocatalytic removal of formaldehyde adducts from RNA and DNA bases

    Science.gov (United States)

    Karmakar, Saswata; Harcourt, Emily M.; Hewings, David S.; Lovejoy, Alexander F.; Kurtz, David M.; Ehrenschwender, Thomas; Barandun, Luzi J.; Roost, Caroline; Alizadeh, Ash A.; Kool, Eric T.

    2015-09-01

    Formaldehyde is universally used to fix tissue specimens, where it forms hemiaminal and aminal adducts with biomolecules, hindering the ability to retrieve molecular information. Common methods for removing these adducts involve extended heating, which can cause extensive degradation of nucleic acids, particularly RNA. Here, we show that water-soluble bifunctional catalysts (anthranilates and phosphanilates) speed the reversal of formaldehyde adducts of mononucleotides over standard buffers. Studies with formaldehyde-treated RNA oligonucleotides show that the catalysts enhance adduct removal, restoring unmodified RNA at 37 °C even when extensively modified, while avoiding the high temperatures that promote RNA degradation. Experiments with formalin-fixed, paraffin-embedded cell samples show that the catalysis is compatible with common RNA extraction protocols, with detectable RNA yields increased by 1.5-2.4-fold using a catalyst under optimized conditions and by 7-25-fold compared with a commercial kit. Such catalytic strategies show promise for general use in reversing formaldehyde adducts in clinical specimens.

  17. levels of formaldehyde and acetaldehyde in selected bottled ...

    African Journals Online (AJOL)

    Accer

    ABSTRACT. The levels of formaldehyde and acetaldehyde in bottled drinking water and the effect of storage time and storage conditions on their levels were determined. A total of 144 samples of six brands of bottled drinking water were purchased from Dar es Salaam, Iringa, Mwanza and Arusha regions in Tanzania.

  18. Study of Antioxidant Status in Morticians Exposed to Formaldehyde ...

    African Journals Online (AJOL)

    Background: Subacute and subchronic formaldehyde inhalation has been reported to deplete the activities of antioxidant enzymes, stimulate oxidative stress and thus promote genotoxicity, amongst others. AIM: To investigate the toxicity and pathobiology of inhaled chemicals in workers occupationally exposed to ...

  19. Levels of formaldehyde and acetaldehyde in selected bottled ...

    African Journals Online (AJOL)

    The levels of formaldehyde and acetaldehyde in bottled drinking water and the effect of storage time and storage conditions on their levels were determined. A total of 144 samples of six brands of bottled drinking water were purchased from Dar es Salaam, Iringa, Mwanza and Arusha regions in Tanzania. Analysis was ...

  20. Effect of cultivar and formaldehyde treatment of barley grain on ...

    African Journals Online (AJOL)

    The aim of this study was to determine the effects of cultivar and formaldehyde treatment of barley grains on rumen fermentation characteristics using the in vitro gas production technique. Amount of gas produced (mL/g organic matter (OM)) during fermentation was determined after 0, 3, 6, 12, 24, 48, 72 and 96 h of ...

  1. Studies of Deactivation of Methanol to Formaldehyde Selective Oxidation Catalyst

    DEFF Research Database (Denmark)

    Raun, Kristian Viegaard; Schumann, Max; Høj, Martin

    This work presents a study of the deactivation behavior of Fe-Mo oxide catalyst during selective oxidation of methanol to formaldehyde in a period of 5 days. The structural changes in the catalyst have been investigated in situ for the initial 10 h by Raman spectroscopy, and the structure after 5...

  2. The histological effects of formaldehyde vapour on the lungs ...

    African Journals Online (AJOL)

    This study was designed to investigate the effects 40% formaldehyde inhalation on the lungs. Twenty adult male albino rats were used for this study and they were subdivided into five groups (A, B, C, D, and E) with each group containing 5 rats. The animals in group A served as control, while groups B, C, D and E served as ...

  3. IRIS Toxicological Review of Formaldehyde (Interagency Science Consultation Draft)

    Science.gov (United States)

    On June 2, 2010, the Toxicological Review of Formaldehyde and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices...

  4. An Alternative to Formaldehyde. Avoiding the Carcinogenic Risks.

    Science.gov (United States)

    Ealy, Julie B.

    1991-01-01

    Demonstrations in which glyoxal may be substituted for formaldehyde, a known carcinogen, are presented. An acid-base clock reaction and a copper mirror on the inside of a test tube are described. Directions for the demonstrations and safety precautions are included. (KR)

  5. Harmful Effects of Formaldehyde and Possible Protective Effect of ...

    African Journals Online (AJOL)

    2017-05-22

    May 22, 2017 ... Formaldehyde (FA) is the simplest member of aldehyde family; it is a chemical with high solubility and an irritant. FA that is found in the natural system of organism and it is used commonly in daily life for many purposes by reason of its chemical properties.[1-3] FA has detrimental effects on the human body, ...

  6. Test procedures and instructions for Hanford tank waste supernatant cesium removal

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, D.W., Westinghouse Hanford

    1996-05-31

    This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test using Hanford Double-Shell Slurry Feed supernatant liquor from tank 251-AW-101 in a bench-scale column.Cesium sorbents to be tested include resorcinol-formaldehyde resin and crystalline silicotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-022, Hanford Tank Waste Supernatant Cesium Removal Test Plan.

  7. Contact allergy to epoxy resin

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil

    2012-01-01

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

  8. Effect of modification with nitrocellulose and phenol formaldehyde ...

    African Journals Online (AJOL)

    GRACE

    2006-05-16

    May 16, 2006 ... to coating flexibility, adhesion, durability, and gloss; while the other resins e.g. phenolic resins, ... in surface coatings (Aigbodion and Pilla, 2000; Ikhuoria et al., 2005; Ikhuoria and .... Note: No effect = 1; whitening = 2; shrinkage of film=3; blistering of film=4 and Removal of film =5. Table 5. Effect of blending ...

  9. Effects of Adding Multiwall Carbon Nanotubes on Performance of Polyvinyl Acetate and Urea-Formaldehyde Adhesives in Tropical Timber Species

    Directory of Open Access Journals (Sweden)

    Róger Moya

    2015-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs functionalized with hydroxyl groups (MWCNTs-OH have been incorporated into polyvinyl acetate (PVAc and urea-formaldehyde (UF adhesives utilized in tropical wood gluing. The Raman spectroscopy, the atomic force microscopy (AFM, and transmission electron microscopy (TEM were used to describe the MWCNTs-OH. The adhesives were evaluated in three concentrations of MWCNTs-OH: 0% (control, 0.05%, and 0.1%. The evaluation included color, the distribution of MWCNTs-OH by TEM and AFM, thermal stability and viscosity of the adhesives, and shear strength (SS of the glue line for nine tropical woods. AFM and TEM confirmed interaction of MWCNTs-OH with adhesives. The viscosity of the PVAc adhesive increases with added MWCNTs-OH. The incorporation of MWCNTs-OH in PVAc and UF resin produces wood adhesives with less brightness, less yellowness, and increased redness. The nanotubes in the adhesive improved the thermal stability of the composites and increased the entropy factor and energy of activation in the kinetic decomposition of the resin. In relation to SS, MWCNTs-OH in any of the two concentrations had no significant effect on SS in dry condition in half of the species studied glued with PVAc adhesive, whereas, for UF-adhesive, the SS and percentage of wood failure improved in most of the 9 species studied.

  10. Analysis of Natural Graphite, Synthetic Graphite, and Thermosetting Resin Candidates for Use in Fuel Compact Matrix

    Energy Technology Data Exchange (ETDEWEB)

    Trammell, Michael P [ORNL; Pappano, Peter J [ORNL

    2011-09-01

    The AGR-1 and AGR-2 compacting process involved overcoating TRISO particles and compacting them in a steel die. The overcoating step is the process of applying matrix to the OPyC layer of TRISO particles in a rotating drum in order to build up an overcoat layer of desired thickness. The matrix used in overcoating is a mixture of natural graphite, synthetic graphite, and thermosetting resin in the ratio, by weight, of 64:16:20. A wet mixing process was used for AGR-1 and AGR-2, in that the graphites and resin were mixed in the presence of ethyl alcohol. The goal of the wet mixing process was to 'resinate' the graphite particles, or coat each individual graphite particle with a thin layer of resin. This matrix production process was similar to the German, Chinese, Japanese, and South African methods, which also use various amount of solvent during mixing. See Appendix 1 for information on these countries matrix production techniques. The resin used for AGR-1 and AGR-2 was provided by Hexion, specifically Hexion grade Durite SC1008. Durite SC1008 is a solvated (liquid) resole phenolic resin. A resole resin does not typically have a hardening agent added. The major constituent of SC1008 is phenol, with minor amounts of formaldehyde. Durite SC1008 is high viscosity, so additional ethyl alcohol was added during matrix production in order to reduce its viscosity and enhance graphite particle resination. The current compacting scale up plan departs from a wet mixing process. The matrix production method specified in the scale up plan is a co-grinding jet mill process where powdered phenolic resin and graphite are all fed into a jet mill at the same time. Because of the change in matrix production style, SC1008 cannot be used in the jet milling process because it is a liquid. The jet milling/mixing process requires that a suite of solid or powdered resins be investigated. The synthetic graphite used in AGR-1 and AGR-2 was provided by SGL Carbon, grade KRB2000. KRB

  11. Reproductive and Developmental Toxicity of Formaldehyde: A Systematic Review

    Science.gov (United States)

    Duong, Anh; Steinmaus, Craig; McHale, Cliona M.; Vaughan, Charles P.; Zhang, Luoping

    2011-01-01

    Formaldehyde, the recently classified carcinogen and ubiquitous environmental contaminant, has long been suspected of causing adverse reproductive and developmental effects, but previous reviews were inconclusive, due in part, to limitations in the design of many of the human population studies. In the current review, we systematically evaluated evidence of an association between formaldehyde exposure and adverse reproductive and developmental effects, in human populations and in vivo animal studies, in the peer-reviewed literature. The mostly retrospective human studies provided evidence of an association of maternal exposure with adverse reproductive and developmental effects. Further assessment of this association by meta-analysis revealed an increased risk of spontaneous abortion (1.76, 95% CI 1.20–2.59, p=0.002) and of all adverse pregnancy outcomes combined (1.54, 95% CI 1.27–1.88, pformaldehyde-exposed women, although differential recall, selection bias, or confounding cannot be ruled out. Evaluation of the animal studies including all routes of exposure, doses and dosing regimens studied, suggested positive associations between formaldehyde exposure and reproductive toxicity, mostly in males. Potential mechanisms underlying formaldehyde-induced reproductive and developmental toxicities, including chromosome and DNA damage (genotoxicity), oxidative stress, altered level and/or function of enzymes, hormones and proteins, apoptosis, toxicogenomic and epigenomic effects (such as DNA methylation), were identified. To clarify these associations, well-designed molecular epidemiologic studies, that include quantitative exposure assessment and diminish confounding factors, should examine both reproductive and developmental outcomes associated with exposure in males and females. Together with mechanistic and animal studies, this will allow us to better understand the systemic effect of formaldehyde exposure. PMID:21787879

  12. National Estimates of Exposure to Formaldehyde in Italian Workplaces.

    Science.gov (United States)

    Scarselli, Alberto; Corfiati, Marisa; Di Marzio, Davide; Iavicoli, Sergio

    2017-01-01

    Formaldehyde is classified as human carcinogen and the association with nasopharyngeal cancer has been observed in many epidemiological studies. The aim of this study is to evaluate data about occupational exposure levels to formaldehyde in the Italian working force. Airborne concentrations of formaldehyde were extracted from the Italian database on occupational exposure to carcinogens and refer to the period 1996-2014. Descriptive statistics were calculated for exposure-related variables. The number of workers potentially exposed was estimated for the activity sectors better characterized in the database. An analysis through linear mixed models was performed to determine factors influencing the exposure level. A total of 1610 formaldehyde exposure measurements were selected from the database, having an overall arithmetic mean of 0.12 mg m-3 and a geometric mean of 0.04 mg m-3. The activity sectors with the highest number of measurements were the manufacturing of chemicals and chemicals products (N = 529) in men and the health and social work in women (N = 105). The number of workers potentially exposed in the selected sectors was 49450, and the most predictive independent variables of the exposure level resulted to be the occupational group and the year of measurement. The occupational exposure to formaldehyde occurs in a variety of different sectors, but currently workers at higher risk are those employed in the healthcare sector and in the wood processing industry. Prevention measures have to be targeted to reduce the risk to workers' health, also in a gender perspective. This study confirms the important role of occupational exposure databases as a valuable source of data for the epidemiological assessment of risks in workplaces.

  13. [Acrylic resin removable partial dentures].

    Science.gov (United States)

    de Baat, C; Witter, D J; Creugers, N H J

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of removable partial dentures, the acrylic resin removable partial denture has 3 favourable aspects: the economic aspect, its aesthetic quality and the ease with which it can be extended and adjusted. Disadvantages are an increased risk of caries developing, gingivitis, periodontal disease, denture stomatitis, alveolar bone reduction, tooth migration, triggering of the gag reflex and damage to the acrylic resin base. Present-day indications are ofa temporary or palliative nature or are motivated by economic factors. Special varieties of the acrylic resin removable partial denture are the spoon denture, the flexible denture fabricated of non-rigid acrylic resin, and the two-piece sectional denture. Furthermore, acrylic resin removable partial dentures can be supplied with clasps or reinforced by fibers or metal wires.

  14. Chromatography resin support

    Science.gov (United States)

    Dobos, James G.

    2002-01-01

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

  15. Synthesis, characterization, thermal behavior, and DNA-cleaving studies of cyano-bridged nickel(II)-copper(II) complexes of 4-(pyridin-2-ylazenyl)resorcinol.

    Science.gov (United States)

    Karipcin, Fatma; Ozmen, Ismail; Cülü, Burcin; Celikoğlu, Umut

    2011-10-01

    We present here the syntheses of a mononuclear Cu(II) complex and two polynuclear Cu(II)-Ni(II) complexes of the azenyl ligand, 4-(pyridin-2-ylazenyl)resorcinol (HL; 1). The reaction of HL (1) and copper(II) perchlorate with KCN gave a mononuclear complex [CuL(CN)] (4). Using 4, one pentanuclear complex, [{CuL(NC)}(4) Ni](ClO(4))(2) (5) and one trinuclear complex, [{CuL(CN)}(2) NiL]ClO(4) (6), were prepared and characterized by elemental analyses, magnetic susceptibility, molar conductance, IR, and thermal analysis. Stoichiometric and spectral results of the mononuclear Cu(II) complex indicated that the metal/ligand/CN ratio was 1 : 1 : 1, and the ligand behaved as a tridentate ligand forming neutral metal chelates through the pyridinyl and azenyl N-, and resorcinol O-atom. The interaction between the compounds (the ligand 1, its Ni(II) and Cu(II) complexes without CN, i.e., 2 and 3, and its complexes with CN, 4-6) and DNA has also been investigated by agarose gel electrophoresis. The pentanuclear Cu(4) Ni complex (5) with H(2) O(2) as a co-oxidant exhibited the strongest DNA-cleaving activity. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  16. 21 CFR 178.3930 - Terpene resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Terpene resins. 178.3930 Section 178.3930 Food and... and Production Aids § 178.3930 Terpene resins. The terpene resins identified in paragraph (a) of this... the terpene resins identified in paragraph (b) of this section may be safely used as components of...

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

    Directory of Open Access Journals (Sweden)

    M. Kubecki

    2012-09-01

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

  18. Reduction of aldehydes and hydrogen cyanide yields in mainstream cigarette smoke using an amine functionalised ion exchange resin

    Directory of Open Access Journals (Sweden)

    Duke Martin G

    2011-04-01

    Full Text Available Abstract Background Cigarette smoking is a well recognized cause of diseases such as lung cancer, chronic obstructive pulmonary disease and cardiovascular disease. Of the more than 5000 identified species in cigarette smoke, at least 150 have toxicological activity. For example, formaldehyde and acetaldehyde have been assigned as Group 1 and Group 2B carcinogens by IARC, and hydrogen cyanide has been identified as a respiratory and cardiovascular toxicant. Active carbon has been shown to be an effective material for the physical adsorption of many of the smoke volatile species. However, physical adsorption of acetaldehyde, formaldehyde and also hydrogen cyanide from smoke is less effective using carbon. Alternative methods for the removal of these species from cigarette smoke are therefore of interest. A macroporous, polystyrene based ion-exchange resin (Diaion®CR20 with surface amine group functionality has been investigated for its ability to react with aldehydes and HCN in an aerosol stream, and thus selectively reduce the yields of these compounds (in particular formaldehyde in mainstream cigarette smoke. Results Resin surface chemistry was characterized using vapour sorption, XPS, TOF-SIMS and 15N NMR. Diaion®CR20 was found to have structural characteristics indicating weak physisorption properties, but sufficient surface functionalities to selectively remove aldehydes and HCN from cigarette smoke. Using 60 mg of Diaion®CR20 in a cigarette cavity filter gave reductions in smoke formaldehyde greater than 50% (estimated to be equivalent to >80% of the formaldehyde present in the smoke vapour phase independent of a range of flow rates. Substantial removal of HCN (>80% and acetaldehyde (>60% was also observed. The performance of Diaion®CR20 was found to be consistent over a test period of 6 months. The overall adsorption for the majority of smoke compounds measured appeared to follow a pseudo-first order approximation to second order

  19. Effects of formaldehyde on mitochondrial dysfunction and apoptosis in SK-N-SH neuroblastoma cells.

    Science.gov (United States)

    Zerin, Tamanna; Kim, Jin-Sun; Gil, Hyo-Wook; Song, Ho-Yeon; Hong, Sae-Yong

    2015-12-01

    Methanol ingestion is neurotoxic in humans due to its metabolites, formaldehyde and formic acid. Here, we compared the cytotoxicity of methanol and its metabolites on different types of cells. While methanol and formic acid did not affect the viability of the cells, formaldehyde (200-800 μg/mL) was strongly cytotoxic in all cell types tested. We investigated the effects of formaldehyde on oxidative stress, mitochondrial respiratory functions, and apoptosis on the sensitive neuronal SK-N-SH cells. Oxidative stress was induced after 2 h of formaldehyde exposure. Formaldehyde at a concentration of 400 μg/mL for 12 h of treatment greatly reduced cellular adenosine triphosphate (ATP) levels. Confocal microscopy indicated that the mitochondrial membrane potential (MMP) was dose-dependently reduced by formaldehyde. A marked and dose-dependent inhibition of mitochondrial respiratory enzymes, viz., NADH dehydrogenase (complex I), cytochrome c oxidase (complex IV), and oxidative stress-sensitive aconitase was also detected following treatment with formaldehyde. Furthermore, formaldehyde caused a concentration-dependent increase in nuclear fragmentation and in the activities of the apoptosis-initiator caspase-9 and apoptosis-effector caspase-3/-7, indicating apoptosis progression. Our data suggests that formaldehyde exerts strong cytotoxicity, at least in part, by inducing oxidative stress, mitochondrial dysfunction, and eventually apoptosis. Changes in mitochondrial respiratory function and oxidative stress by formaldehyde may therefore be critical in methanol-induced toxicity.

  20. Neurotoxicity effect of formaldehyde on occupational exposure and influence of individual susceptibility to some metabolism parameters.

    Science.gov (United States)

    Zendehdel, Rezvan; Fazli, Zohreh; Mazinani, Mohammad

    2016-11-01

    Over the years, neurotoxicity and cognitive dysfunction have separately been associated with endogenous formaldehyde and reduction of acetylcholine signals. However, a limited number of studies have shown a relationship between cholinergic neurotransmitter and formaldehyde exposure. Therefore, the aim of this study was to assess the neurological effect on workers from melamine-dish preparation workshop, who were exposed to formaldehyde. A total of 35 formaldehyde-exposed workers were compared with 32 control employees from the food industry. Occupational exposure to formaldehyde was conducted using the National Institute of Occupational Safety and Health 3500 methods. Using the Ellman method, acetylcholinesterase (AChE) as a biomarker for neurotoxicity was analyzed in blood erythrocyte. The effects of alcohol dehydrogenase III (ADH3) and Mn-superoxide dismutase (Mn-SOD) polymorphism were used to survey the level of AChE activity. In this study, it was found that exposure to airborne formaldehyde increased from 0.024 to 0.74 ppm and the median personnel exposure was 0.057. Induction of AChE activity was observed in formaldehyde-exposed workers as compared with the control group (p formaldehyde. Exposed subjects containing ADH32-2 genotype had higher AChE than others. The findings of this study suggest that the neurotoxic effect of formaldehyde depends on the AChE activity, which is affected by metabolism. It can be concluded that cholinergic signal reduction in cases of cognitive dysfunction could be associated with endogenous formaldehyde.

  1. Regulation of methylamine and formaldehyde metabolism in Arthrobacter P1. Formaldehyde is the inducing signal for the synthesis of the RuMP cycle enzyme hexulose phosphate synthase

    NARCIS (Netherlands)

    Croes, L.M.; Dijkhuizen, L.

    The inducing potential of formaldehyde on the synthesis of hexulose phosphate synthase, a key enzyme of the RuMP cycle in Arthrobacter P1, was investigated in resting cell suspensions. Induction of this enzyme only occurred at formaldehyde concentrations of 0.5 mM and below. No evidence was obtained

  2. Bending characteristics of resin concretes

    Directory of Open Access Journals (Sweden)

    Ribeiro Maria Cristina Santos

    2003-01-01

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

  3. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel

    2015-01-01

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

  4. Epoxy hydantoins as matrix resins

    Science.gov (United States)

    Weiss, J.

    1983-01-01

    Tensile strength and fracture toughness of castings of the hydantoin resins cured with methylenedianiline are significantly higher than MY 720 control castings. Water absorption of an ethyl, amyl hydantoin formulation is 2.1 percent at equilibrium and Tg's are about 160 C, approximately 15 deg below the final cure temperature. Two series of urethane and ester-extended hydantoin epoxy resins were synthesized to determine the effect of crosslink density and functional groups on properties. Castings cured with methylenedianiline or with hexahydrophthalic anhydride were made from these compounds and evaluated. The glass transition temperatures, tensile strengths and moduli, and fracture toughness values were all much lower than that of the simple hydantoin epoxy resins. Using a methylene bishydantoin epoxy with a more rigid structure gave brittle, low-energy fractures, while a more flexible, ethoxy-extended hydantoin epoxy resin gave a very low Tg.

  5. Formaldehyde stabilization facilitates lignin monomer production during biomass depolymerization.

    Science.gov (United States)

    Shuai, Li; Amiri, Masoud Talebi; Questell-Santiago, Ydna M; Héroguel, Florent; Li, Yanding; Kim, Hoon; Meilan, Richard; Chapple, Clint; Ralph, John; Luterbacher, Jeremy S

    2016-10-21

    Practical, high-yield lignin depolymerization methods could greatly increase biorefinery productivity and profitability. However, development of these methods is limited by the presence of interunit carbon-carbon bonds within native lignin, and further by formation of such linkages during lignin extraction. We report that adding formaldehyde during biomass pretreatment produces a soluble lignin fraction that can be converted to guaiacyl and syringyl monomers at near theoretical yields during subsequent hydrogenolysis (47 mole % of Klason lignin for beech and 78 mole % for a high-syringyl transgenic poplar). These yields were three to seven times those obtained without formaldehyde, which prevented lignin condensation by forming 1,3-dioxane structures with lignin side-chain hydroxyl groups. By depolymerizing cellulose, hemicelluloses, and lignin separately, monomer yields were between 76 and 90 mole % for these three major biomass fractions. Copyright © 2016, American Association for the Advancement of Science.

  6. Nanocomposite sensors of propylene glycol, dimethylformamide and formaldehyde vapors

    Directory of Open Access Journals (Sweden)

    Z. Adamyan

    2018-02-01

    Full Text Available The results of research works related to the study of thick-film multiwall carbon nanotube–tin oxide nanocomposite sensors of propylene glycol (PG, dimethylformamide (DMF and formaldehyde (FA vapors are presented in this paper. These sensors were derived using hydrothermal synthesis and sol–gel methods. Investigations of response–recovery characteristics in the 50–300 °C operating temperature range reveal that the optimal operating temperature for PG, DMF and FA vapor sensors, taking into account both high response and acceptable response and recovery times are about 200 and 220 °C, respectively. The dependence of the sensor response on gas concentration is linear in all cases. Minimal propylene glycol, dimethylformamide and formaldehyde gas concentrations, where the perceptible signal was noticed, were 13, 5 and 115 ppm, respectively.

  7. Studies of Deactivation of Methanol to Formaldehyde Selective Oxidation Catalyst

    DEFF Research Database (Denmark)

    Raun, Kristian Viegaard; Schumann, Max; Høj, Martin

    Formaldehyde (CH2O) may be synthesized industrially by selective oxidation of methanol over an iron-molybdate (Fe-Mo) oxide catalyst according to: CH3OH + ½O2 →CH2O + H2O. The reaction is normally carried out in a multitubular reactor with excess of air at 250-400 °C (yield = 90-95 %), known...... as the Formox process [1]. The average lifetime of the industrial catalyst is only 1–2 years depending on the operating conditions. The catalyst consists of a bulk phase of Fe2(MoO4)3 and a surface layer phase of MoO3. The MoO3 surfaceis selective towards formaldehyde while the iron in the sublayer increases...

  8. Simple, rapid method for the preparation of isotopically labeled formaldehyde

    Science.gov (United States)

    Hooker, Jacob Matthew [Port Jefferson, NY; Schonberger, Matthias [Mains, DE; Schieferstein, Hanno [Aabergen, DE; Fowler, Joanna S [Bellport, NY

    2011-10-04

    Isotopically labeled formaldehyde (*C.sup..sctn.H.sub.2O) is prepared from labeled methyl iodide (*C.sup..sctn.H.sub.3I) by reaction with an oxygen nucleophile having a pendant leaving group. The mild and efficient reaction conditions result in good yields of *C.sup..sctn.H.sub.2O with little or no *C isotopic dilution. The simple, efficient production of .sup.11CH.sub.2O is described. The use of the .sup.11CH.sub.2O for the formation of positron emission tomography tracer compounds is described. The reaction can be incorporated into automated equipment available to radiochemistry laboratories. The isotopically labeled formaldehyde can be used in a variety of reactions to provide radiotracer compounds for imaging studies as well as for scintillation counting and autoradiography.

  9. Molecularly Imprinted Polymer Nanoparticles for Formaldehyde Sensing with QCM

    Directory of Open Access Journals (Sweden)

    Munawar Hussain

    2016-06-01

    Full Text Available Herein, we report on molecularly imprinted polymers (MIPs for detecting formaldehyde vapors in air streams. A copolymer thin film consisting of styrene, methacrylic acid, and ethylene glycol dimethacrylate on quartz crystal microbalance (QCM yielded a detection limit of 500 ppb formaldehyde in dry air. Surprisingly, these MIPs showed specific behavior when tested against a range of volatile organic compounds (VOCs, such as acetaldehyde, methanol, formic acid, and dichloromethane. Despite thus being a suitable receptor in principle, the MIPs were not useful for measurements at 50% humidity due to surface saturation by water. This was overcome by introducing primary amino groups into the polymer via allyl amine and by changing the coating morphology from thin film to nanoparticles. This led to the same limit of detection (500 ppb and selectivity as before, but at the real-life conditions of 50% relative humidity.

  10. Liquid monobenzoxazine based resin system

    Science.gov (United States)

    Tietze, Roger; Nguyen, Yen-Loan; Bryant, Mark

    2014-10-07

    The present invention provides a liquid resin system including a liquid monobenzoxazine monomer and a non-glycidyl epoxy compound, wherein the weight ratio of the monobenzoxazine monomer to the non-glycidyl epoxy compound is in a range of about 25:75 to about 60:40. The liquid resin system exhibits a low viscosity and exceptional stability over an extended period of time making its use in a variety of composite manufacturing methods highly advantageous.

  11. Karakteristik Komposit Resin Berkemampuan Mengalir

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The use of resin composites as posterior restoratives has markedly increased over the past decade. The patients demand for better esthetics, concerns related to possible mercury toxicity from amalgam and improvements in resin composite materials have significantly contributed the popularity of these materials. Early problems related to composites included excessive wear, less of anatomic form, post operative sensitivity, secondary caries and marginal leakage. Marginal adaptation still remains an unavoidable problem for composite restoration, especially at the gingival wall of cervical or Class II restoration. In an attempt to improve marginal sealing, many techniques and lining materials have been designed. To reduce stress generated by polymerization shrinkage, applying and curing of resin composites in layers is often recommended. Using a thick adhesive layer or low-viscosity resin may, due to its elastic properties, serve as a flexible intermediate layer and compensate for the polymerization stress created in resin composite. Flowable composites were created by retaining the same small particle size of traditional hybrid composite but reducing the filler content and allowing the increased resin to reduce the viscosity of the mixture. Flowable composites were introduced in 1996 as liners, fissure sealants and also in tunnel preparations. They have been suggested for Class I, II, III and V cavity restorations, preventive resin restorations and composite, porcelain and amalgam repairing. Their usage as a liner under high filled resins in posterior restorations has been shown to improve the adaptation of composites and effectively achieve clinically acceptable results. This article attempts to give a broad characteristics of different types of flowable composites. 

  12. Thermodynamics of the formaldehyde-water and formaldehyde-ice systems for atmospheric applications.

    Science.gov (United States)

    Barret, Manuel; Houdier, Stephan; Domine, Florent

    2011-01-27

    Formaldehyde (HCHO) is a species involved in numerous key atmospheric chemistry processes that can significantly impact the oxidative capacity of the atmosphere. Since gaseous HCHO is soluble in water, the water droplets of clouds and the ice crystals of snow exchange HCHO with the gas phase and the partitioning of HCHO between the air, water, and ice phases must be known to understand its chemistry. This study proposes thermodynamic formulations for the partitioning of HCHO between the gas phase and the ice and liquid water phases. A reanalysis of existing data on the vapor-liquid equilibrium has shown the inadequacy of the Henry's law formulation, and we instead propose the following equation to predict the mole fraction of HCHO in liquid water at equilibrium, X(HCHO,liq), as a function of the partial pressure P(HCHO) (Pa) and temperature T (K): X(HCHO,liq) = 1.700 × 10(-15) e((8014/T))(P(HCHO))(1.105). Given the paucity of data on the gas-ice equilibrium, the solubility of HCHO and the diffusion coefficient (D(HCHO)) in ice were measured by exposing large single ice crystals to low P(HCHO). Our recommended value for D(HCHO) over the temperature range 243-266 K is D(HCHO) = 6 × 10(-12) cm(2) s(-1). The solubility of HCHO in ice follows the relationship X(HCHO,ice) = 9.898 × 10(-13) e((4072/T))(P(HCHO))(0.803). Extrapolation of these data yields the P(HCHO) versus 1/T phase diagram for the H(2)O-HCHO system. The comparison of our results to existing data on the partitioning of HCHO between the snow and the atmosphere in the high arctic highlights the interplay between thermodynamic equilibrium and kinetics processes in natural systems.

  13. Expression, purification, and characterization of formaldehyde dehydrogenase from Pseudomonas aeruginosa.

    Science.gov (United States)

    Zhang, Wangluo; Chen, Shuai; Liao, Yuanping; Wang, Dingli; Ding, Jianfeng; Wang, Yingming; Ran, Xiaoyuan; Lu, Daru; Zhu, Huaxing

    2013-12-01

    As a member of zinc-containing medium-chain alcohol dehydrogenase family, formaldehyde dehydrogenase (FDH) can oxidize toxic formaldehyde to less active formate with NAD(+) as a cofactor and exists in both prokaryotes and eukaryotes. Most FDHs are well known to be glutathione-dependent in the catalysis of formaldehyde oxidation, but the enzyme from Pseudomonas putida is an exception, which is independent of glutathione. To identify novel glutathione-independent FDHs from other bacterial strains and facilitate the corresponding structural and enzymatic studies, high-level soluble expression and efficient purification of these enzymes need to be achieved. Here, we present molecular cloning, expression, and purification of the FDH from Pseudomonas aeruginosa, which is a Gram-negative pathogenic bacterium causing opportunistic human infection. The FDH of P. aeruginosa shows high sequence identity (87.97%) with that of P. putida. Our results indicated that coexpression with molecular chaperones GroES, GroEL, and Tig has significantly attenuated inclusion body formation and improved the solubility of the recombinant FDH in Escherichiacoli cells. A purification protocol including three chromatographic steps was also established to isolate the recombinant FDH to homogeneity with a yield of ∼3.2 mg from 1L of cell culture. The recombinant P. aeruginosa FDH was properly folded and biologically functional, as demonstrated by the mass spectrometric, crystallographic, and enzymatic characterizations of the purified proteins. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Investigation of the detoxification mechanism of formaldehyde-treated tetanus toxin

    DEFF Research Database (Denmark)

    Thaysen-Andersen, Morten; Jørgensen, Sys Borcher; Wilhelmsen, Ellen Sloth

    2007-01-01

     The tetanus vaccine is based on the extremely potent tetanus neurotoxin (TeNT), which is converted by treatment with formaldehyde and lysine into the non-toxic, but still immunogenic tetanus toxoid (TTd). This formaldehyde-induced detoxification, which to a large extend determines the quality...... and formaldehyde in the detoxification process and (ii) characterisation of the chemically detoxified TTd. (i) We examined a number of TTd components that was produced by varying the concentrations of formaldehyde and lysine during the inactivation. Toxicity tests showed that the detoxification failed when...... the lysine or formaldehyde concentration was formaldehyde-dependent and, furthermore, revealed that inter-chain cross-linking was not the only requirement for the inactivation...

  15. In-situ development of carbon nanotubes network and graphitic carbon by catalytic modification of phenolic resin binder in Al2O3–MgO–C refractories

    Directory of Open Access Journals (Sweden)

    Atul V. Maldhure

    2017-09-01

    Full Text Available In-situ formation of cross-linked carbon nanotubes network reinforced the refractory matrix and helps to improve the mechanical properties at elevated temperature. In this paper, the effect of modified phenol-formaldehyde (PF resin binder on the various mechanical properties of alumina–magnesia–carbon (AMC refractories was investigated. Initially, PF resin was modified by adding a different proportion of nickel catalyst. The AMC specimens (with the 7% carbon were prepared by using 5% of modified PF resin. The pressed samples were cured at 180 °C for 24 h and characterized by XRD, Raman spectroscopy, and FE-SEM. The characterisation shows that, in-situ formation of graphitic carbon and carbon nanotubes network in the specimens due to modification of PF resin. In-situ formation of phases leads to enhancement of density and mechanical properties of refractory at elevated temperature due to the reinforcing effect.

  16. Formaldehyde-Induced Genome Instability is Suppressed by an XPF-dependent Pathway

    Science.gov (United States)

    Kumari, Anuradha; Lim, Yun Xin; Newell, Amy Hanlon; Olson, Susan B.; McCullough, Amanda K.

    2011-01-01

    Formaldehyde is a reactive chemical that is commonly used in the production of industrial, laboratory, household, and cosmetic products. The causal association between formaldehyde exposure and increased incidence of cancer led the International Agency for Research on Cancer to classify formaldehyde as a carcinogen. Formaldehyde-induced DNA-protein crosslinks (DPCs) elicit responses involving nucleotide excision repair (NER) and homologous recombination (HR) repair pathways; however, little is known about the cellular and genetic changes that subsequently lead to formaldehyde-induced genotoxic and cytotoxic effects. Herein, investigations of genes that modulate the cytotoxic effects of formaldehyde exposure revealed that of five NER-deficient Chinese Hamster Ovary (CHO) cell lines tested, XPF- and ERCC1-deficient cells were most sensitive to formaldehyde treatment as compared to wild-type cells. Cell cycle analyses revealed that formaldehyde-treated XPF-deficient cells exhibited an immediate G2/M arrest that was associated with altered cell ploidy and apoptosis. Additionally, an elevated number of DNA double-strand breaks (DSBs), chromosomal breaks and radial formation were also observed in XPF-deficient cells following formaldehyde treatment. Formaldehyde-induced DSBs occurred in a replication-dependent, but an XPF-independent manner. However, delayed DSB repair was observed in the absence of XPF function. Collectively, our findings highlight the role of an XPF-dependent pathway in mitigating the sensitivity to formaldehyde-induced DNA damage as evidenced by the increased genomic instability and reduced cell viability in an XPF-deficient background. In addition, centrosome and microtubule abnormalities, as well as enlarged nuclei, caused by formaldehyde exposure are also demonstrated in a repair-proficient cell line. PMID:22186232

  17. A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

    Energy Technology Data Exchange (ETDEWEB)

    Parthasarathy, Srinandini; Spears, Michael; Maddalena, Randy L.; Russell, Marion L; Apte, Michael G.

    2010-10-01

    The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios.

  18. Urine formaldehyde level is inversely correlated to mini mental state examination scores in senile dementia.

    Science.gov (United States)

    Tong, Zhiqian; Zhang, Jinling; Luo, Wenhong; Wang, Weishan; Li, Fangxu; Li, Hui; Luo, Hongjun; Lu, Jing; Zhou, Jiangning; Wan, You; He, Rongqiao

    2011-01-01

    It is widely known that exogenous formaldehyde exposure induces human cognitive impairment and animal memory loss; and recent studies show that formaldehyde at pathological levels induces Aβ deposition and misfolding of tau protein to form globular amyloid-like aggregates. Endogenous formaldehyde may be a marker for progressive senile dementia. The aim of this study was to investigate the correlation of endogenous formaldehyde in urine of senile dementia and mini mental state examination (MMSE) scores. Formaldehyde level was analyzed by high-performance liquid chromatography (with fluorescence detection) in human urine from dementia patients (n=141), patients with hypertension (n=33) or diabetes (n=16) and healthy individuals (n=38), autopsy hippocampus samples from Alzheimer's disease (AD) patients and brains of three types of AD animal model: namely, senescence accelerated mice (SAMP8), APP-transgenic mice and APP/PS1-transgenic mice. In a double-blind study, there was marked elevation of urine formaldehyde levels in patients (n=91) with dementia, and a slight increase in patients (n=50) with mild cognitive impairment. Urine formaldehyde level was inversely correlated with mini mental state examination scores (Rs=-0.441, psenile dementia are probably related to endogenous formaldehyde levels; and the mini mental state examination scores referred to the evaluation of urine formaldehyde level in dementia patients may be used as a non-invasive method for the investigation and diagnosis of senile dementia. Copyright © 2009 Elsevier Inc. All rights reserved.

  19. Porphinogen Formation from the Co-Oligomerization of Formaldehyde and Pyrrole: Free Energy Pathways.

    Science.gov (United States)

    Kua, Jeremy; Loli, Helen

    2017-10-26

    We have investigated the nonoxidative stepwise co-oligomerization of formaldehyde and pyrrole to form porphinogen using density functional theory calculations that include free energy corrections. While the addition of formaldehyde to the pyrrole nitrogen is kinetically favored, thermodynamics suggest that this reaction is reversible in aqueous solution. The more thermodynamically favorable addition of formaldehyde to the ortho-carbon of pyrrole begins a stepwise process, forming dipyrromethane via an azafulvene intermediate. Subsequent additions of formaldehyde and pyrrole lead to bilanes (linear tetrapyrroles), which favorably cyclize to form porphinogen. Porphinogen is a precursor to porphin, the simplest unsubstituted porphyrin that could have played a role in primitive metabolism at the origin of life.

  20. Synthesis and characterization of phenol/formaldehyde nanocomposites: Studying the effect of incorporating reactive rubber nanoparticles or Cloisite-30B nanoclay on the mechanical properties, morphology and thermal stability

    Directory of Open Access Journals (Sweden)

    Walaa S.E. Solyman

    2017-01-01

    Full Text Available In this work, phenol/formaldehyde nanocomposites were synthesized using reactive rubber nanoparticles (RRNP and cloisite30B nanoclay with different percentages and were fully investigated. A little amount of these nanomaterials enhanced the mechanical properties of the produced composites. This enhancement is attributed to the interaction of these nanomaterials with the bakelite matrix. In bakelite/RRNP, the mechanical properties enhancement is due to the chemical connection of RRNP to the bakelite matrix while in bakelite/Cloisite30B, this enhancement is due to polar/polar interaction. It was observed that the composites exhibited an intercalated disordered structure by means of Xray diffraction (XRD and transmission electronic microscopy. The crosslinking density of the bakelite network was greatly influenced by the presence and type of nanomaterial that was added to the resin. The thermal stability was investigated with TGA/DSC which proved that these nanocomposite are (10–20% more thermally stable than neat Bakelite resin.

  1. Low Melt Viscosity Resins for Resin Transfer Molding

    Science.gov (United States)

    Harris, Frank W.

    2002-01-01

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

  2. Epoxy Resins in Electron Microscopy

    Science.gov (United States)

    Finck, Henry

    1960-01-01

    A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed. PMID:13822825

  3. Process for Molding Nonreinforced (Neat) Resins

    Science.gov (United States)

    Dickerson, G. E.

    1983-01-01

    Void free moldings obtained for neat, condensation, thermosetting resins. Thermally and mechanically treat resin prior to molding to reduce amount of volatiles. With volatiles reduced molding temperature and pressure are applied in way to drive out remaining volatiles during molding.

  4. 40 CFR 721.6181 - Fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl ether...

    Science.gov (United States)

    2010-07-01

    ... substituted oxirane, formaldehyde-phenol polymer glycidyl ether, substituted proplyamine and...-phenol polymer glycidyl ether, substituted proplyamine and polyethylenepolyamines (generic). (a) Chemical... as fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl ether...

  5. Properties of Sago Particleboards Resinated with UF and PF Resin

    Directory of Open Access Journals (Sweden)

    Chen Chiang Tay

    2016-01-01

    Full Text Available The sago processing industry in Mukah, Sarawak, had generated huge amount of sago waste after the milling process and scientists have employed the waste into composite material. In this work, sago residues were mixed with the Phenol Formaldehyde (PF and Urea Formaldehyde (UF for particleboard fabrication. The fabrication and testing methods are based on JIS A 5908 Standard. A single layer particleboard using sago particles was fabricated at targeted density of 600 kg/m3. Particles with weight fractions of 90%, 85%, and 80% with two different matrices were used in the fabrication. The results demonstrated that the samples with different weight fraction and matrix have great influence on the mechanical properties such as MOR, MOE, Young’s Modulus, tensile strength, impact strength, screw test, and internal bonding. The sago UF/PF particleboard only displays single stage decomposition. All the panels underwent physical tests which are water absorption and thickness swelling. The combination of sago particles with UF/PF can be utilized for general indoor application purposes such as furniture manufacturing. Sago particleboard made by UF/PF provided the advantages like optimized performance, minimized weight and volume, cost effectiveness, chemical resistance, and resistance to biodegradation.

  6. Formaldehyde emission from particleboard and plywood paneling : measurement, mechanism, and product standards

    Science.gov (United States)

    George E. Myers

    1983-01-01

    A number of commercial panel products, primarily particleboard and hardwood plywood, were tested for their formaldehyde emission behavior using desiccator, perforator, and dynamic chamber methods. The results were analyzed in terms of the source of formaldehyde observed in the tests (free vs. hydrolytically produced) and the potential utility of the testa as product...

  7. Emission of formaldehyde by particleboard : effect of ventilation rate and loading on air-contamination levels

    Science.gov (United States)

    George E. Myers; Muneo Nagaoka

    1981-01-01

    Dynamic tests for determining the formaldehyde emission behavior of UF-bonded boards involve the measurement of formaldehyde concentration in the air within a vessel which contains a specified board loading L (m2 of board area per m3 of vessel free volume) and is being ventilated at a specified air exchange rate N (hr.-1). Such tests constitute a primary...

  8. Effect of ventilation rate and board loading on formaldehyde concentration : a critical review of the literature

    Science.gov (United States)

    George E. Myers

    1984-01-01

    A critical literature review has been carried out on the influence of ventilation rate (N, hr.-1) and board loading (L, m2/m3) on steady state formaldehyde concentrations (Cs, ppm) resulting from particleboard and plywood emissions. Large differences exist among boards in the extent to which their formaldehyde concentrations change with N or L in laboratory chambers....

  9. CeO2 thin film as a low-temperature formaldehyde sensor in mixed ...

    Indian Academy of Sciences (India)

    Administrator

    a good biomarker for diagnosing lung cancer at an earlier stage (Fuchs et al 2010). Hence, there is a need for formaldehyde detection in diseases diagnosing as well as for environmental monitoring. Different traditional techniques were available to detect formaldehyde such as gas chromatography (Poli et al 2010) ...

  10. Simultaneous bond degradation and bond formation during phenol-formaldehyde curing with wood

    Science.gov (United States)

    Daniel J. Yelle; John Ralph

    2016-01-01

    Bonding of wood using phenol–formaldehyde adhesive develops highly durable bonds. Phenol– formaldehyde is believed to form primary bonds with wood cell wall polymers (e.g., lignin). However, it is unclear how this adhesive interacts and bonds to lignin. Through wood solubilisation methodologies, earlywood and latewood bonded assemblies were characterized using two-...

  11. Formaldehyde exposure induces autophagy in testicular tissues of adult male rats.

    Science.gov (United States)

    Han, Shui-Ping; Zhou, Dang-Xia; Lin, Pu; Qin, Zhen; An, Lu; Zheng, Lie-Rui; Lei, Li

    2015-03-01

    Formaldehyde, a ubiquitous environmental pollutant, has long been suspected of causing adverse male reproductive effects. However, the molecular and cellular mechanisms underlying this phenomenon remain elusive. The overall aim of this study is to clarify the role of autophagy in male reproductive injuries induced by formaldehyde exposure, by which we can further understand the molecular mechanism of spermatogenesis and develop new targets for prevention and treatment of male infertility. In this study, electron microscopy, Western blot, and RT-PCR analysis were used to detect autophagy in testicular tissues. Moreover, testicular weights, histopathology, and morphometry were used to evaluate the reproductive injuries of formaldehyde exposure. We found that formaldehyde exposure-induced autophagy in testicular tissues was dose dependent. Increasing autophagosomes in spermatogenetic cells was observed by electron microscopy in formaldehyde exposure group. In addition, RT-PCR and Western blot analysis showed the transcription levels of the LC3-II, as well as the conversion from LC3-I to LC3-II, an indicator of autophagy, significantly increased in testicular tissue of formaldehyde exposure group in a dose dependent manner when compared with those in control group. Furthermore, the alterations of autophage were basically consistent with the changes in testicular weight and morphologic findings. In summary, formaldehyde exposure triggered autophagy, and autophagy may be a scathing factor responsible for male reproductive impairment induced by formaldehyde. © 2013 Wiley Periodicals, Inc.

  12. CeO2 thin film as a low-temperature formaldehyde sensor in mixed ...

    Indian Academy of Sciences (India)

    The vapour sensing characteristics of the annealed film were studied by chemiresistive method for various concentrations of formaldehyde vapour at room temperature (∼ 30 °C). For 0.5 ppm of formaldehyde vapour, the film shows a response and recovery time of 36 and 1 s, respectively. The vapour sensing properties of ...

  13. Solid phase microextraction method development for measuring Henry's Law constants of formaldehyde in aqueous solutions

    Science.gov (United States)

    Formaldehyde (HCHO) has been of special concern as an indoor air pollutant because of its existence in a wide range of products and its adverse health effects. The air-water partitioning behavior of volatile organic compounds (VOCs) such as formaldehyde is an important process th...

  14. Developing a Reference Material for Diffusion-Controlled Formaldehyde Emissions Testing

    Science.gov (United States)

    Emissions of formaldehyde from building materials can contaminate indoor air and create significant risks to human health. The need to control formaldehyde emissions from indoor materials is made more urgent by the prevailing drive to improve building energy by decreasing ventil...

  15. Formaldehyde concentrations in household air of asthma patients determined using colorimetric detector tubes

    Science.gov (United States)

    Dannemiller, Karen C.; Murphy, Johnna S.; Dixon, Sherry L.; Pennell, Kelly G.; Suuberg, Eric M.; Jacobs, David E.; Sandel, Megan

    2013-01-01

    Formaldehyde is a colorless, pungent gas commonly found in homes that is a respiratory irritant, sensitizer, carcinogen and asthma trigger. Typical household sources include plywood and particleboard, cleaners, cosmetics, pesticides, and others. Development of a fast and simple measurement technique could facilitate continued research on this important chemical. The goal of this research is to apply an inexpensive short-term measurement method to find correlations between formaldehyde sources and concentration, and formaldehyde concentration and asthma control. Formaldehyde was measured using 30-minute grab samples in length-of-stain detector tubes in homes (n=70) of asthmatics in the Boston, MA area. Clinical status and potential formaldehyde sources were determined. The geometric mean formaldehyde level was 35.1 ppb and ranged from 5–132 ppb. Based on one-way ANOVA, t-tests, and linear regression, predictors of log-transformed formaldehyde concentration included absolute humidity, season, and the presence of decorative laminates, fiberglass, or permanent press fabrics (pformaldehyde concentration was 57% higher in homes of children with very poorly controlled asthma compared to homes of other asthmatic children (p=0.078). This study provides a simple method for measuring household formaldehyde and suggests that exposure is related to poorly controlled asthma. PMID:23278296

  16. Portable formaldehyde monitoring device using porous glass sensor and its applications in indoor air quality studies.

    Science.gov (United States)

    Maruo, Yasuko Yamada; Nakamura, Jiro

    2011-09-30

    We have developed a portable device for formaldehyde monitoring with both high sensitivity and high temporal resolution, and carried out indoor air formaldehyde concentration analysis. The absorbance difference of the sensor element was measured in the monitoring device at regular intervals of, for example, one hour or 30 min, and the result was converted into the formaldehyde concentration. This was possible because we found that the lutidine derivative that was formed as a yellow product of the reaction between 1-phenyl-1,3-butandione and formaldehyde was stable in porous glass for at least six months. We estimated the reaction rate and to be 0.049 min(-1) and the reaction occurred quickly enough for us to monitor hourly changes in the formaldehyde concentration. The detection limit was 5 μg m(-3) h. We achieved hourly formaldehyde monitoring using the developed device under several indoor conditions, and estimated the air exchange rate and formaldehyde adsorption rate, which we adopted as a new term in the mass balance equation for formaldehyde, in one office. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT

    Science.gov (United States)

    The paper discusses the measurment and analysis of the patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board, using small environmental chamber tests. The formaldehyde emissions resulted in sharp increase of chamber air...

  18. Determination of formaldehyde in frozen fish with formaldehyde dehydrogenase using a flow injection system with an incorporated gel-filtration chromatrography column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ell

    1996-01-01

    A flow injection analysis (FIA) system for determination of formaldehyde in frozen fish products is described. The system provides a rapid and selective determination of formaldehyde in aqueous fish extracts by the combination of a deproteinization procedure and a stopped-now enzymatic approach...... in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...... and less affected by interferences. The limit of detection for the proposed method is 2.5 mg/l of formaldehyde. The sampling frequency is about 10 determinations per hour....

  19. Determination of Formaldehyde in Frozen Fish with Formaldehyde Dehydrogenase Using a Flow Injection System with an Incorporated Gel-filtration Chromatography Column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard

    1996-01-01

    A flow injection analysis (FIA) system for determination of formaldehyde in frozen fish products is described. The system provides a rapid and selective determination of formaldehyde in aqueous fish extracts by the combination of a deproteinization procedure and a stopped-flow enzymatic approach...... in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...... and less affected by interferences. The limit of detection for the proposed method is 2.5 mg/l of formaldehyde. The sampling frequency is about 10 determinations per hour....

  20. 21 CFR 177.1680 - Polyurethane resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyurethane resins. 177.1680 Section 177.1680 Food... of Single and Repeated Use Food Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane...) For the purpose of this section, polyurethane resins are those produced when one or more of the...

  1. Method for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2008-12-30

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

  2. Method of removing contaminants from plastic resins

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-11-18

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

  3. Method of removing contaminants from plastic resins

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-07

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

  4. 21 CFR 177.1595 - Polyetherimide resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyetherimide resin. 177.1595 Section 177.1595... Components of Single and Repeated Use Food Contact Surfaces § 177.1595 Polyetherimide resin. The polyetherimide resin identified in this section may be safely used as an article or component of an article...

  5. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with aliphatic... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4...

  6. 40 CFR 721.5560 - Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz[c...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with... Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6... identified as formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz...

  7. 40 CFR 86.1320-90 - Gas meter or flow instrumentation calibration; particulate, methanol, and formaldehyde measurement.

    Science.gov (United States)

    2010-07-01

    ... calibration; particulate, methanol, and formaldehyde measurement. 86.1320-90 Section 86.1320-90 Protection of... instrumentation calibration; particulate, methanol, and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions requires the use of gas meters or flow instrumentation to determine...

  8. 24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

    Science.gov (United States)

    2010-04-01

    ... certification and qualification of formaldehyde emission levels. 3280.406 Section 3280.406 Housing and Urban... qualification of formaldehyde emission levels. (a) Preconditioning. Preconditioning of plywood or particleboard... with the Standard Test Method for Determining Formaldehyde Levels from Wood Products Under Defined Test...

  9. 40 CFR 721.3830 - Formaldehyde, reaction products with an alkylated phenol and an aliphatic amine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3830 Formaldehyde, reaction... new uses subject to reporting. (1) The chemical substance identified generically as Formaldehyde...

  10. 40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.

    Science.gov (United States)

    2010-07-01

    ... calibration; particulate, methanol and formaldehyde measurement. 86.120-94 Section 86.120-94 Protection of... Procedures § 86.120-94 Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions requires the use of gas meters...

  11. 40 CFR 721.10054 - Phenol, polymer with formaldehyde, 3-[(2-aminocyclohexyl)amino]-2-hydroxypropyl ethers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phenol, polymer with formaldehyde, 3... Significant New Uses for Specific Chemical Substances § 721.10054 Phenol, polymer with formaldehyde, 3- -2... substance identified generically as a phenol, polymer with formaldehyde, 3- -2-hydroxypropyl ethers (PMN P...

  12. 40 CFR 63.1183 - How do I comply with the formaldehyde standards for existing, new, and reconstructed curing ovens?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false How do I comply with the formaldehyde... with the formaldehyde standards for existing, new, and reconstructed curing ovens? To comply with the formaldehyde standards, you must meet all of the following: (a) Install, calibrate, maintain, and operate a...

  13. Formaldehyde concentration in discharge from land based aquaculture facilities in Atlantic Canada.

    Science.gov (United States)

    Lalonde, Benoit A; Ernst, William; Garron, Christine

    2015-04-01

    Formaldehyde is used in freshwater aquaculture facilities in the Maritimes region of Canada to prevent external parasites and is discharged without treatment to freshwater receiving environments. In this study, formaldehyde was measured at effluent outfalls and 100 m downstream of four land based aquaculture facilities at various post-treatment time intervals. Concentrations of formaldehyde ranged from 0.2 to 7.1 mg/L. Based on Environment Canada's environmental no effect value, all of the samples show a potential risk to aquatic life. Furthermore, based on a chronic aquatic life water quality criterion of 1.61 mg/L all but two of the samples had concentrations considered to be toxic to aquatic life. An acute water quality criteria was only exceeded once in all of the environmental measurements of formaldehyde. These results lead us to hypothesize that the discharge of formaldehyde from land-based facilities may cause adverse chronic impacts.

  14. Is it possible to use biomonitoring for the quantitative assessment of formaldehyde occupational exposure?

    Science.gov (United States)

    Chiarella, Pieranna; Tranfo, Giovanna; Pigini, Daniela; Carbonari, Damiano

    2016-12-01

    The European classification, labeling and packaging classified formaldehyde as human carcinogen Group 1B and mutagen 2, fostering the re-evaluation of the exposure risk in occupational settings. Although formaldehyde exposure is traditionally measured in air, many efforts were made to identify specific exposure biomarkers: urinary formaldehyde, formic acid and DNA damage indicators. Though used in combination, none of these seems satisfactory. The influence of the metabolism on exogenous formaldehyde levels, the exposure to other xenobiotics, the difference in genetic background and metabolism efficiency, misled the relationship between genotoxicity and exposure data. Nevertheless, the limitation of adverse effects to the local contact sites hampers biomonitoring. Here we discuss the feasibility of formaldehyde biomonitoring and the use of DNA, DNA-protein cross-links and protein adducts as potential biomarkers.

  15. Sinonasal adenoid cystic carcinoma following formaldehyde exposure in the operating theatre.

    Science.gov (United States)

    Sandvik, Anniken; Klingen, Tor Audun; Langård, Sverre

    2014-01-01

    We present a case report of an auxiliary nurse who developed an adenoid cystic carcinoma in her left maxillary sinus following occupational exposure to formaldehyde in the operating theatre. Currently, the epidemiological evidence that formaldehyde can cause cancer in humans is considered to be limited. Previous case-control-studies of formaldehyde and sinonasal cancer have mainly investigated subjects who were concomitantly exposed to wood dust, a known risk factor to the development of sinonasal adenocarcinoma of intestinal type. Our case report presents a patient who has developed an adenoid cystic carcinoma following exposure to formaldehyde. We suggest that the occupational physician remains alert to formaldehyde as an occupational hazard among health care workers.

  16. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    Science.gov (United States)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  17. Formaldehyde and Epigenetic Alterations: MicroRNA Changes in the Nasal Epithelium of Nonhuman Primates

    Science.gov (United States)

    Rager, Julia E.; Moeller, Benjamin C.; Doyle-Eisele, Melanie; Kracko, Dean; Swenberg, James A.

    2013-01-01

    Background: Formaldehyde is an air pollutant present in both indoor and outdoor atmospheres. Because of its ubiquitous nature, it is imperative to understand the mechanisms underlying formaldehyde-induced toxicity and carcinogenicity. MicroRNAs (miRNAs) can influence disease caused by environmental exposures, yet miRNAs are understudied in relation to formaldehyde. Our previous investigation demonstrated that formaldehyde exposure in human lung cells caused disruptions in miRNA expression profiles in vitro. Objectives: Using an in vivo model, we set out to test the hypothesis that formaldehyde inhalation exposure significantly alters miRNA expression profiles within the nasal epithelium of nonhuman primates. Methods: Cynomolgus macaques were exposed by inhalation to approximately 0, 2, or 6 ppm formaldehyde for 6 hr/day for 2 consecutive days. Small RNAs were extracted from nasal samples and assessed for genome-wide miRNA expression levels. Transcriptional targets of formaldehyde-altered miRNAs were computationally predicted, analyzed at the systems level, and assessed using real-time reverse transcriptase polymerase chain reaction (RT-PCR). Results: Expression analysis revealed that 3 and 13 miRNAs were dysregulated in response to 2 and 6 ppm formaldehyde, respectively. Transcriptional targets of the miRNA with the greatest increase (miR-125b) and decrease (miR-142-3p) in expression were predicted and analyzed at the systems level. Enrichment was identified for miR-125b targeting genes involved in apoptosis signaling. The apoptosis-related targets were functionally tested using RT-PCR, where all targets showed decreased expression in formaldehyde-exposed samples. Conclusions: Formaldehyde exposure significantly disrupts miRNA expression profiles within the nasal epithelium, and these alterations likely influence apoptosis signaling. PMID:23322811

  18. Effects of Sodium Selenite on Formaldehyde Induced Renal Toxicity in Mice

    Directory of Open Access Journals (Sweden)

    Shabnam Mohammadi 1,2 * , Maryam Moghimian 3, Hanieh Torabzadeh 4, Mahla Langari 4, Roghayeh Nazeri 4, Zahra Karimi 4, Elham Sangari 4, Najmeh Jagarmi 5, Alireza Mohammad Zadeh 3, Mehdi Karimi 7, Kamyar Tavakkoli 8, Ali Delshad 9, Fatemeh Mohammadzadeh 3, Majid Ghayour-Mobarhan 10

    2016-12-01

    Full Text Available Background: Formaldehyde is widely used for industrial applications. Renal injury is an adverse effect associated with formaldehyde. Few studies have explored the potential benefits of protective factors on formaldehyde induced renal toxicity. This study evaluated the dose dependent effects of sodium selenite on the biochemical and histopathological effects of formaldehyde on murine kidney. Methods: Forty eight adult Balb/c male mice were randomized into six groups: a control group, a formaldehyde group and experimental III-VI groups. Formaldehyde group was injected with 10 mg/kg formaldehyde and groups III-VI received intraperitoneally doses of 0.1, 0.2, 0.4, 0.8 mg/kg selenium. After two weeks, a stereological study was done in accordance with the principle of Cavalieri and serum concentrations of urea and creatinine were measured. Data were analyzed using ANOVA and SPSS software. Results: Glomerosclerosis, necrosis and vacuolization were observed in the convoluted tubules of animals treated with formaldehyde. The biochemical markers, volume and count of glomeruli in the group treated with formaldehyde was significantly difference compared to the control group (P<0.05. The volume of the glomeruli in the group treated with 0.2 and 0.4 mg selenium and urea level in the group treated with 0.4 and 0.1 mg/kg selenium was significantly difference compared to the control group (P <0.05. The count of glomeruli and creatinine level in the selenium group was significantly difference compared to the control group (P ≤ 0.0001. Conclusions: A dose of 0.2 mg/kg of sodium selenite caused partial protective effect on the renal tissue and function in exposed to formaldehyde.

  19. Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review

    Directory of Open Access Journals (Sweden)

    W.D.P Rengga

    2012-11-01

    Full Text Available Gas storage is a technology developed with an adsorptive storage method, in which gases are stored as adsorbed components on the certain adsorbent. Formaldehyde is one of the major indoor gaseous pollutants. Depending on its concentration, formaldehyde may cause minor disorder symptoms to a serious injury. Some of the successful applications of technology for the removal of formaldehyde have been reported. However, this paper presents an overview of several studies on the elimination of formaldehyde that has been done by adsorption method because of its simplicity. The adsorption method does not require high energy and the adsorbent used can be obtained from inexpensive materials. Most researchers used activated carbon as an adsorbent for removal of formaldehyde because of its high adsorption capacity. Activated carbons can be produced from many materials such as coals, woods, or agricultural waste. Some of them were prepared by specific activation methods to improve the surface area. Some researchers also used modified activated carbon by adding specific additive to improve its performance in attracting formaldehyde molecules. Proposed modification methods on activation and additive impregnated carbon are thus discussed in this paper for future development and improvement of formaldehyde adsorption on activated carbon. Specifically, a waste agricultural product is chosen for activated carbon raw material because it is renewable and gives an added value to the materials. The study indicates that the performance of the adsorption of formaldehyde might be improved by using modified activated carbon. Bamboo seems to be the most appropriate raw materials to produce activated carbon combined with applying chemical activation method and addition of metal oxidative catalysts such as Cu or Ag in nano size particles. Bamboo activated carbon can be developed in addition to the capture of formaldehyde as well as the storage of adsorptive hydrogen gas that

  20. Longevity of resin composite restorations

    Directory of Open Access Journals (Sweden)

    Shisei Kubo

    2011-02-01

    Full Text Available In daily practice, an evidence-based approach is becoming more expected of dentist. However, only outcomes obtained from clinical studies are accepted as evidence. Although many clinical trials have been performed, most of them are short-term studies, whereas long-term studies are likely to provide more reliable evidence. In this article, prospective studies and retrospective longitudinal clinical studies on resin composite restorations were systematically searched with PubMed for literature in English and with Japana Centra Revuo Medicina (Ichushi Web for articles in Japanese. Finally, 21 long-term (8 years or more prospective studies and nine retrospective studies with survival analysis were selected and reviewed from more than 561 papers. The overall findings suggest that at least 60% of resin composite restorations will last more than 10 years when proper materials are applied correctly. Patient-, operator-, material- and tooth-related factors may have an influence on the survival of resin composite restorations. Appropriate maintenance policies based on MI concepts are claimed to enhance the longevity of resin composite restorations.