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Vanessa Fierro - One of the best experts on this subject based on the ideXlab platform.
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Physical gelation of water-borne thermosetting Resins by percolation theory - Urea-Formaldehyde, Melamine-urea-Formaldehyde, and Melamine-Formaldehyde Resins
Journal of Polymer Science, Part B: Polymer Physics, 2008Co-Authors: Alain Celzard, Vanessa FierroAbstract:Percolation and effective-medium theories are applied for calculating the connectivity threshold of colloid particles of given shapes, observed during the physical gelation, distinguished from chemical gelation, of aminoplastic Resins. The rigidity threshold, being the critical solid fraction at which a rigid network is first formed, was also calculated. For that purpose, it was assumed that the central forces that act between the colloidal particles and aggregates were not alone, thus corresponding to the case of physical gelation. It was shown that the observed change of morphology exhibited by such particles and aggregates as a function of time, from elongated to spherical, significantly delays the gel point. Consequently, the latter occurs only after a rather high fraction of solid phase (typically from 30 to 60%) is formed. (C) 2008 Wiley Periodicals, Inc.
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Physical gelation of water-borne thermosetting Resins by percolation theory-urea-Formaldehyde, Melamine-urea-Formaldehyde, and Melamine-Formaldehyde Resins
Journal of Polymer Science Part B: Polymer Physics, 2008Co-Authors: Alain Celzard, Antonio Pizzi, Vanessa FierroAbstract:Percolation and effective-medium theories are applied for calculating the connectivity threshold of colloid particles of given shapes, observed during the physical gelation, distinguished from chemical gelation, of aminoplastic Resins. The rigidity threshold, being the critical solid fraction at which a rigid network is first formed, was also calculated. For that purpose, it was assumed that the central forces that act between the colloidal particles and aggregates were not alone, thus corresponding to the case of physical gelation. It was shown that the observed change of morphology exhibited by such particles and aggregates as a function of time, from elongated to spherical, significantly delays the gel point. Consequently, the latter occurs only after a rather high fraction of solid phase (typically from 30 to 60%) is formed.
Alain Celzard - One of the best experts on this subject based on the ideXlab platform.
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Physical gelation of water-borne thermosetting Resins by percolation theory - Urea-Formaldehyde, Melamine-urea-Formaldehyde, and Melamine-Formaldehyde Resins
Journal of Polymer Science, Part B: Polymer Physics, 2008Co-Authors: Alain Celzard, Vanessa FierroAbstract:Percolation and effective-medium theories are applied for calculating the connectivity threshold of colloid particles of given shapes, observed during the physical gelation, distinguished from chemical gelation, of aminoplastic Resins. The rigidity threshold, being the critical solid fraction at which a rigid network is first formed, was also calculated. For that purpose, it was assumed that the central forces that act between the colloidal particles and aggregates were not alone, thus corresponding to the case of physical gelation. It was shown that the observed change of morphology exhibited by such particles and aggregates as a function of time, from elongated to spherical, significantly delays the gel point. Consequently, the latter occurs only after a rather high fraction of solid phase (typically from 30 to 60%) is formed. (C) 2008 Wiley Periodicals, Inc.
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Physical gelation of water-borne thermosetting Resins by percolation theory-urea-Formaldehyde, Melamine-urea-Formaldehyde, and Melamine-Formaldehyde Resins
Journal of Polymer Science Part B: Polymer Physics, 2008Co-Authors: Alain Celzard, Antonio Pizzi, Vanessa FierroAbstract:Percolation and effective-medium theories are applied for calculating the connectivity threshold of colloid particles of given shapes, observed during the physical gelation, distinguished from chemical gelation, of aminoplastic Resins. The rigidity threshold, being the critical solid fraction at which a rigid network is first formed, was also calculated. For that purpose, it was assumed that the central forces that act between the colloidal particles and aggregates were not alone, thus corresponding to the case of physical gelation. It was shown that the observed change of morphology exhibited by such particles and aggregates as a function of time, from elongated to spherical, significantly delays the gel point. Consequently, the latter occurs only after a rather high fraction of solid phase (typically from 30 to 60%) is formed.
Andre Zoulalian - One of the best experts on this subject based on the ideXlab platform.
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Thermal removal of nitrogen species from wood waste containing urea Formaldehyde and Melamine Formaldehyde Resins
Journal of Hazardous Materials, 2008Co-Authors: Pierre Girods, Anthony Dufour, Yann Rogaume, Caroline Rogaume, Andre ZoulalianAbstract:The removal of nitrogen from wood board waste through a low temperature pyrolysis (523–573 K) is investigated with two analytical methods. The kinetic study of the thermal behaviour of wood board and of its components (wood, UF and MF Resins) shows the feasibility of removing thermally nitrogen from wood board waste. Indeed, the range of temperatures associated with the degradation of wood is different from the one obtained for the degradation of UF and MF resin. Isothermal conditions enable the determination of a kinetic model for degradation of wood board and of its components and demonstrate that the thermal behaviour of wood board is not the reflection of the sum of its components’ behaviour. FTIR analysis of gas products confirms the feasibility removing nitrogen thermally and enables the evaluation of the optimum treatment conditions (temperature/duration). Elementary analysis of the treated samples and study of their low heating value (LHV) enable to quantify the efficiency of the thermal treatment in terms of nitrogen removal and of energy recovery. Results show that around 70% of the initial nitrogen can be removed from the waste, and that the temperature of treatment (between 523 K and 573 K) does not influence the efficiency in terms of nitrogen removal. Nevertheless, the ratio Residual energy/Initial energy (between 76% and 90%) is improved with the lowest temperature of treatment.
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pyrolysis of wood waste containing urea Formaldehyde and Melamine Formaldehyde Resins
Journal of Analytical and Applied Pyrolysis, 2008Co-Authors: Pierre Girods, Anthony Dufour, Yann Rogaume, Caroline Rogaume, Andre ZoulalianAbstract:Abstract Nowadays, wood industry produces huge amounts of wood waste containing various additives. Wood waste containing urea-Formaldehyde (UF) and Melamine-Formaldehyde (MF) Resins such as particleboard or laminated flooring constitutes a consequent resource of energy. However, this type of waste needs a “refinement” to eliminate nitrogen responsible of the production of pollutants. The pyrolysis of particleboard and flooring at low temperature (523–573 K) has been studied on an experimental reactor which allows controlling mainly parameters of the pyrolysis such as temperature, reaction atmosphere or residence time of gases in reactor. Some optimum couples “time/temperature” of treatment are determined by FTIR analysis of the gas products. Quantities of CO, CO 2 , NH 3 produced during the treatment are evaluated in order to estimate the performance of the process. Elementary analyses of residues allow validating the previous results. Thermal analyses of residues in a calorimetric bomb enable to evaluate the energy efficiency of the process.
W Zgrajka - One of the best experts on this subject based on the ideXlab platform.
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characterization of Melamine Formaldehyde Resins by xps saxs and sorption techniques
Langmuir, 2002Co-Authors: Anna Derylomarczewska, J Goworek, Stanislaw Pikus, E Kobylas, W ZgrajkaAbstract:The mesoporous Melamine−Formaldehyde resin was synthesized in the process of polymerization in the presence of fumed silica as an inorganic template. To differentiate the surface properties, the polymer sample was modified by applying 2-methyl-1-butanol. The surface and structural characteristics of obtained sorbents were investigated using various techniques: XPS, SAXS, and sorption from gas phase. The porous structure of initial and modified Melamine−Formaldehyde Resins was determined from nitrogen adsorption/desorption isotherms. To study the polymer activity toward organic substances dissolved in water, the isotherms of sorption of organics from aqueous phase were measured for a wide range of solution concentrations. The liquid sorption data were analyzed to study the effect of polymer structure and surface properties on sorption processes.
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sorption properties of porous Melamine Formaldehyde Resins
Applied Surface Science, 2002Co-Authors: Anna Derylomarczewska, J Goworek, R Kusak, W ZgrajkaAbstract:Abstract Three types of Melamine–Formaldehyde porous sorbents were synthesized by using the fumed silica as an inorganic template. The changes in polymerization conditions lead to a differentiation of the porosity and surface area of these materials. This synthesis allowed preparing the materials of narrow pore size distributions with pore sizes over the range 2.8–6.8 nm, and specific surface areas up to 250 m 2 /g. The analysis of pore structure was based on the comparison of nitrogen adsorption isotherms on a given porous sorbent and a standard nonporous polymer. Additionally the measurements of thermal stability and swelling of synthesized polymers were made. Adsorption of organic substances from aqueous solutions on porous polymers was also investigated.
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studies of Melamine Formaldehyde Resins by sorption from gas and liquid phases
Langmuir, 2001Co-Authors: Derylomarczewska A And, J Goworek, W ZgrajkaAbstract:Three types of mesoporous Melamine−Formaldehyde Resins are synthesized in the process of polymerization in the presence of fumed silica as an inorganic template. The obtained sorbents have differen...
Jianyi Shen - One of the best experts on this subject based on the ideXlab platform.
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Preparation of high surface area mesoporous Melamine Formaldehyde Resins
Microporous and Mesoporous Materials, 2020Co-Authors: Huapeng Cui, Hui Chen, Zhouyang Guo, Jianyi ShenAbstract:Abstract Mesoporous Melamine Formaldehyde Resins (MMF) with high surface areas and large pore volumes and diameters were prepared without the use of a template. Conditions such as solvent, concentration, Formaldehyde/Melamine ratio and curing temperature and time on the pore parameters of synthesized MMF were investigated. The results showed that the sample (MMF9-120) synthesized in the solvent H2O/DMAc had the surface area higher than 1000 m2/g, pore diameter of about 22 nm and pore volume of about 3.5 cm3/g. It was found to be amphiphilic owing to the presence of amino, ether and alkyl groups on its surface, so that it adsorbed great amount of H2O and toluene. Due to the large pore diameter and volume, it also adsorbed great amount of tannic acid (MW = 1701) and bovine serum albumin (MW = 69 k) (850 and 1160 mg/g, respectively), indicating an excellent adsorbent for large molecules. In addition, it was thermally stable and when heated at 350 °C, the formed MMF9-350 still possessed the high surface area (549 m2/g), which was expected to be a new resin support for catalysts, as compared to the traditional porous polystyrene Resins which can only be used at temperatures below 120 °C.
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nitrogen containing mesoporous carbons prepared from Melamine Formaldehyde Resins with cacl2 as a template
Journal of Colloid and Interface Science, 2011Co-Authors: Yuan Huang, Feng Yang, Jianyi ShenAbstract:Abstract Melamine Formaldehyde Resins were synthesized with encapsulated CaCl2 as a template. Carbonization at high temperatures led to the formation of carbon materials containing N atoms. Washing with de-ionized water removed encapsulated CaCl2, resulting in the formation of mesopores (3–30 nm) with the high surface areas (770–1300 m2/g). The template can be recycled and the method is simple and cost effective as compared to the hard template techniques. The mesoporous carbons containing nitrogen (NMC) thus prepared exhibited the amphipathic surfaces (both hydrophilic and lipophilic) and adsorbed great amount of water and benzene. In addition, the incorporated N atoms exhibited quite strong basicity for the adsorption of great amount of SO2.