Showing papers on "Thermogravimetry published in 2009"
TL;DR: In this paper, the effect of nonevaporable water on the strength variation of geopolymers was firstly analyzed and it was shown that it is necessary to keep the strength stable and the optimum content was about 7.4%.
476 citations
TL;DR: In this article, the preparation, characterization, and determination of thermal properties of microencapsulated docosane with polymethylmethacrylate (PMMA) as phase change material for thermal energy storage was focused.
409 citations
TL;DR: In this article, the preparation and characterization of polymethylmetracrylate (PMMA) microcapsules containing n-octacosane as phase change material for thermal energy storage was discussed.
325 citations
TL;DR: In this article, a thin film photoelectrodes were fabricated by aerosol-assisted chemical vapor deposition (AACVD) using a new hexanuclear iron precursor [Fe6(PhCOO)10(acac)2(O)2 (OH)2]·3C7H8 (1) (where PhCOO = benzoate and acac = 2,4-pentanedionate).
Abstract: α-Fe2O3 thin film photoelectrodes were fabricated by aerosol-assisted chemical vapor deposition (AACVD) using a new hexanuclear iron precursor [Fe6(PhCOO)10(acac)2(O)2(OH)2]·3C7H8 (1) (where PhCOO = benzoate and acac = 2,4-pentanedionate). The precursor (1) designed for AACVD has a low decomposition temperature and sufficient solubility in organic solvents and was synthesized by simple chemical techniques in high yield. It was characterized by melting point, FT-IR, X-ray crystallography, and thermogravimetry (TGA). The TGA analysis proved that complex (1) undergoes facile thermal decomposition at 475 °C to give iron oxide residue. In-house designed AACVD equipment was used to deposit highly crystalline thin films of α-Fe2O3 on fluorine-doped SnO2 coated glass substrates at 475 °C in a single step. The material properties were characterized by XRD, XPS, and Raman spectroscopy, and the results confirmed that films were highly crystalline α-Fe2O3 and free from other phases of iron oxide. Further analysis of ...
321 citations
TL;DR: In this article, nanocapsules used as phase change material (PCM) were prepared by using in situ polymerization methods using N -Tetradecane as the core material.
295 citations
TL;DR: Using a single improved synthetic process, three different compounds comprising two known phases such as [Cu 3 (BTC) 2 (H 2 O) 3 ] (1), [Cu 2 (OH)(BTC)(H 2O) 2 n H 2 O (2 ) and a new phase [Cu(BTC)-H 2 ) 2 -(H 2 OM) 2 ]· 3H 2 OD (3 ) have been prepared by microwave-irradiation (MW) of identical reaction mixture of Cu(II) salt and trimesic acid, benzene-1,
288 citations
TL;DR: In this article, a bimetallic catalyst 7Ni3Co/LaAl was used for biogas reforming, and the results showed that the catalytic activity could be closely related to the Ni/Co ratio.
252 citations
TL;DR: In this paper, size-controlled and coated magnetite nanoparticles with glucose and gluconic acid have been successfully synthesized via a simple and facile hydrothermal reduction route using a single iron precursor, FeCl3, and a combination of the inherent chemical reduction capability of sucrose decomposition products and their inorganic coordinating ability.
Abstract: Size-controlled and coated magnetite nanoparticles with glucose and gluconic acid have been successfully synthesized via a simple and facile hydrothermal reduction route using a single iron precursor, FeCl3, and a combination of the inherent chemical reduction capability of sucrose decomposition products and their inorganic coordinating ability. The particle size can be easily controlled in the range of 4−16 nm. Results obtained with and without the addition of sucrose indicate that sucrose is required for the formation of nanoscale and coated magnetite instead of the much larger hematite. Mass spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetry analysis were used to investigate the formation mechanism of the coated nanomagnetite from the single Fe(III) precursor in sucrose. Sucrose acts as a bifunctional agent: (i) it decomposes into reducing species, causing partial reduction of the Fe3+ ions to Fe2+ ions as required for the formation of Fe3O4 an...
235 citations
TL;DR: In this article, four α-cobalt hydroxides with different intercalated anions were synthesized by a chemical precipitation route in which polyethylene glycol was used as the structure-directing reagent for application in the electrode materials of electrochemical capacitors.
Abstract: The four α-cobalt hydroxides (green or blue) with different intercalated anions were synthesized by a chemical precipitation route in which polyethylene glycol was used as the structure-directing reagent for application in the electrode materials of electrochemical capacitors. Every one among the four samples displays an interesting and distinctive morphology although the synthesis conditions were the same except for the anions. The intercalated anions have a critical effect on the basal plane spacing, morphologies, and capacitive properties of the products. Structural and morphological characterizations were performed by using power X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The component and thermal stability of the sample were respectively measured by FT-IR and thermal analyses, including thermogravimetry (TG) and differential thermogravimetry (DTG). The electrochemical behaviors were measured by cyclic voltammogram and galvanostatic charge−discharge. The specific ...
214 citations
TL;DR: In this paper, a nanostructured mesoporous Co x Ni 1− x layered double hydroxides with polyethylene glycol as the structure-directing reagent has been successfully synthesized by a chemical co-precipitation route using polyethylylene glycol.
210 citations
TL;DR: Five silica samples (four precipitated silicas provided by commercial suppliers and one with the MCM-41 structure) have been studied by infrared spectroscopy and by a homemade thermogravimetry-infrared spectrum (TG-IR) setup to determine the integrated molar absorption coefficient of the (nu+delta)OH band and the amount of water adsorbed on silicas through the intensity of the deltaH2O band.
Abstract: Five silica samples (four precipitated silicas provided by commercial suppliers and one with the MCM-41 structure) have been studied by infrared spectroscopy and by a homemade thermogravimetry−infr...
TL;DR: In this article, a sol-gel method using polyvinyl alcohol aqueous solutions and metal nitrate precursors was used to synthesize ZnO, CuO, and Cu0.05Zn0.95O nanoparticles.
TL;DR: A series of mixed matrix membranes were prepared comprising polysulfone Udel matrix and ordered mesoporous silica spheres as filler and an optimum loading of 8 wt % was found in terms of H2/CH4 separation performance.
Abstract: A series of mixed matrix membranes were prepared comprising polysulfone Udel matrix and ordered mesoporous silica spheres as filler with loadings varying between 0 and 32 wt %. The interaction between the filler and the polymer was studied by scanning and transmission electron microscopy, thermogravimetry, differential scanning calorimetry and dynamic mechanical analyses, N2 porosity, X-ray photoelectron spectrometry, and attenuated total reflectance Fourier transform infrared spectroscopy. All these characterizations allowed us to infer an optimum interaction based on both the penetration of the polymer chains into the mesoporosity of the silica spheres and the establishment of hydrogen bondings between the hydroxyl-rich surface and the aryl ether groups of the polymer. An optimum loading of 8 wt % was found in terms of H2/CH4 separation performance. In addition, the optimum membrane was tested for CO2/N2 separation.
TL;DR: In this article, single-walled carbon nanotubes (SWCNTs) were used to construct poly(ether ether ketone) based composites using melt processing.
TL;DR: In this paper, the thermal degradation kinetics of poly(lactic acid) can be interpreted in terms of multi-step degradation mechanisms and the activation energies obtained by Ozawa-Flynn-Wall method and Friedman's method are in good agreement with that obtained by Kissinger's method.
Abstract: Thermal decomposition of poly(lactic acid) (PLA) has been studied using thermogravimetry coupled to Fourier transform infrared spectroscopy (TGA-FTIR). FTIR analysis of the evolved decomposition products shows the release of lactide molecule, acetaldehyde, carbon monoxide and carbon dioxide. Acetaldehyde and carbon dioxide exist until the end of the experiments, whereas carbon monoxide gradually decreases above the peak temperature in that the higher temperature benefits from chain homolysis and the production of carbon dioxide. A kinetic study of thermal degradation of PLA in nitrogen has been studied by means of thermogravimetry. It is found that the thermal degradation kinetics of PLA can be interpreted in terms of multi-step degradation mechanisms. The activation energies obtained by Ozawa–Flynn–Wall method and Friedman’s method are in good agreement with that obtained by Kissinger’s method. The activation energies of PLA calculated by the three methods are 177.5 kJ mol−1, 183.6 kJ mol−1 and 181.1 kJ mol−1, respectively.
TL;DR: Hexaglycidyl cyclotriphosphazene (HGCP) was synthesized, and characterized by FTIR, 31P, 1H, and 13C-NMR.
TL;DR: In this article, a simple sonochemical method was developed to synthesize uniform sphere-like or cubic Co(3)O(4) and Mn( 3)O (4) nanocrystals by using acetate salts and sodium hydroxide or tetramethylammonium hydroxides (TMAH) as precursors.
TL;DR: LiFePO 4 /C composite cathode materials were synthesized by carbothermal reduction method using inexpensive FePO 4 as raw materials and glucose as conductive additive and reducing agent.
TL;DR: Nanocrystalline zinc oxide materials were prepared by sol-gel method and were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry, nitrogen adsorption and infrared spectroscopy techniques and explored the role of hydrolysis reaction in the detoxification of sarin to reveal the values of rate constant and half-life.
TL;DR: The proposed method was successfully applied to the extraction and determination of phenolic compounds in water sample, and the recoveries were 87.7-111.5% for different analytes.
TL;DR: In this article, a solvent-free thermal decomposition method is reported for synthesizing Fe 3 O 4 nanoparticles, which can be tailored by adjusting either reaction temperature or reaction time.
TL;DR: In this paper, the catalytic properties of Ni/La2O3/γ-Al 2O3 catalysts were studied for dry reforming of methane without a diluting gas.
01 Jan 2009
TL;DR: In this article, the chemical modification by esterification of hardwood sawdust and its polymer constituents (cellulose, lignin) using organic anhydrides has been investigated.
Abstract: The chemical modification by esterification of hardwood sawdust and its polymer constituents (cellulose, lignin) using organic anhydrides has been investigated. It was found that the weight percent gain increased with an increment of reaction temperature and time. The characterization of modified hardwood, cellulose and lignin was performed by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry (TGA) studies. Thermal stability of chemically modified wood and wood polymers was found to be lower by comparison with unmodified samples.
TL;DR: In this article, it was shown that the decomposition temperatures of common ionic liquids appear to occur at hundreds of degrees below those temperatures previously reported, and that they are thermally stable to very high temperatures.
TL;DR: In this article, a water-soluble chitosan aerogel derivative was synthesized by reaction of 85% deacetylated chitosa with l -glutamic acid ( l -GA) in aq.AcOH subjected to solvent exchange prior to using supercritical carbon dioxide (sc.CO 2 ) as a nonsolvent for the polymer.
TL;DR: It was shown that the moving boundary model for the two component system can explain the non-linear increase in the deposition yield with increasing HA concentration in chitosan solutions.
TL;DR: In this article, double-ceramic-layer (DCL) thermal barrier coatings of La2Zr2O7 (LZ) and yttria stabilized zirconia (YSZ) were deposited by electron beam-physical vapor deposition (EB-PVD).
TL;DR: In this paper, the authors used a high precision dilatometer to show the dimensional behavior of the Ni-YSZ composites simultaneously with the Degree of Oxidation (DoO) as a function of time during redox cycling and the activation energy for reduction was 84.4 kJ/mol and the kinetics was largely linear.
TL;DR: In this paper, the TGA studies of a pyrolytic decomposition of mixtures of olive residue/plastic were carried out at the temperature ranging from 300 to 1273 K in the nitrogen atmosphere at four heating rates β ǫ = 2, 10, 20 and 50 K min − 1.
15 Aug 2009
TL;DR: This new nanomaterial has the ability to extract the Sumifix Brilliant Orange 3R textile dye from aqueous solution, using a batchwise process, and demonstrated that 4 h is enough to reach equilibrium at 298+/-1 K under pH 4.0.
Abstract: Crystalline layered sodium kenyaite was exchanged to proton kenyaite when reacted with hydrochloric acid solution, providing a new surface with available silanol groups that are able to couple with N-3-trimethoxysilylpropylethylenediamine silylating agent, after prior expansion of the basal distance with the polar organic solvent dimethyl sulfoxide. The resulting organofunctionalized nanomaterial (2N-Ken) was characterized by elemental analysis, infrared spectroscopy, X-ray diffraction, carbon and silicon nuclear magnetic resonances in the solid state, surface analysis, porosity, thermogravimetry, and electron scanning microscopy. The quantity of silylating agent incorporated into the nanospace, calculated from the nitrogen elemental analysis, was determined as 0.48 mmol g−1, after expanding of the acidic precursor basal distance from 1.62 to 1.99 nm. The presence of a covalent silicon–carbon bond of the organosilyl moiety on the inorganic layered structure was confirmed through nuclear magnetic resonance. This new nanomaterial has the ability to extract the Sumifix Brilliant Orange 3R textile dye from aqueous solution, using a batchwise process. The effects of stirring time, adsorbent dosage, and pH on the adsorption capacity demonstrated that 4 h is enough to reach equilibrium at 298 ± 1 K under pH 4.0. Based on error function values (Ferror) the data were best fitted to fractional-order and chemisorption kinetic models when compared to pseudo-first-order and pseudo-second-order kinetic models. The equilibrium data were better fitted to the Sips isotherm model.