Search results for "thermal decomposition"

Thermal kinetics for the energy valorisation of polylactide/sisal biocomposites

2018

[EN] The thermal stability and decomposition kinetics of PLA/sisal biocomposites was discussed to evaluate the suitability of their use in energy recovery processes such as pyrolysis and combustion. The influence of the addition of sisal up to 30%wt, the presence of coupling agent, and the atmosphere of operation, i.e. inert or oxidative was discussed by means of multi-rate linear non-isothermal thermogravimetric experiments. All biocomposites showed a mean high heating value of 15 MJ/kg indicating their suitability for energy recovery processes. The thermal requirements of PLA/sisal decomposition were assessed in terms of onset decomposition temperature and apparent activation energy. A mi…

Synthesis of MoO3 Nanostructures and Their Facile Conversion to MoS2 Fullerenes and Nanotubes.

2007

The fast thermolysis of ammonium molybdate leads to a mixture of MoO3 and Mo5.3O14.5(OH)2.8(H2O)1.36 with spherical and rod-like morphologies. The oxide mixture can be converted in quantitative yield to inorganic fullerene-type (IF) MoS2 and MoS2 nanotubes (NT) by H2S reduction using a facile and quick procedure. The products were studied by X-Ray Diffraction (XRD) and by Transmission Electron Microscopy (TEM). TEM analysis reveals that the spherical and rod-like morphology of the oxide precursor is preserved during the H2S treatment.

Improvement of Biomass Gasification/Combustion Characteristics by Microwave Pretreatment of Biomass Pellets

2021

Arynic species; effect of substituents on the reactivity of monosubstituted dehydrobenzenes

1986

Abstract Evidence is presented demonstrating the existence of free dehydrobenzenes in the thermal decomposition of diaryliodonium-2-carboxylates, and that o-benzyne itself and its 4-methyl-, 4-chloro-,4-bromo- and 4-nitro-derivatives are generated from insoluble polymer-bound precursors and trapped by a second solid phase in Diels-Alder reactions. Lifetimes for these elusive species are determined.

Synthesis and thermoelectric characterisation of bismuth nanoparticles

2009

An effective method of preparation of bismuth nanopowders by thermal decomposition of bismuth dodecyl-mercaptide Bi(SC12H25)3 and preliminary results on their thermoelectric properties are reported. The thermolysis process leads to Bi nanoparticles due to the efficient capping agent effect of the dodecyl-disulfide by-product, which strongly bonds the surface of the Bi clusters, preventing their aggregation and significantly reducing their growth rate. The structure and morphology of the thermolysis products were investigated by differential scanning calorimetry, thermogravimetry, X-ray diffractometry, 1H nuclear magnetic resonance spectroscopy, scanning electron microscopy, and energy dispe…

Properties and Structural Studies of Multi-Wall Carbon Nanotubes-Phosphate Ester Hybrids

2013

Long chain phosphate esters bearing at least one or two aryl groups have been synthesized and used for the preparation of stable multi-walled carbon nanotube (MWCNT) hybrids. The non-covalent interaction ester/MWCNT has been investigated by several techniques (SEM, UV-vis, 31P-NMR, RAMAN). The used phosphate ester derivatives demonstrated the ability to produce an excellent dispersion of MWCNT in CHCl3. The obtained dispersions showed a great stability from one to at least three weeks in the range of concentration considered. Thermal analysis showed an increase in the decomposition temperature for the hybrids with respect to pristine MWCNT.

The impact of baking on chlorinated paraffins: Characterization of C10–C17 chlorinated paraffins in oven-baked pastry products and unprocessed pastry…

2019

Abstract This study presents an HPLC–ESI–Q–TOF method for simultaneous quantification of short-chain chlorinated paraffins (SCCPs, C10–13) and an additional characterization of medium-chain chlorinated paraffins (MCCPs, C14–17) in oven-baked pastry products (n = 38) and unprocessed pastry dough material (n = 15). Almost 2 times higher SCCP levels were found in the dough material. ΣSCCP concentrations in products ranged from 0.3 ng g−1 to 23.0 ng g−1 (mean: 6.3 ng g−1), while the results for dough ranged from 5.8 ng g−1 to 22.8 ng g−1 (mean: 12.9 ng g−1). Regardless of the sample matrix, the most abundant CP homologue groups were hepta- and octa-chlorinated undecanes and dodecanes. The avera…

Low temperature synthesis of monodisperse nanoscaled ZrO2with a large specific surface area

2012

Thermal decomposition of Zr(C(2)O(4))(2)·4H(2)O within an autoclave or in a conventional tube furnace at temperatures below 380 °C resulted in nano- and micron-sized ZrO(2), respectively. Reactions under autogenic pressure yielded monodisperse monoclinic (m) and tetragonal (t) ZrO(2) nanoparticles with an average diameter of ~8 nm and interconnected t-ZrO(2) nanoparticles with diameters of ~4 nm, depending on the synthesis temperature. Samples were characterised by X-ray diffraction (XRD), small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) associated with energy dispersive X-ray spectroscopy (EDS), Raman microspectroscopy and phot…

Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors

2013

Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 10–15 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and the nature of the dopant. In addition,…

Unlocking mixed oxides with unprecedented stoichiometries from heterometallic metalorganic frameworks for the catalytic hydrogenation of CO 2

2021

[EN] Their complex surface chemistry and high oxygen lattice mobilities place mixed-metal oxides among the most important families of materials. Modulation of stoichiometry in mixed-metal oxides has been shown to be a very powerful tool for tuning optical and catalytic properties. However, accessing different stoichiometries is not always synthetically possible. Here, we show that the thermal decomposition of the recently reported metal-organic framework MUV-101(Fe, Ti) results in the formation of carbon-supported titanomaghemite nanoparticles with an unprecedented Fe/Ti ratio close to 2, not achievable by soft-chemistry routes. The resulting titanomaghemite phase displays outstanding catal…