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atmospheres by simultaneous thermogravimetric and differential thermal analysis coupled online with quadrupole mass spectrometer (TG/DTA-MS) or FTIR spectrometric gas cell (TG-FTIR). Experimental Preparation of samples
10 °C min −1 . 5–10 mg of the sample was examined under pure nitrogen at a flowing rate of 50 mL min −1 from 50 to 700 °C. TG coupled with Fourier transform infrared spectroscopy (TG-FTIR) consisted of a TGA/DSC 1 (Mettler/Toledo) coupled
is so far to describe the thermal processes in details. So the aim of this study is to investigate thoroughly the thermal processes of enoxacin and ascertain the decomposition mechanism. For this purpose, the TG-FTIR technique, which can conduct
over a ramped temperature range of preferably 300–900 °C [ 1 ]. In this study, micro-scale combustion calorimetry (MCC) and thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR) has been used to investigate the
Introduction In this article, our previous studies [ 1 – 4 ] on the thermal behavior of potentially active compounds are extended by applying the TG-FTIR technique over some new diazoamino-derivatives able to be used either as
halogenoacetates were analyzed as well as the presence of anions Cl − or Br − were also stated. The TG-FTIR coupled measurements have been carried out only for complexes II and IV using the Netzsch TG 209 apparatus coupled with Bruker FTIR spectrophotometer
Abstract
The world production of tyre waste amounts to 5106 ton year–1, 2106 tons of which are produced in Europe, but the final destination of nearly 65–70% of them is the landfill, despite the high added value materials lost and the consequent environmental impact. Treatments alternative to landfilling take into account reconstruction and reuse of the tyres or the matter and/or energy recovery by means of thermal treatment processes (incineration, gasification and pyrolysis). Among these, pyrolysis seems to be a promising and realistic alternative to attain the conversion of tyre waste into valuable and reusable products. Present work relates to experimental tests and results obtained for the study of tyre waste pyrolysis, conducted by means of thermo-gravimetric analysis (TG) of the material and the simultaneous determination, through Fourier transform infrared (FTIR) and mass spectrometry (MS), of the decomposition products. The analysis of the volatile fraction allows to isolate, within the thermograms, the evolution of products referable to specific tyre components and therefore it suggests the application of a multi-component decomposition model. The kinetic model consequently developed agrees fairly well with the experimental data.
Abstract
The thermal degradation of the aliphatic polyamides 6 and 66 was investigated by means of the combined techniques TA-MS and TA-FTIR. The analyses were performed in three different devices. Sample mass ranged from 13 mg to 1 g and heating rates of 2.6 and 10 K min–1 were used in both air and nitrogen atmospheres. The most important decomposition products were caprolactam for PA 6 and cyclopentanone for PA 66. Evolution of NH3 and HCN was registered. The findings of the two hyphenated techniques led to the same results and complemented each other well. The evolved products were captured and analyzed off-line by GC/MS for further confirmation of results.
Abstract
The thermogravimetric analysis (TG) of two series of tri-block copolymers based on poly(L,L-lactide) (PLLA) and poly(ethyleneglycol) (PEG) segments, having molar mass of 4000 or 600 g mol–1, respectively, is reported. The prepared block copolymers presented wide range of molecular masses (800 to 47500 g mol–1) and compositions (16 to 80 mass% PEG). The thermal stability increased with the PLLA and/or PEG segment size and the tri-block copolymers prepared from PEG 4000 started to decompose at higher temperatures compared to those copolymers from PEG 600. The copolymers compositions were determined by thermogravimetric analysis and the results were compared to other traditional quantitative spectroscopic methods, hydrogen nuclear magnetic resonance spectrometry (1HNMR) and Fourier transform infrared spectrometry (FTIR). The PEG 4000 copolymer compositions calculated by TG and by 1HNMR, presented differences of 1%, demonstrating feasibility of using thermogravimetric analysis for quantitative purposes.
Abstract
Identification and monitoring of gaseous species released during thermal decomposition of the title compound 1, Zn(tu)2Cl2, (tu=thiourea, (NH2)2C=S) have been carried out in flowing air atmosphere up to 800°C by both online coupled TG-EGA-FTIR and simultaneous TG/DTA-EGA-MS. The first gaseous products of 1, between 200 and 240°C, are carbon disulfide (CS2) and ammonia (NH3). At 240°C, an exothermic oxidation of CS2 vapors occurs resulting in a sudden release of sulphur dioxide (SO2) and carbonyl sulphide (COS). An intense evolution of hydrogen cyanide (HCN) and beginning of the evolution of cyanamide (H2NCN) and isothiocyanic acid (HNCS) are also observed just above 240°C. Probably because of condensation and/or polymerization of cyanamide vapors on the windows and mirrors of the FTIR gas cell optics, some strange baseline shape changes are also occurring above 330°C. Above 500°C the oxidation process of organic residues appears to accelerate which is indicated by the increasing concentration of CO2, while above 600°C zinc sulfide starts to oxidize resulting in the evolution of SO2. All species identified by FTIR gas cell were also confirmed by mass spectrometry, except for HNCS.
