Thermal gravimetric analyzer

All of the DBDPO and HBCD thermal degradation experiments reported here were carried out isothermally with a nitrogen purge in a thermal gravimetric analyzer (TGA) at temperatures between 390 and 410° C for DBDPO and 240° C for HBCD, respectively. 

D Commercial COTS controlled by external computer Hybrid systems such as automated dissolution workstation with high-performance liquid chromatography (HPLC) or ultraviolet-visible (UV-Vis) interface Liquid chromatographs, gas chromatographs, UV/Vis spectrophotometers, Fourier transform infrared (FTIR) spectrophotometers, near-infrared (NIR) spectrophotometers, mass spectrometers, atomic absorption spectrometers, thermal gravimetric analyzers, COTS automation workstations... 

Figure 9.23 Thermal gravimetric analyzer (TGA) decomposition of electrochemically generated alane, releases almost full H2 capacity expected in AIH3, Ref [55],...

Coke content was determined using a thermal gravimetric analyzer (TGA). A gas stream (180 ml/min) containing 2 percent O2 in N2 was passed over about 15 mg of catalyst. The initial temperature of the system was 35°C. The temperature was ramped at 10°C/min until it reached 120°C. It was then held at 120°C for 1 h to ensure that all of the water vapor was removed from the catalyst. The temperature was then ramped to 550°C at 10°C/min and held at 550°C for 2 h. Coke content was determined by subtracting the final weight of the catalyst from the catalyst weight after the water was removed. 

The TG-MS assembly consisted of a double-focusing DuPont 21-491 Mass spectrometer coupled through a single-stage glass jet separator to a DuPont 951 Thermal Gravimetric Analyzer which was attached to a DuPont 990 Thermal Analyzer Console. 

Thermal analysis of polymers was performed on DuPont Model 910 Differential Scanning Calorimeter and a Perkin Elmer Model TQS-2 Thermal Gravimetric Analyzer using a heating rate of 10°C/min. Both systems were interfaced to an Omnitherm Data Station for experiment control, and data acquisition and processing. 

Two types of infrared spectroscopic analysis have been applied. The first is to follow the changes in the evolved gas product infrared spectra during heating. The precursor polymer is heated in a thermal gravimetric analyzer (TGA) and the evolved gases are directed into a gas cell in the infrared spectrometer. This TGA-IR method enables us to characterize the composition of the species evolved during the thermal elimination reaction. 

The thennal stability of each metal AcAc was investigated using a Thermal Gravimetric Analyzer (TGA), Model 2050 by TA Instruments. A sample of 20 mg was placed in a platinum pan and heau to 400 °C at a heating rate of 5 °C/min under N2 purge (77 ml/min in the vertical direction and 12 ml/min in the horizontal direction). A curve of wei t loss vosus temperature was obtained. 

Methanol chemisorption experiments have also been carried out at atmospheric pressure in a specially adapted thermal gravimetric analyzer (TGA) microbalance coupled with a PC for temperature and weight monitoring [38]. The system allowed a controlled flow of high purity gases air for pretreatment, helium and a mixture of 2000 ppm methanol in helium for adsorption experiments. 

A Perkin Elmer Pyris 1 Thermal Gravimetric Analyzer (TGA) was used to determine the weight percent concentration of nanotubes in the composite samples. Approximately 20 mg of each sample was heated from 25 to 950 °C at a rate of 20°C/min in a nitrogen environment. As the sample is heated, the mass is measured as function of temperature. The mass retained is calculated by dividing the mass at the temperature of interest by the initial mass. Once the polymer has degraded, the remaining mass is assumed to be the mass of the MWNTs since the MWNTs are thermally stable in nitrogen to temperatures above 1000°C (from discussion with David Carnahan, President of Nano-Lab). 

Fig. IJS Schematic diagram of a thermal gravimetric analyzer (TGA) system for the reactivity test 1 water reservoir and bubbler, 2 gas pre-heater, 3 electric balance, 4 sample basket, 5 heater, 6 personal computer (from Ref. [29])...

Thermal stability of the cured matrix was analyzed under a nitrogen atmosphere using a TGA2950 thermal gravimetric analyzer from TA instruments. 

Thermal gravimetric analyses (TGA) were carried out on a DuPont model 951 analyzer. 

Copolymer Characterization. Copolymer compositions were determined by elemental analysis and thermal gravimetric analysis. A Perkin-Elmer TGS-2 ther-mogravimetric analyzer, programmed from ambient to 800 C in N2 and air, was used. Spectroscopic analysis of the copolymers was not as useful as elemental analysis and thermal gravimetric analysis measurements for analyzing these copolymers. Viscometric measurements were made in a solution of water and NaCl with a Contraves low-shear viscometer. 

Abstract In situ spectroscopy is an important tool to characterize polymers synthesized via a precursor route. Highly conjugated polymers such as po y(p-phenylene vinylene) (PPV) and PPV derivatives are commonly prepared from a precursor polymer because the final polymers are very insoluble and intractable. Preparation in the precursor form enables the polymer materials to be cast as films. The PPV polymers are obtained from the precursor forms using a thermal elimination reaction. The exact conditions of the reaction are important as they influence the properties of the resultant polymer. The details of this thermal elimination reaction have been analyzed using thermal gravimetric analysis (TGA) coupled with infrared analysis of the evolved gas products. In situ infrared spectroscopy of the precursor films during thermal conversion to the polymers has provided further details about the elimination reaction. We have characterized PPV synthesized from a tetrahydrothiophenium monomer (sulfonium precursor route) and via the xanthate precursor route. PPV derivatives under study include poly(2,5-dimethoxy-p-phenylene vinylene) and poly(phenoxy phenylene vinylene). 

Thermal gravimetric analysis and differential thermal analysis (TGA/DTA) can be performed by using a SDT 2960 Simultaneous Differential Thermal Analyzer (TA Instruments, Inc., New Castle, DE). The instrument was calibrated with gold supplied by Perkin-Ehner. Samples (70 mg) of as-prepared powders were hand-pressed in a 3 mm dual action die and placed inside Pt sample cups and heated at the rates of 10 K/ min from ambient temperature to 1400°C. The reference material was used as a pellet of a-alumina. A flow of synthetic air at 50mL/min was maintained during the experiments. 

The surface characteristics of modified whiskers can be analyzed by detecting the thermal weight loss curve. Figure 3.21 shows the thermal gravimetric analysis (TGA) curve of potassium titanate whiskers modified with PMMA. 

Thermal Analysis. Clays, porphyrins, and porphyrin-clay complexes were analyzed by thermal gravimetric analysis under an inert nitrogen atmosphere. One previous study of the thermal stability of porphyrins reports that weight loss is greater and less complex in oxygen compared to nitrogen 10), Weiss... 

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