Thermogravimetric analyzer measurements

A thermogravimetric analyzer measures the change in weight of a sample due to volatilization, reaction, or absorption from the gas phase. With polymers, the TGA is used to measure the amount and loss of moisture or diluent, and rates and tempera-... 

Thermal Properties. The glass transition temperature (Tg) and the decomposition temperature (Td) were measured with a DuPont 910 Differential Scanning Calorimeter (DSC) calibrated with indium. The standard heating rate for all polymers was 10 °C/min. Thermogravimetric analysis (TGA) was performed on a DuPont 951 Thermogravimetric Analyzer at a heating rate of 20 °C/min. 

Analysis. The percent solids of each of the latexes was measured using a DuPont Model 950 Thermogravimetric Analyzer. Solution densities were determined using a Parr Mettler Model DMA-60 precision densitometer. The particle density was calculated from the solution density and the percent solids. 

Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were performed in air at a heating rate of lOK/min. on a PTC-lOA thermogravimetric analyzer. The adsorption isotherms for vapor-phase water and ethanol were measured using the BET method. The saturation pressures, Pq, of water and ethanol at 299K are 758 mmHg. Prior to the adsorption experiments, the samples were dehydrated at 673K in air for 4 h. 

An Instron tensile machine can be used to measure stress and strain in the automotive lab. However, incoming inspection at a supplier is generally where this type of analysis takes place. More often, an automotive chemist at an OEM will be required to analyze a sample for failure analysis of that particular part. A thermogravimetric analyzer (TGA) will measure the change in mass of an elastomer in an inert (nitrogen) atmosphere as the temperature is waived. These instruments are very precise and will give information such as degradation temperature, filler content solvent residue, and absorbed moisture content. 

Thermal analysis (DTA) was performed both on the dried unreacted gel and on the product crystals to determine water and TPA content. Measurements were made using a NETZSCH Model STA 409 thermogravimetric analyzer. Samples were scanned from 30 to 700C at a rate of lOC/min. under a lOml/min. flow of dry nitrogen. Details of the experimental protocol are listed elsewhere (21). 

Temperature programmed reduction (TPR), temperature programmed Ar heating (TPAr) and extent of reduction experiments were all performed in a Perkin Elmer thermogravimetric analyzer (TGA) Model TGA 7 described elsewhere [22]. H2 chemisorption measurements were eonducted using a flow chemisorption method and apparatus described by Jones and Bartholomew [24]. Activity measurements and high-pressure steam treatments were conducted in a fixed-bed microreactor described elsewhere [22]. A Micromeritics Gemini 2360 surface analyzer was used to measure N2 adsorption at liquid N2 temperature for BET surface area measurements. A Micromeritics Tri-Star 3000 analyzer with N2 adsorption was used to obtain the pore size distribution. 

Thermogravimetric analyzers may be connected to a variety of chemical analyzers to determine the exact composition ofthe outgassed materials as they are evolved. Among chemical analysis methods are gas chromatography, infrared spectroscopy, and mass spectroscopy for example, a TGA apparatus may be coupled with a Fourier Transform Infrared (FTIR) spectrophotometer to measure the thermal oxidative stabilities of several fluorinated polyimides. 

Thermogravimetric analyzer (TGA). TGA measures weight changes in a sample as the temperature is varied, providing a useful means to determine degradative processes and heat resistance in polymeric compounds. 

The heart of the thermogravimetric analyzer is the thermobalance, which is capable of measuring the sample mass as a function of temperature and time. The relationship between the components of a thermobalance varies from one instrument to another. A schematic representation as shown in Figs. 3.1a and 3.1b indicates typical thermocouple placements relative to the sample. The three standard sample and furnace positions relative to the balance are depicted in Fig. 3.1a. Figure 3.2 shows actual examples of currently available commercial instruments. 

Setaram offers thermogravimetric analyzers with ambient-1600 °C capability (Labsys TGA), ambient-2400°C capability (SETSYS Evolution TGA), and ambient-2100°C with large-volume capability (96-line TGA). The SETSYS Evolution TGA is a modular TGA with two weighing capacities of 35 or 100 g. Simultaneous TGA-DTA measurements up to 2400 °C and TGA-DSC up to 1600 °C can be made. Coupling to a gas analyzer is also possible. The 96-line TGA can weigh samples up to 100 g, and simultaneous TGA-DTA/DSC measurement is available. A gas humidity generator accessory is available. An advanced thermokinetics software package is available. For more information, see vww.setaram.com. 

E2402, Standard Test Method for Mass Loss and Residue Measurement Validation of Thermogravimetric Analyzers E2403, Standard Test Method for Sulfated Ash of Organic Materials by Thermogravimetry... 

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