Thermogravimetric Balance

Experimental Section. The samples used in the TGA study were crushed to minus 200 mesh. Noniso thermal weight loss data were gathered using a DuPont 951 thermogravimetric balance with a DuPont 990 thermal analyzer. 

The tpd profiles were determined using a Stanton-Redcroft TG 762 thermogravimetric balance with on-line Commodore CBM computer for data collation and analyses.(3.4) The profiles were analysed using the single heating rate, variable coverage (SHR) method. (4.)... 

Although there is some question as to whether the technique should be included in a section related to the pyrolysis of coal, the thermogravimetric balance has also been employed to investigate the thermal decomposition of coal (Voina and Todor, 1978). The data may be recorded in a variety of ways (Figure 13.3) but virtually always involves a record of the weight percent residue with temperature. The cumulative curve is very similar in shape to the true boiling point (ASTM) curve that is employed as an inspection of various petroleum and petroleum products (ASTM, 2011b,c). 

The water adsorption isotherm was measured at 25 0.5 C with a modified P/E TGS-2 Thermogravimetric Balance. Water adsorption is expressed in R(g HjO/g PM). 

The technique of thermogravimetric analysis (TGA), which is used for thermomechanical analysis, is one of the most widely used methods due to its rapidity of operation and a lesser need for sample manipulation compared to other conventional analyses. TGA is defined as a continuous process that involves the measurement of mass variation as a function of temperature or of time, at a constant temperature and/or heating rate. The construction of a thermogravimetric balance is shown schematically in Figure 13.4. 

In a thermogravimetric analysis, the sample is placed in a small weighing boat attached to one arm of a specially designed electromagnetic balance and placed inside an electric furnace. The temperature of the electric furnace is slowly increased at a fixed rate of a few degrees per minute, and the sample s weight is monitored. 

Nitrogen adsorption was performed at -196 °C in a Micromeritics ASAP 2010 volumetric instrument. The samples were outgassed at 80 °C prior to the adsorption measurement until a 3.10 3 Torr static vacuum was reached. The surface area was calculated by the Brunauer-Emmett-Teller (BET) method. Micropore volume and external surface area were evaluated by the alpha-S method using a standard isotherm measured on Aerosil 200 fumed silica [8]. Powder X-ray diffraction (XRD) patterns of samples dried at 80 °C were collected at room temperature on a Broker AXS D-8 diffractometer with Cu Ka radiation. Thermogravimetric analysis was carried out in air flow with heating rate 10 °C min"1 up to 900 °C in a Netzsch TG 209 C thermal balance. SEM micrographs were recorded on a Hitachi S4500 microscope. 

Thermogravimetric analysis In thermogravimetric analysis (TGA) a sensitive balance is used to follow the weight change of the sample as a function of temperature. Its applications include the assessment of thermal stability and decomposition temperature, extent of cure in condensation polymers, composition and some information on sequence distribution in copolymers, and composition of filled polymers, among many others. 

TG-FT-IR, Pyrolysis analyses were performed on the preliquefaction solids using thermogravimetric (TG) analysis with on-line analysis of the evolved products (including an infrared spectrum of the condensables) by FT-IR. The TG-FTIR method has been described previously (23-25). The Bomem TG/plus instrument was employed. A sample is continuously weighed while it is heated. A flow of helium sweeps the products into a multi-pass cell for FT-IR analysis. Quantitative analysis of up to 20 gas species is performed on line. Quantitation of the tar species is performed by comparison with the balance reading. 

Thermogravimetric analysis (TGA) is a suitable technique for the study of explosive reactions. In TGA the sample is placed on a balance inside an oven and heated at a desired rate and the loss in the weight of the sample is recorded. Such changes in weight can be due to evaporation of moisture, evolution of gases, and chemical decomposition reactions, i.e. oxidation. 

The schematic set-up for a thermogravimetric experiment is shown in Figure 16-2. The device is a combination of a sophisticated high temperature furnace (with temperature and gas atmosphere control) and a micro-balance. Since it is meant to... 

Bancroft, G. M., and H. D. Gesser A Combined Automatic Thermal Balance and Pressure Gauge for Thermogravimetric Analysis. J. Inorg. Nucl. Chem. 27, 1537/1543 (1965). 

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