A Thermogravimetric Analysis

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FIGURE 31-1 Thermobalance components. The balance beam is shown as A. The sample cup and holder are 0 C is a counterweight. /) is a lamp and photodiodes, E is a magnetic coil, and F is a permanent magnet. The computer data-acquisition, data-processing, and control systems are components G, //. and /. Component J is the printer and display unit. (Courtesy of Mettler-Toledo.) 

FIGURE 31-2 Controlled atmospheric thermogram lor a bituminous coal sample. A nitrogen atmosphere was used lor about 18 min followed by an oxygen atmosphere for 4 to 5 min. The experiment was then completed in nitrogen. (Reprinied with permission from C. M. Earnest, Ana/. Chem.. 1984.56.1471A.) 

Tutorial l.earn more alx)ut ibermogra liiictric analysi.s. 

FIGURE 31-3 Thermograms lor some common polymeric materials. PVC polyvinyl chloride PMMA polymethylmethacrylate LDPE - low-density polyethylene PTFE polyletrafluoroethylene PI aromatic polypyromelitimide. (From J, Chiu, in Thermoanalysis of Fiber-Forming Polymers, R. F. Schwenker. ed,. New York Wiley, 1966.) 

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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. 

A thermogravimetric analysis is performed in order to evaluate the effectiveness of adding the filler particles on the thermal properties of the composite. 

These observations of char, flow, and structural change indicate significant temperature rises in the impacted zones of these materials, with the implication that thermal parameters are significant in the impact wear process. Consequently, a thermogravimetric analysis of these mate-... 

In addition a thermogravimetric analysis of these polymers was carried out. Their thermal stability was evaluated in the following sequence of the onset decomposition temperature P(cgTFSI) (T = 389°C) > P(dgTFSI) (T = 382°C) > P(egTFSI) T=3Sl°C) > P(bgTFSI) (T=371°C). From these results the IL-type polymer brushes were determined to be thermally stable up to around 400°C. This is an excellent property for application to electrochemical devices. 

Fig. 10. —Thermograms of Cellulose. [(A) Thermogravimetric analysis in helium (B) differential thermal analysis in oxygen (C) difiFerential thermal analysis in nitrogen.]...

SO2 removal experiments with CEB were performed in a thermogravimetric analysis (TGA) set-up to simulate the process during its combustion. The sample was first heated in a mixture of 70% CO2 in N2 to produce CaCOj, followed by the decomposition of CaCOj to CaO under N2 and O2. This calcined material was sulfated using a mixture containing 3000 ppm SO2, 12% O2, and the balance N2. 

The weight of the polymer on the column is determined most commonly by ashing, using a thermogravimetric analysis system (TGA). A typical experiment requires 10 mg of coated support. 

A thermogravimetric analysis performed on sodium cephalothin (Eli Lilly reference standard P-89448) showed no weight loss until 154 C at 154 G weight loss begins resulting in decomposition. The measurement was performed under nitrogen sweep at a heating rate of 5 C/min. 

A thermogravimetric analysis of VCR sulfate (Lilly reference standard lot P-89453) was run using the Du Pont 950 Thermogravimetric Analyzer at a heating rate of 5° 0. 

Weidenkaff A., Reller A.W., Wokaun A., Steinfeld A. Thermogravimetric analysis of the ZnO/Zn water splitting cycle. Thermochimica Acta 2000 359 69-75. 

Figure 3 shows a thermogravimetric analysis performed on the two molding compounds. The scans show that the molding compound based on the stable bromine CEN has a 15-20°C increase in thermal degradation temperature over the standard compound. Even though the stable bromine CEN is more thermally stable than standard resins, it still supplies the bromine necessary to achieve the desired flame retardancy properties. 

Figure 8. Thermal behavior of 2Mg-Fe powders ball milled for 59h. a) Thermogravimetric analysis (TGA) curve and b) four overlaid DSC curves.

The YBa2Cu307 y series with 0starting material was prepared in the manner described in the synthesis section and its oxygen content was evaluated to be 6.96+0.1 by a thermogravimetric analysis method (TGA) described elsewhere (11). This value will be taken as 7.0 (i.e. y = 0) in the following. Different values of y were then obtained by a contolled heat treatment of rectangular bars of the compound in an argon ambient. 

Dyszel (1985) performed a thermogravimetric analysis/atmospheric-pressure chemical-ionization mass spectrometry (TGA/APCIMS) on green coffee beans. Using various combinations of 14 (M+1) ions, the author concluded that unknown coffees can be matched, with varying degrees of certainty, to known coffees for their country of origin. 

A thermogravimetric analysis (TGA) profile of a typical alicyclic copolymer resist resin, poly(CBN-co-NBCA), is shown in Fig. 7.15. All of the alicyclic resist co-and terpolymers show similar TGA profiles. The deprotection temperature and decomposition temperature for the polymers are roughly 250°C and 400°C, respectively. At the deprotection temperature, roughly 25% weight loss associated with the deprotection event and corresponding to the loss of isobutylene and carbon... 

We believe that obtaining of non-agglomerated powders of the stabilized zirconium dioxide after processing its hydrogels by organic solvents is a result of prevention of the interparticle polymerization processes. This conclusion was confirmed by methods of a thermogravimetric analysis and IR spectroscopy. 

A thermogravimetric analysis was carried out for all polymers using a Mettler thermogravimetric analysis device. Both the absolute weight and the rate of weight loss were recorded as a function of temperature. 

One unique characteristic of the borazine oligomer is that it has a very high mass yield observed upon conversion to BN. Figure 2.11 shows a thermogravimetric analysis (TGA) plot of the borazine oligomer. This data reveals that the mass yield upon conversion to BN is approximately 85% which is very high for a ceramic precursor [27]. Additional examination has revealed evidence for viscoplastic flow in the crosslinked oligomer under the application of pressure. This may increase the effective BN mass yield even further for a bulk structure such that the volume yield is between 60 and 70%. 

Figure 15.11 shows a thermogravimetric analysis of pine flour and wood cellulose. Due to its low thermal stability, wood flour is usually used as filler only in plastics that are processed at low temperatures, lower than about 200 °C. Above these temperatures the cell wall polymers begin to decompose. High-purity cellulose pulps, where nearly all of the less thermally stable lignin and hemicelluloses have been removed, have recently been investigated for use in plastic matrices such as nylon that are processed at higher temperatures than most commodity thermoplastics [27]. 

The LaxM(fsa)2cn,N03.H20 complexes (M = Ni, Cu) and some of their pyrolysis products were characterized by Elemental Analysis (Laboratoire Central d Analyse, C.N.R.S., Vernaison, France) in order to control their stoichiometry. Thermal treatments of the complexes and of Mont/LaxM(fsa)2en,H20 were carried out in a ThermoGravimetric Analysis (T.G.A.) apparatus coupled with a Balzers QMG 420 C mass spectrometer, under 02/Ar (1/1, 15 ml/min) atmosphere with a 100°C/h temperature ramp. KBr pellets (0.5% dispersion in O.lg KBr) were analyzed by Infra-Red spectrometry (Nicolet 710 FT-IR spectrometer). X-Ray diffractograms of powdered solids spread on a glass plate were recorded on a Siemens D500 diffractometer (Cu Ka radiation, X = 1.54056 A) in the reflection mode. ... 

Figure 10.10 (a) Thermogravimetric analysis of unvulcanized and sulfur vulcanized... 

In a thermogravimetric analysis (TGA) the mass of a sample in a controlled atmosphere is recorded continuously as a function of temperature or time as the temperature of the sample is increased (usually linearly with time). A plot of mass or mass percentage as a function of time is called a thermogram or a thermal decomposition curve. 

A thermogravimetric analysis of the bis-methylated poljrmer (ma) showed that it was stable to 185° with rapid loss of 10% of its weight between 185 and 195° and continuing rapid degradation with further increases in temperature. The onset of thermal degradation was also clearly visible on the DSC scan of the polymer which showed a very sharp peak at 185°. The thermal stability of polymers inb, V, and VI was somewhat lower with rapid weight loss starting at temperatures between 125 and 150°. 

To evaluate activation energies of thermooxidative decomposion the materials HBPI(ODPA-MTA)11, THBPI(ODPA-MTA)ll and LPI(ODPA-MDA)ll were analyzed by a thermogravimetric analysis using heating rates 2,5 5 10 and 15 C.min. The obtained dependences are collected in Figure 17 a, b. 

A simple method for the determination of the hydroxyl groups of silica utilizing the thermogravimetry (TG) principle is described. A thermogravimetric analysis combined with D2O vapor pretreatment was applied to determine both the surface and the inner... 

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