TGA techniques

The TGA technique can be applied to most materials that degrade due to instability brought on by increased temperature. 

Spectroscopy has become a powerful tool for the determination of polymer structures. The major part of the book is devoted to techniques that are the most frequently used for analysis of rubbery materials, i.e., various methods of nuclear magnetic resonance (NMR) and optical spectroscopy. One chapter is devoted to (multi) hyphenated thermograviometric analysis (TGA) techniques, i.e., TGA combined with Fourier transform infrared spectroscopy (FT-IR), mass spectroscopy, gas chromatography, differential scanning calorimetry and differential thermal analysis. There are already many excellent textbooks on the basic principles of these methods. Therefore, the main objective of the present book is to discuss a wide range of applications of the spectroscopic techniques for the analysis of rubbery materials. The contents of this book are of interest to chemists, physicists, material scientists and technologists who seek a better understanding of rubbery materials. 

Chemical structure of rubbery materials Chapters 1, 2, 3, 4, 5, 6, 9 and 11, describe applications of (multi) hyphenated TGA techniques, optical and high-resolution NMR spectroscopes for the analysis of chain microstructures and conformations, chemical composition of components, additives and volatiles in rubbery materials, vulcanisation chemistry, functional groups analysis and chemical modification of rubbery materials. 

Quality control Applications of NMR relaxation experiments, NMR imaging, NMR MOUSE and (multi) hyphenated TGA techniques for quality control are discussed in Chapters 1, 7 and 10. 

The examples of the use of coupled TA techniques given in 6.3.5 and 6.3.6 show the extended amount of information which is obtained by the use of such a strong combination of techniques. We are convinced that these experiments offered better results than in the case separated/single TGA, FTIR and MS systems were used. This because we experienced that a proper choice of experimental TGA conditions remained always the first (and often critical) step of a series of experimental steps necessary to reach such a result. In other words, during investigations like this, the TGA technique remains the basic technique, while the FTIR and MS are used as sophisticated and sensitive detection systems. 

Turk MJ, Ansari AS, Alston WB, Gahn GS, Frimer AA, Schieman DA. Evaluation of the thermal oxidative stability of pol3dmides via TGA techniques. J Polymer Sci. Part A Polym Chem. 1999 Vol. 37. 

Irgashi and Kambe [3] also studied the thermal degradation of polyethylene and used dynamic thermal analysis (DTA) as well as TGA techniques. The experiments were carried out in both air and nitrogen. The PE studied were, two low-density samples. By means of DTA, the crystallinities of the high-pressure samples were found to be 33% and 36% while those for the low-pressure samples were 64% and 77%, and the melting points of the latter samples were higher than those of the former. 

Anderson [29] studied the pyrolysis of Teflon under vacuum, using TGA techniques, over the temperature range of 450 to 550 C. He found that, based upon 11 replicate TGA experiments, the values of and n were 74.8 3.9 kcal/mole, and 1.02 0.07, respectively. 

Reactive amines other than ammonia have also been employed to distinguish Bronsted acid sites in various zeolites using a combination of TPD and thermo-gravimetric analysis (TGA) techniques [135]. The method is based on the fact that surface Bronsted sites may induce thermal decomposition of aliphatic amines to alkenes and ammonia over a narrow temperature range. The number of amine molecules reacted is equated to the number of strong Bronsted acid sites. By choosing amines of appropriate sizes it is possible to discriminate between acid sites located in pores of different diameters. 

Alemdar and Sain [86] extracted Cellulose nanofibres of wheat straw and soy hulls, by a chemi-mechanical technique. They analysed the morphology and physical properties of the nanofibres by scanning and transmission electron microscopy. The wheat straw nanofibres have diameters in the range of 10-80 nm and lengths of a few thousand nanometres, and the soy hull nanofibres have diameters in the range of 20-120 nm and shorter lengths than the wheat straw nanofibres. Fig. 1.21a and b shows the TEM pictures of the wheat straw and soy hull nanofibres. The image shows the separation of the nanofibres from the micro-sized fibres. The thermal properties of the nanofibres were studied by the TGA technique and found that the... 

Gonzalez, A. Irusta, L. Femandez-Berridi, M.J. Iriarte, M. Iruin, J.J. Application of pyrolysis/gas chromatography/ Fourier transform infrared spectroscopy and TGA techniques in the smdy of thermal degradation of poly (3-hydro-xybutyrate). Polym. Degrad. Stabil. 2005, 87, 347-354. 

There are two TGA techniques to determine the degradation temperature of a plastic. The first is called the isothermal method and is based on setting the sample on a temperature that is between 50 and 150C above its melting temperature and letting the instrument measure the weight loss with time. This is one technique used to determine physical aging of a sample under extreme conditions. A typical decomposition curve is shown in Fig. 6. 

One problem that can occur in the solid state that does not occur in the melt is that a large portion of the antioxidant that was soluble in the melt becomes insoluble in the solid state, where it blooms to the surface and is lost to its surroundings. This process is controlled by the solubility and diffusion of the antioxidant in the polymer, and it can be characterized by a TGA technique developed by Roe et al. (1974). The Roe-Bair-Gieniewski (RBG) method involves analyzing a concentration profile across a stack of polyethylene sheets through which the antioxidant has been forced to diffuse (Bair 1997). The level of antioxidant in the polyethylene sheets was determined by TGA based on an induction time calibration curve (Bair 1973). In this study... 

Femandez-Berridi. M.J.. Gonzalez. N.. Mugica, A., and Bernicot. C. (2006) Pyrolysis-FTIR and TGA techniques as tools in the characterization of blends of natural rubber and SBR. Thermochim. Acta, 444 (1), 65-70. 

Char oxidation kinetics were determined at The Energy Institute of Pennsylvania State University for sawdust, using the TGA technique. This technique is described in Chapter 2. The results of this analysis are shown in Figure 4-4. The char utilized in these experiments was obtained... 

Using the Hi-Res TGA technique, a simplified method has been developed by Salin, et al.,l l to extract kinetic parameters from variable heating experiments by using a mathematical function which takes into account resolution, sensitivity, and initial heating rate. These parameters affect the overall heating rate and ean be controlled by the operator. 

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