History of thermal analysis

Mackenzie RC (1984) A history of thermal analysis. Thermochimica Acta 73 249-367. 

Brief history of thermal analysis is reviewed by Wendlandt, W. W., and Gallagher, P. K., in Turi, E. A. (Ed.), Thermal Characterization of Polymeric Materials. London, Academic Press, 1981 (more than 200 references arc cited). 

Concise history of thermal analysis in Europe and Japan is introduced by Saito, A., Fundamentals of Thermal Analysis for Material Science. Tokyo, Kyoritsu, 1990, Ch. 1 (in Japanese). 

Short history of thermal analysis in Europe, China and Japan and details of present status (statistical data on publications) are summarized by Liu Zhenhai, Introduction to Thermal Analysis. Beijing, Chemical Industry Publisher, 1991, Ch. 1 (in Chinese). 

Definitions, nomenclature, terms and sources of information in thermal analysis are to be found in refs. [15,16]. The basis of thermal analysis has recently been reviewed by Wunderlich [6], thermo-analytical instramentation, techniques and methodology by Gallagher [17] the history of thermal analysis was traced by Mackenzie [18]. Thermal analysis of polymers is described in various books [19-23] and reviews [24-28]. Thermal analysis is a powerful secondary technique. 

R.C. Mackenzie History of Thermal Analysis , special issue of Thermochim. Acta, Vol. 73, Elsevier, Amsterdam 1984... 

Thermal analysis techniques have been applied to almost every science area, from archaeology to zoology, and to every type of substance, from alabaster to zeolites. Indeed, it is difficult to find an area of science and technology in which the techniques have not been applied. This truly universal use of thermal analysis is consistent with its early history in. for example, clays, mineralogy, metallurgy, and inorganic substances. 

It is useful to compare the history of the development of thermal analysis with the history of the development of the quartz crystal microbalance. Scopus (www.Scopus.com) is the largest online abstract and citation database of scientific and technical research literature and quality web sources. A search using the term thermal analysis and the terms QCM or quartz crystal microbalance in Scopus, found all references dating to 1966. A Scopus literature search on the latter terms... 

This book deals almost exclusively with studying polymers, by far the widest application of thermal analysis. In this area, TA is used not only for measuring the actual physical properties of materials but also for clarifying their thermal and mechanical histories, for characterizing and designing processes used in their manufacture, and for estimating their lifetimes in various environments. For these reasons, thermal analysis instruments are routinely used in laboratories of the plastics industry and other industries where polymers and plastics are being manufactured or developed. Thus, thermal analysis is one of the most important research and quality control methods in the development and manufacture of polymeric materials as well as in industries that incorporate these materials into their products. 

Polymeric films are used primarily as substrates for a variety of media (e.g., recording tapes), and as packaging materials. Similar to fibers, the thermal analysis of films may give information about orientation and thermal and mechanical history of the sample. A detailed description of thermal analysis of polymeric films can be found in Menczel et al. (1997b). Fiber and film preparation is also briefly described in Section 5.5 (of Chapter 5). 

In many ways the analysis of polymer-based delivery systems, especially microspheres, illustrates a fundamental problem of the use of thermal analysis in pharmaceutical-based systems. In normal evaluation of polymers, prior history is removed by thermal treatment. Whereas for PEG this can be accomplished by melting giving a more amorphous, less crystalline system which gradually on storage returns to a more crystalline system, this alters the structure of the material. For amorphous materials this can be used to allow evaluation of the glass transition temperature. This has benefits for examination of the polymer alone since prior treatment will probably remove any relaxation endotherm associated with the glass transition. As seen with the work of Hill et al [118] a without prior knowledge heat treatment could result in the loss of... 

F or the purpose of analysis, the thermal history of a metal droplet in the spray can be divided into six regions ... 

Holloway JR, Blank JG (1994) Application of experimental results to C-O-H species in natural melts. In MR Carroll, JR Holloway (eds.) Volatiles in magmas. Rev Miner 30 187-230 Holser WT (1977) Catastrophic chemical events in the history of the ocean. Nature 267 403 08 Holser WT, Kaplan IR (1966) Isotope geochemistry of sedimentary sulfates. Chem Geol 1 93-135 Holt BD, Engelkemeier AG (1970) Thermal decomposition of barium sulfate to sulfur dioxide for mass spectrometric analysis. Anal Chem 42 1451-1453 Hoppe P, Zinner E (2000) Presolar dust grains from meteorites and their stellar sources. J Geophys Res Space Phys 105 10371-10385... 

The glass transition temperature of sorbitol has also been studied using thermal analysis, and temperatures ranging from 0 to -55°C have been reported [8,20-24]. The temperature values were dependent on heating rate, history of the sample, and pressure. The extensive variation in conditions explains the wide range of temperatures reported for this parameter. 

To obtain the cure kinetic parameters K, m, and n, cure rate and cure state must be measured simultaneously. This is most commonly accomplished by thermal analysis techniques such as DSC. In isothermal DSC testing several different isothermal cures are analyzed to develop the temperature dependence of the kinetic parameters. With the temperature dependence of the kinetic parameters known, the degree of cure can be predicted for any temperature history by integration of Equation 8.5. 

The glass transition temperature can be measured in a variety of ways (DSC, dynamic mechanical analysis, thermal mechanical analysis), not all of which yield the same value [3,8,9,24,29], This results from the kinetic, rather than thermodynamic, nature of the transition [40,41], Tg depends on the heating rate of the experiment and the thermal history of the specimen [3,8,9], Also, any molecular parameter affecting chain mobility effects the T% [3,8], Table 16.2 provides a summary of molecular parameters that influence the T. From the point of view of DSC measurements, an increase in heat capacity occurs at Tg due to the onset of these additional molecular motions, which shows up as an endothermic response with a shift in the baseline [9,24]. 

The degree of hydration of the products from these preparations and the water content given by analytical procedures depends upon the heat treatment (method and history) of the product. A sample subjected to TGA (thermal gravimetric analysis) looses water almost continually from room temperature until it becomes the completely anhydrous heteropolytungstate salt at about 400°C. On the other hand, these crystals lose some lattice water rapidly upon removal from the mother liquor and exposure to air even at room temperature. 

The applications of activation analysis are almost innumerable. In the physical sciences, activation analysis is used in trace-element analysis of semiconductor materials, metals, meteorites, lunar samples, and terrestrial rocks. In most cases, the multielemental analysis feature of activation analysis is used to measure the concentrations of several trace-elements simultaneously. From these detailed studies of trace-element abundance patterns, one has been able to deduce information about the thermal and chemical history of the Earth, moon, Mars, and meteorites, as well as the source or age of an object. 

Therefore, for particular values of the conversion of functional groups and temperature, the rate of chainwise polymerizations depends on the concentration of active species which, in turn, depends on the particular thermal history. Thus, phenomenological equations derived from Eq. (5.1), or isoconversional methods of kinetic analysis, should not be applied for this case. 

Packaging Materials. As in the case of fibers, thermal analysis can easily distinguish between most polymeric films on the basis of the glass transition and the thermal history dependence of the melt and recrystallization (20, 21). From the analysis of thin films--as, for example, used in plastic bags recovered with drugs—it should be possible to identify by comparison the bag manufacturer and possibly the manufacturing lot. 

In conclusion, it can be seen that thermal analysis is able to make a considerable contribution to forensic science. Because of its capability to differentiate between manufacturing lots, it has for years been employed in quality control laboratories to monitor production of polymeric products. Its capability of differentiating between materials of identical chemical composition on the basis of differences in molecular weight distribution and thermal or mechanical history should be a capability quite unique and useful to forensic science. With the advent of second-generation instrumentation, this technique can be usefully extended to the realm of submilligram level analysis. 

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