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Abstract  

The methods of thermal analysis are used in many ways in academic research institutions and in industry. The exchange of information leads to an activation of such studies. However, the differences in problems, methods and requirements result in communication problems between the users in the above groups. This may lead to regrettable deficits. Two industrial examples demonstrate that thermoanalytical investigations give useful problem solutions, though they do not meet the requirements of academic research.

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By means of the thermomicroscopy was demonstrated that the discrepancy between the experimental DSC- and TG-data on the decomposition of citric acid in the literature can be explained in terms of superimposing reactions (melting, decomposition, immiscibility, and crystallization), which have different reaction rates. The thermomicroscopy is especially useful explaining such kind of reactions. The thermal behaviour of citric acid can be used as a “model reaction” in technology.

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Abstract  

Aluminium-free layered silicates of the metal silicate hydrate type (M-SH) comprise an interesting supplement to the well-known zeolite-like porous materials. Their specific properties allow these materials to be used as catalysts, adsorbents and ion-exchangers. Comparative X-ray diffraction and thermoanalytical investigations (TG and DSC) have shown that the thermoanalytical methods are useful to follow the process of structure formation of ilerite. The interlayer cations influence the properties of the different ilerites. In particular, the hydration behaviour of ilerite is affected. Thus, H+- and DTMA+-ilerite are stable up to temperatures of about 800°C, while the as-synthesized Na-form loses water irreversibly at about 150°C, is dehydroxylated, and is then desomposed structurally at about 400°C. The course of the dehydration exhibits significant differences for the various cation forms.

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Journal of Thermal Analysis and Calorimetry
Authors:
H. Utschick
,
H. -J. Mallon
,
L. Wohlfahrt
,
M. Arnold
, and
G. Reinhold

The possibility to interpret data obtained by thermoanalysis is increased considerably by combing thermoanalytical method with other chemical and physical ones. This is shown by testing polydimethacrylates and butadiene-ethene-copolymers.

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Due to the increasing importance of quantified results of dynamic calorimetric measurements, the influence of single experimental parameters has been studied by some authors. We found that these results can be represented correctly only in a complex form. According to this experience, the experimental parameters were changed on the basis of statistically planned experiments. The numerous measurements were carried out with samples of indium, 1,3-dinitrobenze and polyethylene prepared in different ways. The results were evaluated in a complex form. The evaluation of the experimental data revealed a significant influence of the substance properties and the experimental parameters.

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Aluminium-free layered silicate hydrates (metal silicate hydrates — M-SH) are an interesting supplement to the well-known zeolite-like porous materials, due to their large number of catalytic, adsorptive and ion-exchange properties. By means of a combination of X-ray diffraction investigations and several thermo-analytic methods (TG, DSC, TMA) it could be shown that the properties of magadiite will be influenced by the cations located in the interlayer and the morphology of the as-synthesized magadiite products. In particular, hydration behaviour and phase transformation behaviour of the magadiite will be affected. Thus, H- and Ce-magadiite are stable up to temperatures of about 800‡C, while the as-synthesized Na-forms will loss water irreversible already at about 200‡C, will be dehydroxylated, and will be decomposed structurally at about 400‡C.

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Journal of Thermal Analysis and Calorimetry
Authors:
G. Matuschek
,
H. Utschick
,
Ch. Namendorf
,
G. Bräuer
, and
A. Kettrup

The investigation of wastes, pollutants, contaminated soil, etc. in preparation of their thermal disposal or decontamination is related to several problems. Due to the heterogeneity of the sample materials, thermoanalytical measurements, using standard sample amounts of about 20–50 mg do not lead to reliable results. For this reason, a new thermoanalytical device for about 100 g sample amount was developed. The “Macro STA 419”, was constructed and built for simultaneous TG- and DTA-investigations with direct coupled measuring techniques for gas analysis (MS/GC-MS). The new developed device is introduced, some problems and their solutions are discussed and the function of the device is shown.

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Poly(butadiene-alt-1-olefin) copolymers and poly[(butadiene-alt-ethene)-co-(butadiene-alt-1lefin)] terpolymers, and the hydrogenated products too, has been characterized with the aid of differential scanning calorimetry (DSC). Both the glass transition and the melting behaviour of the partial crystallized products has been investigated. From the peak area the degree of crystallinity has been calculated in a first approximation. The results allow to draw conclusions about the crystallization behaviour in relation to the number and length of the side chains and about the course of the synthesis in question.

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