Instrument thermal analysis

Estimation of Polymer Lifetime by TGA Decomposition Kinetics, TA Instruments Thermal Analysis Application Brief TA-125, pp. 1-4. 

Sichina WJ. Characterization of electronic materials using thermal analysis, Perkin Elmer Instruments. Thermal Analysis Application Note PETech-24 2000. 

Infrared spectrometers may also be combined with thermal analysis instrumentation. Thermal analysis methods provide information about the temperature-dependent physical properties of materials. However, it is not always possible to gain information about the chemical changes associated with changes in temperature by using standard thermal analysis equipment. It is possible to combine thermal analysis apparatus with an infrared spectrometer in order to obtain a complete picture of the chemical and physical changes occurring in various thermal processes [11, 12]. 

TA Instruments Thermal Analysis Applications Brief Number TA-119, available for downloading from the website at www.tainstruments.com.)... 

Figure 4.20. Shrinkage force curves for two polypropylene copolymer fibers. Measurements were taken at a heating rate of 3°C/min under 50mN tensile load [from TA Instruments Thermal Analysis Apphcation Note TA-208, courtesy of TA Instruments].

TA Instruments, Thermal Analysis Rheology Application Note TA-138. 

The first type are the Specific/Bundled Data Systems. These are written specifically for a particular application and are often bundled with the instrument by the manufacturer. One example is the DuPont Thermal Analysis Data System. The second type are the General CoHsercial data systems which provide a structure that can be configured for many applications. This category includes software like Labtech Notebook and Lotus 1-2-3. The third category are those which are developed In-house and may lie anywhere along the spectrum between specific and general in function. 

In the broadest sense, thermal analysis (TA) measures physical changes in a material as a function of temperature. TA instruments measure variables in a sample such as heat flow, weight, dimensions, etc. A typical fingerprint of a compound might be the endothermic peak on a thermogram indicating a sample s crystalline melt. 

Measurements of differential scanning calorimetry (DSC) were obtained on a TA Instruments 2910 thermal analysis system (Fig. 2). Samples of approximately 1-2 mg were accurately weighed into an aluminum DSC pan, and covered with an aluminum lid that was crimped in place. The samples were then heated over the range of 20-140 °C, at a heating rate of 10 °C/min. Valproic acid was found to boil at 227 °C. 

This instrument was originally proposed for quantitative differential thermal analysis (DTA) (34) and it has proved indeed to be very suitable... 

An instrument designed to follow hysteresis losses in polymers by measuring the resistance to the rolling of small balls over the surface of the test piece it can investigate transitions in polymers to as low a temperature as -120 °C. Superseded by modem dynamic mechanical thermal analysis equipment. 

If the observed AH is positive (endothermic reaction), the temperature of the sample will lag behind that of the reference. If the AH is negative (exothermic reaction), the temperature of the sample will exceed that of the reference. Owing to a variety of factors, DTA analysis is not normally used for quantitative work instead, it is used to deduce temperatures associated with thermal events. It can be a very useful adjunct to differential scanning calorimetry, since with most instrumentation DTA analysis can be performed in such a manner that corrosive... 

Differential. thermal analysis can also be used to construct binary phase diagrams on the basis of observed melting points. This information is of importance since the nature of the phase diagram as would exist for an enantiomeric pair can be instrumental in choosing a resolution strategy [23,24]. When a drug candidate contains one or more chiral centers, it is frequently... 

Thermal Analysis. The DuPont Instruments Model 9900, computer controlled thermal analyzer and Model 951 TGA module were used in the experiments, using a gas flow rate of 100 cc/min. Experiments were performed in dynamic and isothermal mode using air and argon. 

ARC = Accelerating Rate Calorimeter (Columbia Scientific Instrument Corp.) DSC = Differential Scanning Calorimeter DTA = Differential Thermal Analysis RC1 = Reactor Calorimeter (Mettler-Toledo Inc.) RSST = Reactive System Screening Tool (Fauske and Associates) VSP = Vent Size Package (Fauske and Associates) ... 

The purpose of differential thermal systems is to record the difference in the enthalpy changes that occurs between the reference and the test sample when both are heated in an identical fashion. Several publications are available concerning the theoretical aspects and applications of various thermal analysis techniques, including the DSC [71-74]. Commercial instruments are available from a number of companies including Perkin-Elmer, TA Instruments, Toledo-Mettler, SET ARAM, Seiko, and Polymer Laboratories. 

Infrared spectra, of fats and oils, 10 823 Infrared spectral region, 19 564 Infrared spectroscopy, 14 224-243 23 136-143. See also Chromatography-infrared spectroscopy Far- infrared spectroscopy ir-selective surfaces Ir (infrared) spectroscopy Near- infrared spectroscopy Thermal analysis-infrared spectroscopy applications of, 14 239-240 23 140-141 in composition measurements, 20 682 in fiber optic fabrication, 11 138 industrial applications of, 14 240 instrumentation in, 14 225-228 23 137-138... 

Some scientists describe DSC techniques as a subset of DTA. DTA can be considered a more global term, covering all differential thermal techniques, while DSC is a DTA technique that gives calorimetric (heat transfer) information. This is the reason that DSC has calorimetry as part of its name. Most thermal analysis work is DSC, and Sections 15.3.3 and 15.3.4 provide information about the instrumentation and applications of this technique. 

Major instrumentation involved with the generation of thermal property behavior of materials includes thermogravimetric analysis (TG, TGA), DSC, differential thermal analysis (DTA), torsional braid analysis (TBA), thermomechanical analysis (TMA), thermogravimetric-mass spectrometry (TG-MS) analysis, and pyrolysis gas chromatography (PGQ. Most of these analysis techniques measure the polymer response as a function of time, atmosphere, and temperature. 

A variety of techniques have been used to determine the extent of crystallinity in a polymer, including X-ray diffraction, density, IR, NMR, and heat of fusion [Sperling, 2001 Wunderlich, 1973], X-ray diffraction is the most direct method but requires the somewhat difficult separation of the crystalline and amorphous scattering envelops. The other methods are indirect methods but are easier to use since one need not be an expert in the field as with X-ray diffraction. Heat of fusion is probably the most often used method since reliable thermal analysis instruments are commercially available and easy to use [Bershtein and Egorov, 1994 Wendlandt, 1986], The difficulty in using thermal analysis (differential scanning calorimetry and differential thermal analysis) or any of the indirect methods is the uncertainty in the values of the quantity measured (e.g., the heat of fusion per gram of sample or density) for 0 and 100% crystalline samples since such samples seldom exist. The best technique is to calibrate the method with samples whose crystallinites have been determined by X-ray diffraction. 

A wide variety of instrumental techniques, including X-ray diffraction, thermal analysis, electron microscopy, MAS-NMR and infrared spectroscopy, have been employed at different levels of complexity to investigate the effects of mechanochemical treatment on kaolin. Unfortunately, vibrational spectroscopy has only been used at a superficial level in the study of milled kaolin despite the considerable contribution that it has made to the understanding of the structure and reactivity of kaolin itself. 

Since that discovery a major aspect of our research effort has been to develop a method to account for this unwanted pyrolytic conversion of organic to elemental carbon. This report describes a combined thermal-optical instrument in which the reflectance of the filter sample is continuously monitored during the thermal analysis. Dod (14) have also reported a combustion... 

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