High-pressure DTA apparatus

Fig. 4.43 A schematic drawing of a high-pressure DTA apparatus (1) high-pressure pipe, (2) copper tube, (3) sheathed heater, (4) sheathed Alumel-Chromel thermocouple, (5) high-pressure vessel, (6) copper seal, (7) sample, and (8) reference. (Reprinted with permission from Polymer J. 1992, 24, 422.)...

Figure 6.21. Three-wire thermocouple assembly for high-pressure DTA apparatus 74).

Figure 6 22. High-pressure DTA apparatus of KubaMa and Schneider (75). (u) a. r = coolers. b, n = pyrophillite insulating disk c = heating block d = high-pressure vessel e. m — copper seals f, I = Zr02 blocks g = copper shield h = calorimeter block i = thermocouple k = corundum capillary o = fastening screw p = support c] = in- and outlet of refrigerant. (/ )(i) Open Pt/Ir well In) closed teflon well with brass holder lh = steel-sheathed thermocouple).

Figure 2.14 Schematic diagram of a commercial high-pressure DTA apparatus (reproduced by permission of TA Instruments)...

A high-pressure DTA or high-pressure DSC apparatus may be used. 

Figure 6.23. High-pressure DTA system described by Williams and Wendlandt (131. l ) Schematic diagram of apparatus. A. high-pressure DTA cell B. T T Controls Company Model No. TPC-2000 temperature programmer C Du Pont Model 900 recording module D, relief valve E, valve F. pressure gauge G. gas pressure regulator H. gas cylinder, b) Schematic diagram of DTA cell. A. furnace chamber B. high-pressure connectors for furnace wires and thermocouples. C. furnace D. DTA sample and reference holders E. gas outlet tube F, Buna-N O-ring G. base plate H. Conax connector for thermocouple wires 1. gas inlet-outlet connector.

Sample mass, 5 mg apparatus, Rigakudenki R-1 high-pressure DTA crucible, hermetically sealed aluminum crucible with a pinhole in the center of the cover (diameter 5 mm, height 2.5 mm) heating rate, 10 "C min". ... 

The heat effects during physical or chemical conversion are used in differential thermo analysis (DTA) to evaluate the reaction rate together with kinetic and thermodynamic parameters. The apparatus (Fig. 3.3-6) consists of two identical high-pressure cells which are arranged in an oven, a. In one cell the components to be investigated are placed, the other cell... 

Schematic diagram of a high-pressure custom DTA apparatus (courtesy of Y. Maeda)...

There is a wide sphere of applicability of DTA/DSC technique, which is regularly described in satisfactory details in the individual apparatus manuals or other books [1,15,602,613,640,646]. The usage can be sorted in to two classes The methods based on the (1) modified instrumentation such as (i) high-pressure studies [647] or (ii) differential hydrothermal analysis [648] and the measurements applicable under the (2) ordinary apparatus set up such (iii) determination of phase boundaries [646,649], (iv) impurity measurements [650,651] and (ivi) reaction kinetics (see previous Chapter [3,425,508-510,521]. Specifically constructed instrumentations [1,15,602] falls beyond the scope of this book so that we shall concentrate on the second type of applications. 

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