Calorimetry methods

Table 3 lists the selected properties [16] that we have measured for several commercially available acrylate resins manufactured by the Sartomer Company and the Rohm and Haas Company. The resins were cured in an AECL Gammacell Model 240. The temperature rise was measured for an 8-g sample using Acsion s (formerly AECL Radiation Applications Branch) Gamma Calorimetry method [17]. All of this information is being used to evaluate the applicability of EB-cured acrylate adhesives for repairing composite structures. Combinations of these adhesives can be used to create electron-curable adhesives suitable for composite repair. 

The structures of two polymorphs of pleconaril, enantiotropically related with a transition temperature of 35.7°C, have been reported [36], Form I was described as consisting of a network of dimers, while Form III was described as a three-dimensional network of monomers. The two forms contradicted the density rule, and the solid solid transition could occur only through a destructive-reconstructive mechanism. A quantitative differential scanning calorimetry method was also described that enabled the quantitative determination of Form I in bulk Form III to be made at levels as low as 0.1%. 

Spink CH. Differential scanning calorimetry. Methods Cell Biol. 2008 84 115-141. 

The versatility and accuracy of the oxygen consumption method in heat release measurement was demonstrated. The critical measurements include flow rates and species concentrations. Some assumptions need to be invoked about (a) heat release per unit oxygen consumed and (b) chemical expansion factor, when flow rate into the system is not known. Errors in these assumptions are acceptable. As shown, the oxygen consumption method can be applied successfully in a fire endurance test to obtain heat release rates. Heat release rates can be useful for evaluating the performance of assemblies and can provide measures of heat contribution by the assemblies. The implementation of the heat release rate measurement in fire endurance testing depends on the design of the furnace. If the furnace has a stack or duct system in which gas flow and species concentrations can be measured, the calorimetry method is feasible. The information obtained can be useful in understanding the fire environment in which assemblies are tested. 

Experimental calorimetry methods have been developed which ... 

The study of reaction 7.73 is one of the most important thermochemical experiments ever made, and it will be briefly analyzed here to illustrate the flame combustion calorimetry method. The application of flame combustion calorimetry to hydrocarbons and other organic compounds containing oxygen, nitrogen, or chlorine is covered in detail in the review by Pilcher [90]. 

The major differences between the fluorine and oxygen combustion calorimetry methods arise from the exceptional reactivity and toxicity of fluorine. The substances studied by oxygen combustion calorimetry are normally stable when kept inside a bomb at 298.15 K and under 3 MPa of O2. Oxygen- and moisture-sensitive compounds can also be studied because various types of containers are available to prevent their reaction with O2 prior to ignition. Common examples are glass ampules, which are inert toward the combustion process and, more commonly, Melinex bags or polyethene ampules, which burn cleanly to CO2 and H2O. As carbon dioxide and water are also generated in the combustion of the sample, no extra complexity is introduced in the analysis of the final state of the bomb process by the use of those plastic containers. 

As illustrated in this section, the problems associated with using fluorine in combustion calorimetry seem to have been largely overcome. The fluorine bomb and flame calorimetry methods have been perfected to such an extent that, provided the chemistry of the process under study is well characterized, results of very good accuracy and precision can be obtained routinely. 

Doyle, M.L., G. Louie, P.R. Dal Monte, and T.D. Sokoloski. 1995. Tight binding affinities determined from thermodynamic linkage to protons by titration calorimetry. Methods Enzymol 259 183-194. 

The idea of calorimetry is based on the chemical reaction characteristic of molecules. The calorimetry method does not allow absolute measurements, as is the case, for example, with volumetric methods. The results given by unknown compounds must be compared with the calibration curve prepared from known amounts of pure standard compounds under the same conditions. In practical laboratory work there are very different applications of this method, because there is no general rule for reporting results of calorimetric determinations. A conventional spectrophotometry is used with a calorimeter. The limitations of many calometric procedures lie in the chemical reactions upon which these procedures are based rather than upon the instruments available . This method was first adapted for quinolizidine alkaloid analysis in 1940 by Prudhomme, and subsequently used and developed by many authors. In particular, a calorimetric microdetermination of lupine and sparteine was developed in 1957. The micromethod depends upon the reaction between the alkaloid bases and methyl range in chloroform. 

As can be seen, the enthalpies of different apoxy-amine systems, according to different authors, lie in a rather narrow range (100-118 kJ per mole of epoxy groups, i.e. close to the heat of the epoxy ring opening). These data confirm the above conclusion as to the small total contribution of the donor-acceptor interactions in the epoxyamine systems to the observed integrated value of the heat release and the possibility of the application of the isothermal calorimetry method to the reaction kinetic studies. 

In the batch calorimetry method, the adsorbent is initially kept in suspension in the pure solvent by means of continuous stirring. The solution is then introduced by... 

Foubert, I., Vanrolleghem, P.A. and Dewettinck, K. (2003). A differential seanning calorimetry method to determine the isothermal crystallization kinetics of cocoa butter. Thermochemica Acta, 400 131-142. 

We think that the next step will be to associate the as method with this immersion calorimetry method to evaluate the size of the micropores. 

Solid Fat Content Many methods for measuring SFC have been developed. These include dilatometry, calorimetry, and pulsed nuclear magnetic resonance (pNMR). Dilatometry and calorimetry use measurements of volume or heat content ratios between the completely liquid and the completely solid states (42). Dilatometry and calorimetry methods are time consuming and tend to be applicable only when the SFC is less than 50% (42). Therefore, pNMR has become the most commonly used method for SFC determination. 

The chemical structure of the polyimide polymers (named PI-1 and PI-2) studied by Sekkat et al. is shown in Figure 12.12. They prepared the polymer samples by spin-casting onto glass substrates. PTl was cast from a cyclohexanone solution and PI-2 from 1,1,2,2- tetrachloroethane. The Tg values of PI-1 and PI-2 were determined to be 350°C and 252 C, respectively, by scanning calorimetry method. The thicknesses of the PI-1 and PI-2 films were, respectively, approximately 0.72 im and 0.14 im, and their respective optical densities were approximately 0.79 and 0.3 at 543.5 nm. Details of the preparation and characterization of the samples can be found in References 3 and 20. In their EFISH experiment, a typical corona poling technique was used to pole the samples, with a dc electric field about 2-3 MV/cm across a 1-2 lm thick polymer film. They used the SHG output from the EFISH experiment to in situ monitor the photochemical change in the third-order susceptibility of the PI-1 and PI-2 polymers. 

Chrzanowski FA, Ulissi LA, Fegely BJ, Newman AC. Preformulation excipient compatibility testing, application of a differential scanning calorimetry method versus a wet granulation simulating isothermal stress method. Drug Dev Ind Pharm 1986 12 783-800. 

Data for the temperature dependence of the enthalpy of UO2, obtained using drop calorimetry methods, showed a clear peak in the specific heat at 2610 K [87]. However, the structural origin of this feature was questioned by some groups, who proposed an alternative explanation in terms of electronic disorder (small polarons of... 

The heat capacity of CSe2(cr, 1) was studied within the temperature range of 78 to 328 K with the drop calorimetry method, and the data were reproduced by the equations ... 

Velazquez-Campoy, A., Leavitt, S. A., Freire, E. (2004). Characterization of protein-protein interactions by isothamal titration calorimetry. Methods Mol. Biol., 261, 35-54. 

Lewis EA, Murphy KP (2005) Isothermal titration calorimetry. Methods Mol Biol 305 1-15... 

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