Differential scanning calorimetry data reporting

Differential scanning calorimetry data of the inverse temperature transition for hydrophobic association of a series of model proteins, reported in Chapter 5, allowed calculation of... 

Low resolution mass spectra (LRMS) and high resolution mass spectra (HRMS) were recorded on an Associated Electronic Industries (AEI) Model MS-30 spectrometer. Intrinsic viscosities were measured by standard procedures using a Cannon-Ubbelohde semi-micro viscometer (dilution viscometer). Differential scanning calorimetry data for polymers were taken on a Perkin-Elmer DSC IB all data on thermal transitions are reported in degrees centigrade and are uncorrected. 

The enthalpies of phase transition, such as fusion (Aa,s/f), vaporization (AvapH), sublimation (Asut,//), and solution (As n//), are usually regarded as thermophysical properties, because they referto processes where no intramolecular bonds are cleaved or formed. As such, a detailed discussion of the experimental methods (or the estimation procedures) to determine them is outside the scope of the present book. Nevertheless, some of the techniques addressed in part II can be used for that purpose. For instance, differential scanning calorimetry is often applied to measure A us// and, less frequently, AmpH and AsubH. Many of the reported Asu, // data have been determined with Calvet microcalorimeters (see chapter 9) and from vapor pressure against temperature data obtained with Knudsen cells [35-38]. Reaction-solution calorimetry is the main source of AsinH values. All these auxiliary values are very important because they are frequently required to calculate gas-phase reaction enthalpies and to derive information on the strengths of chemical bonds (see chapter 5)—one of the main goals of molecular energetics. It is thus appropriate to make a brief review of the subject in this introduction. 

There appear to be no reported values for the Tg of poly(TBTM) and it proved difficult to measure any meaningful transition by differential scanning calorimetry. The value of 0°C was selected as It gave a reasonable fit to experimental data when using equations 7 and 8. 

Nanophase materials generally have an excess heat capacity and entropy relative to the bulk. These can be obtained by conventional heat capacity measurements (adiabatic calorimetry, differential scanning calorimetry), although problems with the adsorbed water and other gases are more severe for nanomaterials than for bulk phases. Data at present are fragmentary and it is difficult to evaluate their accuracy. Dugdale et al. (1954) report on excess heat capacity for fine grained rutile. Victor (1962) report data for MgO and BeO, and Sorai et al. (1969) for Ni(OH)2 and Co(OH)2. 

Worswick et al. [74WOR/COW] reported low-temperature (adiabatic calorimetry) heat capacity measurements (10 to 300 K) and differential scanning calorimetry (DSC) results from 300 to 550 K. The equation (V.66) (200 to 550 K) is not in the standard form generally used for solids e.g., [93KUB/ALC], p. 166, Equation (116)), however, the original DSC data are unavailable. 

The experimental scatter for the differential scanning calorimetry values was reported to be within 4%, but it is not reported how well the authors equation corresponded to the measured values, or how well measurements obtained from the two techniques agree near 300 K. Unfortunately, the DSC data were not part of the supplementary material. 

Charge transfer complexes of styrene and acrylonitrile have been shown to exist when in the presence of zinc chloride. Proton nuclear magnetic resonance spectroscopy has been used to establish this effect. In the proper solvents styrene and acrylonitrile will form occluded macroradicals which may then be used to form block copolymers. These block copolymers occur both in the presence and absence of zinc chloride. Pyrolysis gas chromatography, differential scanning calorimetry, and solubility studies show the properties of the two copolymers and their various block copolymers to be quite similar. Differences in the copolymers may be seen from carbon-13 nuclear magnetic resonance spectroscopy. Yield data for the block copolymers is reported. 

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