Temperature modulated differential scanning

Figure 18.12. Example heat flow behavior of temperature-modulated differential scanning calorimetry. Reproduced from Young and LeBoeuf (2000), by permission of the American Chemical Society.

Figure 18.17. Temperature-modulated differential scanning calorimetry scan of poly(methyl methacrylate) indicating P-relaxation near 32°C and a relaxation (Tg) near 121 °C. Reproduced from DeLapp et al. (2004), by permission of Elsevier, Ltd.

TABLE 18.4. Select NOM Characterization Studies by Differential Scanning Calorimetry (DSC) and Temperature-Modulated Differential Scanning Calorimetry (TMDSC)... 

Hutchinson, J. M. (1998). Characterising the glass transition and relaxation kinetics by conventional and temperature-modulated differential scanning calorimetry. Thermochimica Acta 324(1-2), 165-174. 

Schawe, J. E. K. (1998). A description of the glass transition measured by temperature modulated differential scanning calorimetry. Colloid Polym. Sci. 276(7), 565-569. 

Dielectric relaxation, temperature-modulated differential scanning calorimetry (TMDSC), and H NMR spectroscopy (see Section 4.05.3.2.1) have been used to perform the dynamic characterization of fananserine 35. The use of these three different techniques gives a coherent set of information and allowed the authors to describe the dynamic properties over a wide range of frequencies and temperatures <2006MI798>. 

Temperature-modulated differential scanning calorimetry Internal energy of segmental interactions Upper critical solution temperature N - Vinylcaprolactam... 

G.M. Wang and A.D.J. Haymet, Trehalose and other sugar solutions at low temperature modulated differential scanning calorimetry (MDSC), J. Phys. Chem. B, 1998, 102, 5341-5347. 

Polymer-Polymer Miscibility Investigated by Temperature Modulated Differential Scanning... 

Figuke 8.1. Component heats of hydrophobic association of an inverse temperature transition obtained by means of temperature-modulated differential scanning calorimetry (TMDSC). (Upper curve) An exothermic component of the inverse temperature transition due to the physical (van der Waals) interaction between associating molecules. (Middle curve) The endothermic component (due to disruption of hydrophobic hydration), which is the fundamental feature of an inverse temperature transition of hydrophobic association. (Lower curve) Net endothermic heat of an inverse temperature transi-... 

Pyda et al. (1998) studied in detail the heat capacity of PTT by adiabatic calorimetry, standard DSC and temperature-modulated differential scanning calorimetry (TMDSC) for this measurement. The computation of the heat capacity of solid PTT is based on an approximate group vibrational spectrum and the general Tarasov approach for the skeletal vibrations, using the well-established Advanced Thermal Analysis System (ATHAS) scheme. The experimental heat capacity at constant pressure is first converted to heat capacity at constant volume using the Nemst-Lindemann approximation... 

Some more insight into the thermal properties of an oriented PET is given by the data from quasi-isothermal, temperature-modulated differential scanning calorimetry. Figure 6.109 displays a comparison of a drawn film of PET [25] with a standard bulk sample which is analyzed in more detail in Eigs. 4.136-139. Compared to the 44%... 

Okazaki I, Wunderlich, B (1997) Reversible Melting in Polymer Crystals Delected by Temperature Modulated Differential Scanning Calorimetry. Macromolecules 30 1758-1764. 

Pyda M, Wunderlich B (2000) Reversible and Irreversible Heat Capacity of Poly(tri-methylene Terephthalate) Analyzed by Temperature-modulated Differential Scanning Calorimetry. J Polymer Sci, Part B Polymer Phys 38 622-631. 

HOhne GWH, Kurelec L (2001) Temperature-modulated Differential Scanning Calorimetric Measurements on Nascoit Ultra-high Molecular Mass Polyethylene. Thermochim Acta 377 141-150. 

The TMDSC with Fourier analysis of the melting pentacontane and the calculations using saw-tooth analysis methods are given in the publication Wunderlich B, Boiler A, Okazaki I, Ishikiriyama K, Chen W, Pyda W, Pak J, Moon, 1, Androsch R (1999) Temperature-modulated Differential Scanning Calorimetry of Reversible and Irreversible First-order Transitions. Thermochim Acta 330 21-38. 

DTA as well as power compensation DSC instruments, and is called temperature modulated DSC, or TMDSC. The following trade marks are used by different TA instrument manufacturers for their temperature modulated differential scanning calorimeters Modulated DSC (MDSC ) of TA Instruments Inc., Oscillating DSC (ODSC ) of Seiko Instruments Inc., Alternating DSC (ADSC ) of Mettler-Toledo Inc. and Dynamic DSC (DDSC ) of Perkin-Elmer Corp. 

J.D. Menczel and L. Judovits (Eds.), Special issue on temperature-modulated differential scanning calorimetry, J. Thermal Anal., 54 (1998). 

Calorimetric studies have depicted the impact of nanoparticles on isothermal curing of epoxy-amine system. Isothermal measurements done at 298 K using temperature-modulated differential scanning calorimetry are shown in Figure 9.15. The heat flow signal recorded during this measurement is directly proportional to the reaction rate of the curing process. It was foxmd that,... 

For many years, the thermodynamic description of macromolecules lagged behind other materials because of the unique tendency of pol5nneric systems to assume nonequilibrium states. Most standard sources of thermodynamic data are, thus, almost devoid of polymer information (1-7). Much of the aversion to include polymer data in standard reference sources can be traced to their nonequilibrium nature. In the meantime, polymer scientists have learned to recognize equilibrium states and utilize nonequilibrium states to explore the history of samples. For a nonequilibrium sample it is possible, for example, to thermally establish how it was transferred into the solid state (determination of the thermal and mechanical history). More recently, it was discovered with the use of temperature-modulated differential scanning calorimetry (TMDSC) that within the global, nonequilibrium structure of semicrystalline polymers, locally reversible melting and crystallization processes are possible on a nanophase level (8). 

Temperature-modulated differential scanning calorimetry is a new analytical technique used to obtain information on the heat capacity in the range close to the phase transformation. It is a method applied in many instraments, e.g. as the Modulated DSC (MDSC ) of TA Instm-... 

The sample (or furnace) temperature is controlled to follow a set course with superimposed periodical changes, and the heat flow rate is measured via the differential temperature between sample and reference (temperature-modulated differential scanning calorimetry, TMDSC [38]). 

Figure 11 Relaxation map for PS where the data were taken from Weyer, S. Hensel, A. Korus, J. etal. Thermochim. Acta 1997, 304/305, 251. A-Datafrom temperature modulated differential scanning calor-Imentry as measured at different places o, data measured by specific heat spectroscopy by employing the 3o method , AC calorimetry , data measured by photoacoustic calorimetry , dielectric data dashed line, data from shear compliance dotted-dotted-dashed line, data from shear modulus solid line, fit of the VF equation using all thermal data dotted line, fit of the VF,equation using the dielectric data.

Glass transition temperature measurements on the solutions of Zdol in PFOM were performed in a temperature-modulated differential scanning calorimeter. 

---