Thermal analysis measurements

The authors would like to thank Mr. R. H. Bott and Ms. B. E. McGrath for thermal analysis measurements and Dr. Wunderlich (Rohm Tech, West Germany) for the generous donation of various acrylic monomers. We also appreciate the support of the Exxon Foundation, Dow USA, the Army Research Office (ARO) and the Defense Advanced Research Projects Agency (DARPA). 

Thermal analysis measurements allow the measure of polymer behavior as a function of temperature, time, and atmosphere. DSC or DTA measures change in energy as temperature is changed and allows the determination of many valuable parameters including Tg and T. TGA measures weight changes as a function of temperature. 

C, differential thermal analysis, measured range -25.1 to 47.1°C, Kemme Kreps 1969)... 

Thermal Analysis Measurements. DSC scans at 40°C/min were obtained on a Perkin-Elmer DSC-2. Dried copolymer powder was used. In situ annealing treatments were applied as discussal below by programming the desired temperature profiles on the instrument. 

The temperature dependence of the resistivity of Li WOs is shown in Figure 4. For x = 0.28, the anomalous peak was very large and occurred at about 600° K. for x = 0.34 the peak was much smaller and occurred at about 300° K. With increasing lithium concentration, therefore, the peak diminished in size and shifted to lower temperatures. The peak was completely reproducible and x-ray diffraction patterns showed that the cubic crystal structure existed both below and above the temperature at which the peak occurred. However, preliminary thermal analysis measurements indicated some sort of phase change. Mackintosh (6) has suggested the possibility of ordering of the lithium atoms, and neutron diffraction studies of these cubic Lia.WOs crystals should be made below and above the transition temperature. 

Differential thermal analysis measurement at atmospheric pressure. 

C, ebulliometry-differential thermal analysis, measured range 22.6-117.8°C, Kemme Kreps... 

Thermal analysis measurements were made using a duFont 990 Thermal Analyzer using aluminum pans and a heating rate of 10 C/ min. Melting endotherms were determined In the presence of helium. Oxidative Induction times were measured Isothermally at 200 C In the presence of oxygen. A detailed description of this technique Is given in reference 4. 

Differential thermal analysis measurement at atmospheric pressure. b Prepared by acylation of 12a with acetic anhydride in refluxing toluene (24h) and recrystallization from benzene. 

Thermosonimetry (TS) is defined by the ICTA as that technique in which the sound emitted by a substance is measured as a function of temperature whilst the substance is subjected to a controlled temperature programme. As a thermal analysis technique, TS is concerned with the detection and interpretation of the various acoustic emissions occurring prior to, during, and after thermal events (127). It can thus contribute to the elucidation of the thermal behavior of solid materials and to an understanding of the dynamic processes of the solid state. The technique has been developed for thermal analysis measurements principally by Lonvik (128, 143) with other applications described by Clark (127) and Rajeshwar et al. (129). 

Study of the enantiomeric separation of 10a by complexation with 112 revealed two interesting modes of transformation of racemic complex 113 into conglomerate complex 114 in the solid state. One is a thermal transformation. Thermogravi-metric and differential thermal analysis measurements of 113 showed the evaporation of MeOH at 120°C, phase transfer from MeOH free-113 to 114 at 183 C and... 

Thermal analysis measurements via DSC were utilized both to follow the curing reaction and to characterize the precursor and network materials. The general techniques for following reactions by differential scanning calorimetry are well established and can be reviewed in reference 15. We have also discussed the procedures for this type of an experiment in one of our earlier publications (16). A Perkin-Elmer Model 2 instrument was utilized. 

The authors wish to thank Mr. Robert G. Marx and Ms. Laura T. Onstott for their help in preparation of formulations and in performing FTIR and thermal analysis measurements. 

Dynamic mechanical thermal analysis measures damping and dynamic moduli and is covered in Chapter 21. Thermal mechanical analysis measures deformation of a test piece. such as the dimensional change due to thermal expansion (also called thermodilatometry) and indentation at the softening point of the material. 

Thermal analysis (measuring changes, e.g., enthalpy, as a function of temperature)... 

DDM = Diamino diphenyl methane For the mixtures of epoxy monomers, 1 1 mol ratio was used. Stoichiometric amounts were used in all cases. From differential scanning calorimetry method measurements (10 °C/min). Maximum of the loss modulus from dynamic mechanical thermal analysis measurements. a relaxation peak of the loss factor. Reproduced with permission from M. Sponton, L.A. Mercado, J.C. Ronda, M. Galia and V. Cadiz, Polymer Degradation and Stability, 2008, 93, 2025. 2008, Elsevier [22] ... 

Differential thermal analysis measurements indicated double TgS for solutions with lower polymer concentrations beyond the depicted cusp in Fig. 12.10 [59]. Creep recovery measurements on this system showed that the solvent molecules in the solutions have higher mobilities than the polymer chain segments. A lower temperature and greater crowding is therefore necessary to force the solvent molecules from an equilibrium response. Therefore, it was... 

The effect of casting solvent on the miscibility behavior of silk fibroin/PVF blends was investigated by Um et al. SF/PVA blend films cast from aqueous and formic acid solution. The p-sheet conformation of SF formed by formic acid casting was retained for aU SF blends regardless of blend ratio. SF/PVA blends from aqueous solution exhibited a phase-separated morphology and immiscibility by SEM observation and DMTA (Dynamic Mechanical Thermal Analysis) measurement (Um and Park 2007) (Figs. 10.35 and 10.36). 

DTA n. Differential thermal analysis measurement of melting temperature generates a plot of heat versus temperature and semiquantiative, but higher temperature range than DSC. DTA is capable of measuring events (e.g., melting, crystallization, and decomposition) but not heat of melting or crystallization whereas DSC is quantitative and appropriate for thermally... 

Because of the partial misdbility of blends of many compositions and consequent complications arising in the positions and breadth of thermal transitions, detailed DSC and dynamic mechanical thermal analysis measurements were restricted to simpler cases. These measurements were restricted to blends with <50 wt % PCL which were the only ones which could be quenched from the melt without the PCL crystallising. For blends with 30 wt % or 40 wt % high-molec-ular-weight PCL only one Tg was observed. 

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