Authors:K. Ngai, S. Capaccioli, M. Shahin Thayyil, and N. Shinyashiki
In several current important problems in different areas of soft matter physics, controversy persists in interpreting the
molecular dynamics observed by various spectroscopies including dielectric relaxation, light scattering, nuclear magnetic
resonance, and neutron scattering. Outstanding examples include: (1) relaxation of water in aqueous mixtures, in molecular
sieves and silica-gel nanopores, and in hydration shell of proteins; and (2) dynamics of each component in binary miscible
polymer blends, in mixtures of an amorphous polymer with a small molecular glassformer, and in binary mixtures of two small
molecular glassformers. We show the applications of calorimetry to these problems have enhanced our understanding of the dynamics
and eliminated the controversies.
Authors:Vikram Kestens, Guy Auclair, Katarzyna Drozdzewska, Andrea Held, Gert Roebben, and Thomas Linsinger
In this study, the use of differential scanning calorimetry (DSC) is demonstrated as a powerful technique that can provide
accurate thermodynamic property values of environmental contaminants such as polycyclic aromatic hydrocarbons (PAHs). In total,
47 high purity PAH certified reference materials were selected and analysed by DSC. Their onset melting temperature, enthalpy
of fusion and eutectic purity were calculated from the obtained melting endotherms. In addition, the entropy of fusion, which
was calculated from the onset melting temperature and enthalpy of fusion, is presented. All measurements were evaluated in
a metrologically rigorous manner, including measurement uncertainties.
The results of comparative thermodynamic analysis of AuIn–Sb section in ternary Au–In–Sb system are presented in this paper.
Investigation was carried out experimentally, using Oelsen calorimetry at the temperature 873 K and analytically, applying
different predicting methods––Toop and Muggianu in the temperature interval from 873 K to 1673 K. The values for integral
molar Gibbs excess energies and antimony activities have been determined and compared at temperature of 873 K, which indicated
to good agreement between experimental results and results obtained using Toop predicting model.
Authors:G. Baert, S. Hoste, G. De Schutter, and N. De Belie
Four paste mixtures with varying replacement level of the cement content by fly ash have been studied. Due to fly ash, the
acceleration period decreased and a third hydration peak was noticed with isothermal calorimetry. The total heat after 7 days
increased with increasing fly ash content. From 1 to 7 days, thermogravimetry showed a higher chemically bound water and Ca(OH)2-content for the pastes with fly ash. Between 7 and 14 days the calcium hydroxide started to be depleted due to the pozzolanic
reaction. A unique relation was found between calcium hydroxide and total heat development.
Authors:P. Pustková, J. Shánělová, P. Čičmanec, and J. Málek
The structural relaxation of Ge38S62 glass has been studied by length dilatometry and calorimetry. The Tool-Narayanaswamy-Moynihan model was applied on obtained
data of structural relaxation and parameters of this model were determined: Δh*= 4832 kJ mol-1, ln(A/s)= -811, β= 0.70.1 and x=0.60.1. Both dilatometric and calorimetric relaxation data were compared on the basis of the fictive relaxation rate. It
was found that the relaxation rates are very similar and well correspond to the prediction of phenomenological model.
Differential Scanning Calorimetry combined with Fourier transform infrared spectroscopy, was applied to the study of a number of fulvic and humic acids extracted from soils, peat, river and seawater. The thermal patterns obtained were related to the nature and origin of samples. The low-temperature endotherms were attributed to dehydration and loss of peripheral polysaccharide chains. The endotherm at 250°C observed for soil FA was ascribed to partial decarboxylation of more labile surface COOH groups, whereas the high-temperature exotherms at about 500°C were related to the degree of polycondensation of the aromatic network of the humic molecules.
Authors:M. Song, D. Hourston, M. Reading, H. Pollock, and A. Hammiche
A modulated-temperature differential scanning calorimetry (M-TDSC) method for the analysis of interphases in multi-component
polymer materials has been developed further. As examples, interphases in a polybutadiene-natural rubber (50:50 by mass) blend,
a poly(methyl methacrylate)-poly(vinyl acetate) (50:50 by mass) structured latex film, a polyepichlorohydrinpoly(vinyl acetate)
bilayer film, and polystyrene-polyurethane (40:60 by mass) and poly(ethyl methacrylate)-polyurethane (60:40 by mass) interpenetrating
polymer networks were investigated. The mass fraction of interphase and its composition can be calculated quantitatively.
These interphases do not exhibit clear separate glass transition temperatures, but occur continually between the glass transition
temperatures of the constituent polymers.
Authors:Chung-Hwei Su, Sheng-Hung Wu, Sun-Ju Shen, Gong-Yih Shiue, Yih-Weng Wang, and Chi-Min Shu
Volatile organic compounds (VOCs) are the main factors involved in pollution control and global warming in industrialized
nations. Various treatment methods involving incineration, adsorption, etc., were employed to reduce VOCs concentration. Various
absorbents, such as activated carbon, zeolite, silica gel or alumina, and so on were broadly used to adsorb VOCs in various
industrial applications. Differential scanning calorimetry (DSC) was handled to analyze the thermal characteristics of absorbents.
Typically, a scanning electron microscope (SEM) has been used to evaluate the structure variation of absorbents under high
temperature situations. In view of pollution control and loss prevention, versatility and analysis of recycled adsorbents
are necessary and useful for various industrial applications.
A critical thermodynamic analysis of differential thermal calorimetry is reported herein to gain further insight into the
phenomena leading to the reported differences between kinetic parameters extracted from isothermal DSC methods and those from
dynamic DSC methods. The sources have been identified for the variations observed in the total heat of reaction as a function
of the heating rate in dynamic DSC experiments. The analysis clearly indicates that these variations are, in fact, to be anticipated.
The relationships necessary for extracting kinetic data from both isothermal and dynamic experiments are derived rigorously
by resorting to classical thermodynamics.
Authors:J. Zhu, H. Jin, D. Dong, D. Qiang, and F. Ma
The glass formation and devitrification of GaF3-based glasses were studied by differential scanning calorimetry. A comparison of various simple quantitative methods to assess
the level of stability of multicomponent fluoride glass systems is presented. Most of these methods are based on critical
temperatures. In this paper a new parameter kb(T) is added to the stability criteria. The stability of several GaF3-based glasses were experimentally evaluated and correlated with the activation energies of crystallization via this new kinetic
criterion and compared with those evaluated by other criteria.