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Abstract  

The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on strict symmetry of the twin calorimeter. This symmetry is of particular importance for temperature-modulated DSC (TMDSC) since positive and negative deviations from symmetry cannot be distinguished in the most popular analysis methods. The heat capacities for sapphire-filled and empty aluminum calorimeters (pans) under designed cell imbalance caused by different pan-masses were measured. In addition, the positive and negative signs of asymmetry have been explored by analyzing the phase-shift between temperature and heat flow for sapphire and empty runs. The phase shifts change by more than 180° depending on the sign of the asymmetry. Once the sign of asymmetry is determined, the asymmetry correction for temperature-modulated DSC can be made.

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Abstract  

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.

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Abstract  

An analysis developed in previous work has been further refined in order to study the effect of heat transfer on the heat capacity and phase angle measurements by TMDSC. In the present model, a temperature gradient within the sample has been taken into account by allowing for heat transfer by thermal conduction within the sample. The influence of the properties of the sensors, the heat transfer conditions between the sensor and sample,and the properties of the sample have been investigated by varying each parameter in turn. The results show that heat capacity measurements are reliable only within a restricted frequency range, for which the experimental conditions are such that the heat transfer phase angle depends linearly on the modulation frequency.

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have been scarcely reported [ 14 ]. Temperature-modulated differential scanning calorimetry (TMDSC) is an easier and accurate method for determining the heat capacity. The structure and principle of the calorimeter have been described in details [ 15

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Biodiesels from beef tallow/soybean oil/babassu oil blends

Correlation between fluid dynamic properties and TMDSC data

Journal of Thermal Analysis and Calorimetry
Authors: G. A. A. Teixeira, A. S. Maia, I. M. G. Santos, A. L. Souza, A. G. Souza, and N. Queiroz

obtained from the temperature-modulated differential scanning calorimetry (TMDSC) curves. Experimental Biodiesel synthesis In the synthesis of the biodiesel samples, different amounts of beef tallow, babassu

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Journal of Thermal Analysis and Calorimetry
Authors: Cheng-Li Jiao, Li-Fang Song, Chun-Hong Jiang, Jian Zhang, Xiao-Liang Si, Shu-Jun Qiu, Shuang Wang, Li-Xian Sun, Fen Xu, Fen Li, and Ji-Jun Zhao

[ 17 , 18 ]. Temperature-modulated differential scanning calorimetry (TMDSC) is one of easier and more accurate methods for determining heat capacity [ 19 ]. TMDSC was initially proposed in 1992 by Reading and co-workers [ 20 ]. TMDSC which applies a

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Journal of Thermal Analysis and Calorimetry
Authors: Li-Fang Song, Chun-Hong Jiang, Cheng-Li Jiao, Jian Zhang, Li-Xian Sun, Fen Xu, Qing-Zhu Jiao, Yong-Heng Xing, Yong Du, Zhong Cao, and Feng-Lei Huang

properties closely. Temperature-modulated differential scanning calorimetry (TMDSC) is one of the easier and more accurate methods for determining the heat capacity. The structure and principle of the calorimeter have been described in detail by the

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