Kinetics of Phase Transformation of Indium in the Presence of Polytetrafluoroethylene: Implications for DSC Measurements on Polymers and Their Composites

Raimo, Maria

doi:10.1155/2015/690718

Cited by 5 publications

(2 citation statements)

References 32 publications

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“…The thermodynamic melting point of a fully crystalline and 100% pure compound is in theory an infinitely sharp peak in a DSC thermogram. 47 However, in real n BA samples, a distribution of crystal sizes exists, which causes an asymmetric shape for the melting transitions in the DSC trace ( Figure 2 a). Other factors broadening the peak include limited instrumental resolution and thermal gradients in the sample.…”

Section: Resultsmentioning

confidence: 99%

Molecular Arrangement and Thermal Properties of Bisamide Organogelators in the Solid State

et al. 2022

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The crystal structure and phase behavior of bisamide gelators are investigated using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy, Xray diffraction (XRD), and molecular modeling, aiming at a better understanding of bisamide gel systems. A homologous series of bisamide model compounds (nBAs) were prepared with the (CH 2 ) n spacer between the two amide groups, where n varies from 5 to 10, and with two symmetric C17 alkyl tails. With increasing spacer length, the thermal properties show a clear odd−even effect, which was characterized using our newly developed analytical model DSC N (T). Using XRD, all studied nBA compounds turn out to have a layer-like structure. The XRD patterns of the odd BA series are very similar but show marked differences compared to the XRD patterns of the even series, which in turn are very similar. The odd-membered 5BA molecules are nearly perpendicular to the stacked layers, as described by a pseudo-orthorhombic unit cell, whereas the even-membered 6BA molecules are tilted at an angle with respect to the layer normal, as described by a triclinic unit cell. In both the odd and even series, the inter-layer interaction is the van der Waals interaction. The 6BA hydrogen bonding scheme is very similar to that of Nylon 6,10 α, unlike the 5BA H bonding scheme. The packing of the C17 alkyl tails in the 5BA layers is similar to polyethylene, and unlike 6BA. The slightly higher crystalline density of 6BA (1.038 g cm −3 ) as compared to 5BA (1.018 g cm −3 ) explains the higher melting point, higher enthalpy of fusion, and the observed shift of N−H stretch bands to higher wave numbers. The structural differences observed between the odd and even BA series reflect the different structure-directing effect of parallel versus antiparallel amide hydrogen bonding motifs. These differences underlie the observed odd−even effect in the thermal properties of nBA compounds.

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Section: Resultsmentioning

confidence: 99%

Molecular Arrangement and Thermal Properties of Bisamide Organogelators in the Solid State

et al. 2022

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“…The DSC trace recorded for melting of an ideal sample, fully crystalline or 100% pure compound with a low thermal resistance, is in theory an infinitely sharp precisely defined temperature, which could be imagined as a delta function spike in the heat capacity (Fig. 1a) [3]. However, in practice DSC records the heat flow as a distribution, which for simplicity could be assumed to be a Gaussian bell-shaped curve (Fig.…”

Section: Introductionmentioning

confidence: 99%

Analysis of differential scanning calorimetry (DSC): determining the transition temperatures, and enthalpy and heat capacity changes in multicomponent systems by analytical model fitting

Ghanbari,

Picken,

van Esch

2023

J Therm Anal Calorim

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We have developed an analytical method to quantitatively analyze differential scanning calorimetry (DSC) experimental data. This method provides accurate determination of thermal properties such as equilibrium melting temperature, latent heat, change of heat capacity which can be performed automatically without intervention of a DSC operator. DSC is one of the best techniques to determine the thermal properties of materials. However, the accuracy of the transition temperature and enthalpy change can be affected by artifacts caused by the instrumentation, sampling, and the DSC analysis methods which are based on graphical constructions. In the present study, an analytical function (DSCN(T)) has been developed based on an assumed Arrhenius crystal size distribution together with instrumental and sample-related peak broadening. The DSCN(T) function was successfully applied to fit the experimental data of a substantial number of calibration and new unknown samples, including samples with an obvious asymmetry of the melting peak, yielding the thermal characteristics such as melting and glass transition temperature, and enthalpy and heat capacity change. It also allows very accurate analysis of binary systems with two distinct but severely overlapping peaks and samples that include a cold crystallization before melting.

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Simple model for particle phase transformation kinetics

Reis

Zanotto

2018

Acta Materialia

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Kinetics of Phase Transformation of Indium in the Presence of Polytetrafluoroethylene: Implications for DSC Measurements on Polymers and Their Composites

Cited by 5 publications

References 32 publications

Molecular Arrangement and Thermal Properties of Bisamide Organogelators in the Solid State

Molecular Arrangement and Thermal Properties of Bisamide Organogelators in the Solid State

Analysis of differential scanning calorimetry (DSC): determining the transition temperatures, and enthalpy and heat capacity changes in multicomponent systems by analytical model fitting

Simple model for particle phase transformation kinetics

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