Numerical modeling and analysis of temperature modulated differential scanning calorimetry: On the separability of reversing heat flow from non-reversing heat flow

Xu, Siqi; Li, Y.; Feng, Yuanping

doi:10.1016/s0040-6031(99)00341-x

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…This gives the total heat flow and the deconvoluted temperature, which is equivalent to information obtained by standard DSC. Then the averaged signal is subtracted from the raw data and DTF procedure is applied with a sliding transform window to obtain the amplitude and phase difference of the heat flow response at modulation frequency ω so as to obtain the reversing heat capacity . The heat capacity in TMDSC can be expressed as: | m c p + C s − C r ± normalΔ C c e l l | = A normalΔ A true( K normalω true) 2 + C r 2 = A H F A italicK italic′ where mc p is the heat capacity of a sample of mass, m , and specific heat capacity, c p ; C s and C r are the heat capacities of the sample pan and empty reference pan, respectively; Δ C cell is the cell asymmetry correction .…”

Section: Methodsmentioning

confidence: 99%

“…Then the averaged signal is subtracted from the raw data and DTF procedure is applied with a sliding transform window to obtain the amplitude and phase difference of the heat flow response at modulation frequency ω so as to obtain the reversing heat capacity. 24 The heat capacity in TMDSC can be expressed as:…”

Section: Thermal Analysis Temperature Modulated Differentialmentioning

confidence: 99%

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Heat Capacity of Spider Silk-Like Block Copolymers

Huang

Krishnaji

et al. 2011

Macromolecules

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We synthesized and characterized a new family of di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, having the form HABn and HBAn (n=1–3), comprising an alanine-rich hydrophobic block, A, a glycine-rich hydrophilic block, B, and a histidine tag, H. The reversing heat capacities, Cp(T), for temperatures below and above the glass transition, Tg, were measured by temperature modulated differential scanning calorimetry. For the solid state, we then calculated the heat capacities of our novel block copolymers based on the vibrational motions of the constituent poly(amino acid)s, whose heat capacities are known or can be estimated from the ATHAS Data Bank. For the liquid state, the heat capacity was estimated by using the rotational and translational motions in the polymer chain. Excellent agreement was found between the measured and calculated values of the heat capacity, showing that this method can serve as a standard by which to assess the Cp for other biologically inspired block copolymers. The fraction of beta sheet crystallinity of spider silk block copolymers was also determined by using the predicted Cp, and was verified by wide angle X-ray diffraction and Fourier transform infrared spectroscopy. The glass transition temperatures of spider silk block copolymer were fitted by Kwei’s equation and the results indicate that attractive interaction exists between the A-block and B-block.

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Section: Methodsmentioning

confidence: 99%

Section: Thermal Analysis Temperature Modulated Differentialmentioning

confidence: 99%

Heat Capacity of Spider Silk-Like Block Copolymers

Huang

Krishnaji

et al. 2011

Macromolecules

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“…The TMDSC output curve was further analyzed to obtain reversing and nonreversing components using the method discussed in the literature (e.g., Refs. 3,14), which are shown in Figure 3. One observes clearly a nonreversing curve-this is contradictory with the experimental assumptions.…”

Section: Resultsmentioning

confidence: 99%

Numerical simulation of DSC and TMDSC curves as well as reversing and nonreversing curve separation

Cao

2007

J of Applied Polymer Sci

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ABSTRACT:The basic physical meaning of temperature modulation for DSC is an arguable research topic, and its interpretation affects the development of thermal analysis and polymer science. This article studies the basic physical meaning of TMDSC by numerical simulation. DSC and TMDSC output curves are computed for a sample with step changes in its specific heat and for a sample with crystallites melting over the temperature range. The TMDSC curves are further analyzed to obtain the reversing and nonreversing components. It is shown that separation of the reversing and nonreversing components from the underlying heat flow cannot be justified. Some common misconceptions regarding TMDSC are discussed as well.

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“…Fundamental understanding of the system from TMDSC relies on the ability to analyze the reversing and nonreversing signals correctly. Consequently, proper analysis of TMDSC signals has been a very important topic in the development and application of this technique [4,5].…”

Section: Introductionmentioning

confidence: 99%

On the frequency correction in temperature-modulated differential scanning calorimetry of the glass transition

Guo

Mauro

Allan

et al. 2012

Journal of Non-Crystalline Solids

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG glass over a wide range of modulation frequencies. Our results reveal that the frequency correction commonly used in the interpretation of TMDSC signals leads to a master nonreversing heat flow curve independent of modulation frequency, provided that sufficiently high frequencies are employed in the TMDSC measurement. A master reversing heat flow curve can also be generated through the frequency correction. The resulting glass transition temperature from the frequency corrected reversing heat flow is thereby shown to be independent of frequency.

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Numerical modeling and analysis of temperature modulated differential scanning calorimetry: On the separability of reversing heat flow from non-reversing heat flow

Cited by 9 publications

References 11 publications

Heat Capacity of Spider Silk-Like Block Copolymers

Heat Capacity of Spider Silk-Like Block Copolymers

Numerical simulation of DSC and TMDSC curves as well as reversing and nonreversing curve separation

On the frequency correction in temperature-modulated differential scanning calorimetry of the glass transition

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