Systematic broadening of the viscoelastic and calorimetric glass transitions in complex glass-forming liquids

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2018-03
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Mcode
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Language
en
Pages
10-17
Series
Journal of Non-Crystalline Solids, Volume 483
Abstract
In this experimental study, we explore the broadening of the glass transition in chemically and structurally complex glass-forming liquids (CGFLs) by means of thermal and rheological characterization techniques. Petroleum fluids with different levels of chemical and structural complexity are used as model materials. Thermal characterization by temperature-modulated differential scanning calorimetry (TMDSC) reveals a systematic increase in the width of the glass transition region ΔT g with increasing chemical and structural complexity. The broadening of the glass transition is also strongly reflected in the linear viscoelastic properties that are measured by small-diameter parallel plate rheometry. Most notably, this is observed as the broadening of the relaxation time spectrum at long times. The recently proposed broadened power-law spectrum model is used to describe the constitutive behavior of the investigated petroleum fluids. In this model, the stretching parameter β serves as a quantitative measure of the spectral broadening. A strong power-law correlation is found between ΔT g and β, manifesting a relationship between the broadness of the calorimetric and viscoelastic glass transition in CGFLs.
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Keywords
Glass-forming liquids, Glass transition, Rheology, Viscoelastic properties, Relaxation time spectrum, Differential scanning calorimetry
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Citation
Laukkanen , O-V , Winter , H H , Soenen , H & Seppälä , J 2018 , ' Systematic broadening of the viscoelastic and calorimetric glass transitions in complex glass-forming liquids ' , Journal of Non-Crystalline Solids , vol. 483 , pp. 10-17 . https://doi.org/10.1016/j.jnoncrysol.2017.12.029