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Koblingen mellem de termiske og mekaniske responsfunktioner ved glasovergangen.
, 3. modul, 2001, id:178
Vejleder:Tage Emil Christensen
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Abstract
English abstract
Supercooled liquids have the property that through continued cooling they will reach a temperture where their behaviour will change from liquidlike to solidlike behaviour - This phenomenon is called the glass transition. The temperture range around the glass transition is characterised by the fact that the physical properties of the material become frequency dependent, because the characteristic times of the relaxation processes in the material become comparable to the times of the experiments. Through an experimental investigation of the heat capacity and mechanical modulus of 1,2,4-butanetriol an attempt is made to describe the connection between the frequency dependent response functions in the thermal and mechanical domain. The experimental data are compared with two existing models of coupling between the respons functions. The first model can not give a full description of the experimental results, but the possibility of making a final conclusion about the model is decreased by the ability of the liquid to absorb water from the surrounding air. This absorption leads to a big change in the glass transition temperture. The second model has a fundamental problem in explaining the experimental data, which can not be explained by the absorption of water. This means that this model can not explain the connection between the thermic and mechanical response functions near the glass transition.

Database opslag den: 23-09-2017