Heat
capacity functions of polystyrene in glassy and in liquid amorphous state
and glass transition |
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Authors: | E Marti E Kaisersberger E Moukhina |
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Institution: | 1. APCh Marti Consulting, Basel, Switzerland, 4054 2. Netzsch-Ger?tebau
GmbH, Selb, Bayern, Germany, 95100
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Abstract: | The
heat capacity or the specific heat is for any crystalline, partially amorphous
or completely amorphous substance or material a significant thermodynamic
property. The glass transition may be regarded as the melting point of amorphous
substances and materials, a transition property of an outstanding technical
importance. A crucial point is the fact that the presence of a glass transition
is an unequivocal proof of an amorphous content of a material. Furthermore,
the change of the specific heat at the glass transition temperature enables
the quantitative determination of the amorphicity on a relative or absolute
level of any substance or material. The absolute determination of the amorphicity
affords a calibration with a reference corresponding to the material under
investigation. The crystallinity for this reference substance must be known
from the preparation and or by any independent analytical method.
The
literature data for the specific heat and the glass transition of polystyrene
were collected and evaluated. Data were found for the specific heat in literature
from 10 to 470 K. The data were unified for each of the reported temperature
in a mean value and the corresponding standard deviation was determined. An
excellent conformity was found in the glassy state of polystyrene with standard
deviations lower than 0.7%. The standard deviations above the glass transition
were considerably higher. |
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Keywords: | |
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