ISSN:
0887-6266
Schlagwort(e):
bulk modulus
;
equation of state
;
heat capacity
;
high pressure
;
poly(propylene glycol)
;
thermal conductivity
;
transient hot-wire method
;
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The thermal conductivity λ and heat capacity per unit volume of poly(propylene glycol) PPG (0.4 and 4.0 kg·mol-1 in number-average molecular weight) have been measured in the temperature range 150-295 K at pressures up to 2 GPa using the transient hot-wire method. At 295 K and atmospheric pressure, λ = 0.147 W m-1K-1 for PPG (0.4 kg·mol-1) and λ = 0.151 W m-1K-1 for PPG (4.0 kg·mol-1). The temperature dependence of λ is less than 4 × 10-4 W m-1K-2 for both molecular weights. The bulk modulus has been measured in the temperature range 215-295 K up to 1.1 GPa. At atmospheric pressure, the room temperature bulk moduli are 1.97 GPa for PPG (0.4 kg·mol-1) and 1.75 GPa for PPG (4.0 kg·mol-1). These data were used to calculate the volume dependence of \documentclass{article}\pagestyle{empty}\begin{document}$ \lambda ,g\, = - \left( {\frac{{\partial \lambda /\lambda }}{{\partial V/V}}} \right)_T $\end{document}. At room temperature and atmospheric pressure (liquid phase) we find g = 2.79 for PPG (0.4 kg·mol-1) and g = 2.15 for PPG (4.0 kg·mol-1). The volume dependence of g, (∂g/∂ log V)T varies between -19 to -10 for both molecular weights. Under isochoric conditions, g is nearly independent of temperature. The difference in g between the glassy state and liquid phase is small and just outside the inaccuracy of g of about 8%. The theoretical model for λ by Horrocks and McLaughlin yields an overestimate of g by up to 120%. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 345-355, 1998
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
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