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Pressure and volume...
Pressure and volume dependence of thermal conductivity and isothermal bulk modulus up to 1 GPa for poly(isobutylene)
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- Andersson, S. Peter (author)
- Umeå universitet,Institutionen för fysik
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(creator_code:org_t)
- John Wiley & Sons, 1998
- 1998
- English.
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In: Journal of Polymer Science Part B. - : John Wiley & Sons. - 0887-6266 .- 1099-0488. ; 36:10, s. 1781-1792
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
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- The thermal conductivity λ and heat capacity per unit volume ρcp of poly(isobutylene)s, one 2.8 in weight average molecular weight and one 85 kg mol-1 in viscosity average molecular weight (PIB-2800 and PIB-85000), have been measured in the temperature range 170-450 K at pressures up to 2 GPa using the transient hot-wire method. At 297 K and atmospheric pressure, λ = 0.115 W m-1 K-1 for PIB-2800 and λ = 0.120 W m-1 K-1 for PIB-85000. The bulk modulus BT has been measured in the temperature range 170-297 K up to 1 GPa. At atmospheric pressure, the room temperature bulk moduli BT are 2.0 GPa for PIB-2800 and 2.5 GPa for PIB-85000 with dBT/dp = 10 for both. These data were used to calculate the volume dependence of λ,g = -(∂λ/λ / ∂V/V)T.At room temperature and atmospheric pressure (liquid phase) we find g = 3.4 for PIB-2800 and g = 3.9 for PIB-85000, but g depends strongly on temperature for both molecular weights. The difference in g between the glassy state and liquid phase is small and just outside the inaccuracy of g of about 8%. The best predictions for g are given by the theoretical model of Horrocks and McLaughlin. We have found that PIE exhibits two relaxations, where one is associated with the glass transition. The value for dTg/dp at atmospheric pressure (for the main glass transition) is about 0.21 K MPa-1 for both molecular weights.
Subject headings
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
Keyword
- Thermal conductivity
- heat capacity
- specific heat
- bulk modulus
- high pressure
- poly(isobutylene)
- glass transition
- liquid
- solid
- relaxation
Publication and Content Type
- ref (subject category)
- art (subject category)
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