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Free Volume Expansi...
Free Volume Expansion of Poly[1-(trimethylsilyl)-1-propyne] Treated in Supercritical Carbon Dioxide As Revealed by Positron Annihilation Lifetime Spectroscopy
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Claes, Stan (författare)
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Vandezande, Pieter (författare)
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Mullens, Steven (författare)
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Van Bael, Marlies K. (författare)
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- Maurer, Frans (författare)
- Lund University,Lunds universitet,Centrum för analys och syntes,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Analysis and Synthesis,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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(creator_code:org_t)
- 2011-03-21
- 2011
- Engelska.
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 44:8, s. 2766-2772
- Relaterad länk:
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http://dx.doi.org/10...
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https://lup.lub.lu.s...
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https://doi.org/10.1...
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Abstract
Ämnesord
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- The free volume changes of poly[1-(trimethyl-silyl)-1-propyne] (PTMSP) treated in supercritical CO2 (scCO(2)) were investigated with positron annihilation lifetime spectroscopy (PALS). CO2 is known to plasticize and increase the free volume size of a broad range of polymers. In this work dense PTMSP films were treated with scCO(2) under different pressures and temperatures, resulting in the enlargement of the characteristic channel-like holes (R-3) and the larger free volume cages (R-4) up to 39% and 19%, respectively. The free volume enlargement was found to have a relaxation time of similar to 30 years. At higher temperatures (110-150 degrees C), the o-Ps intensities and gel permeation chromatography (GPC) data revealed chemical changes of the scCO(2)-treated polymer due to the onset of PTMSP's degradation. However, at lower temperatures (40-70 degrees C), significant free volume cavity size increases to 25% for R-3 and 9% for R-4 were also observed.
Ämnesord
- NATURVETENSKAP -- Kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences (hsv//eng)
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