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2005 | 107 | 5 | 805-810
Article title

Outdoor Ageing of an Ethylene-Propylene Copolymer: A Positron Annihilation Study

Content
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Languages of publication
EN
Abstracts
EN
An investigation on the environmental degradation of an ethylene-propylene copolymer was carried out through positron annihilation lifetime spectroscopy, density and differential scanning calorimetry measurements. Polymer sheets were exposed to sunlight up to 11000 hours. Density and melting enthalpy increase with ageing, while ortho-positronium intensity decreases; ortho-positronium lifetime does not show significant variations up to 4400 hours. At higher exposures it starts to decrease. Outdoor ageing produces an increased crystallinity of the copolymer; also a degradation occurs with formation of carbonyl groups. The corresponding Ps inhibition is the main reason for the decrease in ortho-positronium intensity, the other one being the reduced amount of the amorphous phase available. The lifetime decrease observed at the highest exposures can be interpreted in terms of a shrinking of the nanoholes trapping positronium.
Keywords
EN
Year
Volume
107
Issue
5
Pages
805-810
Physical description
Dates
published
2005-05
received
2004-09-20
References
  • 1. A. Hale, H.E. Bair, in: Thermal Characterization of Polymeric Materials, Vol. 1, Ed. E.A. Turi, Academic Press, New York 1997, p. 745
  • 2. M. Pegoraro, F. Severini, L. Di Landro, R. Braglia, J. Kolaric, Macromol. Mater. Eng., 280/281, 14, 2000
  • 3. J. Kansy, Nucl. Instrum. Methods A, 374, 235, 1996
  • 4. S.J. Tao, J. Chem. Phys., 56, 5499, 1972
  • 5. M. Eldrup, D. Lightbody, N.J. Sherwood, Chem. Phys., 63, 51, 1981
  • 6. R. Gallo, L. Brambilla, C. Castiglioni, S. Ipsale, F. Severini, F. Quasso, G. Consolati, Eur. Polym. J., to be published
Document Type
Publication order reference
YADDA identifier
bwmeta1.element.bwnjournal-article-appv107n513kz
Identifiers
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