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

• Authors: G. Consolati , F. Quasso , R. Gallo , F. Severini
• 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

61.41.+e; 78.70.Bj; 81.05.Lg

Discipline

• 78.70.Bj: Positron annihilation(for positron states, see 71.60.+z in electronic structure of bulk materials; for positronium chemistry, see 82.30.Gg in physical chemistry and chemical physics)
• 61.41.+e: Polymers, elastomers, and plastics(see also 81.05.Lg in materials science; for rheology of polymers, see section 83; for polymer reactions and polymerization, see 82.35.-x in physical chemistry and chemical physics)
• 81.05.Lg: Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials(for polymers and organic materials in electrochemistry, see 82.45.Wx)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2005
• Volume: 107
• Issue: 5
• Pages: 805-810

Dates

published

2005-05

received

2004-09-20

Contributors

author

G. Consolati

• Dipartimento di Fisica and INFM, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy

author

F. Quasso

• Dipartimento di Fisica and INFM, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy

author

R. Gallo

• Dipartimento di Chimica Industriale e Ingegneria dei Materiali, Universitá di Messina, Salita Sperone, 98166 S. Agata di Messina, Italy

author

F. Severini

• Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy

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

Identifiers

DOI

10.12693/APhysPolA.107.805