Journal
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Abstracts
Doppler broadening and positron lifetime spectra have been measured for polypropylene films of constant thickness (≈ 50 μm) and different morphology that crystallized from melt at temperature 0, 100, and 120°C. The S -parameter vs. energy curves do not change in a systematic way with crystallinity of samples. It is supposed that decrease in the fractional free volume for samples of greater crystallinity is not seen in S-values because of their increase resulting from annihilation in defects present both in the crystalline regions and on the lamellae surfaces. Intensities of the components in the positron lifetime spectra: I_{2} (τ_{2}=1.3 ns) and I_{3} (τ_{3}≈ 2.3÷2.8 ns) show changes with crystallinity of samples. The evident trend is observed for the longer-lived τ_{3}-component intensity to decrease with crystallinity while the reverse is true for the shorter, fixed τ_{2}-component. The decrease in the intensity of the longer-lived component can result from reduction of the fractional free volume.
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)
- 71.60.+z: Positron states(for positron annihilation, see 78.70.Bj)
- 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)
- 36.10.Dr: Positronium(see also 82.30.Gg Positronium chemistry)
Journal
Year
Volume
Issue
Pages
496-504
Physical description
Dates
published
1999-04
Contributors
author
- Institute of Experimental Physics, University of Wrocław, Pl. Maksa Borna 9, 50-204 Wrocław, Poland
author
- School of Physics, University of East Anglia, Norwich NR4 7TJ, United Kingdom
author
- Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
References
Document Type
Publication order reference
Identifiers
YADDA identifier
bwmeta1.element.bwnjournal-article-appv95z410kz