INFLUENCE OF THE ISOTHERMAL ANNEALING ON THE FREE VOLUME CHANGES IN THERMO-SHRUNKEN POLYETHYLENE BY POSITRON ANNIHILATION |
| W. Osoba Institute of Physics, Silesian University, Uniwersytecka 4, 40-007 Katowice, Poland |
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| Positron lifetime measurements in polyethylene have been performed. Samples of the polyethylene were isothermally annealed at three temperatures (373 K, 423 K, and 473 K) for different time periods (from 5 min to 5 h). After cooling, the samples were used for the lifetime measurements in air at room temperature. A conventional fast-slow coincidence lifetime spectrometer with plastic scintillators has been used to perform the lifetime measurements. Mean free volumes radii and fractional free volume have been calculated from the lifetime data. |
| DOI: 10.12693/APhysPolA.99.447 PACS numbers: 71.60.+z, 78.70.Bj |