EFFECT OF ANNEALING ON FREE-VOLUME PROPERTIES OF POLY(ETHYLENE TEREPHTHALATE) STUDIED BY POSITRON ANNIHILATION
M. Mishevaa, N. Djourelovb and I. Seganovc
aFaculty of Physics, Sofia University, 5 J. Bourchier Blvd., 1126 Sofia, Bulgaria
bInstitute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences 72 Tzarigradsko shoosse Blvd., 1784 Sofia, Bulgaria
cFaculty of Chemistry, Sofia University, 1 J. Bourchier Blvd., 1126 Sofia, Bulgaria
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The effect of annealing on free-volume properties of poly(ethylene terephthalate) was studied using a set of samples annealed for two hours in air at eight temperatures between 80C and 220C. The fractional free-volume in the samples was estimated from ortho-positronium lifetime and its relative intensity. The variations of fractional free-volume and of the macroscopic specific volume with annealing temperature were compared. The variation of the pore volume probability density functions with the annealing temperature was found. The interdependence between S- and W-parameters was also discussed.
DOI: 10.12693/APhysPolA.99.429
PACS numbers: 78.70.Bj