Some remarks on the relation between free-volume fractions and ortho-positronium lifetimes in amorphous polymers

Authors
Maurer, FHJ Schmidt, M
Citation
Fhj. Maurer et M. Schmidt, Some remarks on the relation between free-volume fractions and ortho-positronium lifetimes in amorphous polymers, RADIAT PH C, 58(5-6), 2000, pp. 509-512
Citations number
23
Categorie Soggetti
Physics
Journal title
RADIATION PHYSICS AND CHEMISTRY
ISSN journal
0969806X → ACNP
Volume
58
Issue
5-6
Year of publication
2000
Pages
509 - 512
Database
ISI
SICI code
0969-806X(200006)58:5-6<509:SROTRB>2.0.ZU;2-T
Abstract
Unique information about the properties of free-volume sites in polymers is gained from Positron Annihilation Lifetime (PAL) measurements. After calib ration with data from other techniques the method may be used to determine free-volume fractions. From pressure-volume-temperature (PVT) and PAL (orth o-Ps lifetime tau(3)) data, measured on identical amorphous poly(methyl met hacrylate) (PMMA) samples with controlled thermal histories, we find a line ar relationship between free-volume fractions, derived from PVT measurement s, the Simha-Somcynsky equation-of-state theory and the mean subnanometer f ree-volume size both below and above the glass transition temperature. (C) 2000 Elsevier Science Ltd. All rights reserved.