Berlin 2001 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 13: Glass Transition
CPP 13.1: Talk
Thursday, April 5, 2001, 17:45–18:05, 111
Determination of changes in free volume in polymers induced by ball milling — •Katja Günther-Schade1, Hessel L. Castricum2, Hans Bakker2, and Franz Faupel1 — 1Technische Fakultät der Universität Kiel, Lehrstuhl für Materialverbunde, Kaiserstr. 2, 24143 Kiel, Germany — 2Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam, Netherlands
To understand the mechanism of the milling process of polymers the influence of milling on free volume in PS and PC powders was determined with positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimetry (DSC) and. The PALS measurements show that free volume is introduced similarly by ball milling and by thermal quenching. During tempering below the glass transition temperature the average lifetime decreased remarkably. Two long components could be separated. One is the surface component and one is related to the free volume. As expected the intensity of the surface component decreased with the increasing particle size. Additionally the milled samples show no “radiation effect” and the total intensity is well below the one for unmilled samples. DSC measurements verify the present positron annihilation results.