Berlin 2001 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 16: Poster: Dynamics of Molecular Systems, Polymer Dynamics, Glass Transition, Crystallization, Electronic Properties of Polymers
CPP 16.21: Poster
Montag, 2. April 2001, 12:30–15:00, AT1
Local Free Volume and Glass Transition in Propene/alpha-Olefin Copolymers with Defined Length and Number of Branches — •G. Dlubek1, J. Stejny2, R. Rodriguez-Gonzalez2, D. Bamford2, S. Bornemann3, O. Henschke3, M. Arnold3, and M. A. Alam2 — 1ITA Inst. f. innov. Technol. GmbH, Koethen, Aussenstelle Halle, Wiesenring 4, D-06120 Lieskau (bei Halle/S.) — 2University of Bristol, H. H. Wills Physics Lab., Tyndall Avenue, Bristol BS8 1 TL, UK — 3Martin-Luther-Universitaet, Inst. Makromol. Chemie, D-06099 Halle/S
Positron lifetime spectroscopy was used to study systematically the size variation of the local free volume v in branched polypropylene (metallocene- based copolymers with alpha-olefins from C4 to C16). It was found that Tg decreases and v increases linearly with the number and the length of branches. Both, Tg and v follow linear mastercurves as a function of the degree of branching DB. From measurements of the specific volume the fractional free volume and the number density of holes was estimated and correlated with the degree of branching.