Regensburg 2002 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 9: Blockcopolymere, Blends und Kompositmaterialien
CPP 9.1: Vortrag
Dienstag, 12. März 2002, 13:30–13:50, H38
Determination of the binodal and spinodal decomposition temperatures in the blend system Luran/Lucryl with positron annihilation lifetime spectroscopy — •Katja Günther-Schade1, Dirk W. Schubert2 und Franz Faupel1 — 1Lehrstuhl für Materialverbunde, Technische Fakultät der Universetät Kiel, 24143 Kiel — 2GKSS Forschungszentrum, Max-Planck-Str., 21502 Geesthachst, now at Freudenberg KG, Höhnerweg 2-4, 69465 Weinheim
Luran (P α MS_0,5-co-AN_0,5) is a statistical copolymer made up of equal parts of α methyl styrene and acrylonitrile. Lucryl is a MMA with 5 wt % MA. Luran and Lucryl form a blend system with upper miscibility gap (LCST), which is a subject of the IUPAC Working Party "Structure and Properties of Commercial Polymers".
Samples of different geometries, produced by hot pressing and solvent casting were investigated in-situ as a function of temperature and composition with PALS. At the binodal the samples show continious changes in the intensity of the longest lifetime. At the spinodal the changes are steplike. The separation temperatures from PALS are in good agreement with other experiments (morphology studies from TEM, optical cloud points, DSC) and theoretical calculations. However, PALS seems to be the first method which is able to detect directly both separation temperatures. In constrast to cloud point experiments the binodal with PALS could be detected at the very early stage. So the complete phase diagramm could be determined.