Untersuchungen zur übermolekularen Struktur in Polybutylenterephthalat/Polycarbonat‐Blends

Abstract

ZUSAMMENFASSUNG:Zur Charakterisierung der iibermolekularen Struktur von schmelzegemischten Poly- butylenterephthalat(PBT)/Polycarbonat(PC)-Blends SUMMARY:Light-microscopic, X-ray and calorimetric investigations were carried out to characterize the morphology of melt-mixed poly(buty1ene terephthalate)(PBT)/polycarbonate(PC)-blends. A completely spherulitic structure up to a concentration of about 20 wt.-% PC was found by polarizing microscopy. A second separate, amorphous phase appears at higher PC concentrations. By differential scanning calorimetry, a shift of the glass transition temperature of PBT as well as PC, a slight melting point depression of the crystalline PBT-phase and different crystallization temperatures depending on the concentration of the pure components were measured. Wide-angle X-ray studies and additional density measurements gave reason to believe that the crystallinity of PBT in the blend is decreasing and that there is a possibility of crystallization of PC, particularly by a thermal post-treatment.* Korrespondenzautor.

Investigations of the equilibrium melting temperature in PBT and PC/PBT blends

“…The error AT,,,,o = ( Tm,o( meas.) -T,,,,o) due to the thermal resistance between the heater and sample pan was experimentally determined a t different heating rates (6 was varied from 10 up to 60 K /min ) to be AT,,,,o = 0.049 * ( 7 ) with p in K/min. Reorganization during the heating scan, which is not negligible, even at 50 K/min, affects the determination of T,,,,o ( meas.)…”