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Glass transition phenomena in melt‐processed polystyrene/polypropylene blends
Author(s) -
Thirtha Vivek,
Lehman Richard,
Nosker Thomas
Publication year - 2005
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20387
Subject(s) - polypropylene , materials science , polystyrene , glass transition , composite material , polymer blend , polymer , amorphous solid , polymer chemistry , copolymer , chemistry , organic chemistry
Blends of an amorphous and a semi‐crystalline polymer—polystyrene and polypropylene, respectively—were prepared by melt processing in an extruder at 220°C. These polymers are known to be immiscible and the composite morphologies were characterized by electron microscopy and thermal analysis. Fine micron‐scale morphologies, ranging from 0.5 to 20 microns were observed. Thermal analysis and dynamic mechanical analysis showed changes in both the polystyrene and polypropylene glass transition temperatures ( T g ) over the composition range. The major effect was a sharp increase in polystyrene T g with increasing polypropylene content in the blend. A T g elevation of 5.5°C was observed at 85% polypropylene. The polypropylene T g also increases with increasing polypropylene content, starting at a depressed value in discrete polypropylene domain environments and approaching the bulk polypropylene value after the phase inversion is crossed. Qualitative structural models are proposed based on spatial and mechanical interactions between the components. POLYM. ENG. SCI., 45:1187–1193, 2005. © 2005 Society of Plastics Engineers