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Effect of composition and component structure on thermal behavior and miscibility of polypropylene catalloys
Author(s) -
Shangguan Yonggang,
Tao Liyang,
Zheng Qiang
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.26501
Subject(s) - electron paramagnetic resonance , miscibility , polypropylene , ethylene propylene rubber , tacticity , glass transition , polymer chemistry , materials science , copolymer , chemical engineering , analytical chemistry (journal) , chemistry , polymer , composite material , organic chemistry , nuclear magnetic resonance , polymerization , physics , engineering
The thermal behavior and the miscibility of an in‐situ polypropylene blend named polypropylene catalloys (PP‐cats) were investigated by using modulated differential scanning calorimeter (MDSC). It is found that all PP‐cats samples present two glass transitions, one of which is ascribed to the ethylene‐propylene random copolymer (EPR), and the other, to isotactic polypropylene (PP). However, no glass transition of ethylene‐propylene block copolymer (E‐ b ‐P) responsible for a third component in PP‐cats could be found. With the increase of EPR, the glass transition temperatures responding to PP and EPR components, T g , PP and T g , EPR , shift to low temperature, because of the enhancement of the interaction between PP and EPR component and the increase of ethylene content in EPR, respectively. Furthermore, the difference between T g , PP and T g , EPR remarkably decreases with the increase of the total ethylene content in PP‐cats, which indicates that the miscibility of PP‐cats is strongly dependent on the composition. Comparing the T g , PP and T g , EPR with T g of fractionated PP and EPR, we ascribe the T g change of PP fraction to the increase of EPR content; while that of EPR, to the increase of ethylene content in EPR. These experimental results suggest that the existence of E‐ b ‐P plays an important role in improving the miscibility between propylene homopolymer and EPR in PP‐cats. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007