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Polymerization of styrene to isotactic polymer with MAO‐Ni(acac) 2 . Examination of the factors that influence activity and stereospecificity
Author(s) -
Crossetti Geraldo Lopes,
Bormioli Carlotta,
Ripa Alberto,
Giarrusso Antonino,
Porri Lido
Publication year - 1997
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1997.030180908
Subject(s) - methylaluminoxane , tacticity , stereospecificity , polystyrene , materials science , yield (engineering) , polymer chemistry , polymer , polymerization , styrene , catalysis , metallocene , copolymer , organic chemistry , chemistry , composite material
The soluble catalyst system methylaluminoxane (MAO)‐Ni(acac), (acac: acetylacetonate) gives polystyrene consisting of an amorphous (aPS) and a crystalline isotactic (ips) fraction. Al(CH 3 ) 3 , which is always present in commercial samples of MAO, decreases both polymer yield and stereospecificity. The polymer yield increases with increasing the MAO/Ni ratio but, at the same time, the iPS/aPS ratio decreases. Addition of N(C 2 H 5 ) 3 (mole ratio N/Ni = 1) increases the proportion of the isotactic fraction, while it decreases the polymer yield. A tentative interpretation of the stereospecificity is reported.