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Styrene/substituted styrene copolymerization by Ph 2 Zn–metallocene–MAO systems: homo‐ and copolymerization of p ‐methoxystyrene with styrene
Author(s) -
Rabagliati Franco M,
Mardones Gabriela V,
Muñoz Héctor E,
Rodríguez Francisco J
Publication year - 2008
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2404
Subject(s) - styrene , copolymer , metallocene , polymer chemistry , polystyrene , materials science , post metallocene catalyst , methylaluminoxane , styrene butadiene , chemistry , polymerization , organic chemistry , polymer
BACKGROUND: The present work is part of a general study regarding the homo‐ and copolymerization of styrene using diphenylzinc–additive initiator systems, with the aim of improving the properties of commercial atactic polystyrene. The study is focused on syndiotactic polystyrene and/or copolymers of styrene (S) with substituted styrene, styrene derivatives or various α‐olefins. This research has been ongoing over the last 15 years. RESULTS: The reported experiments show that binary metallocene–methylaluminoxane (MAO) and ternary Ph 2 Zn–metallocene–MAO, depending on the metallocene employed, are capable of inducing both homo‐ and copolymerization of styrene and p ‐methoxystyrene ( p ‐MeOS). The results indicate that for a styrene/ p ‐MeOS mole ratio with p ‐MeOS > 25% the product obtained has only a minor incorporation of styrene units. The efficiency of the metallocenes studied follows the order bis( n ‐butylcyclopentadienyl)titanium dichloride (( n ‐BuCp) 2 TiCl 2 ) > indenyltitanium trichloride (IndTiCl 3 ) > Cp 2 TiCl 2 . CONCLUSION: Metallocenes ( n ‐BuCp) 2 TiCl 2 , Cp 2 TiCl 2 and IndTiCl 3 in binary systems combined with MAO, as well as in ternary systems combined with Ph 2 Zn and MAO, induce the homopolymerization of p ‐MeOS and its copolymerization with styrene. The styrene/ p ‐MeOS copolymer obtained was enriched in p ‐MeOS with respect to the initial feed, in agreement with the I+ inductive effect of the methoxy group in the para position of styrene. As already reported, the role of Ph 2 Zn was nullified by its complexation with the p ‐MeOS comonomer. Copyright © 2008 Society of Chemical Industry