We describe the synthesis of a styrene-ethylene copolymer using a trivalent titanium-based polymerization catalyst system, tris(acetylacetonate)titanium (Ti(acac) 3 ), combined with triisobutylaluminum-modified methylaluminoxane. Gel-permeation chromatography measurement revealed that copolymerization using the above-mentioned catalyst system yielded a mixture of two different polymers. 13 C nuclear magnetic resonance (NMR) analysis of the Soxhlet-extracted fractions indicated that the insoluble part contained a long ethylene-ethylene sequence and an isolated styrene unit, whereas the soluble part contained a syndiotactic styrene-styrene sequence with ethylene units adjacent to continuous styrene units. The ratio of the styrene-styrene sequence to the styrene-ethylene joint part of the Soxhlet-soluble fraction, estimated from the NMR resonances, increased with the styrene content. The melting temperature of the Soxhlet-soluble fraction also increased with the (styrene-styrene)/ (styrene-ethylene) ratio of the polymers. These two results together indicate that a block-like copolymer was produced that contained long syndiotactic polystyrene portions separated by ethylene units.
Copolymerizations of ethylene or propylene and allyl monomers containing 9‐fluorenyl group, diallyl‐di‐9‐fluorenylsilane (DAFS), 9,9‐diallylfluorene (DAF), and 9‐allylfluorene (AF), were investigated with various zirconocene catalysts using methylaluminoxane as a cocatalyst. The bridged zirconocene catalysts, especially a syndioselective catalyst, showed a higher reactivity for all the comonomers than the nonbridged catalysts. DAFS was mainly incorporated into the polymer chain via cyclization insertion, whereas DAF was copolymerized via both 1,2‐ and cyclization insertions. Cyclization selectivity, ratio of cyclized insertion unit, of DAF in the copolymerization with propylene was higher than that in the copolymerization with ethylene. Copolymerization with AF yielded low‐molecular weight copolymer because of frequent chain transfer reaction. Optical properties of the propylene based‐copolymers were investigated by UV‐vis and photoluminescence spectroscopy, and absorption‐ and emission‐derived from fluorenyl groups were detected in the copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3542–3552, 2010
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