Alternating Ethylene−Styrene Copolymerization with a Methylaluminoxane-Free Half-Titanocene Catalyst

Pellecchia, Claudio; Pappalardo, Daniela; D'arco, M.; Zambelli, Adolfo

doi:10.1021/ma951152v

Cited by 105 publications

(96 citation statements)

References 22 publications

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“…4) give the values of 9 and 0.04, respectively. The value of r E ϫ r S Ϸ 0.4 reflects the alternating comonomers incorporation being in accord with data by Kakugo et al, 13 Zambelli et al, 31 and Oliva et al 42,43 reported for E/S copolymerization catalyzed with MAO-treated mono-Cp titanium complexes and ansazirconocenes. Contradictory, random comonomer incorporation catalyzed with MAO-treated chelatelike titanium complexes was communicated elsewhere.…”

Section: Resultssupporting

confidence: 91%

“…Hence, half-sandwich titanium catalysts (producing sPS) in E/S feed gave rise to a number of products (such as polyethylenes (PE), sPS, and alternating E/S copolymers) that are dependent on polymerization conditions. 14,31 Common behavior was observed for chelatelike titanium complexes, 29,30 binuclear half-sandwich, and biscyclopentadienyll derivatives. 32 Thus, active sites originated under action of cocatalysts (MAO, perfluorophenyl borane, or borates) on mono-Cp titanium complexes, producing sPS, were Ti(III) species.…”

Section: Introductionmentioning

confidence: 95%

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Catalytic systems Me2SiCp*NtBuMX2/(CPh3)(B(C6F5)4) (M?Ti, X?CH3, M?Zr, X?iBu) in copolymerization of ethylene with styrene

Sukhova

Панин

Babkina

et al. 1999

J. Polym. Sci. A Polym. Chem.

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Catalytic activity of Me2SiCp*NtBuMX2/(CPh3)(B(C6F5)4) [MTi, XCH3 (1); MZr, X=iBu (2)] systems in the ethylene/styrene (E/S) feed was examined. Experimental data revealed high activity for the catalytic system (1) for copolymerization ethylene with styrene, whereas the system with enhanced catalytic activity for ethylene homopolymerization (2) was temporarily blocked in the styrene presence yielding, even at high styrene content, homopolyethylene as the final product. Properties of thus obtained polymers were analyzed. Catalytic system (1) occurred very sensitive to S/E ratio in the comonomers feed. The 10‐fold acceleration for ethylene consumption was shown in two experimental sets conducted at S/E = 1.3 ratio, 1 bar, and 7.5 bar ethylene pressure, respectively. The consequent enhancement in S/E ratio resulted in slowing down both ethylene consumption and catalyst deactivation rates. Atactic polystyrene was formed at high styrene content with the catalyst (1). Catalytic system (1) allowed design of products with the highest styrene content (20 mol %) at low ethylene pressure, moderate temperature, and high S/E ratio. The apparent activation energy estimated from the initial rates of ethylene consumption was 54.6 kJ/mol. Analysis of apparent reactivity factors (rE = 9 and rS = 0.04; rE × rS = 0.4) and 13C‐NMR copolymer spectra revealed an alternating tendency of the comonomers for active center incorporation. DSC measurements showed considerable decrease of melting points and crystallinity even for copolymers with low styrene content. The catalyst produced relatively high–molecular weight copolymers (140–150 kg/mol) even at 80°C. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1083–1093, 1999

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 95%

Catalytic systems Me2SiCp*NtBuMX2/(CPh3)(B(C6F5)4) (M?Ti, X?CH3, M?Zr, X?iBu) in copolymerization of ethylene with styrene

Sukhova

Панин

Babkina

et al. 1999

J. Polym. Sci. A Polym. Chem.

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“…Half-titanocenes, such as Cp*TiF 3 , Cp*Ti(OMe) 3 and (indenyl)TiCl 3 , are efficient catalyst precursors for syndiospecific styrene polymerization [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]; however, these catalyst precursors showed low activities in the copolymerization, and the resultant polymers were a mixture of polyethylene (PE), syndiotactic polystyrene (SPS) and the copolymer (E-S) [41][42][43][44][45]. As related examples, Cp*TiMe 3 exhibited catalytic activities for both ethylene polymerization and styrene polymerization in the presence of MAO or B(C 6 F 5 ) 3 , and the resultant polystyrene possessed both atactic (via a cationic mechanism) and syndiotactic (via a coordination insertion mechanism) stereoregularity; the ratios were dependent upon the polymerization temperature [46][47][48][49][50][51].…”

Section: Introductionmentioning

confidence: 99%

Half-Titanocenes Containing Anionic Ancillary Donor Ligands: Effective Catalyst Precursors for Ethylene/Styrene Copolymerization

Nomura

2013

Catalysts

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This review summarizes recent results for ethylene/styrene copolymerization using half-titanocenes containing anionic donor ligands, Cp'TiX 2 (Y) (X = halogen, alkyl; Y = aryloxo, ketimide etc.)-cocatalyst systems. The product composition, the styrene incorporation and microstructures in the resultant copolymers are highly influenced by the anionic donor employed. A methodology for an exclusive synthesis of the copolymers even under high temperature and high styrene concentrations has been introduced on the basis of a proposed catalytically-active species in this catalysis.

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“…One involves the syndiotactic copolymerization of styrene with a second monomer, particularly ethylene, to produce a styrene/olefin copolymer. 27,28 Another modification procedure involves the preparation of functionalized sPS polymers, such as sulfonated sPS, 29 acetylated sPS 30 and maleic anhydride-grafted sPS. 31 In addition, polymer blends also provide a way to modify sPS.…”

Section: Introductionmentioning

confidence: 99%

Exfoliated syndiotactic polystyrene-graft-poly(methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

Jaymand

2011

Polym J

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This study aims to explore an effective route for the graft copolymerization of methyl methacrylate (MMA) monomer onto syndiotactic polystyrene (sPS) using free-radical polymerization, and the effects of an organophilic montmorillonite on the final properties of graft copolymer samples. For this purpose, the chlorine groups of a-phenyl-chloro-acetylated sPS were converted to 9-decen-1-oxy groups by a substitution nucleophilic reaction in the presence of a solvent composed of 9-decen-1-ol moiety, sodium hydride (NaH) and dry N,N-dimethylformamide. The vinyl-terminated sPS multicenter macromonomer (VsPSM) obtained was used in free-radical copolymerization with MMA monomer in a heterogeneous process to yield a graft copolymer (sPS-graftpoly(methyl methacrylate) (sPS-g-PMMA)). The structure of VsPSM and sPS-g-PMMA were determined by 1 H nuclear magnetic resonance and Fourier transform infrared spectroscopy. Thereafter, organophilic MMT was obtained after being treated with hexadecyl trimethyl ammonium chloride salt by an ion-exchange process. Finally, the sPS-g-PMMA/MMT nanocomposite was prepared by a solution intercalation method. X-ray diffraction and transmission electron microscopy were used to confirm nanocomposite formation. It was found that the addition of only a small amount of organoclay (3 wt%) was enough to improve the thermal stabilities and properties of the nanocomposite. Polymer Journal (2011) 43, 901-908; doi:10.1038/pj.2011.79; published online 7 September 2011Keywords: free-radical polymerization; graft copolymer; macromonomer; montmorillonite; nanocomposite; poly(methyl methacrylate); syndiotactic polystyrene INTRODUCTION Nanocomposites are defined as materials in which the particle size of the dispersed phase is in the nanometer range in at least one dimension. Organic-inorganic hybrids based on layered inorganic compounds, such as clays and organic polymers, have been studied because of their exceptional properties, such as increased modulus, strength, reduced gas permeability and enhanced thermal stability. [1][2][3][4][5] The dispersion of the silicate layers in the polymer matrix is improved by replacing the metal cations in the clay (such as sodium MMT; Na + -MMT) with ions bearing an aliphatic chain to compatibilize the silicate. This compatibilization enhances the silicate's interaction with the polymer by enlarging the interlayer, and the compatibilized clay is known as an organoclay. [6][7][8][9] Although complete compatibility between the long aliphatic chain of the organic modifier and the polymer matrix may be desirable for better dispersion of the clay, it appears that the modification of the clay by the introduction of surfactants to obtain better compatibility is less important than the modification of the polymer matrix by the introduction of polar groups. Polymers containing polar groups capable of associative interactions, such as Lewis acid/base interactions or hydrogen bonding, lead to intercalation of polymer chains in the silicate layers. To improve the polarizability or hy...

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Alternating Ethylene−Styrene Copolymerization with a Methylaluminoxane-Free Half-Titanocene Catalyst

Cited by 105 publications

References 22 publications

Catalytic systems Me2SiCp*NtBuMX2/(CPh3)(B(C6F5)4) (M?Ti, X?CH3, M?Zr, X?iBu) in copolymerization of ethylene with styrene

Catalytic systems Me2SiCp*NtBuMX2/(CPh3)(B(C6F5)4) (M?Ti, X?CH3, M?Zr, X?iBu) in copolymerization of ethylene with styrene

Half-Titanocenes Containing Anionic Ancillary Donor Ligands: Effective Catalyst Precursors for Ethylene/Styrene Copolymerization

Exfoliated syndiotactic polystyrene-graft-poly(methyl methacrylate)/montmorillonite nanocomposite prepared by solvent blending

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