High-temperature ethylene/?-olefin copolymerization with a zirconocene catalyst: Effects of the zirconocene ligand and polymerization conditions on copolymerization behavior

Hasegawa, Saiki; Sone, Makoto; Tanabiki, Masao; Sato, Morihiko; Yano, Akihiro

doi:10.1002/1099-0518(200012)38:1+<4641::aid-pola30>3.0.co;2-o

Cited by 8 publications

(7 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The simulated individual patterns, and overall simulated spectra in comparison with the experimental ones (vide infra), are shown in Figures and (for the 1 H and the 1 H{ 1 H} experiment, respectively). In line with the previous literature, , distinctive ranges of 1 H chemical shift could be associated with the various structural types present, namely (from low to high field): vinylenes (RHCCHR‘), 5.5−5.1 ppm; trisubstituted olefins (RHCCR‘R‘ ‘), 5.2−4.9 ppm; vinyls (CH 2 CHR), 5.0−4.8 ppm; vinylidenes (CH 2 CRR‘), 4.8−4.6 ppm. In the following paragraphs, we discuss in more detail the spectral patterns observed for each range.…”

Section: Resultssupporting

confidence: 90%

“…In the 5.41−5.36 ppm range, other multiplets are partially overlapped with the triplet of Vy1- trans , which in the TOCSY map show cross-peaks with two doublets at 1.59 ppm ( J = 6.7 Hz) and 1.63 ppm ( J ∼ 7 Hz), a region typical of resonances from methyls α to a double bond. , Therefore, we assigned the said signals to Vy2 structures; in particular, based on the literature,12a the methyl at 1.63 ppm was attributed to Vy2- trans and that at 1.59 ppm to Vy2- cis . Selective irradiation of the allylic methylenes led to a partial simplification of the multiplets, as expected.…”

Section: Resultsmentioning

confidence: 98%

See 1 more Smart Citation

H NMR Analysis of Chain Unsaturations in Ethene/1-Octene Copolymers Prepared with Metallocene Catalysts at High Temperature

et al. 2005

View full text Add to dashboard Cite

In this paper, we report the full resonance assignments in the olefinic region of the 600 MHz 1H NMR spectra of a typical ethene/1-octene copolymer (4.0 mol % of octene units) produced with a metallocene catalyst at high temperature, and of an ethene homopolymer prepared under similar conditions for comparison. The assignments were based on a thorough analysis of 1D (1H, 1H{1H}, 13C) spectra and of 2D 1H−1H (COSY, TOCSY) and 1H−13C (HSQC, DEPT-HSQC) maps. Thirteen different olefinic structures were identified, and their formation explained in terms of plausible mechanistic paths associated with the high polymerization temperature. The fraction of internal chain unsaturations traceable to allylic activation turned out to be comparable to that of terminal ones in both samples. Despite its complexity, the said spectral region is now amenable to deconvolution and full simulation in terms of known and recognizable patterns, and usable for fast (possibly on-line) measurements of chain unsaturation degree, as well as for catalyst “fingerprinting” studies.

show abstract

Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 98%

H NMR Analysis of Chain Unsaturations in Ethene/1-Octene Copolymers Prepared with Metallocene Catalysts at High Temperature

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Methylaluminoxane (MAO) is the most widely used cocatalyst in metallocene catalysis,1, 2 and its role in olefin polymerization has been extensively investigated 3–8. However, contradictory results have been obtained with different metallocenes and polymerization conditions.…”

Section: Introductionmentioning

confidence: 99%

Possible effects on the polyethene chain structure of trimethylaluminum coordination to zirconocene catalysts

Liu

Støvneng

Rytter

2001

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

Ethene was polymerized with the catalytic systems L2ZrCl2/MAO/TMA (where L = Cp, Me5Cp, or Me4Cp; Cp = η5‐cyclopentadienyl; MAO = methylaluminoxane; and TMA = trimethylaluminum) at 60 °C, 2 bar, and AlTMA/Zr ratios of 0–2700. The polymerization activity was reduced with the addition of TMA for L = Cp but was almost unaffected for the methyl‐substituted catalysts. Increasing the TMA concentration resulted in a lower molecular weight of the polymer, with the largest effect for L = Me5Cp. A gel permeation chromatography analysis of the polymers revealed a high molecular weight shoulder and a nearly bimodal distribution for L = Me5Cp at high TMA concentrations. A possible explanation of such a shoulder in terms of long‐chain branching was ruled out by dynamic viscosity measurements. The origin of this effect more likely stemmed from competition between chain transfer to aluminum and β‐hydrogen transfer reactions at two different sites, one TMA‐sensitive and one TMA‐insensitive. Polymerizations at various pressures and temperatures substantiated this assumption. A clue to the underlying mechanism came from investigations of chain transfer to TMA studied with density functional calculations. Complexation of Me3Al to Zr was much stronger for L = Cp than for L = Me5Cp. However, the overall chain‐transfer barrier was much higher for L = Cp. These results agreed both with the reduced activity for L = Cp and with the strongly reduced molecular weight for L = Me5Cp observed with the addition of TMA. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3566–3577, 2001

show abstract

“…Catalyst (1) was first prepared by Shiomura et al, [8] later by Alt and Zenk, [9] and tested in bulk polymerization of propene only. Furthermore, it was tested in ethene polymerization and copolymerization of ethene and butene or hexene, [10][11][12] while its behavior in propene polymerization was examined in detail by Hopf and Müller. [13][14][15] Catalyst (3) was prepared by Okuda [16] and examined in ethene/norbornene copolymerization by McKnight [17] and Tran.…”

Section: Introductionmentioning

confidence: 99%

Tailored Branched Polyolefins by Metallocene Catalysis

Kaminsky

Hoff

Derlin

2007

Macro Chemistry & Physics

View full text Add to dashboard Cite

Metallocene/methylaluminoxane catalysts are able to design copolymers with tailored architectures. It is possible to copolymerize ethene with higher α‐olefins and cyclic olefins. The terpolymer of ethene/1‐hexene/norbornene shows a better flexibility than the ethene/norbornene copolymer by a similar high transparency. The influence of the comonomer concentration on activity, molecular weight, and glass transition temperature is given as well as the comparison to 1‐hexene/norbornene and propene/norbornene copolymers. Hexene/norbornene copolymers were found to have a predominant alternating microstructure.

show abstract

High-temperature ethylene/?-olefin copolymerization with a zirconocene catalyst: Effects of the zirconocene ligand and polymerization conditions on copolymerization behavior

Cited by 8 publications

References 24 publications

H NMR Analysis of Chain Unsaturations in Ethene/1-Octene Copolymers Prepared with Metallocene Catalysts at High Temperature

H NMR Analysis of Chain Unsaturations in Ethene/1-Octene Copolymers Prepared with Metallocene Catalysts at High Temperature

Possible effects on the polyethene chain structure of trimethylaluminum coordination to zirconocene catalysts

Tailored Branched Polyolefins by Metallocene Catalysis

Contact Info

Product

Resources

About