Characterization of the molecular structure of two highly isotactic polypropylenes

Viville, Pascal; Daoust, Daniel; Jonas, Alain M.; Nysten, Bernard; Legras, Roger; Dupire, Marc; Michel, Jacques C.; Debras, G.

doi:10.1016/s0032-3861(00)00529-2

Cited by 51 publications

(52 citation statements)

References 17 publications

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“…The isotacticity was [mm] ϭ 95.1% with ethylene content of 5.1 mol %, which was determined by 13 C-NMR. The preparative TREF equipment used in this work has been described before.…”

Section: Experimental Preparative Temperature Rising Elution Fractionmentioning

confidence: 99%

“…The injection volume was 200 L, and the flow rate was 1.0 mL/min. 13 WAXD experiments were carried out on powered samples at ambient temperature using a Rigaku D/max 2500V PC X-ray diffractometer. Nickel-filtered Cu K␣ 1 X-rays with wavelength of 0.154056 nm generated at 40 kV and 200 mA were employed.…”

Section: Characterization Of Tref Fractionsmentioning

confidence: 99%

“…[1][2][3] Gel permeation chromatography (GPC) has long been used to determine the molecular weight and molecular weight distribution of polymers. 13 C nuclear magnetic resonance spectroscopy ( 13 C-NMR) has been used to study the comonomer composition and sequence distribution of polyolefin copolymers. 4 In the present article we report on the intermolecular structural heterogeneity of a propylene-ethylene random copolymer characterized using preparative TREF combined with GPC and 13 C-NMR analysis of the obtained fractions.…”

Section: Introductionmentioning

confidence: 99%

“…13 C nuclear magnetic resonance spectroscopy ( 13 C-NMR) has been used to study the comonomer composition and sequence distribution of polyolefin copolymers. 4 In the present article we report on the intermolecular structural heterogeneity of a propylene-ethylene random copolymer characterized using preparative TREF combined with GPC and 13 C-NMR analysis of the obtained fractions. The TREF-GPC cross-fractionation technique provided detailed information on the intermolecular structural heterogeneity of the studied copolymer.…”

Section: Introductionmentioning

confidence: 99%

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Studies on the intermolecular structural heterogeneity of a propylene‐ethylene random copolymer using preparative temperature rising elution fractionation

Liu

Zhu

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:The intermolecular structural heterogeneity of a propylene-ethylene random copolymer was studied by preparative temperature rising elution fractionation combined with GPC, 13 C-NMR, differential scanning calorimetry, and wide-angle X-ray diffraction analysis of the obtained fractions. The isotacticity of fractions increased with increasing elution temperature, and the ethylene content decreased monotonously. Fitting of the obtained comonomer triad sequences by Bernoullian and first-order Markovian statistical models indicated that lower isospecific active sites are more active toward ethylene. The isolated ethylene unit disrupted the crystallizable isotactic sequence and lowered the crystallizability of the polypropylene chain.

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“…The isotacticity was [mm] ϭ 95.1% with ethylene content of 5.1 mol %, which was determined by 13 C-NMR. The preparative TREF equipment used in this work has been described before.…”

Section: Experimental Preparative Temperature Rising Elution Fractionmentioning

confidence: 99%

Section: Characterization Of Tref Fractionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Studies on the intermolecular structural heterogeneity of a propylene‐ethylene random copolymer using preparative temperature rising elution fractionation

Liu

Zhu

et al. 2005

J of Applied Polymer Sci

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“…The curves of D9, D8 and D7 polymers in Figure 3 The characterization results of the fractions for D9, D8 and D7 polymers are summarized in Table 3. Other researchers have clearly demonstrated that for polypropylene samples the TREF profiles qualitatively reflect the distribution of isotacticity, with isotacticity increasing almost linearly with the elution temperature (Kioka et al, 1994;Viville et al, 2001;Soares & Hamielec, 1996). Table 3 shows that D9, D8 and D7 polymers are composed of fractions with different tacticities, ranging from rather atactic (elution temperature 25 °C) to highly isotactic (elution temperature 100 °C).…”

Section: Transactionsmentioning

confidence: 80%

Fractionation and Crystallization of Isotactic Polypropylenes Prepared Using Homogenous Metallocene Catalyst

Mokrani¹,

Amer²,

Reenen³

2015

International Conference on Advances in Science, Engineering, Technology and Natural Resources (ICASETNR-15) Aug. 27-28, 2015 K

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A b s t r a c tA series of polypropylenes were prepared using rac-ethylene-bis (4,5,6,7-tetrahydro-1-indenyl) zirconium dichloride (Et(H4Ind) 2 ZrCl 2 (EI(4H)) as a homogeneous metallocene catalyst. The molecular weight of the polypropylene polymers was controlled using molecular hydrogen which was used as a transfer agent. To obtain materials with differing molecular weight and tacticities, polymers were fractionated with prep-TREF. Polypropylene polymers and fractions were fully characterized using various analytical techniques: differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), 13 C nuclear magnetic resonance spectroscopy ( 13 C-NMR) and high temperature gel permeation chromatography (HT-GPC). It was found that the addition of molecular hydrogen to propylene polymerizations catalyzed using EI(4H) catalyst system resulted in a reduction in polymer molecular weight and isotacticity. Furthermore, the molecular weight, the isotacticity and the degree of crystallinity of the TREF fractions increased significantly with increasing elution temperature for all samples. Also, only the  crystal form existed in all TREF fractions of different samples.

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Salalen Titanium Complexes in the Highly Isospecific Polymerization of 1‐Hexene and Propylene

et al. 2011

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Taktisch geschickt: C1‐symmetrische oktaedrisch koordinierte Titankomplexe (siehe Struktur; Ti dunkelgrau, N blau, O rot, I lila), deren labile Positionen sich in unterschiedlichen elektronischen Umgebungen befinden, wurden ausgehend von dem leicht verfügbaren Salalen‐Liganden entworfen. Mit Methylalumoxan als Cokatalysator resultierten hochaktive Katalysatoren, die hochmolekulares Polypropylen mit ultrahohen Isotaktizitäten (siehe 13C‐NMR‐Spektrum) und Schmelzübergängen lieferten.

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Characterization of the molecular structure of two highly isotactic polypropylenes

Cited by 51 publications

References 17 publications

Studies on the intermolecular structural heterogeneity of a propylene‐ethylene random copolymer using preparative temperature rising elution fractionation

Studies on the intermolecular structural heterogeneity of a propylene‐ethylene random copolymer using preparative temperature rising elution fractionation

Fractionation and Crystallization of Isotactic Polypropylenes Prepared Using Homogenous Metallocene Catalyst

Salalen Titanium Complexes in the Highly Isospecific Polymerization of 1‐Hexene and Propylene

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