Chain conformation of polyethylene in the solid state as studied by 13C cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy

Ando, Isao; Sorita, Tetsushi; Yamanobe, Takeshi; Kōmoto, Tadashi; Sato, Hisaya; Deguchi, K.; Imanari, Mamoru

doi:10.1016/0032-3861(85)90016-3

Cited by 52 publications

(23 citation statements)

References 23 publications

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“…Investigations of long-chain cycloalkanes by means of IR-spectroscopy [15,16], Raman spectroscopy [12,13,16] and NMR-spectroscopy [17,18] confirm the conformation of the fold in the monoclinic lattice and establish differences for the folds in the orthorhombic lattice. These methods contribute to the knowledge of conformation by evaluating the vibrations of small groups of atoms, made possible under conditions of mutual chain orientation, and by interpreting segmental motions.…”

Section: Introductionmentioning

confidence: 83%

Packing of long-chain cycloalkanes in various crystalline modifications: an electron diffraction investigation

Lieser

Lee

Wegner

1988

Colloid & Polymer Sci

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Abstract:The structure and thermal behavior of long-chain cycloalkanes (CH2) n with n = 48, 72, 96,144 and 288 have been investigated by electron diffraction, WAXS and SAXS analysis. Five different modifications have been characterized by their subcells as a function of ring size, crystallization conditions and temperature. The rings adopt, in all modifications, a conformation with two straight stems connected by folds. Similarity with the polyethylene lattice is achieved only for n > 144. In this case, the stems are perpendicular to the layer surface and pack in the well-known orthorhombic subcell regardless of whether the rings are crystallized from solution or melt. (CH2)96 forms the same type of subcell when crystallized from the melt, but the stems are oblique to the layer surface. Rings of all sizes undergo a transition into a phase in which the stems are arranged similarly as in the "rotator phase" of linear paraffins. (CH2)72 and (CH2)96 exhibit additional transitions at lower temperatures. One significant feature of some transitions is the change of conformation and length of the folds.

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Section: Introductionmentioning

confidence: 83%

Packing of long-chain cycloalkanes in various crystalline modifications: an electron diffraction investigation

Lieser

Lee

Wegner

1988

Colloid & Polymer Sci

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“…The monoclinic crystal structure shows a resonance at 34:4 ppm: The chemical shift of the resonance for the amorphous phase is determined by the g-gauche effect, which causes an upfield shift. According to the g-effect concept [30,31], the resonance of methylene carbons appears at higher field by 4-6 ppm if a carbon atom is situated three bonds away in a gauche, rather than trans, conformation. Therefore, if a chain unit, bearing the methylene carbons, undergoes rapid conformational transitions, the chemical shift of the corresponding methylene carbon appears at a higher field than in the trans-trans chain conformation in the crystalline phase.…”

Section: The Chemical Composition Of Phases In Previously Studied Pe mentioning

confidence: 99%

Partitioning of Main and Side-Chain Units between Different Phases: A Solid-State 13C NMR Inversion-Recovery Cross-Polarization Study on a Homogeneous, Metallocene-Based, Ethylene-1-Octene Copolymer

Litvinov

Mathot

2002

Solid State Nuclear Magnetic Resonance

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“…The methylene carbons in the amorphous phase undergo transitions between trans and gauche conformations, which causes an up-field shift of %4 ppm. [26] The narrow proton line on peak (3) (Figure 3a) is surprising at first sight, since peak (3) ordered methylene groups. However, it is understandable, if we attribute this feature to overlapping signal from the amorphous region.…”

Section: Mobility Of Different Components In the Alloymentioning

confidence: 99%

Solid‐State NMR Characterization of the Multiphase Structure of Polypropylene In‐reactor Alloy

Zhu

Graf

Hou

et al. 2010

Macro Chemistry & Physics

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A variety of solid‐state NMR techniques were used to characterize the chain dynamics, miscibility and the micro‐phase structure of a polypropylene (PP) in‐reactor alloy system. The alloy was physically separated into three fractions, and the molecular dynamics and relaxation behavior of the pure fractions was then compared with the components in the alloy to achieve comprehensive understanding of the phase structure of the PP in‐reactor alloy. The miscibility among different components of the alloy was studied by the rotational frame spin‐lattice relaxation time. Proton spin‐diffusion methods were used to quantify the domain thicknesses of different regions in the alloy. The results show that the alloy is composed of three phases, namely, a homo‐polyethylene (HPE) matrix, a homo‐polypropylene (HPP) dispersed phase, and a linear low‐density polyethylene (LLDPE) interphase. The thickness of the LLDPE interphase is estimated to be 7.7 nm at room temperature, and changes dramatically with temperature. Finally, based on all the solid‐state NMR results, a model for the micro‐phase‐structure of the PP in‐reactor alloy is proposed, and a correlation between the micro‐phase structure and the excellent mechanical property is established.magnified image

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Chain conformation of polyethylene in the solid state as studied by 13C cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy

Cited by 52 publications

References 23 publications

Packing of long-chain cycloalkanes in various crystalline modifications: an electron diffraction investigation

Packing of long-chain cycloalkanes in various crystalline modifications: an electron diffraction investigation

Partitioning of Main and Side-Chain Units between Different Phases: A Solid-State 13C NMR Inversion-Recovery Cross-Polarization Study on a Homogeneous, Metallocene-Based, Ethylene-1-Octene Copolymer

Solid‐State NMR Characterization of the Multiphase Structure of Polypropylene In‐reactor Alloy

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