記述言語：英語   出版者・発行元：Elsevier BV  

The crystal structure of isotactic poly(2-vinylpyridine) (iP2VP) established in 1977 by Puterman et al. is shown to conform to a recently proposed frustrated packing scheme which involves three isochiral three-fold helices packed in a trigonal unit-cell, and observed in a number of polymers and biopolymers. Single crystals of iP2VP grown from thin films at high temperature (Tc ≈ 200°C) display highly unusual morphologies with six (100) growth sectors but a three-fold overall symmetry apparent through different lamellar thicknesses in adjacent growth sectors, and oblique growth facets of three of the sectors. These features are morphological manifestations of the frustration of the helix packing, and support the P31 or P32 space group of the unit-cell. The different lamellar thicknesses are mainly due to an isothermal thickening process, which has different impacts depending on the nature of the growth faces. Analysis of the growth features of frustrated structures can be of help when dealing with finer details of theories of polymer crystal growth. © 1998 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0032-3861(98)00220-1

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DOI： 10.1016/S0032-3861(98)00220-1

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DOI： 10.1002/(SICI)1097-4628(19990808)73:6<961::AID-APP13>3.0.CO;2-C

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記述言語：英語   出版者・発行元：John Wiley &amp; Sons Inc  

The facilitated transport of ethyl docosahexaenoate (DHA-Et) through the thin solution-cast perfluorosulfonated ionomer membranes has been studied. The carrier of DHA-Et was silver ion and was immobilized in the support ionomer membrane by electrostatic forces. In this system, the feed phase, membrane phase, and receiving phase had the same solvent. This system was already proved to be highly stable in our previous work. When ethanol/water (85/15) was used as the solvent, the DHA-Et permeance in the cast membrane was about four times higher than that in the commercial Nafion 117 membrane, due to the smaller membrane thickness. In the case of acetone solvent, a high selectivity of DHA-Et to ethyl oleate of 42 and a high facilitation factor of 153 were obtained. These membrane performances were superior to those of the Nafion 117 membrane. The effects of membrane preparation conditions, such as annealing temperature and kinds of polar solvents added to the ionomer solution before annealing, on the membrane performance was investigated in detail. Furthermore, small-angle X-ray scattering (SAXS) measurement was carried out to study the membrane structure. The experimental result suggests higher crystallinity in the cast membrane annealed at higher temperature.

DOI： 10.1002/(SICI)1097-4628(19990808)73:6<961::AID-APP13>3.0.CO;2-C

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記述言語：英語   出版者・発行元：John Wiley &amp; Sons Inc  

The facilitated transport of ethyl docosahexaenoate (DHA-Et) through the thin solution-cast perfluorosulfonated ionomer membranes has been studied. The carrier of DHA-Et was silver ion and was immobilized in the support ionomer membrane by electrostatic forces. In this system, the feed phase, membrane phase, and receiving phase had the same solvent. This system was already proved to be highly stable in our previous work. When ethanol/water (85/15) was used as the solvent, the DHA-Et permeance in the cast membrane was about four times higher than that in the commercial Nafion 117 membrane, due to the smaller membrane thickness. In the case of acetone solvent, a high selectivity of DHA-Et to ethyl oleate of 42 and a high facilitation factor of 153 were obtained. These membrane performances were superior to those of the Nafion 117 membrane. The effects of membrane preparation conditions, such as annealing temperature and kinds of polar solvents added to the ionomer solution before annealing, on the membrane performance was investigated in detail. Furthermore, small-angle X-ray scattering (SAXS) measurement was carried out to study the membrane structure. The experimental result suggests higher crystallinity in the cast membrane annealed at higher temperature.

DOI： 10.1002/(SICI)1097-4628(19990808)73:6<961::AID-APP13>3.0.CO;2-C

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記述言語：英語  

DOI： 10.1021/ma9719059

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記述言語：英語   出版者・発行元：American Chemical Society  

The crystal structure of syndiotactic polystyrene (sPS) in its stable α form (a so-called "superstructure" named α″) is reevaluated. As shown by all previous investigations, the trigonal unit cell contains three triplets of extended sPS chains. The azimuthal orientation of the three triplets is shown to differ from those assumed so far, which generates a clear-cut example of frustrated packing. The azimuthal settings and relative shifts of the triplets indicate that two triplets maximize their interactions, while the third one interacts less favorably with its neighbors. This frustrated packing scheme fully justifies the three-triplets unit cell and constitutes an interesting variant of related frustrated packings previously described for isochiral three-fold helices.

DOI： 10.1021/ma9719059

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記述言語：英語   出版者・発行元：American Chemical Society  

The crystallographic origins leading to the formation of polymer single crystals with highly unusual triangular shapes are analyzed. Triangular crystals are obtained: (a) for stereocomplexes of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) crystallizing in a trigonal unit cell with A3c (or A-3c) symmetry. In this case, the triangular morphology results from the different molecular characteristics (mainly molecular weight) of the stereoisomer polymers used to form the complex, which in turn introduce different rates of deposition on opposite sides of the (110) crystallographic growth plane and therefore to the triangular morphology. A contrario, when molecularly (near) identical stereoisomers are used in equal concentrations, or when an (achiral) homopolymer crystallizing in the same crystal structure is used, the growth rates are equal and hexagonal crystals are formed (b) for some multiple twins, in particular triple growth twins of PLLA in its α form (c) for frustrated trigonal polymer crystal structures, in which different nucleation sites exist on opposite sides of a given growth plane. This difference in growth rates results from a genuine lack of symmetry of the crystal structure: triangular crystals are a morphological marker of the frustrated character of the packing in the unit cell. Further consequences of this frustration, such as differences in lamellar thicknesses for nominally equivalent growth sectors, shed new light on the details of nucleation and growth theories of polymer single crystals.

DOI： 10.1021/ma9707998

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記述言語：英語   出版者・発行元：American Chemical Society  

The crystallographic origins leading to the formation of polymer single crystals with highly unusual triangular shapes are analyzed. Triangular crystals are obtained: (a) for stereocomplexes of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) crystallizing in a trigonal unit cell with A3c (or A-3c) symmetry. In this case, the triangular morphology results from the different molecular characteristics (mainly molecular weight) of the stereoisomer polymers used to form the complex, which in turn introduce different rates of deposition on opposite sides of the (110) crystallographic growth plane and therefore to the triangular morphology. A contrario, when molecularly (near) identical stereoisomers are used in equal concentrations, or when an (achiral) homopolymer crystallizing in the same crystal structure is used, the growth rates are equal and hexagonal crystals are formed (b) for some multiple twins, in particular triple growth twins of PLLA in its α form (c) for frustrated trigonal polymer crystal structures, in which different nucleation sites exist on opposite sides of a given growth plane. This difference in growth rates results from a genuine lack of symmetry of the crystal structure: triangular crystals are a morphological marker of the frustrated character of the packing in the unit cell. Further consequences of this frustration, such as differences in lamellar thicknesses for nominally equivalent growth sectors, shed new light on the details of nucleation and growth theories of polymer single crystals.

DOI： 10.1021/ma9707998

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記述言語：英語  

Isotactic polypropylene (iPP) was crystallized from solution on a uniaxially‐oriented iPP film. Small‐angle x‐ray scattering patterns obtained from the sample showed two perpendicularly crossed lameliae 9.3 nm thick that overgrew flat‐on and edge‐on on the substrate. In the through wide‐angel x‐ray diffraction pattern (taken with incident x‐rays normal to the iPP film surface), strong hkO reflections were arranged in an hkO net pattern indicating that the a‐axis of the monoclinic α unit cell was oriented parallel to the chain direction of the substrate. From this, it was concluded that the flat‐on lamellae grew with the a‐axis parallel to the chain axis of the substrate and with the b‐axis parallel to its surface. In the edge wide‐angle x‐ray diffraction pattern (X‐rays incident on the edge of the film), arced, strong 110 and 220 reflections from overgrown crystals were observed on the equator of the fiber pattern of the substrate. This indicated that the edge‐on lamellae epitaxially grew with the c‐axis aligned parallel to the chain axis of the substrate. The homoepitaxy explains the correlated growth mode between the orthogonally crossed lamellae: they grew epitaxially, the a‐axis of one lamella coinciding with the c‐axis of the other and the {010} planes in contact. © 1993 John Wiley &amp
Sons, Inc. Copyright © 1993 John Wiley &amp
Sons, Inc.

DOI： 10.1002/polb.1993.090310712

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記述言語：英語  

Isotactic polypropylene (iPP) was crystallized from solution on a uniaxially‐oriented iPP film. Small‐angle x‐ray scattering patterns obtained from the sample showed two perpendicularly crossed lameliae 9.3 nm thick that overgrew flat‐on and edge‐on on the substrate. In the through wide‐angel x‐ray diffraction pattern (taken with incident x‐rays normal to the iPP film surface), strong hkO reflections were arranged in an hkO net pattern indicating that the a‐axis of the monoclinic α unit cell was oriented parallel to the chain direction of the substrate. From this, it was concluded that the flat‐on lamellae grew with the a‐axis parallel to the chain axis of the substrate and with the b‐axis parallel to its surface. In the edge wide‐angle x‐ray diffraction pattern (X‐rays incident on the edge of the film), arced, strong 110 and 220 reflections from overgrown crystals were observed on the equator of the fiber pattern of the substrate. This indicated that the edge‐on lamellae epitaxially grew with the c‐axis aligned parallel to the chain axis of the substrate. The homoepitaxy explains the correlated growth mode between the orthogonally crossed lamellae: they grew epitaxially, the a‐axis of one lamella coinciding with the c‐axis of the other and the {010} planes in contact. © 1993 John Wiley &amp
Sons, Inc. Copyright © 1993 John Wiley &amp
Sons, Inc.

DOI： 10.1002/polb.1993.090310712

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記述言語：英語  

An equimolar mixture of poly (L-lactide) and poly(D-lactide) was crystallized into a stereocomplex whose crystal system is triclinic (P1) with cell dimensions: a = 0.916 nm, b = 0.916 mm, c (chain axis) = 0.870 nm, a = 109.2°, β = 109.2°, and y = 109.8°. In the unit cell, a poly(L-lactide) segment and a poly (D-lactide) segment are contained as a pair and packed laterally in parallel fashion. The L- and D-poly(Iactides) in the complex take a 31helical conformation, which is a little extended from a 103 helix in the homopolymer crystal with the α-form. Homopolymers are also able to take the 31helical conformation and form the β-form crystal. The 31helix in the homopolymer crystal is less stable than the 103one, and hence the β-form is easily transformed to the a-form by annealing. © 1991, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1080/00222349108245788

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記述言語：英語  

An equimolar mixture of poly (L-lactide) and poly(D-lactide) was crystallized into a stereocomplex whose crystal system is triclinic (P1) with cell dimensions: a = 0.916 nm, b = 0.916 mm, c (chain axis) = 0.870 nm, a = 109.2°, β = 109.2°, and y = 109.8°. In the unit cell, a poly(L-lactide) segment and a poly (D-lactide) segment are contained as a pair and packed laterally in parallel fashion. The L- and D-poly(Iactides) in the complex take a 31helical conformation, which is a little extended from a 103 helix in the homopolymer crystal with the α-form. Homopolymers are also able to take the 31helical conformation and form the β-form crystal. The 31helix in the homopolymer crystal is less stable than the 103one, and hence the β-form is easily transformed to the a-form by annealing. © 1991, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1080/00222349108245788

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記述言語：英語  

Oriented polyethylene (PE) films with surfaces bounded by the (100) plane were prepared. On the film surfaces, isotactic polypropylene (iPP) was crystallized epitaxially from solution as quadrits with their sides parallel and perpendicular to the polyethylene chain axis. In the through wide‐angle x‐ray diffraction pattern (taken with incident x‐rays normal to the polyethylene film surface), the 111 iPP reflections was observed on the meridian (Parallel to the polyethylene chain axis). In the edge patterns (taken with x‐rays incident on the edge of the polyethylene film), 040 and 060 reflections were observed on the equator. From the diffraction patterns, the following lattice coincidence was observed between polyethylene and isotactic polypropylene: (010)iPP//(100) PE, [101]iPP//[001] PE. The Small‐angle x‐ray scattering patterns showed that edge‐on isotactic polypropylene lamellae 9 nm thick were arranged with their long axes inclined at an angle of 40° from the polyethylene axis. Molecular chains were oriented within the lamellae normal to the surfaces. Copyright © 1991 John Wiley &amp
Sons, Inc.

DOI： 10.1002/polb.1991.090290606

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記述言語：英語  

Oriented polyethylene (PE) films with surfaces bounded by the (100) plane were prepared. On the film surfaces, isotactic polypropylene (iPP) was crystallized epitaxially from solution as quadrits with their sides parallel and perpendicular to the polyethylene chain axis. In the through wide‐angle x‐ray diffraction pattern (taken with incident x‐rays normal to the polyethylene film surface), the 111 iPP reflections was observed on the meridian (Parallel to the polyethylene chain axis). In the edge patterns (taken with x‐rays incident on the edge of the polyethylene film), 040 and 060 reflections were observed on the equator. From the diffraction patterns, the following lattice coincidence was observed between polyethylene and isotactic polypropylene: (010)iPP//(100) PE, [101]iPP//[001] PE. The Small‐angle x‐ray scattering patterns showed that edge‐on isotactic polypropylene lamellae 9 nm thick were arranged with their long axes inclined at an angle of 40° from the polyethylene axis. Molecular chains were oriented within the lamellae normal to the surfaces. Copyright © 1991 John Wiley &amp
Sons, Inc.

DOI： 10.1002/polb.1991.090290606

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記述言語：英語  

n-Paraffins of n-C20H42 to n-C50 H102 were epitaxially crystallized on oriented polyolefins
polyethylene, polypropylene, poly-1-butene and poly-4-methyl-1-pentene. In most cases, n-paraffin crystals were epitaxially grown on the substrate surface with the (001) basal plane parallel to it, maintaining a two-dimensional lattice coincidence with the polymer substrate. The epitaxial modes with this orientation were classified into the following three types irrespective of the polymers: 1. (1) (001)p{norm of matrix}SS, 〈110〉p{norm of matrix}FA, 2. (2) (001)p{norm of matrix}SS, [010]p{norm of matrix}FA, 3. (3) (001)p{norm of matrix}SS, 〈110〉 p $ ̊ $ ̌gaFA, where p, SS and FA denote n-paraffin crystals, substrate surface and fiber axis of the polymers, respectively. The angle α depends on the kind of polymer substrate. n-Paraffins longer than n-C40H82 were laid down in parallel on the polypropylene substrate with their axes at a 46° angle with respect to the substrate fiber axis. © 1989.

DOI： 10.1016/0022-0248(89)90118-8

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記述言語：英語  

n-Paraffins of n-C20H42 to n-C50 H102 were epitaxially crystallized on oriented polyolefins
polyethylene, polypropylene, poly-1-butene and poly-4-methyl-1-pentene. In most cases, n-paraffin crystals were epitaxially grown on the substrate surface with the (001) basal plane parallel to it, maintaining a two-dimensional lattice coincidence with the polymer substrate. The epitaxial modes with this orientation were classified into the following three types irrespective of the polymers: 1. (1) (001)p{norm of matrix}SS, 〈110〉p{norm of matrix}FA, 2. (2) (001)p{norm of matrix}SS, [010]p{norm of matrix}FA, 3. (3) (001)p{norm of matrix}SS, 〈110〉 p $ ̊ $ ̌gaFA, where p, SS and FA denote n-paraffin crystals, substrate surface and fiber axis of the polymers, respectively. The angle α depends on the kind of polymer substrate. n-Paraffins longer than n-C40H82 were laid down in parallel on the polypropylene substrate with their axes at a 46° angle with respect to the substrate fiber axis. © 1989.

DOI： 10.1016/0022-0248(89)90118-8

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開催年月日： 2021年6月24日 - 2021年6月25日

記述言語：日本語   会議種別：ポスター発表  

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P41A

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P10B

開催年月日： 2021年6月16日 - 2021年6月17日

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P-17

開催年月日： 2021年5月26日 - 2021年5月28日

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3Pc073

開催年月日： 2021年5月26日 - 2021年5月28日

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2Pe045

開催年月日： 2021年5月26日 - 2021年5月28日

記述言語：日本語   会議種別：ポスター発表  

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2Pe077