Preparation and Morphology of Ring-Shaped Polystyrene-<i>b</i><i>lock</i>-polyisoprenes

Takano, Atsushi; Kadoi, Osamu; Hirahara, Kazuro; Kawahara, Seiichi; Isono, Yoshinobu; Suzuki, Jirô; Matsushita, Yushu

doi:10.1021/ma021357l

Cited by 76 publications

(81 citation statements)

References 23 publications

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“…The detailed synthetic procedure of I was followed by the same manners as reported by Hayashi et al, 36 and the purification of I was in the same ways as reported previously. 31,35,37 …”

Section: Methodsmentioning

confidence: 99%

“…After being freezedried, the telechelic polymers were transferred into vacuum glass apparatuses and then diluted with purified THF for subsequent cyclization reactions. 35,37 Excess amount of potassium naphthalenide, used as the linking agent, was introduced into THF solutions (0.05-0.2 (w/v)%) of the telechelic polymers at room temperature, and stirred for 1 d. The stoichiometry of the molar amount of end C=C groups on linear telechelic polymers and that of the lithium naphthalenide is [Li]/[C=C] ! 5.…”

Section: Preparation Of Cyclic Polystyrenesmentioning

confidence: 99%

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Preparation and Characterization of Cyclic Polystyrenes

Cho

Masuoka

Koguchi

et al. 2005

Polym J

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ABSTRACT:Macrocyclic polystyrenes with various molecular weight were prepared by the reaction of linear polystyrene having two end vinyl groups and potassium naphthalenide as a coupling agent. Intermolecular side reactions produced higher molecular weight polycondensates and undesirable chain termination reactions also produced linear precursors in addition to the designed molecules. In order to isolate cyclic polymers from the ring closure reaction mixtures, preparative size exclusion chromatography (SEC) method was employed. The purity of SEC-fractionated cyclic polystyrenes was rigorously examined by liquid chromatography at the critical condition (LCCC) and interaction chromatography (IC). After SEC-fractionation, we obtained large amount of highly pure cyclic polymers, though high molecular weight cyclic polymers contain very small amount of linear precursor (< 5%). The purity and isotope effect on reversed-phase liquid chromatography (RPLC) were also rigorously investigated by preparing a deuterated cyclic polystyrene. [DOI 10.1295/polymj.37.506] KEY WORDS Cyclic Polystyrene / GPC Fractionation / LCCC / Isotope Effect / Cyclic macromolecules are of great interest in the investigation of the influence of cyclization on their solution, melt, and solid-state properties. Various physical properties of cyclic polymers have been predicted not only by theoretical methods 1-4 but also by computer simulation studies, 5-7 while they have also been examined experimentally. [8][9][10][11][12][13][14] Cyclic polymers were usually synthesized by the coupling reaction between living precursor polymers with functional groups on both ends and bifunctional linking agents. For example, polystyrenes 9,15-19 and poly(2-vinylpyridine)s 20,21 have been synthesized by this method. Furthermore, , !-heterobifunctional polymers have been used for the synthesis of cyclic polymers.22-24 However, side reactions produce linear precursor polymers, and intermolecular reactions simultaneously produce dimeric and higher molecular weight linear polycondensates. Therefore, it is very difficult to obtain pure cyclic polymers directly, and fractionation is necessary in order to obtain cyclic polymers with high purity. For the isolation of cyclic polymers from the ring closure reaction mixtures, two major fractionation methods have been employed: fractional precipitation method 9,14,[16][17][18] and preparative size exclusion chromatography (SEC). 25,26 Furthermore, liquid chromatography at the critical condition method (LCCC) has been successfully applied for the characterization of cyclic polymers.27-30 Throughout these experimental studies, however, the direct evidence of cyclic structure was not shown, in addition to the fact that the purity of the cyclic molecules has not been determined quantitatively in most of the works. Only for the low molecular weight cyclic polymers, the detailed cyclic structures were directly confirmed by NMR analysis of linking points, 22,23 pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 31 and matri...

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“…The detailed synthetic procedure of I was followed by the same manners as reported by Hayashi et al, 36 and the purification of I was in the same ways as reported previously. 31,35,37 …”

Section: Methodsmentioning

confidence: 99%

Section: Preparation Of Cyclic Polystyrenesmentioning

confidence: 99%

Preparation and Characterization of Cyclic Polystyrenes

Cho

Masuoka

Koguchi

et al. 2005

Polym J

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Besides a simple ring construction, [15] there exist three dicyclic polymer topologies, [16] that is, eight-shaped, [17] y-shaped, [18,19] and manacle-shaped [18,20] constructions. Attempts to realize such unusual polymer topologies are an ongoing challenge in synthetic polymer chemistry.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Polymeric Topological Isomers through Electrostatic Self‐Assembly and Covalent Fixation with Star Telechelic Precursors

Tezuka¹,

Tsuchitani²,

Oike³

2004

Macromol. Rapid Commun.

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Summary: A pair of macromolecular constitutional isomers having topologically distinctive, dicyclic constructions, that is, θ‐shaped and manacle‐shaped polymers, has been synthesized from a polymer self‐assembly, comprised of three‐armed star poly(tetrahydrofuran) [poly(THF)] having N‐phenylpyrrolidinium salt end groups carrying dicarboxylate counteranions (1S/2d). The presence of the two constitutional polymeric isomers was confirmed by means of a reversed‐phase liquid chromatography (RPC) technique. Moreover, size exclusion chromatography (SEC) showed that a major component possesses notably larger hydrodynamic volume than the others, and is assignable as a manacle‐shaped isomer while a minor component is assigned as a θ‐shaped isomer. The statistics of the covalent‐linking process of 1S/2d were consistent with the other experimental results.An “electrostatic self‐assembly and covalent fixation” process of a trifunctional star‐shaped precursor gives rise to θ‐shaped and manacle‐shaped polymers.imageAn “electrostatic self‐assembly and covalent fixation” process of a trifunctional star‐shaped precursor gives rise to θ‐shaped and manacle‐shaped polymers.

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“…Other various copolymer systems, such as AB 2 graft copolymers [119][120][121], star-shaped molecules of the (AB) n type [122,123], (AB) n multiblock copolymer systems [124][125][126], AB ring-shaped copolymers [127,128], and ABC star-shaped terpolymers [129][130][131], were also widely studied.…”

Section: Bulk Morphologiesmentioning

confidence: 99%

Dynamic Assembly of Block-Copolymers

Quémener¹,

Deratani²,

Lecommandoux³

2011

Constitutional Dynamic Chemistry

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Block copolymers (BCs) are well-known building blocks for the creation of a large variety of nanostructured materials or objects through a dynamic assembly stage which can be either autonomous or guided by an external force. Today's nanotechnologies require sharp control of the overall architecture from the nanoscale to the macroscale. BCs enable this dynamic assembly through all the scales, from few aggregated polymer chains to large bulk polymer materials. Since the discovery of controlled methods to polymerize monomers with different functionalities, a broad diversity of BCs exists, giving rise to many different nanoobjects and nanostructured materials. This chapter will explore the potentialities of block copolymer chains to be assembled through dynamic interactions either in solution or in bulk.

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Preparation and Morphology of Ring-Shaped Polystyrene-block-polyisoprenes

Cited by 76 publications

References 23 publications

Preparation and Characterization of Cyclic Polystyrenes

Preparation and Characterization of Cyclic Polystyrenes

Synthesis of Polymeric Topological Isomers through Electrostatic Self‐Assembly and Covalent Fixation with Star Telechelic Precursors

Dynamic Assembly of Block-Copolymers

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