Ring Structure of Cyclic Poly(2-vinylpyridine) Proved by Pyrolysis−GC/MS

Ohtani, Hajime; Kotsuji, Hiroyuki; Momose, Hikaru; Matsushita, Yushu; Noda, Ichiro; Tsuge, Shin

doi:10.1021/ma981921l

Cited by 24 publications

(28 citation statements)

References 11 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%

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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%

“…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 matrix-assisted laser desorption/ionization timeof-flight (MALDI-TOF) mass spectrometry.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Cyclic Polystyrenes

Cho

Masuoka

Koguchi

et al. 2005

Polym J

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“…Many efforts have been devoted to synthesize and characterize cyclic polymers so far. 3,[18][19][20][21][22][23][24][25][26][27][28][29] The basic strategies preparing cyclic polymers are end-to-end ring closure reactions: coupling reaction between living polymers with functional groups on both ends and bifunctional linking agents 3,18,21,23,25 or intramolecular coupling reaction between chain ends of telechelic macromonomers. 26 It should be noted that cyclization products include undesired linear precursors, and dimmer and/or catanated polymers for both preparing methods.…”

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confidence: 99%

“…It is well-recognized that conventional NMR is useful to pursue chemical structure of junction point produced by cyclization reaction occurred and that matrix-assisted laser desorption/ ionization mass spectrometry (MALDI-MASS) was also applicable to analyze cyclic structures. 21,23 However, these methods are limited to a relatively low molecular weight polymer (< 10 k). Recently, liquid chromatography at the critical condition (LCCC) based on a combination of entropic and enthalpic separations has been also applied to separate a cyclic polymer from cyclic/linear mixture.…”

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confidence: 99%

Direct Observation of an Isolated Cyclic Sodium Poly(styrenesulfonate) Molecule by Atomic Force Microscopy

Kawaguchi

Nishu

Takano

et al. 2007

Polym J

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“…18 -21 Throughout these experimental studies, however, the direct evidence of cyclic structure was not shown; moreover, the purity of the cyclic molecules has not been determined quantitatively in most of the works. Among them, Ohtani et al have proved the cyclic structure directly by using poly͑2-vinylpyridine͒ with detectable junction point by pyrolysis gas chromatography/mass spectroscopy and determined the ring fraction, 16 while Lee et al determined the fractions of cyclic polystyrenes precisely by liquid chromatography at the critical condition method. 17 Takano et al have reported on preparation and characterization of cyclic polystyrenes with short poly ͑2-tert-butyl-butadiene͒ sequence and proposed a novel method to prove the purity of cyclic molecule, 21 while they also prepared polystyreneblock-polyisoprene cyclic copolymers with three different compositions and determined the purity of cyclic molecules included in the samples accurately.…”

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confidence: 99%

Chain elongation suppression of cyclic block copolymers in lamellar microphase-separated bulk

Matsushita

Iwata

Asari

et al. 2004

The Journal of Chemical Physics

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Chain elongation suppression of cyclic block copolymers in microphase-separated bulk was determined quantitatively. Solvent-cast and annealed films are confirmed to show alternating lamellar structure and their microdomain spacing D increases with increasing total molecular weight M according to the relationship D proportional, variant M0.59, which agrees quite consistently with the theoretically predicted power law, i.e., D proportional, variant M3/5. This result is in contrast to the well-established issue for linear block copolymers, where the relationship D proportional, variant M2/3 has been confirmed to hold both experimentally and theoretically. This means that chain elongation of each component block is suppressed considerably, owing to their looped conformation in strongly segregated bulk.

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Ring Structure of Cyclic Poly(2-vinylpyridine) Proved by Pyrolysis−GC/MS

Cited by 24 publications

References 11 publications

Preparation and Characterization of Cyclic Polystyrenes

Preparation and Characterization of Cyclic Polystyrenes

Direct Observation of an Isolated Cyclic Sodium Poly(styrenesulfonate) Molecule by Atomic Force Microscopy

Chain elongation suppression of cyclic block copolymers in lamellar microphase-separated bulk

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