Hydrogen-bond-assisted syndiotactic-specific radical polymerizations of N-alkylacrylamides: The effect of the N-substituents on the stereospecif¡ cities and unusual large hysteresis in the phase-transition behavior of aqueous solution of syndiotactic poly(N-n-propylacrylamide)

Tomohiro Hirano, Kimihiko Nakamura, Takahiro Kamikubo, Satoshi Ishii, Kanami Tani, Takeshi Mori, Tsuneyuki Sato

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Abstract

The radical polymerizations of N-alkylacrylamides, such as N-methyl-(NMAAm), Ar-rc-propyl-(NNPAAm), N-benzyl-(NBnAAm), and N-(1-phenylethyl)acrylamides (NPhEAAm), at low temperatures were investigated in the absence or presence of hexamethylphosphoramide (HMPA) and 3-methyl-3-pentanol (3Me3PenOH), which induced the syndiotactic specificities in the radical polymerization of AT-isopropylacrylamide (NIPAAm). In the absence of the syndiotactic-specificity inducers, the syndiotacticities of the obtained polymers gradually increased as the bulkiness of the iV-substituents increased. Both HMPA and 3Me3PenOH induced the syndiotactic specificities in the NNPAAm polymerizations as well as in the NIPAAm polymerizations. The addition of 3Me3PenOH into the polymerizations of NMAAm significantly induced the syndiotactic specificities, whereas the tacticities of the obtained polymers were hardly affected by adding HMPA. In the polymerizations of bulkier monomers, such as NBnAAm and NPhEAAm, HMPA worked as the syndiotactic specificity inducer at higher temperatures, whereas 3Me3PenOH hardly influenced the stereospecificity, regardless of the temperatures. The phase-transition behaviors of the aqueous solutions of poly(NNPAAm)s were also investigated. It appeared that the poly (NNPAAm) with racemo dyad content of 70% exhibited unusual large hysteresis between the heating and cooling processes.

Original languageEnglish
Pages (from-to)4575-4583
Number of pages9
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Volume46
Issue number13
DOIs
Publication statusPublished - Jul 1 2008

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Hempa
Free radical polymerization
Hysteresis
Acrylamides
Hydrogen bonds
Phase transitions
Polymerization
Polymers
Pentanols
Temperature
Monomers
Cooling
Heating
N-n-propylacrylamide

All Science Journal Classification (ASJC) codes

  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

Cite this

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title = "Hydrogen-bond-assisted syndiotactic-specific radical polymerizations of N-alkylacrylamides: The effect of the N-substituents on the stereospecif¡ cities and unusual large hysteresis in the phase-transition behavior of aqueous solution of syndiotactic poly(N-n-propylacrylamide)",
abstract = "The radical polymerizations of N-alkylacrylamides, such as N-methyl-(NMAAm), Ar-rc-propyl-(NNPAAm), N-benzyl-(NBnAAm), and N-(1-phenylethyl)acrylamides (NPhEAAm), at low temperatures were investigated in the absence or presence of hexamethylphosphoramide (HMPA) and 3-methyl-3-pentanol (3Me3PenOH), which induced the syndiotactic specificities in the radical polymerization of AT-isopropylacrylamide (NIPAAm). In the absence of the syndiotactic-specificity inducers, the syndiotacticities of the obtained polymers gradually increased as the bulkiness of the iV-substituents increased. Both HMPA and 3Me3PenOH induced the syndiotactic specificities in the NNPAAm polymerizations as well as in the NIPAAm polymerizations. The addition of 3Me3PenOH into the polymerizations of NMAAm significantly induced the syndiotactic specificities, whereas the tacticities of the obtained polymers were hardly affected by adding HMPA. In the polymerizations of bulkier monomers, such as NBnAAm and NPhEAAm, HMPA worked as the syndiotactic specificity inducer at higher temperatures, whereas 3Me3PenOH hardly influenced the stereospecificity, regardless of the temperatures. The phase-transition behaviors of the aqueous solutions of poly(NNPAAm)s were also investigated. It appeared that the poly (NNPAAm) with racemo dyad content of 70{\%} exhibited unusual large hysteresis between the heating and cooling processes.",
author = "Tomohiro Hirano and Kimihiko Nakamura and Takahiro Kamikubo and Satoshi Ishii and Kanami Tani and Takeshi Mori and Tsuneyuki Sato",
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T1 - Hydrogen-bond-assisted syndiotactic-specific radical polymerizations of N-alkylacrylamides

T2 - The effect of the N-substituents on the stereospecif¡ cities and unusual large hysteresis in the phase-transition behavior of aqueous solution of syndiotactic poly(N-n-propylacrylamide)

AU - Hirano, Tomohiro

AU - Nakamura, Kimihiko

AU - Kamikubo, Takahiro

AU - Ishii, Satoshi

AU - Tani, Kanami

AU - Mori, Takeshi

AU - Sato, Tsuneyuki

PY - 2008/7/1

Y1 - 2008/7/1

N2 - The radical polymerizations of N-alkylacrylamides, such as N-methyl-(NMAAm), Ar-rc-propyl-(NNPAAm), N-benzyl-(NBnAAm), and N-(1-phenylethyl)acrylamides (NPhEAAm), at low temperatures were investigated in the absence or presence of hexamethylphosphoramide (HMPA) and 3-methyl-3-pentanol (3Me3PenOH), which induced the syndiotactic specificities in the radical polymerization of AT-isopropylacrylamide (NIPAAm). In the absence of the syndiotactic-specificity inducers, the syndiotacticities of the obtained polymers gradually increased as the bulkiness of the iV-substituents increased. Both HMPA and 3Me3PenOH induced the syndiotactic specificities in the NNPAAm polymerizations as well as in the NIPAAm polymerizations. The addition of 3Me3PenOH into the polymerizations of NMAAm significantly induced the syndiotactic specificities, whereas the tacticities of the obtained polymers were hardly affected by adding HMPA. In the polymerizations of bulkier monomers, such as NBnAAm and NPhEAAm, HMPA worked as the syndiotactic specificity inducer at higher temperatures, whereas 3Me3PenOH hardly influenced the stereospecificity, regardless of the temperatures. The phase-transition behaviors of the aqueous solutions of poly(NNPAAm)s were also investigated. It appeared that the poly (NNPAAm) with racemo dyad content of 70% exhibited unusual large hysteresis between the heating and cooling processes.

AB - The radical polymerizations of N-alkylacrylamides, such as N-methyl-(NMAAm), Ar-rc-propyl-(NNPAAm), N-benzyl-(NBnAAm), and N-(1-phenylethyl)acrylamides (NPhEAAm), at low temperatures were investigated in the absence or presence of hexamethylphosphoramide (HMPA) and 3-methyl-3-pentanol (3Me3PenOH), which induced the syndiotactic specificities in the radical polymerization of AT-isopropylacrylamide (NIPAAm). In the absence of the syndiotactic-specificity inducers, the syndiotacticities of the obtained polymers gradually increased as the bulkiness of the iV-substituents increased. Both HMPA and 3Me3PenOH induced the syndiotactic specificities in the NNPAAm polymerizations as well as in the NIPAAm polymerizations. The addition of 3Me3PenOH into the polymerizations of NMAAm significantly induced the syndiotactic specificities, whereas the tacticities of the obtained polymers were hardly affected by adding HMPA. In the polymerizations of bulkier monomers, such as NBnAAm and NPhEAAm, HMPA worked as the syndiotactic specificity inducer at higher temperatures, whereas 3Me3PenOH hardly influenced the stereospecificity, regardless of the temperatures. The phase-transition behaviors of the aqueous solutions of poly(NNPAAm)s were also investigated. It appeared that the poly (NNPAAm) with racemo dyad content of 70% exhibited unusual large hysteresis between the heating and cooling processes.

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