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Cellulose

, Volume 16, Issue 6, pp 1179–1185 | Cite as

Syntheses of 6-O-ethyl/methyl-celluloses via ring-opening copolymerization of 3-O-benzyl-6-O-ethyl/methyl-α-d-glucopyranose 1,2,4-orthopivalates and their structure–property relationships

  • Hiroshi KamitakaharaEmail author
  • Toshihiro Funakoshi
  • Shinji Nakai
  • Toshiyuki Takano
  • Fumiaki Nakatsubo
Article

Abstract

6-O-Alkyl-celluloses with well-defined ratio of ethyl and methyl groups at position 6 were prepared by ring-opening copolymerization of 6-O-ethyl and 6-O-methyl glucose 1,2,4-orthopivalate derivatives. An aqueous solution of 6-O-ethyl-cellulose having no methyl group was found to be thermo-responsive to be turbid at ~70 °C. An aqueous solution of 6-O-ethyl-cellulose with higher molecular weight showed endothermic and exothermic peaks in the heating and cooling curves of DSC measurements, respectively. However, 6-O-alkyl-cellulose having 10% methyl group lost its thermo-responsive character. 6-O-Alkyl-celluloses having more than ten percent of ethyl group at position 6 became water-soluble, though 6-O-methyl-cellulose is insoluble in water. Thus, 6-O-ethyl group was found to be of importance for the water solubility of regioselective 6-O-alkyl-celluloses. Furthermore, a small amount of methyl group introduced at C6 position was found to affect some of physical properties of 6-O-alkyl-celluloses such as thermo responsive property.

Keywords

Ring-opening polymerization Cellulose Regioselective functionalization Copolymer Ethylcellulose Methylcellulose Water-solubility LCST 

Notes

Acknowledgments

This investigation was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (No. 18680009).

References

  1. Ifuku S, Nakai S, Kamitakahara H, Takano T, Tsujii Y, Nakatsubo F (2005) Preparation and characterization of monolayer and multilayer langmuir-blodgett films of a series of 6-O-alkylcelluloses. Biomacromolecules 6(4):2067–2073CrossRefGoogle Scholar
  2. Kamitakahara H, Hori M, Nakatsubo F (1996) Substituent effect on ring-opening polymerization of regioselectively acylated α-d-glucopyranose 1, 2, 4-orthopivalate derivatives. Macromolecules 29(19):6126–6131CrossRefGoogle Scholar
  3. Kamitakahara H, Nakatsubo F, Klemm D (2006) Block co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides as model compounds for methylcellulose and its dissolution/gelation behavior. Cellulose 13(4):375–392CrossRefGoogle Scholar
  4. Kamitakahara H, Nakatsubo F, Klemm D (2007) New class of carbohydrate-based nonionic surfactants: diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides. Cellulose 14(5):513–528CrossRefGoogle Scholar
  5. Kamitakahara H, Koschella A, Mikawa Y, Nakatsubo F, Heinze T, Klemm D (2008) Syntheses and comparison of 2, 6-di-O-methyl celluloses from natural and synthetic celluloses. Macromol Biosci 8(7):690–700CrossRefGoogle Scholar
  6. Kamitakahara H, Funakoshi T, Takano T, Nakatsubo F (2009) Syntheses of 2,6-O-alkyl celluloses: influence of methyl and ethyl groups regioselectively introduced at O-2 and O-6 positions on their solubility. Cellulose. doi: https://doi.org/10.1007/s10570-009-9332-y
  7. Karakawa M (2003) Chemical synthesis of high-regioselectively methylated celluloses by a cationic ring-opening polymerization (Kyoto). Ph.D. Thesis, Kyoto UniversityGoogle Scholar
  8. Nakatsubo F, Kamitakahara H, Hori M (1996) Cationic ring-opening polymerization of 3, 6-di-O-benzyl-α-d-glucose 1, 2, 4-orthopivalate and the first chemical synthesis of cellulose. J Am Chem Soc 118(7):1677–1681CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Hiroshi Kamitakahara
    • 1
    Email author
  • Toshihiro Funakoshi
    • 1
  • Shinji Nakai
    • 1
  • Toshiyuki Takano
    • 1
  • Fumiaki Nakatsubo
    • 1
  1. 1.Graduate School of AgricultureKyoto UniversityKyotoJapan

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