Journal of Polymers and the Environment

, Volume 21, Issue 2, pp 555–563

TEMPO-Mediated Oxidation of Hemp Bast Holocellulose to Prepare Cellulose Nanofibrils Dispersed in Water

  • Buapan Puangsin
  • Shuji Fujisawa
  • Ryota Kuramae
  • Tsuguyuki Saito
  • Akira Isogai
Original Paper

DOI: 10.1007/s10924-012-0548-9

Cite this article as:
Puangsin, B., Fujisawa, S., Kuramae, R. et al. J Polym Environ (2013) 21: 555. doi:10.1007/s10924-012-0548-9

Abstract

Hemp bast holocellulose fiber (Cannabis sativa L. Subsp. Sativa) was oxidized by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation at various NaClO addition levels in water at pH 10. When carboxylate contents of the oxidized products were 1.5–1.7 mmol/g, TEMPO-oxidized cellulose nanofibrils almost completely dispersed at the individual nanofibril were obtained by mechanical disintegration of the TEMPO-oxidized hemp bast holocelluloses in water, where the nanofibrillation yields were 98–100 %. The sugar composition analysis revealed that most of hemicelluloses originally present in the hemp bast holocellulose were degraded and removed from the solid oxidized products, providing almost pure TEMPO-oxidized celluloses. X-ray diffraction patterns of all TEMPO-oxidized hemp bast holocelluloses had the same cellulose I crystal structure and similar crystallinity indices and crystal widths, indicating that carboxylate groups formed by the oxidation were selectively present on the crystalline cellulose microfibril surfaces in the holocellulose. However, the weight recovery ratios and viscosity-average degrees of polymerization of the TEMPO-oxidized hemp bast holocelluloses decreased to 69–59 % and 470–380, respectively, when their carboxylate contents increased to 1.5–1.7 mmol/g by the TEMPO-mediated oxidation. Atomic force microscopy height images showed that the nanofibril widths were 2.7–2.9 nm, and the average nanofibril lengths decreased from 590 to 400 nm as the NaClO addition level was increased from 7.5 to 12.5 mmol/g in the TEMPO-mediated oxidation.

Keywords

TEMPO Hemp bast Nanofibril Cellulose AFM 

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  • Buapan Puangsin
    • 1
    • 2
  • Shuji Fujisawa
    • 1
  • Ryota Kuramae
    • 1
  • Tsuguyuki Saito
    • 1
  • Akira Isogai
    • 1
  1. 1.Department of Biomaterial SciencesThe University of TokyoBunkyo-ku, TokyoJapan
  2. 2.Faculty of ForestryKasetsart UniversityBangkokThailand

Personalised recommendations