Journal of Materials Science

, Volume 49, Issue 5, pp 2362–2371

The water vapour sorption behaviour of acetylated birch wood: how acetylation affects the sorption isotherm and accessible hydroxyl content

  • Carmen-Mihaela Popescu
  • Callum A. S. Hill
  • Simon Curling
  • Graham Ormondroyd
  • Yanjun Xie
Article

DOI: 10.1007/s10853-013-7937-x

Cite this article as:
Popescu, CM., Hill, C.A.S., Curling, S. et al. J Mater Sci (2014) 49: 2362. doi:10.1007/s10853-013-7937-x

Abstract

The water vapour sorption isotherms and sorption kinetics of birch (Betula pendula L) acetylated to different levels have been determined using a dynamic vapour sorption (DVS) apparatus. A DVS instrument was also used to determine the accessible hydroxyl content in the wood samples using deuterium exchange. The results are reported in terms of the reduced equilibrium moisture content (EMCR), in which the moisture content per unit mass of wood substance is used for the calculation. As the level of acetylation of the wood samples increased there was a corresponding reduction in EMCR of the wood samples, which was accompanied by a decrease in hysteresis in the same order. The sorption kinetics were also determined using the DVS and analysed using the parallel exponential kinetics model, in which the sorption kinetics curve is composed of two processes (labelled fast and slow). Using this analysis, it is possible to calculate two pseudo-isotherms associated with the two processes. The sorption isotherm is a composite of the sorption isotherms associated with the fast process water and the slow process water and there are significant differences in behaviour between the two. It is suggested in this paper that the fast process is related to diffusion limited kinetics, whereas the slow process is a relaxation-limited phenomenon. The reduction in accessible OH content due to acetylation was well correlated with the weight gain due to acetylation, although the relationship did not exactly correspond with that theoretically determined.

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Carmen-Mihaela Popescu
    • 1
  • Callum A. S. Hill
    • 2
    • 3
  • Simon Curling
    • 4
  • Graham Ormondroyd
    • 4
  • Yanjun Xie
    • 5
  1. 1.“Petru Poni” Institute of Macromolecular Chemistry of Romanian AcademyIasiRomania
  2. 2.Norsk Institutt for Skog og LandskapÅsNorway
  3. 3.JCH Industrial Ecology LimitedBangorUK
  4. 4.The BioComposites CentreBangor UniversityBangorUK
  5. 5.Key Laboratory of Biobased Material Science and Technology, Ministry of EducationNortheast Forestry UniversityHarbinChina

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