Effects of thermo-hygro-mechanical (THM) treatment on the viscoelasticity of <i>in-situ</i> lignin

DOI Web Site Web Site XML 1 Citations
  • Juan Guo
    Research Institute of Wood Industry, Chinese Academy of Forestry , Beijing 100091 , China
  • Jiangping Yin
    Research Institute of Wood Industry, Chinese Academy of Forestry , Beijing 100091 , China
  • Yonggang Zhang
    Research Institute of Wood Industry, Chinese Academy of Forestry , Beijing 100091 , China
  • Lennart Salmén
    RISE Bioeconomy , Box 5604 , Stockholm , SE-11486, Sweden , Phone: +468-6767340, Fax: +468-4115518
  • Yafang Yin
    Research Institute of Wood Industry, Chinese Academy of Forestry , Beijing 100091 , China , Phone: +86-10-62889468, Fax: +86-10-62881937, e-mail:

Search this article

Description

<jats:title>Abstract</jats:title> <jats:p>For producing wood products without fractures based on thermo-hygro-mechanical (THM) treatments, it is essential to understand how steaming and compression change the wood softening and cell wall components. In this paper, the effects of compression combined with steam treatment (CS) on the viscoelasticity of the <jats:italic>in-situ</jats:italic> lignin of Chinese fir has been investigated through dynamic mechanical analysis (DMA) under fully saturated conditions. Several variations were studied, such as the softening temperature (T<jats:sub>g</jats:sub>) and apparent activation energy (ΔH<jats:sub>a</jats:sub>) of the softening process in response to CS treatment conditions (such as steam temperature and compression ratio) under separate consideration of earlywood (EW) and latewood (LW). No difference between EW and LW with respect to the viscoelasticity was noted. T<jats:sub>g</jats:sub> and ΔH<jats:sub>a</jats:sub> of the lignin softening were nearly unaffected by the compression ratio, but were highly influenced by the steam temperature. The T<jats:sub>g</jats:sub> decreased significantly with CS treatments at or above 160<jats:sup>o</jats:sup>C, but showed no appreciable change, compared to the native wood, at the lower steaming temperature of 140<jats:sup>o</jats:sup>C. ΔH<jats:sub>a</jats:sub> increased at higher steam temperatures, while ΔH<jats:sub>a</jats:sub> showed a decreasing tendency with decreasing T<jats:sub>g</jats:sub>. This indicates that lignin undergoes a simultaneous depolymerization as well as a condensation during CS treatment.</jats:p>

Journal

  • Holzforschung

    Holzforschung 71 (6), 455-460, 2017-03-25

    Walter de Gruyter GmbH

Citations (1)*help

See more

Keywords

Report a problem

Back to top