Water vapour sorption properties of thermally modified and pressurised hot-water-extracted wood powder

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • KTH Royal Institute of Technology
  • Lahti University of Applied Sciences

Abstract

The objective of the study was to investigate the water vapour sorption behaviour of thermally modified (TM) wood powder, e.g. ground wood prepared from waste streams of TM solid wood, and wood powder that was extracted in pressurised hot water. Solid spruce wood was TM in steam conditions (210°C for 3 h), milled and hot-water-extracted (HWE) at elevated pressure (140°C for 1 h). The results evidence that the hot-water extraction reduced the water sorption and the accessible hydroxyl group concentration by the removal of amorphous carbohydrates. In contrast, the enhanced cross-linking of the cell wall matrix and the annealing of amorphous matrix polymers during thermal modification reduced the sorption behaviour of wood additionally, without further reducing the hydroxyl accessibility. These additional effects of thermal modification were at least partially cancelled by hot-water extraction. The results bring novel insights into the mechanisms that reduce the water vapour sorption of wood by compositional and structural changes induced by heating.

Details

Original languageEnglish
JournalHolzforschung
Publication statusE-pub ahead of print - Jul 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • carbohydrate analysis, deuterium exchange, dynamic vapour sorption, hot-water extraction, thermal modification

ID: 35526939