On sorption hysteresis in wood: Separating hysteresis in cell wall water and capillary water in the full moisture range

Research output: Contribution to journalArticle

Abstract

Moisture influences most physical wood properties and plays an important role in degradation processes. Like most other porous materials, wood exhibits sorption hysteresis. That is, the moisture content is higher if equilibrium is reached by desorption than if it is reached by absorption under the same ambient climate conditions. The mechanism of moisture uptake by wood are different in the hygroscopic and over-hygroscopic moisture ranges and due to methodical issues, most studies of sorption hysteresis have been performed in the hygroscopic range. In the present study, total sorption hysteresis was separated into hysteresis in cell wall water and capillary water respectively in the whole moisture range by a novel combination of experimental techniques. Wood specimens were conditioned to several high moisture contents using a new system based on the pressure plate technique, and the distinction between cell wall water and capillary water was done with differential scanning calorimetry. The results showed that sorption hysteresis in wood cell walls exists in the whole moisture range. The cell walls were not saturated with water until the whole wood specimen was saturated which contradicts the long-held dogma that cell walls are saturated before significant amounts of capillary water are present in wood.

Details

Authors
Organisations
External organisations
  • University of Copenhagen
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Wood Science
  • Composite Science and Engineering
Original languageEnglish
Article numbere0225111
Number of pages16
JournalPLoS ONE
Volume14
Issue number11
Publication statusPublished - 2019 Nov 15
Publication categoryResearch
Peer-reviewedYes