Effect of natural weathering on water absorption and pore size distribution in thermally modified wood determined by nuclear magnetic resonance

Change log
Cai, C 
Javed, MA 
Komulainen, S 
Telkki, VV 
Haapala, A 

jats:titleAbstract</jats:title>jats:pThermally modified wood (TMW) is widely used in outdoor applications due to its advanced properties towards weathering stresses. Although the structure changes of TMW from weather factors have been reported, investigation of the quantitative analysis of water states and cell wall structure of TMW after weathering is limited. In this work, the amount of bound water, fiber saturation point (FSP), cell wall pores, and free water distribution of thermally modified Scots pine, Norway spruce, and European ash were measured before and after a 2-year natural weathering via NMR relaxometry, cryoporometry, and magnetic resonance imaging. The results show that weathering increased Tjats:sub2</jats:sub> relaxation time of lumens, indicating the degradation of tracheids and vessels, especially in TMW compared to unmodified wood. The amounts of bound water, FSP value, and cell wall pores were increased after weathering; however, an increase in thermal modification intensity resulted in lower FSP and limited the increase in number of pores. In summary, TMW showed better performance than unmodified wood after weathering.</jats:p>


Funder: Teollisuusneuvos Heikki Väänänen's Fund

Funder: International Thermowood Association

Funder: Quantum Institute, University of Oulu

Bound water, Free water, Fiber saturation point (FSP), Cell wall pores, Nuclear magnetic resonance (NMR), Thermally modified wood
Journal Title
Conference Name
Journal ISSN
Volume Title
Springer Science and Business Media LLC
H2020 European Research Council (772110)
Academy of Finland (grants #289649, 294027, 319216)