In-situ penetration of ionic liquids during surface densification of Scots pine

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-06-01
Major/Subject
Mcode
Degree programme
Language
en
Pages
8
Series
Holzforschung
Abstract
The moisture-induced recovery of compressed wood is one of the major problems of wood densification technology. Achieving a cost-efficient surface densification process without the need for additional resins to eliminate the set-recovery may lead to an increase in value of low-density wood species. A previous study has shown that a pre-treatment with ionic liquids (ILs) can nearly eliminate the set-recovery. It was however observed that during the pre-treatment process the IL did not penetrate sufficiently deep into the wood to explain the achieved reduction in set-recovery. Based on these findings, the hypothesis was posed that further penetration of the IL into the wood occurs during the densification stage as a consequence of the applied heat and pressure. Thermo-gravimetric analysis (TGA) and gas-chromatography mass-selective-detection (GC-MSD) showed that the depth of penetration of the IL was greater after the densification process than before. Digital image correlation (DIC) showed that in regions with a high IL concentration, there was almost no set-recovery, and it gradually increased with a decrease in the IL concentration, as observed with TGA and GC-MSD analysis.
Description
Keywords
compressed wood, digital image correlation, set-recovery, spectroscopy, thermo-gravimetric analysis, wood modification
Other note
Citation
Neyses, B, Peeters, K, Buck, D, Rautkari, L & Sandberg, D 2021, ' In-situ penetration of ionic liquids during surface densification of Scots pine ', Holzforschung, vol. 75, no. 6, pp. 555-562 . https://doi.org/10.1515/hf-2020-0146