The role of accessible hydroxyl groups in reversible and irreversible EMC changes by thermal wood modification

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Willems, Wim
dc.contributor.author Altgen, Michael
dc.contributor.author Rautkari, Lauri
dc.contributor.editor Creemers, Jos
dc.contributor.editor Houben, Thomas
dc.contributor.editor Tjeerdsma, Bôke
dc.contributor.editor Militz, Holger
dc.contributor.editor Junge, Brigitte
dc.contributor.editor Gootjes, Jos
dc.date.accessioned 2019-01-14T09:20:38Z
dc.date.available 2019-01-14T09:20:38Z
dc.date.issued 2018-09-17
dc.identifier.citation Willems , W , Altgen , M & Rautkari , L 2018 , The role of accessible hydroxyl groups in reversible and irreversible EMC changes by thermal wood modification . in J Creemers , T Houben , B Tjeerdsma , H Militz & B Junge (eds) , Proceedings of the 9th European Conference on Wood Modification . Arnhem, The Netherlands , European Conference on Wood Modification , Arnhem , Netherlands , 16/11/2018 . en
dc.identifier.other PURE UUID: 4114607c-2ac6-47e0-9da8-c1f93ae948ff
dc.identifier.other PURE ITEMURL: https://research.aalto.fi/en/publications/the-role-of-accessible-hydroxyl-groups-in-reversible-and-irreversible-emc-changes-by-thermal-wood-modification(4114607c-2ac6-47e0-9da8-c1f93ae948ff).html
dc.identifier.other PURE FILEURL: https://research.aalto.fi/files/29740264/Willems_Wim_The_role_of_accessible_hydroxyl_groups_in_reversible_and_irreversible_EMC_changes_by_thermal_wood_modific.pdf
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/35943
dc.description.abstract Heat treatment (HT) is a well-known means to reduce the room-temperature equilibrium wood moisture content (EMC) at a specified relative humidity (RH). Already at slightly elevated temperature above room temperature, EMC is decreased in proportion to the exposed temperature. At higher elevated temperature, where wood chemical changes become activated, the EMC is profoundly reduced, mainly caused by the loss of accessible hydroxyl groups (OHacc) in the wood matrix. However, earlier experiments have shown that the obtained EMC reduction after HT can be partly reversible, depending on the ability of the wood matrix polymers to fully mechanically relax during HT. We present an experimental study on the OHacc content and the associated EMC decrease at 93%RH by a relaxation inhibiting dry-HT versus a relaxation enabling wet-HT. The results of this study quantitatively support a molecular explanation of this phenomenon, in which wood moisture is principally bound by OHacc-pairs, instead of solitary OHacc. The irreversible part of EMC reduction is assigned to the thermochemical removal of OHacc from the wood matrix. The reversible part (EMC recovery), is attributed to a regrouping of solitary OHacc into pairs, thereby restoring moisture sorption sites. Each solitary OHacc, may either be the remaining half of an OHacc-pair after thermal destruction of its partner OHacc, or originate from thermally disrupted OHacc-pairs without OHacc removal. The OHacc-pair recovery mechanism explains the involvement of wood polymer relaxation, necessary to translocate OHacc in the wood matrix. en
dc.format.extent 6
dc.format.mimetype application/pdf
dc.language.iso en en
dc.relation.ispartof European Conference on Wood Modification en
dc.relation.ispartofseries Proceedings of the 9th European Conference on Wood Modification en
dc.rights openAccess en
dc.subject.other 215 Chemical engineering en
dc.title The role of accessible hydroxyl groups in reversible and irreversible EMC changes by thermal wood modification en
dc.type A4 Artikkeli konferenssijulkaisussa fi
dc.description.version Non peer reviewed en
dc.contributor.department FirmoLin Technologies BV
dc.contributor.department Wood Material Science
dc.contributor.department Department of Bioproducts and Biosystems en
dc.subject.keyword elemental composition
dc.subject.keyword equilibrium moisture content
dc.subject.keyword heat treatment
dc.subject.keyword hydrogen-deuterium exchange
dc.subject.keyword mass loss
dc.subject.keyword mechanical relaxation
dc.subject.keyword 215 Chemical engineering
dc.identifier.urn URN:NBN:fi:aalto-201901141126
dc.type.version publishedVersion


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