One-stage thermo-hydro treatment (THT) of hardwoods: an analysis of form stability after five soaking-drying cycles
-
Vladimirs Biziks
,
Bruno Andersons
Abstract
A newly developed thermo-hydro treatment (THT) for use in a one-stage heat treatment process was examined by focusing on the form stability-related properties of European aspen (Populus tremula), birch silver (Betula pendula), and gray alder (Alnus incana). In particular, wood specimens were subjected to THT in a saturated steam atmosphere in a pilot-scale autoclave heated between 140 and 180°C for 1–3 h. Several parameters of untreated and treated samples after several soaking and drying cycles were compared, namely, the changes in the volumetric swelling, swelling in the radial and tangential directions, cell wall total water capacity, and anti-swelling efficiency (ASE). Due to repeated wetting in the cyclic water submersion-drying test, the original ASE of 73% decreased to 65% (180°C for 1 h), and the original ASE of 33% decreased to 5% (140°C for 1 h). Wood modified at 170°C presented good results that were not significantly lower than wood treated at higher temperatures while consuming less energy to deliver ASE improvement and was selected as optimum. To increase the ASE by 1%, the amount of energy consumed was decreased by 41%, 39%, and 17% compared with the treatment regimes of 160°C for 1 h, 160°C for 3 h, and 180°C for 1 h, respectively. The new THT regime led to improved long-term dimensional stability due to the cross-linking of cell wall polymers, which resulted in increased cell wall rigidity.
Acknowledgments
The authors gratefully acknowledge the financial support received from the European Regional Development Fund project, “Innovative wood and its processing materials with upgraded service properties”, No. 2010/0324 2DP/2.1.1.1.0/10/APIA/VIAA/057 and from the Latvian State Research Program NatRes.
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©2015 by De Gruyter
Articles in the same Issue
- Frontmatter
- Original Articles
- Study on the residual lignin in Eucalyptus globulus sulphite pulp
- Hydrogenolysis of lignin in ZnCl2 and KCl as an inorganic molten salt medium
- Synthesis of lignin polyols via oxyalkylation with propylene carbonate
- Preparation of water-dispersive poly(3,4-ethylenedioxythiophene) (PEDOT) conductive nanoparticles in lignosulfonic acid solution
- Properties of polyurethane (PUR) films prepared from liquefied wood (LW) and ethylene glycol (EG)
- Dynamic response of earlywood and latewood within annual growth ring structure of Scots pine subjected to changing relative humidity
- One-stage thermo-hydro treatment (THT) of hardwoods: an analysis of form stability after five soaking-drying cycles
- The variation of tangential rheological properties caused by shrinkage anisotropy and moisture content gradient in white birch disks
- Inheritance of basic density and microfibril angle and their variations among full-sib families and their parental clones in Picea glehnii
- Mechanical properties and chemical composition of beech wood exposed for 30 and 120 days to white-rot fungi
- Chemical improvement of surfaces. Part 3: Covalent modification of Scots pine sapwood with substituted benzoates providing resistance to Aureobasidium pullulans staining fungi
- Chemical and ultrastructural changes of ash wood thermally modified using the thermo-vacuum process: I. Histo/cytochemical studies on changes in the structure and lignin chemistry
- Chemical and ultrastructural changes of ash wood thermally modified (TMW) using the thermo-vacuum process: II. Immunocytochemical study of the distribution of noncellulosic polysaccharides
- Revisiting hardboard properties from the fiber sorting point of view
- Effects of acetylation and formalization on the dynamic water vapor sorption behavior of wood
- Immune-regulatory activity of methanolic extract of Acacia confusa heartwood and melanoxetin isolated from the extract
- Stereomicroscopic optical method for the assessment of load transfer patterns across the wood-adhesive bond interphase
Articles in the same Issue
- Frontmatter
- Original Articles
- Study on the residual lignin in Eucalyptus globulus sulphite pulp
- Hydrogenolysis of lignin in ZnCl2 and KCl as an inorganic molten salt medium
- Synthesis of lignin polyols via oxyalkylation with propylene carbonate
- Preparation of water-dispersive poly(3,4-ethylenedioxythiophene) (PEDOT) conductive nanoparticles in lignosulfonic acid solution
- Properties of polyurethane (PUR) films prepared from liquefied wood (LW) and ethylene glycol (EG)
- Dynamic response of earlywood and latewood within annual growth ring structure of Scots pine subjected to changing relative humidity
- One-stage thermo-hydro treatment (THT) of hardwoods: an analysis of form stability after five soaking-drying cycles
- The variation of tangential rheological properties caused by shrinkage anisotropy and moisture content gradient in white birch disks
- Inheritance of basic density and microfibril angle and their variations among full-sib families and their parental clones in Picea glehnii
- Mechanical properties and chemical composition of beech wood exposed for 30 and 120 days to white-rot fungi
- Chemical improvement of surfaces. Part 3: Covalent modification of Scots pine sapwood with substituted benzoates providing resistance to Aureobasidium pullulans staining fungi
- Chemical and ultrastructural changes of ash wood thermally modified using the thermo-vacuum process: I. Histo/cytochemical studies on changes in the structure and lignin chemistry
- Chemical and ultrastructural changes of ash wood thermally modified (TMW) using the thermo-vacuum process: II. Immunocytochemical study of the distribution of noncellulosic polysaccharides
- Revisiting hardboard properties from the fiber sorting point of view
- Effects of acetylation and formalization on the dynamic water vapor sorption behavior of wood
- Immune-regulatory activity of methanolic extract of Acacia confusa heartwood and melanoxetin isolated from the extract
- Stereomicroscopic optical method for the assessment of load transfer patterns across the wood-adhesive bond interphase
