Stress Relaxation of Sugi (Cryptomeria japonica D.Don) Wood in Radial Compression under High Temperature Steam
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W. Dwianto
Summary
To clarify the mechanism of the permanent fixation of compressive deformation of wood by high temperature steaming, stress relaxation and stress-strain relationships in the radial compression for Sugi (Cryptomeria japonica D.Don) wood were measured under steam at temperatures up to 200°C. The stress relaxation curves above 100°C were quite different in shape from those below 100°C, showing a rapid decrease in stress with increasing temperature. In the stress-strain relationships measured above 140°C, the stress reduced as pre-steaming time increased when compared at the same strain. The recovery of compressive deformation (strain recovery) was decreased with steaming time and reached almost 0 in 10 min at 200°C. The relationship between the residual stress and the strain recovery at the end of relaxation measurements could be expressed by a single curve regardless of time and temperature. The permanent fixation of deformation by steaming below 200°C was considered to be due to chain scission of hemicelluloses accompanying a slight cleavage of lignin. In some cases, the increase in regularity of the crystalline lattice space of microfibrils or the formation of crosslinks between the cell wall polymers seemed to play an important role in the permanent fixation of compressive deformation.
Copyright © 1999 by Walter de Gruyter GmbH & Co. KG
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Articles in the same Issue
- The Significance of Accelerated Laboratory Testing Methods Determining the Natural Durability of Wood
- The Thermomechanical Behaviour of Wood Subject to Fungal Decay
- Fixation of Chromium in Wood from Trivalent Chromium Salt Solutions
- Spatial Distribution of Metal Ions in Spruce Wood by Synchrotron Radiation Microbeam X-Ray Fluorescence Analysis
- Chemical Composition of Lipophilic Extractives from Eucalyptus globulus Labill. Wood
- Antifungal Compounds in the Ethyl Acetate Soluble Fraction of the Extractives of Taiwania (Taiwania cryptomerioides Hayata) Heartwood
- Efficacy of Pinosylvins against White-Rot and Brown-Rot Fungi
- Investigations into Laccase-Mediator Delignification of Kraft Pulps
- Cell-Wall-Associated Oxidases from the Lignifying Xylem of Angiosperms and Gymnosperms: Monolignol Oxidation
- Atmospheric Acetic Acid Pulping of Rice Straw IV: Physico-Chemical Characterization of Acetic Acid Lignins from Rice Straw and Woods. Part 1. Physical Characteristics
- Lignin-Polyphenol Interaction in Azobe (Lophira alata) Heartwood. A Study on Milled Wood Lignin (MWL) and Klason Residues
- Electrospray Ionization Mass Spectrometry as a Tool for Lignins Molecular Weight and Structural Characterisation
- Determination of Phenolic Hydroxyl Groups in Lignin by Combined Use of 1H NMR and UV Spectroscopy
- The Effective Diffusion Coefficient and Mass Transfer Coefficient of Nordic Softwoods as Calculated from Direct Drying Experiments
- Stress Relaxation of Sugi (Cryptomeria japonica D.Don) Wood in Radial Compression under High Temperature Steam
- Structural Performance of Fire-Retardant Treated Plywood: Effect of Elevated Temperature
- Sorption Behaviour and Dimensional Changes of Wood-Coating Composites
- Literature Reports
