MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS

Heat treatment of wood is an effective method to improve the dimensional stability and durability against biodegradation. Optimisation of a two-stage heat treatment process at relatively mild conditions (<200°C) and its effect on the anatomical structure of softwoods were investigated by means of...

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Autores principales:	Boonstra,M.J, Rijsdijk,J.F, Sander,C, Kegel,E, Tjeerdsma,B, Militz,H, Van Acker,J, Stevens,M
Lenguaje:	English
Publicado:	Universidad del Bío-Bío 2006
Materias:	Wood modification heat treatment softwood microscopy
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2006000300006
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spelling	oai:scielo:S0718-221X20060003000062006-12-01MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODSBoonstra,M.JRijsdijk,J.FSander,CKegel,ETjeerdsma,BMilitz,HVan Acker,JStevens,M Wood modification heat treatment softwood microscopy Heat treatment of wood is an effective method to improve the dimensional stability and durability against biodegradation. Optimisation of a two-stage heat treatment process at relatively mild conditions (<200°C) and its effect on the anatomical structure of softwoods were investigated by means of a light and scanning electron microscopic analysis. Heat treatment did have an effect on the anatomical structure of wood, although this depends on the wood species considered and on the process method and conditions used. Softwood species with narrow annual rings and/or an abrupt transition from earlywood into latewood were sensitive to tangential cracks in the latewood section. Radial cracks occurred mainly in impermeable wood species such as Norway spruce, caused by large stresses in the wood structure during treatment. Sapwood of treated pine species revealed some damage to parenchyma cells in the rays and epithelial cells around resin canals, whereas this phenomenon has not been noticed in the heartwood section. Treated radiata pine resulted in a very open and permeable wood structure limiting the applications of this species. Broken cell walls perpendicular to the fibre direction resulting in transverse ruptures have been noticed in treated softwood species. This contributes to abrupt fractures of treated wood as observed in bending tests which can lead to considerably different failure behavior after impact or mechanical stress. In some treated softwood species maceration (small cracks between tracheids) was noticed after heat treatment. Heat treatment did not cause damage to the ray parenchyma pit membranes, bordered pits and large window pit membranes; the margo fibrils appeared without damage. Compared to the other softwood timbers tested European grown Douglas fir was the timber that stands heat treatment the bestinfo:eu-repo/semantics/openAccessUniversidad del Bío-BíoMaderas. Ciencia y tecnología v.8 n.3 20062006-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2006000300006en10.4067/S0718-221X2006000300006
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Wood modification heat treatment softwood microscopy
spellingShingle	Wood modification heat treatment softwood microscopy Boonstra,M.J Rijsdijk,J.F Sander,C Kegel,E Tjeerdsma,B Militz,H Van Acker,J Stevens,M MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS
description	Heat treatment of wood is an effective method to improve the dimensional stability and durability against biodegradation. Optimisation of a two-stage heat treatment process at relatively mild conditions (<200°C) and its effect on the anatomical structure of softwoods were investigated by means of a light and scanning electron microscopic analysis. Heat treatment did have an effect on the anatomical structure of wood, although this depends on the wood species considered and on the process method and conditions used. Softwood species with narrow annual rings and/or an abrupt transition from earlywood into latewood were sensitive to tangential cracks in the latewood section. Radial cracks occurred mainly in impermeable wood species such as Norway spruce, caused by large stresses in the wood structure during treatment. Sapwood of treated pine species revealed some damage to parenchyma cells in the rays and epithelial cells around resin canals, whereas this phenomenon has not been noticed in the heartwood section. Treated radiata pine resulted in a very open and permeable wood structure limiting the applications of this species. Broken cell walls perpendicular to the fibre direction resulting in transverse ruptures have been noticed in treated softwood species. This contributes to abrupt fractures of treated wood as observed in bending tests which can lead to considerably different failure behavior after impact or mechanical stress. In some treated softwood species maceration (small cracks between tracheids) was noticed after heat treatment. Heat treatment did not cause damage to the ray parenchyma pit membranes, bordered pits and large window pit membranes; the margo fibrils appeared without damage. Compared to the other softwood timbers tested European grown Douglas fir was the timber that stands heat treatment the best
author	Boonstra,M.J Rijsdijk,J.F Sander,C Kegel,E Tjeerdsma,B Militz,H Van Acker,J Stevens,M
author_facet	Boonstra,M.J Rijsdijk,J.F Sander,C Kegel,E Tjeerdsma,B Militz,H Van Acker,J Stevens,M
author_sort	Boonstra,M.J
title	MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS
title_short	MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS
title_full	MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS
title_fullStr	MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS
title_full_unstemmed	MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS
title_sort	microstructural and physical aspects of heat treated wood. part 1. softwoods
publisher	Universidad del Bío-Bío
publishDate	2006
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2006000300006
work_keys_str_mv	AT boonstramj microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT rijsdijkjf microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT sanderc microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT kegele microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT tjeerdsmab microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT militzh microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT vanackerj microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods AT stevensm microstructuralandphysicalaspectsofheattreatedwoodpart1softwoods
_version_	1714202534381355008

MICROSTRUCTURAL AND PHYSICAL ASPECTS OF HEAT TREATED WOOD. PART 1. SOFTWOODS

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