Natural weathering performance of thermally treated poplar and black pine wood

Abstract: The wood of poplar (Populus sp.) and black pine (Pinus nigra) species was subjected to thermal treatment under variant conditions of temperature, 180 ºC and 200 ºC, and duration of 3 h, 5 h, 7 h, and its resistance to natural weathering was investigated through the determination of crucial...

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Autores principales:	Kamperidou,Vasiliki, Barboutis,Ioannis
Lenguaje:	English
Publicado:	Universidad del Bío-Bío 2021
Materias:	Colour pine poplar surface roughness thermal modification weathering
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2021000100424
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spelling	oai:scielo:S0718-221X20210001004242021-05-30Natural weathering performance of thermally treated poplar and black pine woodKamperidou,VasilikiBarboutis,Ioannis Colour pine poplar surface roughness thermal modification weathering Abstract: The wood of poplar (Populus sp.) and black pine (Pinus nigra) species was subjected to thermal treatment under variant conditions of temperature, 180 ºC and 200 ºC, and duration of 3 h, 5 h, 7 h, and its resistance to natural weathering was investigated through the determination of crucial properties, such as the colour and surface roughness, while the appearance of the boards was assessed both visually and through a microscope, prior to and after their exposure outdoors. Prior to the outdoors exposure, it was observed that, as the intensity of heat treatment increases, wood tends to darken, with the parallel decrease of L* index, referring to the tangential, radial and cross-sectional surface of both species specimens. The surface roughness of both wood species was found to decrease only in the boards of the mildest treatment, while as the treatment intensity increases, the roughness degree demonstrated a strong increase compared to unmodified wood. After the 100-day exposure of poplar and pine boards to external conditions, they acquired a wilder look and new checks and cracks emerged in the boards surface, while fungi infestation signs appeared, most apparent in control and boards treated at milder treatments, with modified poplar boards to demonstrate more dense defects patterns on their surfaces, compared to modified black pine boards. A similar degree of discoloration recorded on unmodified boards was observed also on the thermally modified boards, which was except for the visual assessment, confirmed by the recorded progress of L, a and b* colour indexes of poplar and pine surfaces and is probably attributed to leaching of the water soluble extractives. The roughness of all of the exposed boards surfaces was found higher than the respective values recorded prior to the exposure and among the treated boards only those of the milder treatments presented lower roughness values than the unmodified ones. Thermal treatment enhanced the biological durability and dimensional stability of both species, but it did not adequately protect the wood from the weathering effect when it was exposed outdoors. Nevertheless, wood modified at short-term heat treatments exhibited enhanced properties compared to unmodified wood and taking into account that the milder treatments did not cause mechanical strength loss, these materials could be utilized in applications where structures are not continually and directly exposed to aging factors, such as under shelter applications, or after the application of a thermal and surface modification with protective preservatives combination.info:eu-repo/semantics/openAccessUniversidad del Bío-BíoMaderas. Ciencia y tecnología v.23 20212021-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2021000100424en10.4067/s0718-221x2021000100424
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Colour pine poplar surface roughness thermal modification weathering
spellingShingle	Colour pine poplar surface roughness thermal modification weathering Kamperidou,Vasiliki Barboutis,Ioannis Natural weathering performance of thermally treated poplar and black pine wood
description	Abstract: The wood of poplar (Populus sp.) and black pine (Pinus nigra) species was subjected to thermal treatment under variant conditions of temperature, 180 ºC and 200 ºC, and duration of 3 h, 5 h, 7 h, and its resistance to natural weathering was investigated through the determination of crucial properties, such as the colour and surface roughness, while the appearance of the boards was assessed both visually and through a microscope, prior to and after their exposure outdoors. Prior to the outdoors exposure, it was observed that, as the intensity of heat treatment increases, wood tends to darken, with the parallel decrease of L* index, referring to the tangential, radial and cross-sectional surface of both species specimens. The surface roughness of both wood species was found to decrease only in the boards of the mildest treatment, while as the treatment intensity increases, the roughness degree demonstrated a strong increase compared to unmodified wood. After the 100-day exposure of poplar and pine boards to external conditions, they acquired a wilder look and new checks and cracks emerged in the boards surface, while fungi infestation signs appeared, most apparent in control and boards treated at milder treatments, with modified poplar boards to demonstrate more dense defects patterns on their surfaces, compared to modified black pine boards. A similar degree of discoloration recorded on unmodified boards was observed also on the thermally modified boards, which was except for the visual assessment, confirmed by the recorded progress of L, a and b* colour indexes of poplar and pine surfaces and is probably attributed to leaching of the water soluble extractives. The roughness of all of the exposed boards surfaces was found higher than the respective values recorded prior to the exposure and among the treated boards only those of the milder treatments presented lower roughness values than the unmodified ones. Thermal treatment enhanced the biological durability and dimensional stability of both species, but it did not adequately protect the wood from the weathering effect when it was exposed outdoors. Nevertheless, wood modified at short-term heat treatments exhibited enhanced properties compared to unmodified wood and taking into account that the milder treatments did not cause mechanical strength loss, these materials could be utilized in applications where structures are not continually and directly exposed to aging factors, such as under shelter applications, or after the application of a thermal and surface modification with protective preservatives combination.
author	Kamperidou,Vasiliki Barboutis,Ioannis
author_facet	Kamperidou,Vasiliki Barboutis,Ioannis
author_sort	Kamperidou,Vasiliki
title	Natural weathering performance of thermally treated poplar and black pine wood
title_short	Natural weathering performance of thermally treated poplar and black pine wood
title_full	Natural weathering performance of thermally treated poplar and black pine wood
title_fullStr	Natural weathering performance of thermally treated poplar and black pine wood
title_full_unstemmed	Natural weathering performance of thermally treated poplar and black pine wood
title_sort	natural weathering performance of thermally treated poplar and black pine wood
publisher	Universidad del Bío-Bío
publishDate	2021
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2021000100424
work_keys_str_mv	AT kamperidouvasiliki naturalweatheringperformanceofthermallytreatedpoplarandblackpinewood AT barboutisioannis naturalweatheringperformanceofthermallytreatedpoplarandblackpinewood
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Natural weathering performance of thermally treated poplar and black pine wood

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