Color stability of heat-treated wood during artificial weathering

Ayadi, N.; Lejeune, Fabienne; Charrier, Fatima; Charrier, Bertrand; Merlin, André

doi:10.1007/s00107-003-0389-2

Cited by 208 publications

(163 citation statements)

References 9 publications

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“…En tanto que la disminución de los valores de color a* y b* (Figura 1a-1e). Algunos autores (Kamdem y Grelier 2002, Ayadi et al 2003) lo atribuyen a la formación de quinonas y quinamos debido a la despolimerización y oxidación de la lignina. Estos cambios en coloración dan como resultado el color gris típico de la madera expuesta a la intemperie.…”

Section: Figuraunclassified

Efectos De La Intemperie en El Color De Dos Acabados Aplicados en Madera De Cedrela Odorata Y Carapa Guianensis

Valverde

Moya

2010

Maderas, Cienc. tecnol.

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RESUMENCedrela odorata y Carapa guianensis son maderas utilizadas para la elaboración de muebles, puertas e inmobiliario de casas en Costa Rica. Así mismo, dos tipos de acabados (tipo nitrocelulosa y de poliuretano) son muy utilizados en estas maderas. No obstante, los cambios en los parámetros del color (CIE L*a*b*) por el intemperismo es poco conocido para estas especies y estos acabados. Al evaluar estos acabados ante el intemperismo se encontró que el acabado con poliuretano y nitrocelulasa producen cambios en la coloración de la madera apreciables en los primeros 40-60 días de exposición a la interperie y este cambio del color fue diferente en cada acabado. Ademas, los resultados mostraron que en C. guianensis los cambios medido por ∆E* de color fueron inferiores a los obtenidos en la C. odorata en los dos acabados con el tiempo y que estos a su vez son inferiores si no se aplica ningún tipo de acabado. Finalmente fue encontrado que las relaciones de los parámetros de color (L*, a*, c*) y la relación entre los mismo parámetros (L*-a*, L*-b* y a*-b*) son alterados ante la intemperie por la aplicación de los acabados.Palabras claves: CIE Lab, fotodegradación, UV, cambio de color, madera tropical ABSTRACT Carapa guianensis and Cedrela odorata wood are used for furniture and doors manufacturing in Costa Rica. Similarly, two kind wood coatings (nitrocellulose and polyurethane) are widely used in these manufactures. However, the effects of degradation in the components of color (CIE L* a* b*) of these coatings by the weathering is little known for these wood species and these coatings. It was evaluated these coatings under weathering and it was found that surface painted with polyurethane and nitrocellulose produced significant change in wood color during the first 40-60 days of weathering and the intensity of color change was different in two coatings. The results showed that color changes in Carapa guianensis wood were lower measured by ∆E* than Cedrela odorata wood in two coating of surface treatments. Finally, it was found that there are relationships among wood color parameters (L*, a*, c*) with weathering time and the relationship between color parameters (L*-a*, L*-b* and a*-b*) are altered by the coatings.Key words: CIE Lab, photodegradation, UV, color change, tropical wood INTRODUCCIÓN La madera ha sido usada por su durabilidad natural, por ser un material sumamente versátil y con excelentes características de trabajabilidad (Peña y Rojas 2005). Sin embargo, una de las principales debilidades de este material es la susceptibilidad a la degradación del color natural por el intemperismo. La degradación del color de la madera ocurre rápidamente, en especial cuando es expuesta al intemperismo sin ningún tipo de protección o aislante (Peña y Rojas 2005). Factores ambientales como la radiación solar, la temperatura, el viento y la lluvia inciden sobre el cambio del color y se da en superficie debido a la penetración de luz ultravioleta y luz visible en la madera (George et al. 2005). La incidencia de estos tip...

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Section: Figuraunclassified

Efectos De La Intemperie en El Color De Dos Acabados Aplicados en Madera De Cedrela Odorata Y Carapa Guianensis

Valverde

Moya

2010

Maderas, Cienc. tecnol.

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“…The total color difference (ΔE * ) as a single number is often used to monitor the color change caused by photodegradation (Chang and Chang 2001;Ayadi et al 2003;Oltean et al 2008Oltean et al , 2010, but the ΔE * is not always reliable by itself. In some cases, ΔE * values do not match the visual observations.…”

Section: Introductionmentioning

confidence: 99%

Effects of Air Relative Humidity and Temperature on Photodegradation Processes in Beech and Spruce Wood

Tolvaj¹,

Popescu²,

Molnár³

et al. 2015

BioResources

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Spruce and beech samples were irradiated by UV light in humid (100% air humidity) and dry conditions to clarify the effects of vapor on photodegradation. UV-irradiated samples were also soaked in distilled water for comparison. The color change and the IR absorption spectra were measured. The wet condition generated considerably greater discoloration than did the dry condition. The intensity of the color change was higher at elevated temperature (53 °C) than at 32 °C. The results showed that the presence of water as vapor increased the degradation of lignin. The nonconjugated carbonyl groups absorbing around 1760 cm -1 were found not to be stable, and the number of these chemical groups decreased in the presence of vapor when compared against the dry condition. The rising temperature amplified this degradation effect.

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“…According to the same reports, lignin is altered chemically during the thermal modification through condensation and cross-linking reactions limiting free radical formation during weathering and related reactions on wood surface. On the other hand, such structure in lignin prevents leaching and ease removal of the products caused by photochemical degradation of wood surface (Nuopponen et al 2004, Ayadi et al 2003. Moreover, degradation of lignin molecules due to the heat treatments causes to increase phenolic monomers preventing less free radical formation during weathering.…”

Section: Color Changesmentioning

confidence: 99%

“…Moreover, degradation of lignin molecules due to the heat treatments causes to increase phenolic monomers preventing less free radical formation during weathering. Because, this phenomenon limits the reaction of oxygen and radicals (Ayadi et al 2003). Also, oil uptake by wood during the treatment and the formation of oil layer on the wood surface, cause to reduce intensity of color change (Dubey et al 2010).…”

Section: Color Changesmentioning

confidence: 99%

“…In the field of chemical modification, Rowell 2007 indicated that acetylation reduces wood weathering up to 50%, because the acetylation protects wood against the weathering (Akhtari et al 2007). Also, wood thermal modification in high temperatures greatly improves the durability of the wood against the weathering (Nuopponen et al 2004, Ayadi et al 2003. Thermal treatments affect the chemical structure of wood by heating in 160-260˚C and change its physical and mechanical properties (Militz 2002).…”

Section: Introductionmentioning

confidence: 99%

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Effects of oleothermal treatment and polydimethylsiloxane (PDMS) coating on natural weathering of beech and fir woods

Saei

Mohebby

Abdeh

2015

Maderas, Cienc. tecnol.

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Effects of natural weathering on oleothermally treated wood and coated with an organic silicone compound were studied. Slats of beech and fir woods were cut in sizes of 20×10×1 cm. The slats were treated by soybean oil at 230˚C for 1 h. Then, the half of the untreated and oleothermally treated slats were coated with polydimethylsiloxane (PDMS) and the rest of them were considered as control. All slats were hanged in 45˚ angle at the southwest (SW) direction for 90 days. They were analyzed for color changes, roughness, and contact angle properties at 30-day intervals. Results showed that the oleothermal treatment of wood reduced discoloration of fir samples against natural weathering; however, the reducing effect was lower in the Beech samples. This treatment also reduced the surface roughness of the fir samples during weathering while it increased the surface roughness of beech. Wettability of the samples in both species, before and after weathering, was reduced by the oleothermal treatment. Results also revealed that coating of the wood surface with PDMS does not prevent the discoloration and surface roughness against weathering. Nevertheless, the coating could considerably decrease the hydrophilicity of the woods even after weathering.

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Color stability of heat-treated wood during artificial weathering

Cited by 208 publications

References 9 publications

Efectos De La Intemperie en El Color De Dos Acabados Aplicados en Madera De Cedrela Odorata Y Carapa Guianensis

Efectos De La Intemperie en El Color De Dos Acabados Aplicados en Madera De Cedrela Odorata Y Carapa Guianensis

Effects of Air Relative Humidity and Temperature on Photodegradation Processes in Beech and Spruce Wood

Effects of oleothermal treatment and polydimethylsiloxane (PDMS) coating on natural weathering of beech and fir woods

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