Changes in surface and mechanical properties of heat treated wood during natural weathering

Tomak, Eylem Dizman; Ustaömer, Derya; Yıldız, Sibel; Peşman, Emrah

doi:10.1016/j.measurement.2014.03.018

Cited by 81 publications

(52 citation statements)

References 40 publications

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“…In addition, the increased fiber crystallinity during heat treatment may have caused the brittleness of the wood surface (Sun et al 2010;Tomak et al 2014;Pelit et al 2015).…”

Section: Effects Of Temperature On Surface Brittlenessmentioning

confidence: 99%

Surface Characteristics of Poplar Wood with High-Temperature Heat Treatment: Wettability and Surface Brittleness

et al. 2016

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The many uses of wood are greatly affected by its surface properties, which are significantly altered by heat treatment. Investigated here are the wettability and surface brittleness when treating poplar wood with heat at 160, 180, 200, and 220 °C for 2 h. Contact angles were measured by the sessile drop method, and surface free energy was calculated. Surface brittleness was expressed by hardness (HD value), roughness (Ra, Rq, Ry, and Rz values), and abrasive resistance (K value). Next, non-destructive Fourier transform near-infrared spectroscopic (FT-NIR) and X-ray photoelectron spectroscopic (XPS) measurements were employed to analyze the surface chemical changes. Scanning electron microscopy (SEM) revealed the post-heating microscopic structure. The results demonstrated that heat treatment reduces the surface wettability while increasing the surface brittleness, which becomes more apparent with increased temperature. Significant differences were determined (p < 0.05) between the surface parameters at four different temperatures. The degradation of cell wall components and the deterioration of microstructures was further expounded by FT-NIR, XPS, and SEM analyses. Furthermore, the abrasive resistance and hardness values decreased in line with the rate of weight loss (WL, %) and temperature. This indicates a strong correlation between the surface characteristics and the WL or temperature. The intensity of heat treatment appears to be predictable and easy to regulate.

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“…In addition, the increased fiber crystallinity during heat treatment may have caused the brittleness of the wood surface (Sun et al 2010;Tomak et al 2014;Pelit et al 2015).…”

Section: Effects Of Temperature On Surface Brittlenessmentioning

confidence: 99%

Surface Characteristics of Poplar Wood with High-Temperature Heat Treatment: Wettability and Surface Brittleness

et al. 2016

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“…La decoloración es el primer aspecto evidente durante el proceso de degradación de la madera expuesta en un ambiente exterior, seguido por la pérdida de masa, la cual según Kishino y Nakano (2004) y Tomak et al (2014) implica una disminución de las propiedades mecánicas. Conjuntamente, son identificados otros inconvenientes como la disminución del rendimiento de los productos aplicados a la superficie de la madera (Pastore et al 2008), productos tales como adhesivos y recubrimientos.…”

Section: Introductionunclassified

“…Numerosos trabajos científicos, tales como los de Chang et al (2010), Tovaj y Varga (2012) y Huang et al (2012) han sido dirigidos hacia la predicción del comportamiento de la madera y materiales a base de madera en exteriores, realizando para ello ensayos de envejecimiento artificial o acelerado por medio de cámaras climáticas, no obstante, los ensayos de campo (envejecimiento natural) son más realistas aunque mucho más lentos, ya que se exponen las muestras a condiciones más cercanas al uso práctico, como los presentan diversos autores, tales como Valverde y Moya (2010), Mattos et al (2013) Tomak et al (2014), los cuales evaluaron maderas de frondosas provenientes respectivamente de Brasil, Japón, Costa Rica y Turquía. Además, se han evaluado los tratamientos empleados sobre las muestras como en Temiz et al (2005), Silva et al (2007) y Huang et al (2012.…”

Section: Introductionunclassified

Color de la madera de dos eucaliptos expuestas al intemperismo natural en tres entornos ambientales diferentes

Delucis

Herrera²,

Labidi³

et al. 2016

Maderas, Cienc. tecnol.

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RESUMENLa degradación superficial en madera de exteriores se debe a una combinación de factores meteorológicos inherentes al entorno de exposición y a la colonización de organismos xilófagos. Desde un punto de vista técnico y económico se trata de uno de los principales problemas para la industria de productos y materiales hechos a partir de la madera. El objetivo del presente trabajo es el de monitorizar la degradación superficial de las maderas de Corymbia citriodora y Eucalyptus tereticornis originarias de plantaciones de rápido crecimiento de Brasil, las cuales han sido expuestas a ensayos de intemperismo natural en tres entornos ambientales distintos. La monitorización de los cambios en el material fue realizada mediante estimaciones del color (método CIEL*a*b*), en ciclos de 45 días, hasta completar un periodo de 360 días de exposición. Los resultados mostraron que el material expuesto al entorno forestal fue menos afectado por los factores ambientales, lo que ha sido probablemente debido al aislamiento térmico y solar que proporciona este tipo de ecosistema. A su vez, se observó que las probetas de madera de Corymbia citriodora presentaron mayor resistencia al deterioro que las probetas de madera de Eucalyptus tereticornis, posiblemente debido a ciertas diferencias en su constitución química.Palabras clave: Biodegradación, biodeterioro, Corymbia citriodora, Eucalyptus tereticornis, fotodegradación. ABSTRACTSurface degradation in outdoor wood and products is due to a combination of inherent climate factors together with colonization of decay organisms. From a technical and economic standpoint it is one of the main problems for the industry of products and materials made from wood. The aim of this work is to track the surface degradation of Corymbia citriodora and Eucalyptus tereticornis timbers originating from fast-growing plantations in Brazil, which have been exposed to outdoor weathering tests in three different environmental conditions. Changes in the material were monitoring using color measurement (CIEL*a*b* method), in cycles of 45 days up to a period of 360 days of exposure. The results showed that timber exposed to a forest ecosystem was less affected by environmental factors; this is probably due to climate insulation provided by these ecosystems. Besides, it was observed that samples of Corymbia citriodora had higher resistance to degradation compared with samples of Eucalyptus tereticornis, possibly due to differences in its chemical constitution.

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“…Tomak et al (2014) and Yildiz et al (2013) observed that natural or accelerated weathering led to a reduction in compression strength, modulus of rupture (MOR), and modulus of elasticity (MOE) in thermally modified wood. Although the color stability and photostability of thermally modified wood has improved (Ayadi et al 2003;Nuopponen et al 2004;Dubey et al 2010;Huang et al 2012a;Huang et al 2013), the color of most thermally modified wood is lightened during UV exposure or solar irradiation (Srinivas and Pandey 2012;Huang et al 2012b;Tomak et al 2014). Yildiz et al (2013) investigated the color change during artificial weathering of four heat-treated wood species (ash, iroko, Scots pine, and spruce) at 200 °C and suggested that the protective effect of heat-treatment was lost during longer weathering exposures.…”

Section: Introductionmentioning

confidence: 99%

Influence of Post-extraction on Photostability of Thermally Modified Scots Pine Wood during Artificial Weathering

Shen¹,

Cao²,

Sun³

et al. 2016

BioResources

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The photo-stabilizing effect of post-extraction was evaluated for thermally modified wood. Extracted and non-extracted thermally modified Scots pine (Pinus sylvestris L.) samples were exposed in a xenon weather-ometer for 1008 h, and the surface color and chemical changes were characterized using a chroma meter, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that: (1) the weight losses of thermally modified wood were higher than those of unmodified wood after extraction due to the leaching of some low molecular weight compounds that were generated during thermal modification; (2) the photodegradation of thermally modified wood during weathering was hindered by the presence of extractives; and (3) the color change during weathering was a little more severe in sapwood than in heartwood because more extractives were present in heartwood.

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Changes in surface and mechanical properties of heat treated wood during natural weathering

Cited by 81 publications

References 40 publications

Surface Characteristics of Poplar Wood with High-Temperature Heat Treatment: Wettability and Surface Brittleness

Surface Characteristics of Poplar Wood with High-Temperature Heat Treatment: Wettability and Surface Brittleness

Color de la madera de dos eucaliptos expuestas al intemperismo natural en tres entornos ambientales diferentes

Influence of Post-extraction on Photostability of Thermally Modified Scots Pine Wood during Artificial Weathering

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