Effect of Heat Treatment Conditions on Color Change and Termite Resistance of Heat-Treated Wood

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

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COLOR CHANGE — MASS LOSS CORRELATION FOR HEAT-TREATED WOOD

CBU International Conference Proceedings ◽

10.12955/cbup.v2.483 ◽

2014 ◽

Vol 2 ◽

pp. 345-352 ◽

Cited By ~ 2

Author(s):

Cristina Marinela Olarescu ◽

Mihaela Campean

Keyword(s):

Heat Treatment ◽

Mass Loss ◽

Color Change ◽

Treated Wood ◽

Untreated Wood ◽

Cost Effective ◽

Assessment Procedure ◽

Mathematical Correlation ◽

Heat Treated ◽

Two Parameters

Heat treatment is renowned as the most environmentally friendly process of dimensional stabilization that can be applied to wood, in order to make it suitable for outdoor uses. It also darkens wood color and improves wood durability. The intensity of heat treatment can be appreciated by means of two parameters: the color change occured in wood due to the high temperature, and the mass loss, which is a measure of the degree of thermal degradation. In order to find a mathematical correlation between these two parameters, an experimental study was conducted with four European wood species, which were heat-treated at 180°C and 200ºC, for 1-3 hours, under atmosheric pressure.The paper presents the results concerning the color changes and mass losses recorded for the heat-treated wood samples compared to untreated wood. For all four species, the dependency between the color change and the mass loss was found to be best described by a logarithmic regression equation with R2 of 0.93 to 0.99 for the soft species (spruce, pine and lime), and R2 of 0.77 for beech. The results of this study envisage to simplify the assessment procedure of the heat treatment efficiency, by only measuring the color – a feature that is both convenient and cost-effective.

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Heat-Treated Wood as a Substrate for Coatings, Weathering of Heat-Treated Wood, and Coating Performance on Heat-Treated Wood

Advances in Materials Science and Engineering ◽

10.1155/2019/8621486 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Vlatka Jirouš-Rajković ◽

Josip Miklečić

Keyword(s):

Heat Treatment ◽

Wood Species ◽

Treated Wood ◽

Wood Properties ◽

Treatment Method ◽

Coating Performance ◽

Treatment Processes ◽

Treatment Conditions ◽

Heat Treated ◽

Trade Names

Heat treatment is a method of wood modification with increasing market acceptance in Europe. The major patented European commercial heat treatment processes have trade names ThermoWood, Platowood, Retiwood, Le Bois Perdure, and Oil-Heat-Treated Wood (OHT). To what extent modification of wood affects the resistance of wood to weathering is also an important aspect for wood applications, especially where appearance is important. Unfortunately, heat-treated wood has poor resistance to weathering, and surface treatment with coatings is required for both protection and aesthetic reasons. As a substrate for coating, heat-treated wood has altered characteristics such as lower hygroscopicity and liquid water uptake and changed acidity, wettability, surface free energy, and anatomical microstructure. Various wood species, heat treatment method, treatment intensity, and treatment conditions exhibited a different extent of changes in wood properties. These altered properties could affect coating performance on heat-treated wood. The reported changes in acidity and in surface energy due to heat treatments are inconsistent with one another depending on wood species and temperature of the treatments. This paper gives an overview of the research results with regards to properties of heat-treated wood that can affect coating performance and weathering of uncoated and coated heat-treated wood.

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Termite Resistance, Chemical and Mechanical Characterization of Paulownia tomentosa Wood before and after Heat Treatment

Forests ◽

10.3390/f12081114 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1114

Author(s):

Bruno Esteves ◽

Helena Ferreira ◽

Hélder Viana ◽

José Ferreira ◽

Idalina Domingos ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

New Species ◽

Thermal Degradation ◽

Dimensional Stability ◽

Treated Wood ◽

Extractive Content ◽

Paulownia Tomentosa ◽

Termite Resistance ◽

Heat Treated

The introduction of new species in forest management must be undertaken with a degree of care, to help prevent the spread of invasive species. However, new species with higher profitability are needed to increase forest products value and the resilience of rural populations. Paulownia tomentosa has an extremely fast growth. The objective and novelty of this work was to study the potential use of young Paulownia trees grown in Portugal by using heat treatment to improve its properties, thereby allowing higher value applications of the wood. The average chemical composition of untreated and heat-treated wood was determined. The extractive content was determined by successive Soxhlet extraction with dichloromethane (DCM), ethanol and water as solvents. The composition of lipophilic extracts was performed by injection in GC-MS with mass detection. Insoluble and soluble lignin, holocellulose and α-cellulose were also determined. Physical (density and water absorption and dimensional stability) and mechanical properties (bending strength and bending stiffness) and termite resistance was also determined. Results showed that extractive content increased in all solvents, lignin and α-cellulose also increased and hemicelluloses decreased. Compounds derived from the thermal degradation of lignin were found in heat-treated wood extractions. Dimensional stability improved but there was a decrease in mechanical properties. Resistance against termites was better for untreated wood than for heat-treated wood, possibly due to the thermal degradation of some toxic extractives.

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Influence of Heat Treatment Process on the Acceptability of Pasteurized Beetroot

Quality of Life (Banja Luka) - APEIRON ◽

10.7251/qol1401039v ◽

2014 ◽

Vol 9 (1-2) ◽

Author(s):

Dragan P Vujadinović ◽

Božana V Odžaković ◽

Radoslav D Grujić ◽

Milija Perić

Keyword(s):

Heat Treatment ◽

Treatment Process ◽

Color Change ◽

Heat Treatment Process ◽

Optimal Conditions ◽

Optimum Time ◽

Treatment Conditions ◽

Heat Treated ◽

Treatment Procedures ◽

Temperature Time

Abstract: A heat-treated beet is defined as a food that is subject to a temperature, high enough to destroy microorganisms and to preserve all the nutrients. The aim of the study presented in this paper was to investigate the effect by cooking on the properties of heat threated beetroot in the temperature range between 75 °C and 115 °C during the 40, 50 and 60 minutes of cooking. In order to determine the optimal conditions for the implementation of various heat treatment procedures consequently, was followed the influence of heat treatment conditions (temperature/time) on the composition, rheological properties, pH, color change (L*, a*, b*) and sensory characteristics during the development of the “pasteurized/sterilized” beet product. This study has shown that the optimum time and temperature for processing of beetroot is 105 °C at 50 minutes. Samples of beetroot, processed under these conditions had the best softness, the most acceptable taste and color (sensory and instrumentally determined).

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Effect of copper incorporation on phase transformation behavior of electroless nickel–phosphorous coating and its effect on the tribological behavior

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420720981602 ◽

2020 ◽

pp. 146442072098160

Author(s):

Abhijit Biswas ◽

Suman Kalyan Das ◽

Prasanta Sahoo

Keyword(s):

Heat Treatment ◽

Phase Transformation ◽

Tribological Behavior ◽

Electroless Nickel ◽

Two Phase ◽

Microstructural Changes ◽

Treatment Conditions ◽

Heat Treated ◽

Higher Temperature ◽

Effect Of Copper

The microstructural changes of electroless Ni–P–Cu coating at various heat-treatment conditions are investigated to understand its implications on the tribological behavior of the coating. Coatings are heat-treated at temperatures ranging between 200°C and 800 °C and for 1–4 h duration. Ni–P–Cu coatings exhibit two-phase transformations in the temperature range of 350–450 °C and the resulting microstructural changes are found to significantly affect their thermal stability and tribological attributes. Hardness of the coating doubles when heat-treated at 452 °C, due to the formation of harder Ni3P phase and crystalline NiCu. Better friction and wear performance are also noted upon heat treatment of the coating at the phase transformation regime, particularly at 400 °C. Wear mechanism is characterized by a mixed adhesive cum abrasive wear phenomena. Heat treatment at higher temperature (600 °C and above) and longer duration (4 h) results in grain coarsening phenomenon, which negatively influences the hardness and tribological characteristics of the coating. Besides, diffusion of iron from the ferrous substrate as well as greater oxide formation are noticed when the coating is heat-treated at higher temperatures and for longer durations (4 h).

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Mechanical Behavior of Friction Stir Welded AA-6061 Thick Plates in Different Heat Treatment Conditions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.875.203 ◽

2021 ◽

Vol 875 ◽

pp. 203-210

Author(s):

Talha Ahmed ◽

Wali Muhammad ◽

Zaheer Mushtaq ◽

Mustasim Billah Bhatty ◽

Hamid Zaigham

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Aging Treatment ◽

Travel Speed ◽

Butt Joint ◽

Tensile Fracture ◽

Friction Stir ◽

Treatment Conditions ◽

Heat Treated ◽

Joint Form

In this study, mechanical properties of friction stir welded Aluminum Alloy (AA) 6061 in three different heat treatment conditions i.e. Annealed (O), Artificially aged (T6) and Post Weld Heat Treated (PWHT) were compared. Plates were welded in a butt joint form. Parameters were optimized and joints were fabricated using tool rotational speed and travel speed of 500 rpm and 350 mm/min respectively. Two sets of plates were welded in O condition and out of which one was, later, subjected to post weld artificial aging treatment. Third set was welded in T6 condition. The welds were characterized by macro and microstructure analysis, microhardness measurement and mechanical testing. SEM fractography of the tensile fracture surfaces was also performed. Comparatively better mechanical properties were achieved in the plate with PWHT condition.

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Wood Surface Changes of Heat-Treated Cunninghamia lanceolate Following Natural Weathering

Forests ◽

10.3390/f10090791 ◽

2019 ◽

Vol 10 (9) ◽

pp. 791

Author(s):

Xinjie Cui ◽

Junji Matsumura

Keyword(s):

Heat Treatment ◽

Wood Surface ◽

Color Change ◽

Thermal Modification ◽

Protective Measure ◽

Surface Color ◽

Natural Exposure ◽

Heat Treated ◽

The Impact ◽

Cunninghamia Lanceolate

To quickly clarify the effect of heat treatment on weatherability of Cunninghamia lanceolate (Lamb.) Hook., we investigated the surface degradation under natural exposure. A comparison between heat-treated and untreated samples was taken based on surface color changes and structural decay at each interval. Over four weeks of natural exposure, multiple measurements were carried out. Results show that color change decreased in the order of 220 °C heat-treated > untreated > 190 °C heat-treated. The results also indicate that the wood surface color stability was improved via the proper temperature of thermal modification. Low vacuum scanning electron microscopy (LVSEM) results expressed that thermal modification itself had caused shrinking in the wood surface structure. From the beginning of the weathering process, the heat treatment affected the surface structural stability. After natural exposure, the degree of wood structure decay followed the pattern 220 °C heat-treated > 190 °C heat-treated > untreated. Therefore, when considering the impact on the structure, thermal modification treatment as a protective measure to prevent weathering was not an ideal approach and requires further improvement.

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Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

European Journal of Wood and Wood Products ◽

10.1007/s00107-020-01616-8 ◽

2020 ◽

Author(s):

Lijie Qu ◽

Zhenyu Wang ◽

Jing Qian ◽

Zhengbin He ◽

Songlin Yi

Keyword(s):

Heat Treatment ◽

Thermal Stability ◽

Thermal Degradation ◽

Structural Changes ◽

Aluminum Sulfate ◽

Treated Wood ◽

Treatment Temperature ◽

Chinese Fir ◽

Heat Treated ◽

Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

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Calorific Power Improvement of Wood by Heat Treatment and Its Relation to Chemical Composition

Energies ◽

10.3390/en13205322 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5322

Author(s):

Idalina Domingos ◽

Umit Ayata ◽

José Ferreira ◽

Luisa Cruz-Lopes ◽

Ali Sen ◽

...

Keyword(s):

Heat Treatment ◽

Chemical Composition ◽

Lignin Content ◽

Treated Wood ◽

Untreated Wood ◽

High Heating Value ◽

Heat Treated ◽

Positive Linear Correlation ◽

Total Extractives ◽

Calorific Power

Chemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process ® for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54–19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R2 = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R2 = 0.04). The same was obtained in relation to ethanol extractives with R2 = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.

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