scholarly journals Effects of Shellac Treatment on Wood Hygroscopicity, Dimensional Stability and Thermostability

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 881
Author(s):  
Mihaela Liu ◽  
Guanglin Xu ◽  
Jianan Wang ◽  
Xinwei Tu ◽  
Xinyou Liu ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Moisture Absorption ◽  
Morphological Characteristics ◽  
Treated Wood ◽  
Wood Products ◽  
Control Group ◽  
Water Repellent ◽  
Thermoplastic Resin ◽  
Weight Percentage ◽  
Thermogravimetric Curve

Dimensional stability proves to be an important factor affecting the quality of wooden products. As a sort of crude and thermoplastic resin, shellac excreted by lac insects demonstrates water-repellent and environmental-friendly features. The research impregnated shellac with wood at room temperature and with a vacuum-pressure procedure. Efforts were made to examine how shellac treatment affected the dimensional stability, moisture absorption, chemical structure, thermostability, as well as morphological characteristics of wood. Results indicated that shellac treatment was a type of efficient solution useful in the enhancement of the dimensional stability of wood. Shellac solution had good permeability in the wood, and the weight percentage gain reached 13.01% after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 20.13% and 24.12%, respectively, indicating that impregnation could improve wood dimensional stability. The moisture absorption of shellac-treated wood was reduced by 38.15% under 20 °C and 65% relative humidity. Moreover, shellac treatment significantly modified wood structure, although there were no drastic changes in the spectra. Specimens for shellac treatment ran across two decomposition peaks at 350 and 390 °C, and specimens in the control group saw one more common derivative thermogravimetric curve when the sharp peak approached 355 °C. After impregnation of shellac into wood, the shellac blocked pits and hardened on the intrinsic layer of the wood for fear of hygroscopicity. The practice was applicable to a variety of wood products, such as buildings, furniture, and landscape architecture.

scholarly journals A comparative study on the effects of linseed oil and shellac treatment on the hygroscopicity, dimensional stability, and color changes of Chinese ash wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8085-8092
Author(s):  
Mihaela Liu ◽  
Xinwei Tu ◽  
Xinyou Liu ◽  
Zhihui Wu ◽  
Jiufang Lv ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Moisture Absorption ◽  
Linseed Oil ◽  
Morphological Characteristics ◽  
Treated Wood ◽  
Water Repellency ◽  
Wood Products ◽  
Color Changes

Linseed oil and shellac are natural, environmentally friendly materials with good water repellency. They were used to impregnate Chinese ash wood at room temperature (20 °C) using a vacuum-pressure procedure (consisting of three cycles of 0.01 MPa for 1.5 h and atmospheric pressure for 1.5 h) to improve the dimensional stability of wood. The effects of the impregnation treatment on wood color changes, dimensional stability, moisture absorption, and morphological characteristics were evaluated. The linseed oil and shellac treatment improved the dimensional stability of wood. Linseed oil and shellac displayed good permeability in Chinese ash wood, with weight gains of 21.7% and 19.0%, respectively, after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 15 to 22%, indicating that impregnation improved the dimensional stability of wood. Linseed oil and shellac solidified and occluded the pits within the wood interior to prevent moisture absorption. This method can be used to improve the dimensional stability of a variety of wood products, such as buildings, furniture, and landscape architecture.

scholarly journals EFFICACY OF LINSEED OIL-TREATED WOOD TO IMPROVE HYDROPHOBICITY, DIMENSIONAL STABILITY, AND THERMOSTABILITY

Wood Research ◽  
2021 ◽  
Vol 66 (5) ◽  
pp. 777-788
Author(s):  
MIHAELA LIU ◽  
JIANAN WANG ◽  
GUANGLIN XU ◽  
XIN WEI TU ◽  
XIN YOU LIU ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Landscape Architecture ◽  
Chemical Structure ◽  
Room Temperature ◽  
Moisture Absorption ◽  
Linseed Oil ◽  
Morphological Characteristics ◽  
Treated Wood ◽  
Wood Products ◽  
Wood Moisture

Inthis work, linseed oil was impregnated into the wood at room temperature, under vacuum pressure. The properties of linseed oil-treated wood, including dimensional stability, wood moisture absorption, chemical structure, thermostability, and morphological characteristics, were evaluated. Linseed oil displayed good permeability in Ailanthuswood, with weight gains of 30.95% after impregnation. The swelling coefficients of treated woodin the tangential and radial directions decreased by 25.97 to 33.33%, indicating that impregnation improved the dimensional stability of wood.Moreover, linseed oil treatment significantly modified the wood structure, although the FTIR spectra generally remained unchanged. Observation by scanning electron microscopy showed, that linseed oil impregnated into the wood and occluded pits, thereby prevented moisture absorption. This technique can be used in a variety of wood products, such as buildings, furniture, and landscape architecture.

scholarly journals Establishment of moisture diffusion regularities through the polymer shell of thermally modified wood

2021 ◽  
Vol 12 (1) ◽  
pp. 41-47
Author(s):  
Yu. V. Tsapko ◽  
O. Yu. Horbachova
Keyword(s):  
Dimensional Stability ◽  
Experimental Studies ◽  
Treated Wood ◽  
Moisture Diffusion ◽  
Wood Products ◽  
Heating Process ◽  
Polymer Shell ◽  
Coating Application ◽  
Thermally Modified Wood ◽  
Modified Wood

An analysis of the process of thermal modification of wood, which was obtained by a controlled heating process, was done. The unique technological properties (durability, low hygroscopicity and dimensional stability) of thermomodified wood make it possible to use it in various scope. Due to the influence of temperature there are some chemical changes in the structures of the wood cell wall components (lignin, cellulose and hemicellulose). This leads to an increase in density, hardness, improved hydrophobicity (water repellency), thereby reducing their ability to absorb moisture and swell. The products absorb moisture gradually, are less prone to swelling and shrinkage, but still need the elastic coatings application. It is proved that heat-treated wood turns gray over time under the influence of sunlight, and therefore requires additional surface treatment with a coating. Additional protective substances application on the thermo-modified wood products surface promotes dimensional stability and protects against rapid weathering of the surface in open air conditions. The use of transparent coatings and oils does not protect the surface from discoloration during weathering. They are recommended for products are manufactured from thermomodified wood, which are operated away from direct sunlight and rain. The parameters of moisture penetration into wood are mathematically modeled on the basis of the moisture diffusion quasi-stationary equation through the polymer coating on the flat sample surface. The dynamics of moisture content changes in thermally modified wood by different schedules parameters has been experimentally studied. The obtained mathematical relations based on the experimental studies results make it possible to calculate the moisture diffusion coefficient in thermally modified wood in the presence of a polymer shell. It is established that the wax coating application on the surface of the product reduces the moisture diffusion process more than 10 times for surfaces treated at a temperature of 160 °C for 1 hour. That is, such products can be used on objects with high humidity.

Evaluation of water related properties of birch wood products modified with different molecular weight phenol-formaldehyde oligomers

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Juris Grinins ◽  
Vladimirs Biziks ◽  
Janis Rizikovs ◽  
Ilze Irbe ◽  
Holger Militz
Keyword(s):  
Molecular Weight ◽  
Dimensional Stability ◽  
Phenol Formaldehyde ◽  
Treated Wood ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Solid Wood ◽  
Wood Products ◽  
Birch Wood ◽  
Molecular Weights

Abstract This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the dimensional stability of birch solid wood and plywood. Therefore, three different low molecular weight PF resins with average molecular weights (M w ) of 292, 528, and 884 g/mol were synthesized and used for silver birch (Betula pendula) solid wood (20 × 20 × 20 mm3) and veneer (100 × 100 × 1.4 and 300 × 300 × 1.4 mm3) impregnation to produce plywood. The weight percent gain (WPG) and bulking after curing of resin treated wood specimens were determined. The leaching was performed to evaluate the PF resin fixation stability. All tested resins at all concentrations were similarly fixed in wood blocks after the leaching (1.5–2.0% WPG loss). The dimensional stability of birch wood after treatment with all tested PF resins was significantly improved. The anti-swelling efficiency (ASE) of birch wood blocks treated with PF resins after seven water soaking-drying cycles was in the range of 39–53%, 46–65% and 49–65% using 10, 15 and 20% solution concentrations, respectively. Whereas, the ASE of plywood obtained from veneers treated with 10% of PF solution was improved by 6–20%. The equilibrium moisture content (EMC) and volumetric swelling (VS) of PF treated plywood at 98% of relative humidity (RH) decreased significantly. All PF resin treated plywood surfaces were more hydrophobic compared to untreated plywood.

Effect of High Temperature and Steam on Dimensional Stability of Wood

2014 ◽  
Vol 513-517 ◽  
pp. 151-155 ◽  
Author(s):  
Hua Chun Qi ◽  
Yao Xing Sun
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
High Temperature ◽  
Dimensional Stability ◽  
Cryptomeria Japonica ◽  
Superheated Steam ◽  
Moisture Absorption ◽  
Treated Wood ◽  
Ambient Condition ◽  
Wood Flooring

Japanese Sugi (Cryptomeria japonica D.Don) wood was dried by superheated steam under the temperature of 140,160,180°C and the relative humidity of 100% to make wood flooring. Moisture absorption and desorption characteristics, Fourier Transform Infrared Spectroscopy of treated wood were analyzed to investigate the dimensional stability at saturated and dry ambient condition. The results showed that the dimensional stability of wood treated with superheated steam under high temperature was significantly improved.

scholarly journals Currency Note Paper and Banana Fiber Pulp Waste Utilization and its Effect of Density, Moisture and Temperature on Wood Products

2019 ◽  
Vol 8 (3) ◽  
pp. 6484-6487
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Moisture Absorption ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Waste Utilization ◽  
Wood Products ◽  
Control Group ◽  
Banana Fiber ◽  
Currency Note

Possibilities for use of banana fiber and currency notes thermally modified groups were evaluated for the production of plywood boards in industrial conditions. Formats of groups were treated at temperatures of 190 °C, 200 °C, 210 °C, and 215 °C for each 9 h to making the pulp process. By combining the treated and non-treated formats of veneer in types of board groups, thirteen different types of board were made. Analysis showed that the examined physical and mechanical properties were influenced by both the type of construction and the applied thermal treatment. Boards composed only of thermally modified group achieved the best results regarding moisture absorption and dimensional stability, and boards composed of the combined currency notes and banana fiber had better mechanical properties. As per the analysis of plywood board when used banana fiber used in pulp of plywood board is suitable at190 °C temperature rather than 215 °C temperature with comparing the other types of board. 25 °C temperature is less requires for control group board. We can consume cost of heat which is used in this process and getting the hard quality of plywood. At 215 °C temperature of processing cost of heat is 10% of plywood cost and when at 190°C of processing the cost of heat is 9.06% of plywood cost so that we can consume 0.94% cost of heat. Moisture content of temperature conditioned boards of control group is 9.01% density of conditioned boards 436.36 kg/m3 . Highest bending strength and modulus of elasticity of boards is 48.07MPa and 6078 MPa in longitudinal direction and bending strength and modulus of elasticity of boards in cross-section 28.40MPa and 2027 MPa.

Study on the Impact of Two Kinds Modification Methods on the Dimensional Stability of Poplar

2013 ◽  
Vol 341-342 ◽  
pp. 42-48
Author(s):  
Zhi Bo Feng ◽  
Guo Zheng Zou ◽  
Gang Chen ◽  
Jia Bin Cai
Keyword(s):  
Water Absorption ◽  
Dimensional Stability ◽  
Absorption Rate ◽  
Moisture Absorption ◽  
Tangential Direction ◽  
Resistance Rate ◽  
Shrinkage Rate ◽  
Control Group ◽  
Swelling Rate ◽  
The Impact

Fast-growing poplars are used as test materials in this study, which are respectively first carbonized then impregnated treatment and carbonized treatment, to test the dimensional stability of modified wood. The results show: the shrinkage rate of specimen which is first carbonized then impregnated is higher than the control group as much as 87.80% ~ 89.16% in radical direction, 76.20%~82.43% in tangential direction; from oven-dry state to air-dry state, the swelling rate of specimen is higher than the control group as much as 5.26% , 9.09%, and to saturated state, the rate is lower than the control group as 14.55% and 0.13% respectively in radical direction and tangential direction, as a result, the characters of shrinkage and swelling are not improved. When carbonized, the shrinkage rate of specimen is lower than the control group as 3.01%~8.47% and 5.08%~5.86% respectively in radical direction and tangential direction; the swelling rate is lower than control group as 23.84%~41.05% and 12.01%~43.75% respectively in radical direction and tangential direction, as a result, the character of shrinkage is poorly improved but swelling is obviously improved. After the two modified treatments, moisture absorption rate is respectively 6.99% and 4.91%, both lower than the control group8.80%; moisture resistance rate respectively 20.57% and 44.20%; water absorption rate 107.27% and 123.74%, lower than the control group 210%; resistance to water absorption up to 48.92% and 41.08%. Know then, carbonization treatment is better in terms of the affect on improving dimensional stability of wood.

scholarly journals Low viscosity melamine urea formaldehyde resin as a bulking agent in reducing formaldehyde emission of treated wood

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2195-2211
Author(s):  
Rabiatol Adawiah Mohd Ali ◽  
Zaidon Ashaari ◽  
Seng Hua Lee ◽  
Mohd Khairun Anwar Uyup ◽  
Edi Suhaimi Bakar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dimensional Stability ◽  
Urea Formaldehyde ◽  
Treated Wood ◽  
Physical And Mechanical Properties ◽  
Formaldehyde Emission ◽  
Wood Products ◽  
Formaldehyde Resin ◽  
Low Viscosity ◽  
Resin Impregnation

Melamine urea formaldehyde (MUF) resin impregnation followed by heat compression is a prominent method in improving mechanical properties and dimensional stability of wood. In addition, melamine is reactive to formaldehyde, and therefore able to reduce the free formaldehyde of the treated wood. This study aimed to produce compressed sesenduk (Endospermum diadenum) wood with low formaldehyde emission using low viscosity MUF resin. The effects of treatment efficiency on the physical and mechanical properties of the wood products were evaluated. The experimental design included impregnation of sesenduk strips with 20% and 30% MUF at five different formulations. Then, it was pre-cured at a temperature of 70 °C for 90 min, followed by hot compression at 140 °C with the compression ratio of 80%. The optimum treatment combination was determined through treatability, mechanical strength, dimensional stability, and formaldehyde emission. It was also compared to other treatments, including impregnation without further compression using formulated MUF and commercial MUF. The results revealed that F4 MUF, which consisted of 30% melamine, 50% formaldehyde, and 20% urea, was the optimal MUF formulation that resulted in low formaldehyde emission and acceptable physical and mechanical properties.

Evaluation of the hygroscopicity and dimensional stability of silicone oil treated wood

Holzforschung ◽  
2020 ◽  
Vol 74 (8) ◽  
pp. 811-815
Author(s):  
Zhengbin He ◽  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Songlin Yi
Keyword(s):  
Service Life ◽  
Dimensional Stability ◽  
Moisture Absorption ◽  
Silicone Oil ◽  
Treated Wood ◽  
Lignocellulosic Material ◽  
Different Temperatures ◽  
Swelling Coefficient ◽  
Stability Results

AbstractWood is a renewable natural lignocellulosic material. However, its hygroexpansion characteristics dramatically shorten its service life, and limit its application. In this study, wood was treated in a silicone oil bath at different temperatures to improve its dimensional stability. Results demonstrated that the silicone oil treatment decreased the tangential swelling coefficient by 13% when treated at 80 °C and by 34% when treated at 160 °C and the radial swelling coefficient by 12% when treated at 80 °C and by 49% when treated at 160 °C. Also, the moisture absorption was reduced by the treatment.

A review on life cycle assessments of thermally modified wood

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kévin Candelier ◽  
Janka Dibdiakova
Keyword(s):  
Life Cycle ◽  
Environmental Impacts ◽  
Treated Wood ◽  
Single Step ◽  
Thermal Modification ◽  
Wood Products ◽  
Wood Preservation ◽  
Cumulative Energy ◽  
Thermally Modified Wood ◽  
Cumulative Energy Intake

AbstractThis review compiles various literature studies on the environmental impacts associated with the processes of thermal modification of wood. In wood preservation field, the wood modification by heat is considered as an ecofriendly process due to the absence of any additional chemicals. However, it is challenging to find proper scientific and industrial data that support this aspect. There are still very few complete studies on the life cycle assessment (LCA) and even less studies on the environmental impacts related to wood heat treatment processes whether on a laboratory or on an industrial scales. This comprehensive review on environmental impact assessment emphasizes environmental categories such as dwindling of natural resources, cumulative energy intake, gaseous, solid and liquid emissions occurred by the thermal-treated wood industry. All literature-based data were collected for every single step of the process of wood thermal modification like resources, treatment process, transport and distribution, uses and end of life of treated wood products.

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