scholarly journals Effect of Heat Treatment on the Physic-Mechanical Characteristics of Eucalyptusurophylla S.T. Blake

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6643
Author(s):  
Lin Yang ◽  
Honghui Jin
Keyword(s):  
Dimensional Stability ◽  
Color Change ◽  
Chemical Change ◽  
Water Vapor Adsorption ◽  
Moderate Temperature ◽  
Modulus Of Rupture ◽  
Dry Density ◽  
Hydroxyl Groups ◽  
Eucalyptus Urophylla ◽  
Wood Color

Eucalyptus plantations wood have great potential application in high quality solid wood product. In order to improve the overall characteristics, heat treatments (HT) were carried out using Eucalyptus urophylla S.T. Blake wood at 150, 170 and 190 °C, for 2 and 4 h, separately. The effects of HT on physical and mechanical properties, wood color, dimensional stability and chemical change were investigated. The results indicate that: Mass loss (ML) of wood at a moderate temperature of 150 °C was small, but increased remarkably when temperature exceeds 170 °C. A maximum ML of 5.83% was observed at 190 °C/4 h; the velocity of water vapor adsorption and equilibrium moisture content (EMC) of HT wood decreased significantly, and varied considerably with treating severity; absolute dry density of HT wood decreased, presenting a similar tendency with ML, but the reduction was greater than ML; HT reduced the tangential and radial swelling ratio and swelling coefficients of wood, and improved the dimensional stability by 71.88% at 190 °C; modulus of rupture (MOR) and modulus of elasticity (MOE) of HT wood varied significantly in severer conditions, but there were no obvious changes in a moderate conditions at 150 °C; there was a slight color change at 150 °C, but wood color became more dark and uniform with treating severity; HT decreased the relative content of hydroxyl groups in wood components, improving wood dimensional stability. Color change of wood may be caused by variations of chromophoric groups and its own structure of lignin due to HT. Moderate temperature HT at 150 °C improved dimensional stability and color uniform of wood, but without reducing mechanical stress. This is a practical HT condition for Eucalyptus urophylla S.T. Blake.

scholarly journals Effect of Moderate Temperature Thermal Modification Combined with Wax Impregnation on Wood Properties

2020 ◽  
Vol 10 (22) ◽  
pp. 8231
Author(s):  
Jing-Wen Zhang ◽  
Hong-Hai Liu ◽  
Lin Yang ◽  
Tian-Qi Han ◽  
Qin Yin
Keyword(s):  
Mechanical Strength ◽  
Dimensional Stability ◽  
Color Change ◽  
Strength Loss ◽  
Wood Properties ◽  
Thermal Modification ◽  
Moderate Temperature ◽  
Modulus Of Rupture ◽  
Internal Surfaces ◽  
Higher Temperature

Thermal modification (TM) improves the hydrophobicity, dimensional stability, and durability of wood, but TM commonly results in severe color change and mechanical strength loss as wood is treated at higher temperature. In this study, Pterocarpus macrocarpus Kurz wood was thermally modified at moderate temperature (150 °C) and higher temperature (200 °C), and subsequently TM wood at 150 °C was subjected to wax impregnation (WI), the effect of a combination of TM and WI on the hygroscopicity, dimensional stability, and mechanical properties, as well as the micro-structure of wood, were investigated and compared. The results showed that the mass loss of wood was slight at 150 °C TM, while it became severe at 200 °C TM conditions. TM conditions affected the amount of the subsequent wax impregnation; the equilibrium moisture content (EMC), water absorption ratio, and adsorption and absorption swelling of the 150 °C TM + WI group were lower than that of 200 °C TM, and presented the lowest value. Moderate temperature TM could improve the hydrophobicity and dimensional stability of wood, but WI played a key role in the improvement. TM decreased the modulus of rupture (MOR) of wood, while WI improved the MOR. TM increased the modulus of elasticity (MOE) of wood, but WI had little effect on MOE; Scanning electron microscope (SEM) observation showed that the wax was successfully impregnated into the wood interior, and presented an even distribution on the internal surfaces of wood cells; Fourier-transform infrared spectroscopy (FTIR) spectra verified the changes of –OH and C=O after TM and TM + WI, which contributed to decreasing hygroscopicity and improving the dimensional stability of the wood. Impregnated wax improved wood mechanical strength, but decreased the lightness, and deepened the color of wood. The combination of thermal modification at moderate temperature with subsequent wax impregnation is a practical approach for improving wood properties.

scholarly journals Physical and chemical properties of Castanopsis fargesii wood after heat treatment in sand or vacuum media

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5821-5837
Author(s):  
Wen-Yu Qi ◽  
Cai Liu ◽  
Xiao-Lian Wu ◽  
Ji-Qing Li ◽  
Xin Guan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Dimensional Stability ◽  
Color Change ◽  
Lignin Content ◽  
Chemical Properties ◽  
Dry Density ◽  
Physical And Chemical Properties ◽  
Castanopsis Fargesii ◽  
Physical And Chemical ◽  
And Chemical Properties

Castanopsis fargesii is among the most prevalent hardwood species in South China. To improve the poor dimensional stability of C. fargesii wood, heat treatments were performed using vacuum or sand as the medium at four temperatures from 170 °C to 215 °C for 4 h. As a medium, vacuum or sand can create a low oxygen environment. The results showed that, as the temperature increased, the oven-dry density decreased, whereas the dimensional stability and the total color change (∆E*) increased with both media, two different changing patterns of a* and b* were observed, the lignin content increased, and the holocellulose content decreased. The oven-dry density decreased 9.4% and 25.5%, volume shrinkage ratio decreased 27.8% and 37.7%, and the ∆E* was 19.63 and 45.52, the lignin contents increased from 17.62% to 28.62% and 42.87%, and the holocellulose contents decreased from 80.49% to 69.43% and 51.04% when C. fargesii wood was heated under vacuum and with sand at 215 °C, respectively. Overall, sand heat treatment affected wood physical and chemical properties more than vacuum heat treatment. The analysis of functional groups and crystallinity also showed that there were severe changes in C. fargesii wood under sand heat treatment.

scholarly journals Effect of Thermal Modification Treatment on Some Physical and Mechanical Properties of Pinus oocarpa Wood

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 249
Author(s):  
Jhon F. Herrera-Builes ◽  
Víctor Sepúlveda-Villarroel ◽  
Jairo A. Osorio ◽  
Linette Salvo-Sepúlveda ◽  
Rubén A. Ananías
Keyword(s):  
Dimensional Stability ◽  
Color Change ◽  
Treated Wood ◽  
Heat Treatments ◽  
Thermal Modification ◽  
Raw Material ◽  
Added Value ◽  
Modulus Of Rupture ◽  
Promising Alternative ◽  
Pinus Oocarpa

This study deals with the effect of heat treatment on Pinus oocarpa specimens from forest plantations in Colombia. The effects of two heat treatments at 170 and 190 °C for 2.5 h in saturated vapor were evaluated based on the color, dimensional stability, air-dry and basic densities, modulus of elasticity (MOE), and modulus of rupture (MOR) in static bending of samples. The evaluations were carried out following the Colombian Technical Standards NTC 290 and 663, and the color changes resulting from heat treatments were monitored using the CIE-Lab, as well as other standards from the literature. The results show that there was 2.4% and 3.3% mass loss of wood modified at 170 and 190 °C, respectively. The air-dry and basic densities were higher in 170 °C treatment than after 190 °C treatment, and the thermal modifications applied increased the dimensional stability of the treated wood. After treatment at 170 and 190 °C, the lightness to darkness (L*) was reduced by 10% and 22%; the a* coordinate increased by 11% and 26%, causing redness in the treated wood; the b* coordinate increased by 14% and 17%; and the values of the wood color saturation (c*) increased by 14% and 18%, respectively. The general color change (ΔE*) increased gradually with the increase in the treatment temperature, resulting in a high color change to a very different color. The bending strength of thermally modified wood was improved and significantly increased to values higher than those of unmodified Pinus oocarpa wood. The high air-dry and basic densities, improved dimensional stability and resistance to bending, and attractive appearance of the treated wood indicate that thermal modification is a promising alternative for the transformation of Pinus oocarpa wood into a raw material with a high added value.

scholarly journals DECAY RESISTANCE, DIMENSIONAL STABILITY AND MECHANICAL STRENGTH OF POPLAR WOOD MODIFIED WITH PLANT-DERIVED COMPOUNDS

Wood Research ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 556-568
Author(s):  
JIAPENG WANG ◽  
ZHENJU BI ◽  
ZHANGJING CHEN ◽  
LI YAN ◽  
YAFANG LEI
Keyword(s):  
Mechanical Properties ◽  
Citric Acid ◽  
Dimensional Stability ◽  
Color Change ◽  
White Rot Fungi ◽  
Brown Rot ◽  
Decay Resistance ◽  
White Rot ◽  
Modulus Of Rupture ◽  
Weight Percentage

The cinnamaldehyde, salicylic acid, stearolic acid and citric acid were plant-derived organic compounds that can be activated to fungi, that could degrade the wood in long term. The compounds with concentrations of 3%, 5% and 7% assisted by different dispersants were impregnated into poplar (Populus nigra L.) specimens by the vacuum-pressure method. After that, weight percentage gain (WPG), decay resistance against white-rot fungi (Trametes versicolor) and brown-rot fungi (Gloeophyllum trabeum), color change, dimensional stability and mechanical properties including modulus of elasticity (MOE) and modulus of rupture (MOR) were measured. The results indicated that cinnamaldehyde impregnated poplar showed antifungi activity against both G. trabeumand T. versicolor, and citric acid impregnated poplar showed antifungi activity against G. trabeum. The color of poplar specimens before and after impregnated cinnamaldehyde and citric acid had a little change, dimensional stability had been improved and mechanical properties especially for MOR increased significantly.

scholarly journals Optimization of processing parameters for the manufacturing of jute stick binderless particleboard

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Ireen Parvin Nitu ◽  
Md Nazrul Islam ◽  
Md Ashaduzzaman ◽  
Md Khairul Amin ◽  
Md Iftekhar Shams
Keyword(s):  
Dimensional Stability ◽  
Processing Parameters ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Mixing Ratio ◽  
Press Temperature ◽  
Particle Mixing ◽  
Press Time

Abstract This study investigated the effects of processing parameters, namely particle mixing ratios, press temperatures, and time for the manufacturing of jute stick binderless particleboard (JBPB). Different ratios of fine and coarse particles, press temperature (160 to 240 °C) and press time (4 to 10 min) were used for JBPB fabrication with a target density of 0.9 g/cm3. The dimensional stability and mechanical properties of JBPB were determined according to Japanese Industrial Standard JIS A 5908 (2003). The result shows that the most favorable pressing conditions in the manufacturing process were press temperature of 220 °C for 6 min with a mixing ratio of 50:50 (fine: coarse). The modulus of rupture (MOR), modulus of elasticity (MOE), and internal bonding (IB) of JBPB was 16.35 N/mm2, 3872.99 N/mm2, and 1.07 N/mm2, respectively, which met the minimum requirement for type-18 of particleboard JIS A 5908 (2003) except for the value of MOR. The bonding mechanism was analyzed by the chemical changes in the raw materials after the fabrication of JBPBs. The pentosans present in the raw material decreased with the increased press temperatures. In this study, the hemicellulose was decomposed which may accelerate the self-bonding of the JBPB at high temperatures. The thermal gravimetric analysis (TGA) revealed that the JBPB showed good thermal stability with the increase of press temperatures. Fourier transform infrared (FTIR) spectra indicated that the removal of hydroxyl groups which increased the dimensional stability of JBPBs. Hence, it could be concluded that by controlling particle mixing ratio (50:50) at high press temperature with proper press time, high-performance jute stick binderless particleboard could be successfully developed which has a variety of applications.

Selected Properties of Parallel Strand Lumber Made from Southern Pine and Yellow-Poplar

Holzforschung ◽  
2003 ◽  
Vol 57 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Y. Liu ◽  
A.W.C. Lee
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Specific Gravity ◽  
Moisture Content ◽  
Dimensional Stability ◽  
Modulus Of Rupture ◽  
Southern Pine ◽  
Yellow Poplar ◽  
Average Modulus ◽  
Parallel Strand Lumber

Summary This study was conducted to explore basic physical and mechanical properties of parallel strand lumber (PSL) made exclusively from southern pine and yellow-poplar, respectively, and to examine their relationships using statistical analysis. Small specimens were prepared from commercial southern pine PSL and yellow-poplar PSL billets and tested for specific gravity, moisture content, dimensional stability, bending properties, shear strength and compressive strength. Results indicate average specific gravity of southern pine PSL is higher than that of yellow-poplar PSL, while their average moisture content and dimensional stability are very similar. Southern pine PSL has higher average modulus of elasticity but lower average modulus of rupture than yellow-poplar PSL. While average longitudinal shear strength does not exhibit differences between southern pine PSL and yellow-poplar PSL, average compressive strength of southern pine PSL is higher than that of yellow-poplar PSL. There are positive correlations among modulus of elasticity, modulus of rupture and specific gravity. PSL improves some properties of solid wood from which PSL is made.

Comparison of the color and weight change in Paulownia tomentosa and Pinus koraiensis wood heat-treated in hot oil and hot air

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Treated Wood ◽  
Pinus Koraiensis ◽  
Weight Changes ◽  
Paulownia Tomentosa ◽  
Wood Color ◽  
Color Changes ◽  
Hot Air ◽  
Heat Treated

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.

Wood-Polymer Composite Prepared by In Situ Synthesis of Copolymer within Wood and its Dimensional Stability

2010 ◽  
Vol 150-151 ◽  
pp. 1-5
Author(s):  
Yong Feng Li ◽  
Chi Jiang ◽  
Duo Jun Lv ◽  
Xiao Ying Dong ◽  
Yi Xing Liu
Keyword(s):  
Contact Angle ◽  
Porous Structure ◽  
Polymer Composite ◽  
Dimensional Stability ◽  
Value Added ◽  
Hydroxyl Groups ◽  
Wood Polymer ◽  
Volume Swelling ◽  
Wood Polymer Composite

In order to improve the value-added applications of low-quality wood, a novel Wood-Polymer Composite was fabricated by in-situ synthesis of copolymer from monomers within wood porous structure. The structure was characterized with SEM and FTIR, and its dimensional stability was also tested. The SEM observations showed that copolymer filled up wood pores and contact tightly with wood matrix, indicating strong interactions between them. FTIR analysis indicated that when the monomers copolymerized in situ wood porous structure, they also reacted with wood matrix by reaction of hydroxyl groups and ester groups, indicating chemical bond between the two phases, which is agreement with SEM observations. The volume swelling efficiency and contact angle of such composite were higher than those of wood, respectively, indicating good dimensional stability involving volume swelling efficiency and contact angle. Such composite could be potentially applied in fields of construction, traffic and indoor decoration.

scholarly journals Influence of wood properties and technological parameters of processing on cutting power in milling of thermally modified beechwood

2011 ◽  
pp. 109-124
Author(s):  
Marija Mandic ◽  
Nebojsa Todorovic ◽  
Ranko Popadic ◽  
Gradimir Danon
Keyword(s):  
Beech Wood ◽  
Untreated Wood ◽  
Treatment Temperature ◽  
Modulus Of Rupture ◽  
Dry Density ◽  
Technological Parameters ◽  
Cross Sectional ◽  
Measuring Device ◽  
Cutting Power ◽  
Wood Processing

The paper presents results of influence of thermal modification on cutting power required for milling wood processing. The experiment was conducted for the different treatment temperatures (170?C, 190?C and 210?C) and different technological parameters of processing (feed and cutting depth). Cutting powers during milling were measured on four groups of beech wood samples, dimensions 35?16?400 mm, separately for heartwood and sapwood. The following mechanical and physical properties of the processed samples were tested: bending properties (modulus of rupture and modulus of elasticity), cross-sectional and tangential hardness, and air-dry density. The measuring device used for measuring, monitoring and displaying cutting power was developed at the Wood Machining Centre at the Faculty of Forestry in Belgrade. The results point out the differences in the powers required for processing heat-treated wood compared to untreated wood. The analysis shows that with the increase in treatment temperature, the required cutting powers decrease.

Colorimetric H2O2 Detection Using Ag-Nanoparticle-Decorated Silica Microspheres

NANO ◽  
2020 ◽  
Vol 15 (01) ◽  
pp. 2050009 ◽  
Author(s):  
Zhikun Zhang ◽  
Qingqing Liu ◽  
Yumin Liu ◽  
Ran Qi ◽  
Lilong Zhou ◽  
...  
Keyword(s):  
Color Change ◽  
Colorimetric Detection ◽  
Hydroxyl Groups ◽  
Ag Nanoparticle ◽  
Silica Microspheres ◽  
Ag Nps ◽  
Practical Applications ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
H2o2 Detection

In view of the importance of convenient and rapid H2O2 detection for biological analysis, we herein propose Ag nanoparticle (NP)-decorated silica microspheres as a probe for instant and non-enzymatic on-site colorimetric detection of H2O2. The surface hydroxyl groups of silica microspheres were reacted with (3-mercaptopropyl)trimethoxysilane to afford thiolated microspheres that subsequently bind Ag NPs. The oxidation of residual –SH groups on the silica surface to –S–S– moieties in the presence of H2O2 induces the aggregation of decorated microspheres and is accompanied by a color change. Sensor response is found to be proportional to H2O2 concentration in the range from 100[Formula: see text]nM to 1[Formula: see text]mM, with UV–Vis and colorimetric detection limits determined as 10[Formula: see text][Formula: see text]M and 10[Formula: see text][Formula: see text]M, respectively. The developed platform is successfully used to detect H2O2 in simulated human urine and is, therefore, concluded to be sufficiently stable and selective for practical applications.

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