Water absorption behavior of heat-treated and untreated red balau saw dust/LDPE composites: Its kinetics and effects on mechanical properties

2018 ◽  
Vol 32 (10) ◽  
pp. 1408-1426 ◽  
Author(s):  
Ruth A Lafia-Araga ◽  
Aziz Hassan ◽  
R Yahya ◽  
N Abd Rahman ◽  
Fauzani Md Salleh
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Water Absorption ◽  
Water Immersion ◽  
Treated Wood ◽  
Untreated Wood ◽  
Thermoplastic Composites ◽  
Wood Composites ◽  
Saw Dust ◽  
Heat Treated

The hygroscopic nature of wood limits the use of wood thermoplastic composites (WTC) in outdoor industrial and domestic applications. To reduce this tendency, red balau saw dust was heat treated at 180 and 200°C for 1 h and compounded with Low Density Poly(ethylene) (LDPE) into 20 and 37 wt% and then molded into test specimens by injection molding. Samples were immersed in distilled water at room temperature for 4 months. Heat-treated wood composites showed remarkable water resistance relative to untreated ones. Wood composites made from wood treated at 180 and 200°C exhibited almost similar water absorption pattern. Reduced water absorption of heat-treated wood composites relative to untreated ones indicates that heat treatment has resulted in a degree of modification of the wood. Most of the composites displayed the Fickian mode of water absorption with n values close to 0.5. Also, the diffusion coefficient reduced with wood content in untreated wood composites due to interaction of water with the polar groups in wood through hydrogen bonding. Untreated wood composites exhibited poorer mechanical properties with water immersion as a result of degradation due to moisture. The mechanical properties of the heat-treated wood composites were not adversely affected with water absorption. Therefore, heat treatment can reduce the proneness to water absorption in WTCs and alleviate the detrimental effects on mechanical properties.

scholarly journals COLOR CHANGE — MASS LOSS CORRELATION FOR HEAT-TREATED WOOD

2014 ◽  
Vol 2 ◽  
pp. 345-352 ◽  
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. 

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

Energies ◽  
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.

Wettability of Heat-Treated Wood

Holzforschung ◽  
2003 ◽  
Vol 57 (3) ◽  
pp. 301-307 ◽  
Author(s):  
M. Pétrissans ◽  
P. Gérardin ◽  
I. El bakali ◽  
M. Serraj
Keyword(s):  
Heat Treatment ◽  
Water Drop ◽  
Chemical Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Adsorbed Water ◽  
Inert Atmosphere ◽  
Contact Angles ◽  
Heat Treated ◽  
Before And After

Summary The aim of this work was to study the wettability and chemical composition of heat-treated wood. Heat treatment was performed at 240°C under inert atmosphere on four European wood species (pine, spruce, beech and poplar). Contact angle measurements before and after treatment indicated a significant increase in wood hydrophobicity. Advancing contact angles of a water drop were in all cases systematically higher for heat-treated than for untreated wood. Chemical modifications of wood after heat treatment were investigated using FTIR and 13C NMR analysis. FTIR spectra indicated little structural change which could be attributed either to carbon-carbon double bond formation or to adsorbed water. NMR spectra also revealed little chemical change except for the degree of cellulose crystallinity which was considerably higher in heat-treated wood and could explain the higher contact angles.

scholarly journals Dimensional stability, fungal resistance and mechanical properties of radiata pine after combined thermo-mechanical compression and oil heat-treatment

Holzforschung ◽  
2016 ◽  
Vol 70 (8) ◽  
pp. 793-800 ◽  
Author(s):  
Manoj Kumar Dubey ◽  
Shusheng Pang ◽  
Shakti Chauhan ◽  
John Walker
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Dimensional Stability ◽  
Linseed Oil ◽  
Treated Wood ◽  
Untreated Wood ◽  
Radiata Pine ◽  
Fungal Resistance ◽  
Compression Set ◽  
Decay Test

Abstract The dimensional stability and mechanical properties of radiata pine (Pinus radiata) has been investigated after thermo-mechanically compression (TMC) followed by oil heat-treatment (OHT). Wood specimens were first compressed in the radial direction then heat-treated in a linseed oil bath at 160–210°C. Spring-back percentage, water repellence efficiencies, and compression set recovery percentage were determined as indicators of dimensional stability. The resistance of treated wood against a brown rot fungi was assessed based on an accelerated laboratory fungal decay test. Strength, stiffness and hardness were determined as a function of different treatment parameters. After TMC, high compression set (39%) was achieved without any surface checks and cracks. Specimens undergoing TMC followed by OHT showed relatively less swelling and low compression set recovery under high moisture conditions. The fungal resistance of wood after TMC+OHT slightly increased compared to untreated wood and TMC wood. The mechanical properties of TMC+OHT wood were inferior to those of TMC wood.

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

Forests ◽  
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.

scholarly journals Effect of Heat Treatment on Water Absorption of Chinese fir Using TD-NMR

2018 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Yulei Gao ◽  
Kang Xu ◽  
Hui Peng ◽  
Jiali Jiang ◽  
Rongjun Zhao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Water Absorption ◽  
Bound Water ◽  
Treated Wood ◽  
Free Water ◽  
Scientific Basis ◽  
Transport Processes ◽  
Chinese Fir ◽  
Frequency Coding ◽  
Heat Treated

Knowledge of the dynamic changes in the water absorption process of heat-treated wood is important for providing a scientific basis for the reasonable application of heat-treated wood, especially for outdoor applications. Nuclear magnetic resonance (NMR) techniques provide detailed information about the moisture components and moisture transport processes in wood, which are not available with other methods. In this work, water absorption of untreated and heat treated Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) heartwood was investigated using various NMR methods. The heat treatment temperatures were varied between 160 °C and 220 °C. According to the spin-spin relaxation time (T2), there were two components of water in the samples heat-treated at 160 °C and 180 °C as well as the untreated sample, while three components of water were found in the samples heat-treated at 200 °C and 220 °C, and the mass of each component was calculated by the integral peak areas of the T2 curve. The amount of bound water and free water in heat-treated samples were less compared to the untreated ones, and the water absorption decreased correspondingly, due to the increasing heat-treated temperature. The results obtained by one dimensional frequency coding indicated that the heat treatment made wood difficult to be accessed by moisture. Besides, NMR images revealed that the free water absorption in latewood was faster than in earlywood, but earlywood could absorb more water than latewood.

Untersuchungen zum Einfluss der Wärmebehandlung auf die Beständigkeit von Fichtenholz gegenüber holzzerstörenden Pilzen | Examination of the influence of heat treatment on the resistance of spruce timber to wood decaying fungi

2004 ◽  
Vol 155 (12) ◽  
pp. 548-554 ◽  
Author(s):  
Fritz Bächle ◽  
Peter Niemz ◽  
Markus Heeb
Keyword(s):  
Heat Treatment ◽  
Mass Loss ◽  
Ph Value ◽  
Treated Wood ◽  
Untreated Wood ◽  
Brown Rot ◽  
Nitrogen Atmosphere ◽  
White Rot ◽  
Heat Treated ◽  
Blue Stain

Spruce wood that was heat treated in rape oil (laboratory scale) and in an autoclave with a nitrogen atmosphere (industrial scale), respectively, was tested according to EN 113 for its resistance to basidiomycetes (4 brown and 1 white rot). In addition,resistance to blue-stain fungi was tested according to EN 152 and pH-values were measured in an outdoor ageing process. Influenced by the thermal treatment a clear decrease of mass loss induced by brown rot can be seen. There is an obvious influence of the kind of fungi and the level of treatment. Inoculated with Trametes versicolor (simultaneous white rot) a higher mass loss can be seen in the heat-treated specimens than in the untreated specimens. The big differences in the results between the fungi show that the type of fungi plays a role in the degree of influence. It would therefore seem that tests using only one fungus are insufficient. Similar results were achieved by testing previously weathered samples. The tendencies are not always similar. Blue-stain was occasionally detected near the surface of heat-treated wood. The pH-value of wood treated in an autoclave is clearly lower than that of untreated wood. The colour of the heat-treated wood is not UV stable. However, the colour achieved by the oil-heat-treatment is more stable than that achieved by a treatment in an autoclave.

scholarly journals The effect of heat treatment on the moisture absorption characteristics of Cu-impregnated Masson’s pine wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8459-8471
Author(s):  
Lamei Li ◽  
Guijun Xie ◽  
Wanju Li ◽  
Yixin Li ◽  
Xingwei Li
Keyword(s):  
Heat Treatment ◽  
Surface Area ◽  
Water Adsorption ◽  
Moisture Absorption ◽  
Bound Water ◽  
Treated Wood ◽  
Free Water ◽  
Untreated Wood ◽  
Pine Wood ◽  
Heat Treated

The accumulation of water inside wood creates a favorable environment not only for molds, but also for wood-decaying fungi and insects. Therefore, the ability to limit water adsorption and retention is key to the longevity and performance of wood. In this study, the effect of heat-treatment and Cu nanoparticle (CuNP) impregnation on surface contact angle, specific surface area, and hygroscopicity of Masson’s pine wood was examined. Heat-treatment caused thermal degradation of hydroxyl-rich biopolymers, leading to an increase in hydrophobicity; while the resulting breakdown and blockage of the interior cell cavity network caused a decrease in effective surface area. In turn, the hygroscopicity of the heat-treated wood was considerably lower than the untreated wood. Analysis of water adsorption isotherms enabled the differentiation between bound water and free water, where the latter was a prerequisite for mold growth. The research showed that the amount of free water was reduced by both impregnation with CuNP and heat-treatment, but the previously observed antimicrobial activity was shown to rely on the presence of CuNPs as opposed to the reduced free water content. This study presented a detailed methodology for the preparation and analysis of heat-treated, CuNP-impregnated wood, and provided further insight into the mechanism of antimicrobial action of treated woods.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

scholarly journals Effect of Water Ingress on the Mechanical and Chemical Properties of Polybutylene Terephthalate Reinforced with Glass Fibers

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1261
Author(s):  
Catarina S. P. Borges ◽  
Alireza Akhavan-Safar ◽  
Eduardo A. S. Marques ◽  
Ricardo J. C. Carbas ◽  
Christoph Ueffing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Water Uptake ◽  
Significant Influence ◽  
Water Immersion ◽  
Water Diffusion ◽  
Polybutylene Terephthalate ◽  
Chemical Changes ◽  
Water Ingress ◽  
Effect Of Water

Short fiber reinforced polymers are widely used in the construction of electronic housings, where they are often exposed to harsh environmental conditions. The main purpose of this work is the in-depth study and characterization of the water uptake behavior of PBT-GF30 (polybutylene terephthalate with 30% of short glass fiber)as well as its consequent effect on the mechanical properties of the material. Further analysis was conducted to determine at which temperature range PBT-GF30 starts experiencing chemical changes. The influence of testing procedures and conditions on the evaluation of these effects was analyzed, also drawing comparisons with previous studies. The water absorption behavior was studied through gravimetric tests at 35, 70, and 130 °C. Fiber-free PBT was also studied at 35 °C for comparison purposes. The effect of water and temperature on the mechanical properties was analyzed through bulk tensile tests. The material was tested for the three temperatures in the as-supplied state (without drying or aging). Afterwards, PBT-GF30 was tested at room temperature following water immersion at the three temperatures. Chemical changes in the material were also analyzed through Fourier-transform infrared spectroscopy (FTIR). It was concluded that the water diffusion behavior is Fickian and that PBT absorbs more water than PBT-GF30 but at a slightly higher rate. However, temperature was found to have a more significant influence on the rate of water diffusion of PBT-GF30 than fiber content did. Temperature has a significant influence on the mechanical properties of the material. Humidity contributes to a slight drop in stiffness and strength, not showing a clear dependence on water uptake. This decrease in mechanical properties occurs due to the relaxation of the polymeric chain promoted by water ingress. Between 80 and 85 °C, after water immersion, the FTIR profile of the material changes, which suggests chemical changes in the PBT. The water absorption was simulated through heat transfer analogy with good results. From the developed numerical simulation, the minimum plate size to maintain the water ingress unidirectional was 30 mm, which was validated experimentally.

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