Mechanical properties changes in fir wood (abies sp.), linden wood (tilia sp.), and beech wood (fagus sp.) subjected to various thermal modification process conditions

Abstract Wood is one of the most important construction materials in Europe and its use in building applications has increased in the recent decades. To enable even more extensive and reliable use of wood, this article aimed to determine the effect of thermal modification on mechanical properties of fir wood (lat. Abies sp.), linden wood (lat. Tilia sp.), and beech wood (lat. Fagus sp.). The thermal modification was conducted in a laboratory oven at five different temperatures of 170, 180, 195, 210, 220 °C and processed with a different maximum duration of the process of 78, 120, 180, 240, 276 minutes. Mechanical properties of treated wood have shown statistically insignificant fluctuations at lower temperatures compared to control samples. On the other hand, raising the temperature to 210 °C significantly affected the strength of all the species. The results revealed that thermal modification at high temperatures and longer exposure causes a decrease in the maximum force of the three wood species.

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Physical and Mechanical Properties of Thermally-Modified Beech Wood Impregnated with Silver Nano-Suspension and Their Relationship with the Crystallinity of Cellulose

Polymers ◽

10.3390/polym11101538 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1538 ◽

Cited By ~ 11

Author(s):

Siavash Bayani ◽

Hamid R. Taghiyari ◽

Antonios N. Papadopoulos

Keyword(s):

Mechanical Properties ◽

Physical Properties ◽

Low Temperatures ◽

Beech Wood ◽

Treated Wood ◽

Physical And Mechanical Properties ◽

Thermal Modification ◽

Crystalline Cellulose ◽

Cross Linking ◽

Amorphous Cellulose

The aim of this study was to investigate the physical and mechanical properties of thermally modified beech wood impregnated with silver nano-suspension and to examine their relationship with the crystallinity of cellulose. Specimens were impregnated with a 400 ppm nanosilver suspension (NS); at least, 90% of silver nano-particles ranged between 20 and 100 nano-meters. Heat treatment took place in a laboratory oven at three temperatures, namely 145, 165, and 185 °C. Physical properties and mechanical properties of treated wood demonstrated statistically insignificant fluctuations at low temperatures compared to control specimens. On the other hand, an increase of temperature to 185 °C had a significant effect on all properties. Physical properties (volumetric swelling and water absorption) and mechanical properties (MOR and MOE) of treated wood demonstrated statistically insignificant fluctuations at low temperatures compared to control specimens. This degradation ultimately resulted in significant decrease in MOR, impact strength, and physical properties. However, thermal modification at 185 °C did not seem to cause significant fluctuations in MOE and compression strength parallel to grain. As a consequence of the thermal modification, part of amorphous cellulose was changed to crystalline cellulose. At low temperatures an increased crystallinity caused some of the properties to be improved. Crystallinity also demonstrated a decrease in NS-HT185 in comparison to HT185 treatment. TCr indices in specimens thermally treated at 145 °C revealed a significant increase as a result of impregnation with nanosilver suspension. This improvement in TCr index resulted in a noticeable increase in MOR and MOE values. Other properties did not show significant fluctuations, suggesting that the effect of the increased crystallinity and cross-linking in lignin was more than the negative effect of the low cell-wall polymer degradation caused by thermal modification. Change of amorphous cellulose to crystalline cellulose, as well as cross-linking in lignin, partially ameliorated the negative effects of thermal degradation at higher temperatures and therefore, compression parallel to grain and modulus of elasticity did not decrease significantly. Overall, it can be concluded that increased crystallinity and cross-linking in lignin can compensate for some decreased properties caused by thermal modification, but it would be significantly dependent on the temperature under which modification is carried out. Impregnating specimens with silver nano-suspension prior to thermal modification enhanced the effects of thermal modification as a result of improved thermal conductivity.

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Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests

Holzforschung ◽

10.1515/hf.2009.085 ◽

2009 ◽

Vol 63 (4) ◽

Cited By ~ 21

Author(s):

Stefanie Stanzl-Tschegg ◽

Wilfried Beikircher ◽

Dieter Loidl

Keyword(s):

Mechanical Properties ◽

Cell Wall ◽

Thermal Treatment ◽

Mechanical Performance ◽

Growth Ring ◽

Beech Wood ◽

Thermal Modification ◽

Wood Structure ◽

Instrumented Indentation ◽

Indentation Tests

Abstract Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.

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Physical and Mechanical Properties of Ammonia-Treated Black Locust Wood

Polymers ◽

10.3390/polym12020377 ◽

2020 ◽

Vol 12 (2) ◽

pp. 377 ◽

Cited By ~ 5

Author(s):

Mariana Domnica Stanciu ◽

Daniela Sova ◽

Adriana Savin ◽

Nicolae Ilias ◽

Galina A. Gorbacheva

Keyword(s):

Mechanical Properties ◽

Black Locust ◽

Loss Modulus ◽

Colour Change ◽

Treated Wood ◽

Physical And Mechanical Properties ◽

Mechanical Analysis ◽

Modulus Of Rupture ◽

Elastic Behaviour ◽

Control Samples

Because of the uneven colour of black locust wood, different technologies are used to change the colour, the bestknown being chemical and thermal treatments. Some of them affect the mechanical properties of wood, such as elasticity modulus, strength, durability. This study aims to compare the physical and mechanical properties of black locust wood control samples and treated wood samples with ammonia hydroxide, in terms of density profile, colour values (CIE L*, a*, b*), mechanical properties of samples subjected to static bending, viscous-elastic properties (storage modulus (E’), loss modulus (E”) and damping (tanδ)). Two types of ammonia-fuming treatment were applied on samples: first treatment T1-5% concentration of ammonia hydroxide for 30 days; second treatment T2-10% concentration for 60 days. The results highlighted the following aspects: the overall colour change in the case of the second treatment is 27% in comparison with 7% recorded for the control samples; the lightness and yellowness values are the most affected by the second ammonia treatment of black locust wood. The density increased with almost 20% due to ammonium fuming (10% concentration/60 days); in case of static bending, the elastic modulus (MOE) tends to decrease with increasing the exposure time to ammonium, but the modulus of rupture (MOR) increases with almost 17% and the breaking force increases too, with almost 41%. In the case of dynamic mechanical analysis, the temperature leads to different viscous-elastic behaviour of each type of samples.

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A study of mineral coal physical and mechanical properties changes in thermal modification process

Obogashchenie Rud ◽

10.17580/or.2016.03.01 ◽

2016 ◽

pp. 3-8

Author(s):

V. A. Arsentyev ◽

◽

A. M. Gerasimov ◽

S. V. Dmitriev ◽

A. D. Samukov ◽

...

Keyword(s):

Mechanical Properties ◽

Physical And Mechanical Properties ◽

Thermal Modification ◽

Modification Process

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INFLUENCE OF THERMAL MODIFICATION ON THE PHYSICAL AND MECHANICAL PROPERTIES OF Eucalyptus badjensis MIXED PARTICLEBOARD / OSB PANELS

FLORESTA ◽

10.5380/rf.v51i2.69403 ◽

2021 ◽

Vol 51 (2) ◽

pp. 419

Author(s):

Giuliano Ferreira Pereira ◽

Setsuo Iwakiri ◽

Rosilani Trianoski ◽

Polliana D'angelo Rios ◽

Renan Zunta Raia

Keyword(s):

Mechanical Properties ◽

Water Absorption ◽

Phenol Formaldehyde ◽

Physical And Mechanical Properties ◽

Dry Mass ◽

Thermal Modification ◽

Modulus Of Rupture ◽

Thickness Swelling ◽

Swelling Properties ◽

Different Temperatures

The objective of this research was to evaluate the effects of thermal modifications, at different temperatures and exposure times, on the technological properties of mixed particleboard / OSB panels made out of Eucalyptus badjensis. Using the wood of Eucalyptus badjensis, Particleboard, OSB and mixed Particleboard/OSB panels (control and thermally modified) were manufactured. The mixed panels’ thermal modification was carried out under three temperatures (180ºC, 200ºC and 220ºC) and two exposure times (10 minutes and 12 minutes). For the panels’ manufacturing, 6% of phenol-formaldehyde adhesive and 1% of paraffin were employed, which was calculated based on the particles’ dry mass. The water absorption and thickness swelling properties were evaluated after 2 and 24 hours of immersion, in addition to the panels’ modulus of elasticity, modulus of rupture and internal bond. Based on the results, we were able to conclude that the thermal modification affected most of the physical properties positively. From the different exposure times studied, the most effective one was the period of 12 minutes, especially for water absorption after 2 hours, which caused a reduction of 11.27%. In turn, the most effective temperature was of 220ºC, highlighting the thickness swelling after 24 hours, which caused a swelling decrease of 23.76% in comparison with the control panels. Regarding the mechanical properties, the thermal modification, in terms of the studied exposure times and temperatures, did not affect the results of the mixed particleboard /OSB panels.

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Use of Thermo-Modified Wood Massif in Making Parametric Exterior Furniture

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.36.25045 ◽

2018 ◽

Vol 7 (4.36) ◽

pp. 1112 ◽

Cited By ~ 3

Author(s):

A. R. Shaikhutdinova ◽

R. R. Safin ◽

F. V. Nazipova ◽

S. R. Mukhametzyanov

Keyword(s):

Treated Wood ◽

Thermal Modification ◽

Saturated Steam ◽

Polished Surface ◽

Duration Of Treatment ◽

Heat Treated ◽

Different Temperatures ◽

Convective Thermal ◽

Thermally Modified Wood ◽

Modified Wood

This paper proposes the use of an array of heat-treated wood of various species to make parametric furniture for the purpose of operation in the exterior, and on objects in conditions of high humidity. The dependence of change in the color range of thermowoods depending on the temperature and duration of treatment is presented. Experiments were carried out to study the biological stability of thermally modified wood treated by various technologies including: vacuum-convective thermal modification in superheated steam, convective thermal modification in high-pressure saturated steam, as well as in hydrophobic liquids, in flue gas and vacuum-conductive thermal-modifying. The degree of resistance of wood was determined, which allows to conclude that the mass losses of heat-treated specimens caused by the destructive action of fungi are significantly lower compared to untreated ones. The researchwas conducted to determine the numerical characteristics of microroughness of the polished surface of wood, thermally modified at different temperatures.

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Efficacy of Caffeine Treatment for Wood Protection—Influence of Wood and Fungi Species

Polymers ◽

10.3390/polym13213758 ◽

2021 ◽

Vol 13 (21) ◽

pp. 3758

Author(s):

Miloš Pánek ◽

Vlastimil Borůvka ◽

Jana Nábělková ◽

Kristýna Šimůnková ◽

Aleš Zeidler ◽

...

Keyword(s):

Mechanical Properties ◽

Beech Wood ◽

Ecological Integrity ◽

Treated Wood ◽

Physical And Mechanical Properties ◽

Brown Rot ◽

European Beech ◽

Brown Rot Fungi ◽

Wood Protection ◽

Caffeine Treatment

In the future, we can expect increased requirements to the health and ecological integrity of biocides used for the protection of wood against bio-attacks, and it is therefore necessary to search for and thoroughly test new active substances. Caffeine has been shown to have biocidal efficacy against wood-destroying fungi, moulds and insects. The aim of the research was to determine whether the effectiveness of caffeine, as a fungicide of natural origin, is affected by a different type of treated wood. Norway spruce mature wood (Picea abies), Scots pine sapwood (Pinus sylvestris), and European beech wood (Fagus sylvatica) were tested in this work. The samples were treated using long-term dipping technology or coating (according to EN 152:2012) and then tested against selected wood-destroying brown rot fungi according to the standard EN 839:2015, wood-staining fungi according to EN 152:2012, and against mould growth according to EN 15457:2015. The penetration of caffeine solution into wood depth was also evaluated using liquid extraction chromatography, as well as the effect of the treatment used on selected physical and mechanical properties of wood. The test results showed that the type of wood used and the specific type of wood-degrading agent had a significant effect on the effectiveness of caffeine protection. The most resistant wood was the treated spruce, whereas the most susceptible to deterioration was the treated white pine and beech wood. The results of the work showed that caffeine treatment is effective against wood-destroying fungi at a concentration of 2%, and at 1% in some of the tested cases. It can be used as an ecologically acceptable short-term protection alternative against wood-staining fungi in lumber warehouses and is also partially effective against moulds. It also does not have negative effects on changes in the physical and mechanical properties of the tested wood species.

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INFLUENCE OF COMMERCIAL THERMAL TREATMENT ON Eucalyptus grandis Hill ex Maiden WOOD PROPERTIES

Revista Árvore ◽

10.1590/1806-908820210000027 ◽

2021 ◽

Vol 45 ◽

Author(s):

Carolina Aparecida Barros Oliveira ◽

Karina Aparecida de Oliveira ◽

Julio Cesar Molina ◽

Vinicius Borges de Moura Aquino ◽

André Luis Christoforo

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Thermal Treatment ◽

Eucalyptus Grandis ◽

Treated Wood ◽

Wood Properties ◽

Treatment Temperature ◽

Saturated Steam ◽

Physical Chemical ◽

Different Temperatures

ABSTRACT This study aimed to evaluate the influence of commercial thermal treatment on Eucalyptus grandis considering its physical, chemical, and mechanical properties. The wood samples were heat-treated in an autoclave with saturated steam and pressure application at four different temperatures: 155, 165, 175, and 185 ºC. The physical, chemical, and mechanical properties were altered due to the heat treatment. The extractives content varied between 6.06% and 28.75%; lignin between 28.93% and 37.96%; holocellulose between 65.01% and 38.12%. The mechanical properties reduced significantly with the increase of the heat treatment temperature. Through the set of data obtained, it was possible to generate significant and high precision regression models capable of estimating such properties for heat treatment temperatures not studied experimentally, enabling the determination of the most suitable temperature of heat treatment to achieve a certain property value of the treated wood.

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The toughness of hygrothermally modified wood

Holzforschung ◽

10.1515/hf-2014-0184 ◽

2015 ◽

Vol 69 (7) ◽

pp. 851-862 ◽

Cited By ~ 18

Author(s):

Mark Hughes ◽

Callum Hill ◽

Alexander Pfriem

Keyword(s):

Mechanical Properties ◽

Coupling Agent ◽

Thermal Modification ◽

Point Of View ◽

Interfacial Coupling ◽

Modification Process ◽

Thermally Modified Wood ◽

Wall Components ◽

Modified Wood

Abstract The mechanical properties of thermally modified wood are discussed with regard to toughness. The molecular origins of the mechanical properties and, in particular, the role of the hemicelluloses are considered. The important role of water and its interaction with the cell wall components is also examined. The properties are discussed from the point of view of composite theory, with the three main macromolecular components acting as reinforcement, matrix and interfacial coupling agent. The important role that hemicelluloses play as a coupling agent between the cellulosic microfibril reinforcement and the lignin-rich matrix is highlighted. Destruction of the hemicelluloses during the thermal modification process has a profound effect upon the mechanical behaviour.

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Changes of Mechanical Properties of Lightweight Cement Mortar Mixed with Recycled Expanded Polystyrene and Subjected to High Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1051.752 ◽

2014 ◽

Vol 1051 ◽

pp. 752-756 ◽

Cited By ~ 1

Author(s):

Rocío Sancho ◽

Ángel Castillo ◽

Ma Eugenia Maciá ◽

Rosa Corral

Keyword(s):

Mechanical Properties ◽

High Temperatures ◽

Mechanical Response ◽

Cement Mortar ◽

Construction Materials ◽

Lightweight Aggregate ◽

Expanded Polystyrene ◽

Partial Replacement ◽

Different Temperatures ◽

Residual Product

The main aim of this paper is to evaluate the influence of the recycled expanded polystyrene as lightweight aggregate on the mechanical properties of lightweight cement mortar when subjected to high temperatures.Various tests have been carried out on different mixtures of mortar. The water/cement mix proportion has always been the same and only the nature of the aggregates has changed, with a partial replacement of the conventional aggregate by recycled ground EPS (EPS-G) with values ranging from 10% to 30%, achieving significant results in relation to exposure to high temperatures. In this research, the samples have been subjected to different temperatures of exposure, in order to analyze the influence of the lightweight recycled arid dosage in the mechanical properties of mortars.The results of this study show the ability of mechanical response at high temperatures with light mortars EPS-G. This study shows how this new mix can be used in different building types, optimizing construction materials and reducing mortars density while transforming a residual product into an active product.

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