scholarly journals Influence of Zwitterionic Buffer Effects with Thermal Modification Treatments of Wood on Symbiotic Protists in Reticulitermes grassei Clément

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 139
Author(s):  
Sónia Duarte ◽  
Lina Nunes ◽  
Davor Kržišnik ◽  
Miha Humar ◽  
Dennis Jones
Keyword(s):  
Heat Treatment ◽  
Thermal Modification ◽  
Subterranean Termites ◽  
Reaction Systems ◽  
Maillard Reactions ◽  
Termite Attack ◽  
Chemical Behaviour ◽  
Thermally Modified Wood ◽  
Zwitterionic Buffer ◽  
Modified Wood

The majority of thermal modification processes are at temperatures greater than 180 °C, resulting in a product with some properties enhanced and some diminished (e.g., mechanical properties). However, the durability of thermally modified wood to termite attack is recognised as low. Recent attempts at combining thermal modification with chemical modification, either prior to or directly after the thermal process, are promising. Buffers, although not influencing the reaction systems, may interact on exposure to certain conditions, potentially acting as promoters of biological changes. In this study, two zwitterionic buffers, bicine and tricine, chosen for their potential to form Maillard-type products with fragmented hemicelluloses/volatiles, were assessed with and without thermal modification for two wood species (spruce and beech), with subsequent evaluation of their effect against subterranean termites (Reticulitermes grassei Clément) and their symbiotic protists. The effect of the wood treatments on termites and their symbionts was visible after four weeks, especially for spruce treated with tricine and bicine and heat treatment (bicine HT), and for beech treated with bicine and bicine and heat treatment (bicine HT). The chemical behaviour of these substances should be further investigated when in contact with wood and also after heat treatment. This is the first study evaluating the effect of potential Maillard reactions with zwitterionic buffers on subterranean termite symbiotic fauna.

scholarly journals Flammability Characteristics of Thermally Modified Meranti Wood Treated with Natural and Synthetic Fire Retardants

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2160
Author(s):  
Milan Gaff ◽  
Hana Čekovská ◽  
Jiří Bouček ◽  
Danica Kačíková ◽  
Ivan Kubovský ◽  
...  
Keyword(s):  
Burning Rate ◽  
Flame Retardants ◽  
Thermal Modification ◽  
Positive Contribution ◽  
Spearman Correlation ◽  
Chemical Changes ◽  
Combustion Properties ◽  
Flammability Characteristics ◽  
Thermally Modified Wood ◽  
Modified Wood

This paper deals with the effect of synthetic and natural flame retardants on flammability characteristics and chemical changes in thermally treated meranti wood (Shorea spp.). The basic chemical composition (extractives, lignin, holocellulose, cellulose, and hemicelluloses) was evaluated to clarify the relationships of temperature modifications (160 °C, 180 °C, and 210 °C) and incineration for 600 s. Weight loss, burning speed, the maximum burning rate, and the time to reach the maximum burning rate were evaluated. Relationships between flammable properties and chemical changes in thermally modified wood were evaluated with the Spearman correlation. The thermal modification did not confirm a positive contribution to the flammability and combustion properties of meranti wood. The effect of the synthetic retardant on all combustion properties was significantly higher compared to that of the natural retardant.

Hygroscopic properties of thermally modified false Iroko [Antiaris toxicara (Lesch)]

2021 ◽  
Vol 18 (1) ◽  
pp. 51-57
Author(s):  
F.A. Faruwa ◽  
K. Duru
Keyword(s):  
Weight Loss ◽  
Dimensional Stability ◽  
Thermal Process ◽  
Colour Change ◽  
Wood Properties ◽  
Thermal Modification ◽  
Hygroscopic Properties ◽  
Different Temperatures ◽  
Thermally Modified Wood ◽  
Modified Wood

The study investigated the use of thermal modification to improve the hygroscopic properties of False Iroko [Antiaris toxicaria (Lesch)]. Samples of Antiaris toxicara Lesch wood were subjected to thermal modification in a furnace at temperatures of 160, 180 and 200°C for 30 and 60 minutes. Results showed that wood properties were improved with exposure to different temperatures. Subsequent to the thermal process, a colour change from pale yellow to darkish brown was observed progressively with increase in temperature, accompanied by a weight loss in the range of 12.08% to 23.67%. The outcome of these treatments resulted in a decrease in volumetric swelling and increase in dimensional stability of modified wood; this can be attributed to observed decrease in moisture intake. The thermal modification of Antiaris toxicara Lesch wood affected the dimensional stability properties. Thus, due to significant changes via modification carried out on the selected species which is classified as lesser utilized wood species, lesser utilized wood,Antiaristoxicara Lesch wood is recommended for use due to its efficient dimensional stability after modification . keywords:, Thermally modified wood ;False Iroko

Response of hygroscopicity to heat treatment and its relation to durability of thermally modified wood

2017 ◽  
Vol 144 ◽  
pp. 671-676 ◽  
Author(s):  
Tao Li ◽  
Da-li Cheng ◽  
Stavros Avramidis ◽  
Magnus E.P. Wålinder ◽  
Ding-guo Zhou
Keyword(s):  
Heat Treatment ◽  
Thermally Modified Wood ◽  
Modified Wood

Thermal modification of Southern pine combined with wax emulsion preimpregnation: effect on hydrophobicity and dimensional stability

Holzforschung ◽  
2015 ◽  
Vol 69 (4) ◽  
pp. 405-413 ◽  
Author(s):  
Wang Wang ◽  
Yuan Zhu ◽  
Jinzhen Cao ◽  
Xi Guo
Keyword(s):  
Water Absorption ◽  
Dimensional Stability ◽  
Photoelectron Spectroscopy ◽  
Water Repellency ◽  
Solid Content ◽  
Thermal Modification ◽  
Paraffin Wax ◽  
Southern Pine ◽  
Thermally Modified Wood ◽  
Modified Wood

Abstract The aim of this study was to enhance the water repellency and dimensional stability of thermally modified wood by combining the preimpregnation of paraffin wax emulsion. To achieve this, Southern pine (SP; Pinus spp.) samples were first impregnated with paraffin wax emulsion (with 2.0% solid content) and then subjected to thermal modification (TM) in an oven at 180°C and 220°C for 4 and 8 h. The contact angle (CA), surface free energy, water absorption rate (WAR), anti-swelling efficiency (ASE), and bending properties of the control and modified samples were investigated. Moreover, the chemical and morphological alterations were analyzed by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Both the wax impregnation and TM decreased the surface wettability, water absorption, and tangential swelling, while the combination of wax and thermal treatment exhibited the best water repellency and dimensional stability, indicating the synergism between the two procedures. However, the wax preimpregnation did not affect the mechanical properties of thermally modified wood. The FTIR, SEM, and XPS analyses confirmed that the synergistic effect is mainly due to the redistribution of the paraffin wax during TM rather than its impact on the chemical changes caused by thermal degradation.

scholarly journals Welding of thermally modified wood and thermal modification of the welded wood: Effects on the shear strength under climatic conditions

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3224-3234
Author(s):  
Mojgan Vaziri ◽  
Dick Sandberg
Keyword(s):  
Shear Strength ◽  
Welded Joints ◽  
Negative Influence ◽  
Climatic Conditions ◽  
Thermal Modification ◽  
Modes Of Failure ◽  
Computed Tomography Scanning ◽  
Thermally Modified Wood ◽  
Welding Pressure ◽  
Modified Wood

This work investigated how thermal modification affects the shear strength of welded joints under different climatic conditions. The order of the thermal modification, before or after the welding, was investigated for its effect on the shear strength of the welded wood. Two groups of thermally modified specimens were prepared in a laboratory kiln under controlled conditions, one thermally modified before welding and the other after welding of the specimens. The shear strength of the specimens were measured at four different moisture contents of 10%, 12%, 16%, and 18%, and the results for the two different approaches were compared. Moreover, observations of the X-ray computed tomography scanning and digital microscopy were used to study the density profile and the structural details of the welded joints. The results showed that thermal treatment of the wood either before or after welding had a negative influence on the shear strength, and the modes of failure of the joints in mechanical tests were in most cases brittle. In the weld interface of the wood modified before welding, a rigid material similar to charcoal was produced as a result of the further degradation of wood by welding pressure and frictional motion. Welding of wood before thermal modification, however, yielded thicker and more densified joints with less susceptibility to higher moisture variations than the joints obtained by welding the thermally modified wood.

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

2018 ◽  
Vol 7 (4.36) ◽  
pp. 1112 ◽  
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.   

Influence of Different Modifications on Bending Strength of Wood

2019 ◽  
Vol 800 ◽  
pp. 240-245
Author(s):  
Andis Antons ◽  
Dace Cīrule ◽  
Ingeborga Andersone ◽  
Anrijs Verovkins ◽  
Edgars Kuka
Keyword(s):  
Thermal Treatment ◽  
Bending Strength ◽  
Treatment Method ◽  
Thermal Modification ◽  
Wood Products ◽  
Bending Properties ◽  
Wood Protection ◽  
Thermally Modified Wood ◽  
Mild Temperature ◽  
Modified Wood

Despite intensive research in wood protection, no simple wood treatment method is available for satisfactory wood protection that could ensure appropriate strength and bio-resistance of wood products during their service life. The present study is a part of a project that is aimed to improve wood service properties by combining wood thermal treatment and impregnation with copper containing preservatives. The objective of the present study was to investigate the effect of conventional modifications (thermal modification at relatively mild temperature range (150 - 180°C) and impregnation) and double-treatments (impregnation after thermal treatment and vice versa) on the bending properties of birch (Betula spp.) and pine (Pinussylvestris L.) wood. Bending strength considerably decreased after thermal modification of wood, however MOE values generally did not significantly change. Moreover, impregnation had no effect on the bending properties for both unmodified and thermally modified wood specimens. For double-treatment in which impregnation was carried out before thermal modification no changes in bending strength were observed comparing to thermally modified wood. However, MOE values of these specimens were 10 % for birch and 19 % for pine smaller comparing to just thermally modified wood. The results of double-treatment tests imply that, regarding wood bending properties, wood impregnation after thermal modification is more appropriate.

scholarly journals Corrosiveness of Thermally Modified Wood

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 50 ◽  
Author(s):  
Samuel Zelinka ◽  
Leandro Passarini ◽  
Frederick Matt ◽  
Grant Kirker
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Water Vapor Sorption ◽  
Thermal Modification ◽  
Wood Products ◽  
Galvanized Steel ◽  
Exposure Test ◽  
Corrosion Rates ◽  
Thermally Modified Wood ◽  
Modified Wood

Thermally modified wood is becoming commercially available in North America for use in outdoor applications. While there have been many studies on how thermal modification affects the dimensional stability, water vapor sorption, and biodeterioration of wood, little is known about whether thermally modified wood is corrosive to metal fasteners and hangers used to hold these members in place. As thermally modified wood is used in outdoor applications, it has the potential to become wet which may lead to corrosion of embedded fasteners. Here, we examine the corrosiveness of thermally modified ash and oak in an exposure test where stainless steel, hot-dip galvanized steel, and carbon steel nails are driven into wood and exposed to a nearly 100% relative humidity environment at 27 °C for one year. The corrosion rates were compared against control specimens of untreated and preservative-treated southern pine. Stainless steel fasteners did not corrode in any specimens regardless of the treatment. The thermal modification increased the corrosiveness of the ash and oak, however, an oil treatment that is commonly applied by the manufacturer to the wood after the heat treatment reduced the corrosiveness. The carbon steel fasteners exhibited higher corrosion rates in the thermally modified hardwoods than in the preservative-treated pine control. Corrosion rates of galvanized fasteners in the hardwoods were much lower than carbon steel fasteners. These data can be used to design for corrosion when building with thermally modified wood, and highlight differences between corrosion of metals embedded in wood products.

Thermal Modification of Wood in Production of Finishing Materials

2017 ◽  
Vol 265 ◽  
pp. 171-176 ◽  
Author(s):  
Aigul Ravilevna Shaikhutdinova ◽  
Ruslan R. Safin ◽  
Farida V. Nazipova
Keyword(s):  
Thermal Treatment ◽  
Treatment Duration ◽  
Construction Material ◽  
Thermal Modification ◽  
Saturated Steam ◽  
Processing Temperature ◽  
Roughness Parameters ◽  
High Moisture ◽  
Thermally Modified Wood ◽  
Modified Wood

The ways of wood thermal treatment applied in Russia and abroad and the scopes of thermo wood as a construction material are considered in the article. The technology of thermal treatment of high moisture wood with moisture content of 60% in the environment of saturated steam without preliminary drying, developed by authors, is described. The results of the research of the color scale change of oak wood depending on the processing temperature and treatment duration, and also the influence of thermal treatment on the main mechanical properties of thermally modified wood as the finishing material, in particular on the Ra and Rz roughness parameters are presented. As a result of the conducted research the improvement of final physic mechanical and esthetic characteristics of the material after the processing of wood under this technology is proven.

The toughness of hygrothermally modified wood

Holzforschung ◽  
2015 ◽  
Vol 69 (7) ◽  
pp. 851-862 ◽  
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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