scholarly journals Colour Stability of Thermally Modified Wood during Short-Term Photodegradation

BioResources ◽  
2014 ◽  
Vol 9 (4) ◽  
Author(s):  
Laszlo Tolvaj ◽  
Robert Nemeth ◽  
Zoltan Pasztory ◽  
Laszlo Bejo ◽  
Peter Takats
Keyword(s):  
Colour Stability ◽  
Short Term ◽  
Thermally Modified Wood ◽  
Modified Wood

Colour stability of surface finishes on thermally modified beech wood

2021 ◽  
Vol 114 ◽  
pp. 116-124
Author(s):  
Gabriela Slabejová ◽  
MÁRIA ŠMIDRIAKOVÁ
Keyword(s):  
Surface Finish ◽  
Beech Wood ◽  
Surface Finishing ◽  
Colour Stability ◽  
Colour Difference ◽  
Surface Finishes ◽  
Before And After ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Modified Wood

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ∆E* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

Experimental investigation of the hygrothermal creep strain of wood–plastic composite lumber made from thermally modified wood

2019 ◽  
Vol 33 (9) ◽  
pp. 1248-1268 ◽  
Author(s):  
Murtada Abass A Alrubaie ◽  
Roberto A Lopez-Anido ◽  
Douglas J Gardner ◽  
Mehdi Tajvidi ◽  
Yousoo Han
Keyword(s):  
Creep Strain ◽  
Water Immersion ◽  
Creep Recovery ◽  
Short Term ◽  
Creep Response ◽  
Plastic Composites ◽  
Thermally Modified Wood ◽  
Term Creep ◽  
Modified Wood ◽  
Short Term Creep

The hygrothermal effect on the short-term creep behavior of extruded thermally modified wood fiber–high-strength styrenic copolymer plastic composites (wood–plastic composites (WPCs)) was investigated on specimens preconditioned for 1 month under water immersion (distilled water (DW) and saltwater (SW)). These specimens were then tested in the same conditions for short-term creep and creep-recovery response using a submersible clamp. The short-term creep tests of WPC specimens (that are immersed in water as a function of different temperatures) have not yet been reported in previous studies. The objective of this study was to determine whether the hygrothermal creep response of WPC material evaluated through water immersion differs from the creep response published in the literature for other environmental exposure conditions. The experiments included measuring 30 min of creep and 30 min of creep recovery on the specimens immersed in SW and DW at two different levels of flexural stresses (9% and 14% of the flexural strength) and three temperature values (25, 35, and 45°C). The average creep strain recovery (%) of the specimens was higher for the specimens immersed in SW during testing than the control specimens. The WPC material is considered to have a potential use in structural applications in environments where the temperature is below 45°C because of the following factors: the low deformation under the short-term sustained loading, the decrease in the deformation rate with respect to the increase in load duration, maintaining the modulus of elasticity over a range of temperatures from 25°C to 45°C under sustained load, and the ability to recover more than 69% of the average creep strain under water immersion when the loading source is removed. The creep strain fractional increment (CSFI) of the WPC in this study under all conditions was 13% which is 86% lower than the CSFI of the WPCs reported in previous studies.

scholarly journals Increasing the Strength of the Glue Line in the Production of Thermally Modified Wood Paneling

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 253
Author(s):  
Ruslan Rushanovich Safin ◽  
Aigul Ravilevna Shaikhutdinova ◽  
Ruslan Khasanshin ◽  
Shamil Mukhametzyanov ◽  
Albina Safina
Keyword(s):  
Wood Products ◽  
Ultraviolet Rays ◽  
Surface Activation ◽  
Wood Block ◽  
Two Stage ◽  
Adhesion Properties ◽  
Wood Processing ◽  
Ultraviolet Treatment ◽  
Thermally Modified Wood ◽  
Modified Wood

This work is devoted to the study of the effect of ultraviolet rays for the surface activation of pine wood thermally modified at temperatures of 180−240 °C in order to increase the surface roughness, enhance the wettability of thermal wood and the adhesive strength of the glue in the production of wood block furniture panels. Studies were carried out to measure the contact angle of wettability of thermally modified wood samples of pine, as a result of which it was determined that the ultraviolet treatment process contributes to an increase in the adhesion properties of the surface layer of thermally modified wood by more than 13% due to the reactivity of ultraviolet rays to oxidize and degrade ligno-containing wood products. At the same time, the most active process of surface activation takes place during 60 min of ultraviolet irradiation of wood with a total irradiation of at least 125 W/cm2. It was revealed that the combined effect of two-stage wood processing, including preliminary volumetric thermal modification followed by surface ultraviolet treatment, causes an increase in the moisture resistance of glued wood products by 24%. So, if the strength of the glue seam when gluing natural wood samples after boiling decreased by 46%, then the samples that underwent two-stage processing showed a decrease only by 22%. In connection with the results obtained, an improved technology for the production of furniture boards for the manufacture of moisture-resistant wood products is proposed.

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

Effect of DCSBD plasma treatment on surface properties of thermally modified wood

2019 ◽  
Vol 16 ◽  
pp. 8-14 ◽  
Author(s):  
R. Talviste ◽  
O. Galmiz ◽  
M. Stupavská ◽  
Z. Tučeková ◽  
K. Kaarna ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Surface Properties ◽  
Thermally Modified Wood ◽  
Modified Wood

scholarly journals Particleboards from Recycled Thermally Modified Wood

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1462
Author(s):  
Ján Iždinský ◽  
Zuzana Vidholdová ◽  
Ladislav Reinprecht
Keyword(s):  
Mechanical Properties ◽  
Urea Formaldehyde ◽  
Brown Rot ◽  
Decay Resistance ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Negative Effect ◽  
Serpula Lacrymans ◽  
Thermally Modified Wood ◽  
Modified Wood

In recent years, the production and consumption of thermally modified wood (TMW) has been increasing. Offcuts and other waste generated during TMWs processing into products, as well as already disposed products based on TMWs can be an input recycled raw material for production of particleboards (PBs). In a laboratory, 16 mm thick 3-layer PBs bonded with urea-formaldehyde (UF) resin were produced at 5.8 MPa, 240 °C and 8 s pressing factor. In PBs, the particles from fresh spruce wood and mixed particles from offcuts of pine, beech, and ash TMWs were combined in weight ratios of 100:0, 80:20, 50:50 and 0:100. Thickness swelling (TS) and water absorption (WA) of PBs decreased with increased portion of TMW particles, i.e., TS after 24 h maximally about 72.3% and WA after 24 h maximally about 64%. However, mechanical properties of PBs worsened proportionally with a higher content of recycled TMW—apparently, the modulus of rupture (MOR) up to 55.5% and internal bond (IB) up to 46.2%, while negative effect of TMW particles on the modulus of elasticity (MOE) was milder. Decay resistance of PBs to the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F.Gray increased if they contained TMW particles, maximally about 45%, while the mould resistance of PBs containing TMW particles improved only in the first days of test. In summary, the recycled TMW particles can improve the decay and water resistance of PBs exposed to higher humidity environment. However, worsening of their mechanical properties could appear, as well.

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