Combustion behavior of oak wood (Quercus mongolica L.) modified by 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU)

Abstract The modification of wood with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) is an efficient strategy to improve its dimensional stability and durability during its service period. In this study, oak wood (Quercus mongolica L.) was treated with DMDHEU and the combustion behavior of the treated wood was examined. The bench-scale thermogravimetry and cone calorimetry showed that the treatment with DMDHEU alone enhanced the flammability of wood, but a combined treatment with DMDHEU and traces of magnesium chloride as a catalyst lowered the flammability to the level of untreated wood. In full-scale fire tests for flooring materials, it could be confirmed that both the untreated and treated woods have similar combustion behavior and can be classified as Dfl-S1 (capable of resisting a small flame and, for a certain period, a heat flux attack; the total smoke production is limited). Accordingly, further fire-retardant treatments may be required if DMDHEU-treated wood is used in public areas.

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Functionalized Surface Layer on Poplar Wood Fabricated by Fire Retardant and Thermal Densification. Part 2: Dynamic Wettability and Bonding Strength

Forests ◽

10.3390/f10110982 ◽

2019 ◽

Vol 10 (11) ◽

pp. 982 ◽

Cited By ~ 1

Author(s):

Demiao Chu ◽

Jun Mu ◽

Stavros Avramidis ◽

Sohrab Rahimi ◽

Shengquan Liu ◽

...

Keyword(s):

Contact Angle ◽

Surface Layer ◽

Surface Energy ◽

Bonding Strength ◽

Sessile Drop ◽

Combined Treatment ◽

Treated Wood ◽

Fire Retardant ◽

Tangential Section ◽

Droplet Volume

In continuation of our former study on a novel combined treatment of nitrogen–phosphorus fire retardant and thermomechanical densification on wood, this study focuses on the dynamic wettability and the bonding strength. The contact angle was measured using the sessile drop method and the surface energy was calculated according to the van Oss method. Water surface penetrating and spreading is analyzed by both the Shi and Gardner model and the droplet volume changing model. The results reveal that the combined treatment increased the surface energy, especially the acid–base component. The contact angle declined and the water droplet spread more easily on the surface. Meanwhile, the rate of relative droplet volume decreased by 32.6% because the surface layer was densified and stabilized by the combined process. Additionally, the surface possesses the lowest roughness and highest abrasion resistance on the tangential section. Thus, the bonding strength of the combined treated poplar decreased by 29.7% compared to that of untreated poplar; however, it is still 53.3% higher than that of 220 °C heat-treated wood.

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Functionalized Surface Layer on Poplar Wood Fabricated by Fire Retardant and Thermal Densification. Part 1: Compression Recovery and Flammability

Forests ◽

10.3390/f10110955 ◽

2019 ◽

Vol 10 (11) ◽

pp. 955 ◽

Cited By ~ 4

Author(s):

Demiao Chu ◽

Jun Mu ◽

Stavros Avramidis ◽

Sohrab Rahimi ◽

Shengquan Liu ◽

...

Keyword(s):

Surface Layer ◽

Combined Treatment ◽

Surface Hardness ◽

Treated Wood ◽

Fire Retardant ◽

Densified Wood ◽

Fire Retardancy ◽

Alternative Approach ◽

Vertical Density ◽

Functionalized Surface

To enhance compression stability and fire retardancy of densified wood, a new modification method i.e., combined nitrogen–phosphorus (NP) fire retardant pre-impregnation with surface thermo-mechanical densification is used to fabricate a certain thickness of functionalized surface layer on poplar. This combined treated wood is investigated via vertical density profile (VDP), and the compression stability is revealed by both soaking test and cone analysis. Results demonstrate that the combined treatment hardened the surface of wood and reformed the interface combination of the NP with the wood cell wall, thus making the surface tissue more close-grained. Fire retardancy was also enhanced; the total heat release and CO generation values decreased by 21.9% and 68.4%, respectively, when compared with that of solely NP-treated wood. Moreover, surface hardness increased by 15.8%, and the recovery of surface hardness and thickness were 56.8% and 77.2% lower than that of simply densified wood. It appears that this NP-involved thermal densification could be considered as an alternative approach to enhance both the compression stability and fire resistance of wood.

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Inorganic Antiflaming Wood Caused by aTiO2-Decorated ZnO Nanorod Arrays Coating Prepared by a Facile Hydrothermal Method

Journal of Nanomaterials ◽

10.1155/2016/2358276 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Hong Zhang ◽

Weigang Zhang ◽

Chunde Jin ◽

Song Li

Keyword(s):

Hydrothermal Method ◽

Treated Wood ◽

Untreated Wood ◽

Zno Nanorod ◽

Nanorod Arrays ◽

Zno Nanorod Arrays ◽

Cone Calorimetry ◽

One Pot ◽

X Ray ◽

Smoke Production

Wood materials with antiflaming capability were successfully fabricated by depositing a TiO2-decorated ZnO nanorod arrays (ZNAs) film on wood surface using a facile and one-pot hydrothermal method. The prepared specimens were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), and powder X-ray diffraction (XRD). To explore the antiflaming properties, the combustion parameters of the wood treated by TiO2-decorated ZNAs were measured using the cone calorimetry technique compared with the untreated wood. For treated wood, the burning duration was prolonged for 55 s; smoke production rate (SPR) and total smoke production (TSP) were obviously reduced, especially for the production of CO was almost zero. As a result, thin inorganic film of TiO2-decorated ZNAs had desirable fire resistance, and one-pot hydrothermal method was a feasible method to fabricate nonflammable wood materials.

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Promotion effect of NP fire retardant pre-treatment on heat-treated poplar wood. Part 2: hygroscopicity, leaching resistance, and thermal stability

Holzforschung ◽

10.1515/hf-2016-0213 ◽

2017 ◽

Vol 71 (3) ◽

pp. 217-223 ◽

Cited By ~ 9

Author(s):

Demiao Chu ◽

Jun Mu ◽

Li Zhang ◽

Yushuang Li

Keyword(s):

Thermal Stability ◽

Moisture Absorption ◽

Degradation Products ◽

Combined Treatment ◽

Treated Wood ◽

Fire Retardant ◽

Crystallinity Index ◽

Hydroxyl Groups ◽

Heat Treated ◽

Wood Polysaccharides

Abstract In continuation of the previous study concerning the effects of a combined treatment of wood with nitrogen-phosphorus (NP) fire retardant and heat treatment (HT), the hygroscopicity, leachability, thermal stability, Fourier transform-infrared (FT-IR) spectra, and X-ray diffraction (XRD) properties of Populus beijingensis W.Y. Hsu have been investigated. The wood samples were impregnated with 10% NP fire retardant solution and exposed to HTs at 140°C–160°C for 30 min. HT of NP treated wood reduced the moisture absorption and enhanced the leaching resistance of NP and improved the thermal stability. The HT decomposes the NP and the acidity of these degradation products has a dehydration effect on the wood polysaccharides, and the number of hydroxyl groups in wood decreased substantially. The crystallinity index of the NP-impregnated and heat-treated wood also increased. The post low-temperature HT enhanced the fixation of the NP fire retardant and hydrophobicity of the NP-treated wood.

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Air permeability and sound absorption coefficient changes from ultrasonic treatment in a cross section of Malas (Homalium foetidum)

Journal of Wood Science ◽

10.1186/s10086-020-01940-w ◽

2021 ◽

Vol 67 (1) ◽

Author(s):

Chun-Won Kang ◽

Eun-Suk Jang ◽

Nam-Ho Lee ◽

Sang-Sik Jang ◽

Min Lee

Keyword(s):

Absorption Coefficient ◽

Ultrasonic Treatment ◽

Sound Absorption ◽

Gas Permeability ◽

Treated Wood ◽

Untreated Wood ◽

Sound Absorption Coefficient ◽

Permeability Constant ◽

Average Value ◽

Permeability Increase

AbstractWe investigated the effect of ultrasonic treatment on Malas (Homalium foetidum) gas permeability and sound absorption coefficient using the transfer function method. Results showed a longitudinal average Darcy permeability constant of 2.02 (standard deviation SD 0.72) for untreated wood and 6.15 (SD 3.07) for ultrasound-treated wood, a permeability increase of 3.04 times. We also determined the average sound absorption coefficients in the range of 50 to 6.4 kHz and NRC (noise reduction coefficient: average value of sound absorption coefficient value at 250, 500, 1000, and 2000 Hz) of untreated Malas. Those values were 0.23 (SD 0.02) and 0.13 (SD 0.01), respectively, while those of ultrasonic-treated Malas were 0.28 (SD 0.02) and 0.14 (SD 0.02), a 19.74% increase in average sound absorption coefficient.

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Growth behavior of wood-destroying fungi in chemically modified wood: wood degradation and translocation of nitrogen compounds

Holzforschung ◽

10.1515/hf-2020-0252 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Lukas Emmerich ◽

Maja Bleckmann ◽

Sarah Strohbusch ◽

Christian Brischke ◽

Susanne Bollmus ◽

...

Keyword(s):

Protective Action ◽

Treated Wood ◽

Untreated Wood ◽

Brown Rot ◽

Decay Resistance ◽

White Rot ◽

Decay Fungi ◽

Chemically Modified ◽

Decay Tests ◽

Modified Wood

Abstract Chemical wood modification has been used to modify wood and improve its decay resistance. However, the mode of protective action is still not fully understood. Occasionally, outdoor products made from chemically modified timber (CMT) show internal decay while their outer shell remains intact. Hence, it was hypothesized that wood decay fungi may grow through CMT without losing their capability to degrade non-modified wood. This study aimed at developing a laboratory test set-up to investigate (1) whether decay fungi grow through CMT and (2) retain their ability to degrade non-modified wood. Acetylated and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood were used in decay tests with modified ‘mantle specimens’ and untreated ‘core dowels’. It became evident that white rot (Trametes versicolor), brown rot (Coniophora puteana) and soft rot fungi can grow through CMT without losing their ability to degrade untreated wood. Consequently, full volume impregnation of wood with the modifying agent is required to achieve complete protection of wooden products. In decay tests with DMDHEU treated specimens, significant amounts of apparently non-fixated DMDHEU were translocated from modified mantle specimens to untreated wood cores. A diffusion-driven transport of nitrogen and DMDHEU seemed to be responsible for mass translocation during decay testing.

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The Effects of Heat Treatment on the Chemical Alterations of Oak Wood

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.688.44 ◽

2016 ◽

Vol 688 ◽

pp. 44-49 ◽

Cited By ~ 1

Author(s):

Iveta Čabalová ◽

František Kačík ◽

Tereza Tribulová

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

High Performance Liquid Chromatography ◽

Renewable Energy ◽

Liquid Chromatography ◽

Thermal Treatment ◽

High Performance ◽

Treated Wood ◽

National Renewable Energy Laboratory ◽

Oak Wood

Samples prepared from oak (Quercusrobur L.) wood were exposed to heat treatment at temperatures of 160, 180, 200 and 220 oC for 3, 6, 9 and 12 hours. In both untreated and thermally treated wood there were determined extractives and lignin by National Renewable Energy Laboratory (NREL) procedures, cellulose by Seifert's method, holocellulose according to Wise, hemicelluloses as difference between holocellulose and cellulose. Monosaccharides were determined by high performance liquid chromatography (NREL).The results show that hemicelluloses are less stable at thermal treatment than cellulose. The amounts of lignin and extractives rose by increasing both temperature and time of the treatment while the amounts of hemicelluloses decreased. Thermal treatment also resulted in significant decreases of the yields of non-glucosic saccharides. Degradation of carbohydrates can cause the deterioration of mechanical properties of wood.

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Laccase-catalyzed functionalization with 4-hydroxy-3-methoxybenzylurea significantly improves internal bond of particle boards

Holzforschung ◽

10.1515/hf.2008.045 ◽

2008 ◽

Vol 62 (2) ◽

pp. 223-229 ◽

Cited By ~ 25

Author(s):

Karin Fackler ◽

Thomas Kuncinger ◽

Thomas Ters ◽

Ewald Srebotnik

Keyword(s):

Internal Bond ◽

Treatment Time ◽

Urea Formaldehyde ◽

Treated Wood ◽

Untreated Wood ◽

Strength Properties ◽

Positive Interactions ◽

Formaldehyde Resin ◽

Significant Difference ◽

Wood Particles

Abstract Enzymatic functionalization is an attractive tool to provide a reactive interface for further processing of lignocellulosic materials, such as wood particles and fibers. Here, spruce wood particles have been functionalized by fungal laccase combined with 4-hydroxy-3-methoxy-benzylamine (HMBA) or 4-hydroxy-3-methoxybenzylurea (HMBU). The expectation was crosslinking with resins in subsequent glueing processes, which should improve strength properties of particle boards. Essential process parameters, such as liquid to solid mass ratio and treatment time, were optimized on a laboratory scale resulting in HMBA and HMBU binding yields of 90% and above as determined by radiochemical mass balance analysis. We employed a multifactorial experimental design for board production from treated wood particles and urea/formaldehyde resin. Mechanical testing and multivariate data analysis revealed, for the first time, an increase of internal bond (IB) as a result of functionalization with HMBU. HMBA was not successful. Variance analysis of relevant parameters and their interactions demonstrated a highly significant difference (P>99.99%) between boards treated with laccase/HMBU versus untreated wood particles. Due to positive interactions, functionalization was most effective at high bulk density (750 kg m-3) and high resin content (10%) resulting in a calculated IB improvement of 0.12 N m-2 (21%).

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Application of Waterborne Acrylic and Solvent-Borne Polyester Coatings on Plasma-Treated Fir (Abies alba M.) Wood

Materials ◽

10.3390/ma15010370 ◽

2022 ◽

Vol 15 (1) ◽

pp. 370

Author(s):

Hadi Gholamiyan ◽

Behnam Gholampoor ◽

Reza Hosseinpourpia

Keyword(s):

Plasma Treatment ◽

Treated Wood ◽

Abies Alba ◽

Untreated Wood ◽

Contact Angle Measurement ◽

Angle Measurement ◽

Accelerated Weathering ◽

Water Contact ◽

Before And After ◽

Carbon Dioxide Co2

This research investigates the effect of plasma treatment with air, nitrogen (N2), and carbon dioxide (CO2) gases on the performance of waterborne (acrylic) and solvent-borne (polyester) coated fir (Abies alba M.) wood samples. The properties of the plasma-coated samples were analyzed before and after exposure to accelerated weathering and compared with those of untreated and solely treated ones. According to pull-off testing, the coating adhesion of the wood samples was considerably improved by plasma treatment, and obvious differences were observed between different plasma gases. The effect was more pronounced after the weathering test. Similar results were obtained for the abrasion resistance of the samples. The water contact angle measurement illustrated more hydrophilic character in the solely plasma-treated wood in comparison with the untreated wood. The application of coatings, however, strongly improved its hydrophobic character. The performances of waterborne and solvent-borne coatings on plasma-treated wood were comparable, although slightly better values were obtained by the waterborne system. Our results exhibit the positive effect of plasma treatment on coating performances and the increased weather resistance of the waterborne and solvent-borne coating systems on plasma-treated wood.

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Enhancement of Wood Biological Resistance and Fire Retardant Properties after Laccase Assisted Enzymatic Grafting

Forests ◽

10.3390/f12081102 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1102

Author(s):

Cristian Bolaño ◽

Sabrina Palanti ◽

Luigi Benni ◽

Diego Moldes

Keyword(s):

Silver Nanoparticles ◽

Flame Retardant ◽

Toxic Substance ◽

Treated Wood ◽

Fire Retardant ◽

Wood Preservative ◽

Decay Resistance ◽

Kraft Lignin ◽

Fire Retardant Properties ◽

Wood Surfaces

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O2, a co-factor of laccase.

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