Particleboards from Recycled Thermally 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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Particleboards from Recycled Pallets

Forests ◽

10.3390/f12111597 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1597

Author(s):

Ján Iždinský ◽

Ladislav Reinprecht ◽

Zuzana Vidholdová

Keyword(s):

Urea Formaldehyde ◽

Brown Rot ◽

Decay Resistance ◽

Modulus Of Rupture ◽

Thickness Swelling ◽

Uf Resin ◽

Worldwide Production ◽

Negative Effect ◽

Growth Activity ◽

Serpula Lacrymans

Worldwide production of wooden pallets continually increases, and therefore in future higher number of damaged pallets need to be recycled. One way to conveniently recycle pallets is their use for the production of particleboards (PBs). The 3-layer PBs, bonded with urea-formaldehyde (UF) resin, were prepared in laboratory conditions using particles from fresh spruce logs (FSL) and recycled spruce pallets (RSP) in mutual weight ratios of 100:0, 80:20, 50:50 and 0:100. Particles from RSP did not affect the moisture properties of PBs, i.e., the thickness swelling (TS) and water absorption (WA). The mechanical properties of PBs based on particles from RSP significantly worsened: the modulus of rupture (MOR) in bending from 14.6 MPa up to 10 MPa, the modulus of elasticity (MOE) in bending from 2616 MPa up to 2012 MPa, and the internal bond (IB) from 0.79 MPa up to 0.61 MPa. Particles from RSP had only a slight negative effect on the decay resistance of PBs to the brown-rot fungus Serpula lacrymans, while their presence in surfaces of PBs did not affect the growth activity of moulds at all.

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Mode of action of brown rot decay resistance in modified wood: a review

Holzforschung ◽

10.1515/hf-2013-0057 ◽

2014 ◽

Vol 68 (2) ◽

pp. 239-246 ◽

Cited By ~ 66

Author(s):

Rebecka Ringman ◽

Annica Pilgård ◽

Christian Brischke ◽

Klaus Richter

Keyword(s):

Cell Wall ◽

Mode Of Action ◽

Wood Decay ◽

Brown Rot ◽

Decay Resistance ◽

Hydroxyl Groups ◽

Decay Fungi ◽

Brown Rot Decay ◽

Thermally Modified Wood ◽

Modified Wood

Abstract Chemically or physically modified wood materials have enhanced resistance to wood decay fungi. In contrast to treatments with traditional wood preservatives, where the resistance is caused mainly by the toxicity of the chemicals added, little is known about the mode of action of nontoxic wood modification methods. This study reviews established theories related to resistance in acetylated, furfurylated, dimethylol dihydroxyethyleneurea-treated, and thermally modified wood. The main conclusion is that only one theory provides a consistent explanation for the initial inhibition of brown rot degradation in modified wood, that is, moisture exclusion via the reduction of cell wall voids. Other proposed mechanisms, such as enzyme nonrecognition, micropore blocking, and reducing the number of free hydroxyl groups, may reduce the degradation rate when cell wall water uptake is no longer impeded.

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Monitoring electrical properties of thermally modified wood as a possible tool for quality assessment

Holzforschung ◽

10.1515/hf-2014-0366 ◽

2016 ◽

Vol 70 (4) ◽

pp. 351-359 ◽

Cited By ~ 3

Author(s):

Wang Wang ◽

Yuan Zhu ◽

Jinzhen Cao ◽

Pascal D. Kamdem

Keyword(s):

Mechanical Properties ◽

Electrical Properties ◽

Electrical Resistance ◽

Close Relation ◽

Modulus Of Rupture ◽

Bending Properties ◽

Polar Groups ◽

Mobility Of Ions ◽

Thermally Modified Wood ◽

Modified Wood

Abstract The electrical properties of thermally modified wood (TMW) of southern pine (Pinus spp.) have been investigated, while the samples were modified at 150°C, 175°C, 200°C, and 225°C for 4 h. After conditioning the samples at five relative humidities, the constants for electrical resistance (kR) and dielectricity (kP) were measured and calculated according to the model “electrical properties vs. moisture content”. The correlations between kR and kP and mass loss (ML), CIEL*a*b* color and bending properties in terms of modulus of rupture and modulus of elasticity were established. The coefficients of determination (R2) between these parameters were found to be between 0.926 and 0.999. TM influenced both kR and kP via changing the concentration and mobility of ions inside the wood and decreasing amount of polar groups of wood polymers. The conclusion is that the severity of TM such as the mechanical properties of TMW is in a close relation to the electrical properties.

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Using Fourier Transform Near-Infrared Spectroscopy to Predict the Mechanical Properties of Thermally Modified Southern Pine Wood

Applied Spectroscopy ◽

10.1177/0003702816644453 ◽

2016 ◽

Vol 70 (10) ◽

pp. 1676-1684

Author(s):

Li Tong ◽

Wenbo Zhang

Keyword(s):

Mechanical Properties ◽

Near Infrared ◽

Nir Spectroscopy ◽

Modulus Of Rupture ◽

Coefficient Of Determination ◽

Southern Pine ◽

Pine Wood ◽

Close Relationship ◽

Thermally Modified Wood ◽

Modified Wood

This study seeks to estimate the mechanical properties of thermally modified wood (TMW) using near-infrared (NIR) spectroscopy to measure 80 samples in three-point bending tests. Near-infrared spectra collected from the transverse, radial, and tangential sections of wood, coupled with chemometric techniques, were used to predict the mechanical properties of southern pine wood, from which NIR models were constructed based on partial least squares and corresponding cross-validation. The coefficient of determination between NIR transverse section spectra, as well as two mechanical properties of wood samples, modulus of rupture (MOR) and modulus of elasticity (MOE), were above 0.92 and greater than values for other sections. Spectral data from the transverse sections were richer than data from other sections, and thus, a model based on transverse sections better predicts the mechanical properties of wood. A close relationship between the values for mechanical properties (MOE and MOR) and the NIR spectra of thermally modified southern pine wood can be demonstrated, which provides the potential to predict the mechanical properties of untreated and thermally modified wood.

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DECAY RESISTANCE, DIMENSIONAL STABILITY AND MECHANICAL STRENGTH OF POPLAR WOOD MODIFIED WITH PLANT-DERIVED COMPOUNDS

Wood Research ◽

10.37763/wr.1336-4561/66.4.556568 ◽

2021 ◽

Vol 66 (4) ◽

pp. 556-568

Author(s):

JIAPENG WANG ◽

ZHENJU BI ◽

ZHANGJING CHEN ◽

LI YAN ◽

YAFANG LEI

Keyword(s):

Mechanical Properties ◽

Citric Acid ◽

Dimensional Stability ◽

Color Change ◽

White Rot Fungi ◽

Brown Rot ◽

Decay Resistance ◽

White Rot ◽

Modulus Of Rupture ◽

Weight Percentage

The cinnamaldehyde, salicylic acid, stearolic acid and citric acid were plant-derived organic compounds that can be activated to fungi, that could degrade the wood in long term. The compounds with concentrations of 3%, 5% and 7% assisted by different dispersants were impregnated into poplar (Populus nigra L.) specimens by the vacuum-pressure method. After that, weight percentage gain (WPG), decay resistance against white-rot fungi (Trametes versicolor) and brown-rot fungi (Gloeophyllum trabeum), color change, dimensional stability and mechanical properties including modulus of elasticity (MOE) and modulus of rupture (MOR) were measured. The results indicated that cinnamaldehyde impregnated poplar showed antifungi activity against both G. trabeumand T. versicolor, and citric acid impregnated poplar showed antifungi activity against G. trabeum. The color of poplar specimens before and after impregnated cinnamaldehyde and citric acid had a little change, dimensional stability had been improved and mechanical properties especially for MOR increased significantly.

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Oversized Planer Shavings for the Core Layer of Lightweight Particleboard

Polymers ◽

10.3390/polym13071125 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1125

Author(s):

Jakob Gößwald ◽

Marius Cătălin Barbu ◽

Alexander Petutschnigg ◽

Ľuboš Krišťák ◽

Eugenia Mariana Tudor

Keyword(s):

Mechanical Properties ◽

Internal Bond ◽

Urea Formaldehyde ◽

Core Layer ◽

Solid Wood ◽

Raw Material ◽

Modulus Of Rupture ◽

Low Density ◽

The Core ◽

Adhesive Application

Planer shavings (PS) are side-products generated during the processing of solid wood, typically used for heating, packaging, or insulation purposes. PS has been used for decades in particleboard manufacture, particularly in the core layer. The aim of this research is to investigate the use of PS with a length over 4 mm in low-density one-layer particleboard manufacturing with a thickness of 10 mm, as an option to reduce the raw material demand for wood-based panels. Correlations towards the mechanical properties of the particleboards, fabricated at a density of 475 kg/m3, could be drawn by analyzing the effects of different urea-formaldehyde adhesive contents (6%, 9%, and 12%). Two methods of adhesive application (pouring and spraying) and two types of blending of PS with adhesive (plowshare mixer and drum mixer) were investigated, with the aim that PS will have controlled resin application. The difference between the adhesive application methods was examined by analyzing the mechanical properties as an internal bond, modulus of rupture, and modulus of elasticity as well as indirectly by visualizing the adhesive distribution by adding a green pigment to the adhesive before application. PS demonstrated reduced bending properties in comparison with the EN 312 standard requirements of particleboards for internal use in dry conditions (type P2), due to the low density. The internal bond strength in the case of the particleboard without pigment application (up to 0.5 N/mm2) was higher compared to the P2 requirements (0.4 N/mm2), and significantly lower (0.15 N/mm2) in combination with the pigment (2.5% based on the board weight, compared to 0.1%, specific for such industry applications), but still superior to the values of the reference panel manufactured with wood particles.

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Suitability of Muli Bamboo (Melocanna baccifera) for Making Bamboo Mat Plywood

Bangladesh Journal of Scientific and Industrial Research ◽

10.3329/bjsir.v46i4.9605 ◽

1970 ◽

Vol 46 (4) ◽

pp. 543-548 ◽

Cited By ~ 1

Author(s):

M Ashaduzzaman ◽

R Rana ◽

MNH Khan ◽

MI Shams

Keyword(s):

Mechanical Properties ◽

Modulus Of Elasticity ◽

Urea Formaldehyde ◽

Physical And Mechanical Properties ◽

High Strength ◽

Average Density ◽

Raw Material ◽

Modulus Of Rupture ◽

Formaldehyde Resin ◽

Alternative Source

This paper investigated the potentiality of muli (Melocanna baccifera) for making bamboo mat plywood. Bamboo mat plywood with the length, width and thickness of 2.4 m × 1.2 m × 7 mm was made using liquid urea formaldehyde resin. The physical and mechanical properties of such plywood were compared with the existing market plywood. The average density of bamboo mat plywood was much higher compared to the existing market plywood. The modulus of rupture (MOR) of bamboo mat plywood was 3 times and the modulus of elasticity (MOE) was 6 times higher compared to commercial (Bombax ceiba) plywood. Interestingly, the specific MOR and MOE were significantly higher than those of market plywood. The high strength values might be due to the long fiber length of the bamboo. Furthermore, the lamination of decorative thin garjan (Dipterocarpus turbinatus) veneer did not significantly reduce mechanical properties of the products. Bamboo plywood mat as well as garjan laminated bamboo mat plywood showed better performance in respect to thickness swelling, linear expansion and water absorption. Hence, muli bamboo can be a potential alternative source of raw material for the manufacture of plywood materials. Key words: Bamboo mat plywood; Density; Dimensional stability; Modulus of elasticity; Modulus of rupture DOI: http://dx.doi.org/10.3329/bjsir.v46i4.9605 BJSIR 2011; 46(4): 543-548

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Chemical composition as factor affecting the mechanical properties of thermally modified black poplar (Populus nigra L.)

BioResources ◽

10.15376/biores.15.2.3915-3929 ◽

2020 ◽

Vol 15 (2) ◽

pp. 3915-3929

Author(s):

Paweł Kozakiewicz ◽

Michał Drożdżek ◽

Agnieszka Laskowska ◽

Marek Grześkiewicz ◽

Olga Bytner ◽

...

Keyword(s):

Mechanical Properties ◽

Chemical Composition ◽

Thermal Processing ◽

Wood Properties ◽

Populus Nigra ◽

Modulus Of Rupture ◽

Wood Moisture ◽

Black Poplar ◽

Thermally Modified Wood ◽

Modified Wood

Black poplar (Populus nigra L.) was thermally modified in superheated steam at 160 °C, 190 °C, and 220 °C for 2 h. The research identified correlations between the chemical composition and selected mechanical properties of thermally modified wood. The higher treatment temperatures significantly lowered the modulus of rupture (MOR) and the Brinell hardness (BH). These correlations were particularly apparent at higher temperatures (190 °C and 220 °C) when thermally modified wood experienced stronger hemicelluloses degradation, which was indicated by an increase in the content of non-structural substances. The wood properties including compressive strength parallel to the grain (CS), modulus of elasticity during bending (MOE), and compressing (MCS) were affected less by the chemical changes caused by the thermal processing of wood. Moreover, the level of wood moisture content also affected these changes.

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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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Mechanical Properties of Commercial Particleboard from Rubberwood (Hevea Brasiliensis) and Recycle Mix-Tropical Wood with Different Board Density

Science Proceedings Series ◽

10.31580/sps.v3i1.1941 ◽

2021 ◽

Vol 3 (1) ◽

pp. 41-44

Author(s):

Nur Wafa Amalina Amali ◽

Nor Yuziah Mohd Yunus ◽

Wan Mohd Nazri Wan Abdul Rahman

Keyword(s):

Mechanical Properties ◽

Modulus Of Elasticity ◽

Hevea Brasiliensis ◽

Urea Formaldehyde ◽

Wood Particle ◽

Modulus Of Rupture ◽

Internal Bonding ◽

Board Density ◽

Tropical Wood ◽

Minimum Requirements

In this study, mechanical properties of commercially manufactured hybrid particleboard from mix-tropical wood and rubberwood with four different densities at 25mm thickness have been investigated. The particleboard sample cutting and testing was in accordance to EN312:2013. The density of particleboard is identified with interval of 10kg/m3 for different densities which include 660kg/m3, 670kg/m3, 680kg/m3 and 690kg/m3. Particleboards were made with the ratio of 40:60 for mix-tropical wood particle and rubberwood particle respectively. The particleboards were prepared with urea formaldehyde (UF) with E1 formulation with addition of wax and hardener. Increment of 10kg/m3 density for each particleboard led to increase in internal bonding (IB), bending testing include modulus of rupture (MOR) and modulus of elasticity (MOE), surface soundness (SS) and screw edge (SE) withdrawal. It was found that with board increment of 10kg/m3, the improvement was not statically significant except that for MOR. All panels met the minimum requirements of standard.

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