WOOD RESEARCH Volume 70, Number 4, 2025
QINYI GU, HONGHAI LIU, and TAO LI

THE STUDY OF SURFACE DENSIFICATION AND TEMPERATE SUPERHEATED STEAM MODIFICATION FOR RUBBERWOOD

This study aimed to develop a high-value wood composite by surface-densification combined with temperate superheated steam modification technology. Rubberwood boards were hot-pressed, the impact of the peak density and thickness of densified layer on the physical and mechanical properties of wood were studied. In this study the platen temperature was kept constant, after hot-pressing the platen cooling phase was omitted replaced by special compression pressure decreasing and steam discharging technic, which could save much energy and time. Superheated steam treatment (190°C for 1.5 h) and conditioning (110°C for 2 h) were recommended for improving dimensional stability and durability. Study results indicated that the surface hardness and modulus of rupture of surface-densified followed by superheated steam modified rubberwood increased by 55.9% and 41.6% compared with non-densified one respectively. Dimensional stability improved substantially. The durability was improved to ‘durable class’ according to GB/T 13942.1-2009.

WOOD RESEARCH Volume 70, Number 3, 2025
HARUNA SEIDU, LÁSZLÓ BEJÓ, and RÓBERT NÉMETH

COMPARATIVE ANALYSIS OF MOE AND MOR OF PF AND MUF-BONDED EUCALYPTUS PLYWOOD OF VARYING THICKNESS. Short notes

This study assesses the mechanical characteristics of eucalyptus plywood produced in Ghana, particularly focusing on how panel thickness (9–21 mm) and adhesive type (phenol formaldehyde (PF), and melamine urea formaldehyde (MUF) influence the modulus of elasticity (MOE) and modulus of rupture (MOR) of the panels. The panels were tested according to EN 310: 1993. The results indicate that mechanical strength and thickness are inversely correlated, with thinner panels exhibiting superior performance. MOR decreased from 59.85 N/mm² to 39.36 N/mm² for PF-bonded plywood, while longitudinal MOE declined from 7096 N/mm² (9 mm) to 4627 N/mm² (21 mm). Although their values were lower (from 6093 N/mm² to 4155 N/mm²), the MUF-bonded panels demonstrated comparable trends. Significant differences based on orientation were confirmed by ANOVA analysis (p < 0.01), showing that longitudinal samples significantly recorded higher values than transverse ones, particularly in thinner panels. Thicker panels exhibited less anisotropy due to stress homogenization, but PF adhesives provided greater mechanical stability compared to MUF.

WOOD RESEARCH Volume 70, Number 1, 2025
QIANHUI HUO, LEI YAN, XINJIE ZHOU, LILI YU, LIHUA HE, XIAO WANG, HUI LI, and LONGZE AN

WEATHERABILITY OF BAMBOO/PPC COMPOSITES MODIFIED WITH IPBC/DDAC AND UV1130

In this study, a compound anti-mold agent IPBC/DDAC and an ultraviolet absorber UV1130 were used to enhance the weatherability of bamboo/polypropylene carbonate (PPC) composites exposed outdoors. The samples were evaluated by mechanical test, surface color difference analysis, anti-ageing test and mold resistance test. The results indicated that the appropriate addition of IPBC/DDAC and UV1130 effectively mitigated the decline in tensile strength and flexural strength caused by changes in environmental factors; however, their impact on the variation in impact strength was not as significant. At the same level of IPBC/DDAC modification, the higher contents of the UV1130 introduction into the composites, the better surface color stability could be obtained. The introduction of appropriate amount of IPBC/DDAC and UV1130 can effectively improve the mold resistance, water vapor and thermal resistance of bamboo/PPC composite, in which the water vapor resistant level could be up to Grade 5, and no obvious cracks or bubbling were observed on the surface of the composites; the anti-mold efficiency of the composites could be above 90%

WOOD RESEARCH Volume 70, Number 1, 2025
LI LILI, LUO ZHIYING, LIU WENWEN, LIU DE, WANG XIMING, and YU JIANFANG

THE EFFECT OF COMBINED FLAME RETARDANTS ON THE PHYSICAL AND MECHANICAL PROPERTIES OF MONGOLIAN PINE

To enhance the flame-retardant properties and physical-mechanical performance of wood, this experiment selected Mongolian pine as the material and employed a vacuum-pressure impregnation method, with different ratios of borax and ammonium polyphosphate (BO:APP) (1:1, 2:1, 1:2) applied and compared with untreated wood (BCW). The treated and untreated Mongolian pine samples were analyzed using scanning electron microscopy (SEM), a universal mechanical testing machine, a limiting oxygen index (LOI) tester, and thermogravimetric analysis (TG) to assess microstructure, weight gain rates, density, physical-mechanical properties, flame retardancy, and thermal stability. Results indicate that the flame retardants were uniformly dispersed within the wood’s pores, achieving excellent impregnation. The weight gain rates and density of the treated wood improved when the weight ratio of borax to ammonium polyphosphate was in ratio1:1 (BO-1:APP-1 group).The weight gain rates was 10.36% and a density of 0.632 cm³/g and the MOE and MOR reached 12,076 MPa and 116.3 MPa, respectively, representing increases of 26.5% and 16.7% compared to untreated samples. The oxygen index of the BCW group was 23.1%, while that of the BO-1:APP-1 group was 42.5%, reflecting an 84% improvement over the BCW group. The thermal decomposition temperature of the treated samples decreased by 50°C, with the BCW group’s char yield at 11.35%, whereas the char yield for treated samples exceeded 20%, reaching 37.44% for the BO-1:APP-1 group, marking a 230% increase compared to the BCW group

WOOD RESEARCH Volume 69, Number 4, 2024
HARUNA SEIDU, RÓBERT NÉMETH, and FRANCIS WILSON OWUSU

MECHANICAL STRENGTH CHARACTERIZATION OF THREE LESSER-UTILISED TIMBER SPECIES IN GHANA

This study investigates the mechanical properties of three lesser-utilized timber species in Ghana: Blighia sapida, Gilbertiodendronlimba, and Lanneawelwitschii. Despite their potential, these species are underexplored compared to widely used commercial timbers. Six trees, two from each species, were tested for properties such as modulus of elasticity (MOE), modulus of rupture (MOR), compressive strength, shear strength, hardness, and density. Results indicate that Blighia sapida has superior mechanical properties, placing it in the D50 strength class, suitable for high-resistance structural applications. Gilbertiodendronlimba and Lanneawelwitschii are categorized under the D40 strength class, appropriate for moderate load-bearing uses. This research demonstrates that lesser-utilized species can serve as viable alternatives to traditional timbers, potentially reducing pressure on overexploited species. By promoting their use, the study supports sustainable forestry practices and contributes to a more diversified and resilient timber industry in Ghana

WOOD RESEARCH Volume 69, Number 2, 2024
XUXAN ALYN ROSAS-RAMOS, MA. AMPARO MÁXIMA BORJA-DE LA ROSA, ROBERTO MACHUCA-VELASCO, ALEJANDRO CORONA-AMBRIZ, LILIANA CUAPIO-HERNÁNDEZ, and LUIS ACUÑA-RELLO

EVALUATION OF WOOD QUALITY OF PINUS MONTEZUMAE LAMB. IN A DISTURBED FOREST USING NON-DESTRUCTIVE ACOUSTIC METHODS

The objective of this study was to evaluate the modulus of elasticity and wood quality for structural use in standing trees of Pinus montezumae Lamb. in a natural forest. An acoustic method was used, measuring the ultrasonic flight time for one cross-sectional and two longitudinal sections in 70 trees. Significant differences were found between the two longitudinal moduli of elasticity, and the P. montezumae trees in the study area show potential for structural use according to the modulus of elasticity. It is concluded that for sustainable management, wood of medium quality would be obtained in the same proportion for the first two sections of the tree stems, while high-quality logs would be obtained in the second longitudinal section (2–4 m)

WOOD RESEARCH Volume 69, Number 1, 2024
VLADIMÍR MANCEL, JOZEF KRILEK, IVETA ČABALOVÁ, ROMAN RÉH, MÁRIA OSVALDOVÁ, and ANNA DARABOŠOVÁ

EVALUATION OF SELECTED MECHANICAL AND PHYSICAL PROPERTIES OF PARTICLEBOARDS CONTAINING WASTE PLASTICS

This article is focused on the research of particleboards (PB) composed of wood particles from spruce logs and recycled crushed plastic granulates. Crushed plastic granulates sized from 1.0 to 4.0 mm were obtained from worn automobiles by recycling, specifically painted and unpainted bumpers. The proportion of plastic granulate in the particleboards represented 10%, 15%, and 20% of the total weight of the composites. In the production of PB, urea-formaldehyde resin and paraffin emulsion were used as a binder and ammonium nitrate was used as a hardener. The aim of the article was to compare the selected properties of PB containing plastic filler with pure PB. Mechanical properties (tensile and bending strength), and physical properties (water absorption and thickness swelling) were evaluated according to EN 319, EN 310 and EN 317. Based on the results, it can be stated that the bending strength and physical properties of PB containing plastic filler were significantly better compared to pure PB. On the contrary, the tensile strength values were lower in most cases

WOOD RESEARCH Volume 69, Number 1, 2024
QUANJI LU, HUICHUAN JIANG, JIANING LI, MIN LI, and GUANJUN LI

SOME PHYSICAL AND MECHANICAL PROPERTIES OF COCONUT PALM (COCOS NUCIFERA) STEM IN HAINAN ISLAND, CHINA

The physical and mechanical properties of 40-year-old coconut stem were investigated in different radial directions and height positions. The results showed that in the radial direction, the properties of the number of vascular bundles (NVB), density, shrinkage, compressive strength parallel to the grain (CS), modulus of rupture (MOR), and modulus of elasticity (MOE) decreased continuously from the outer area to the inner area, except for the water absorption (WA) value which increased from the outer area to the inner area. The density and MOE decreased from the bottom to the top in the height direction while NVB and WA increased. The shrinkage, CS, and MOE first increased and then decreased from the bottom to the top. NVB in coconut stem affects the density and determines the main mechanical properties of CS, MOR, and MOE. The analysis of variance (two-way ANOVA) showed a significant difference in density, NVB, WA, CS, MOR, and MOE in radial direction and height position. These findings can be useful for the development of new applications for coconut stems, such as in construction, landscaping, or furniture manufacturing, as well as for improving our understanding of their structural characteristics

WOOD RESEARCH Volume 68, Number 4, 2023
HARUNA SEIDU, RÓBERT NÉMETH, FRANCIS WILSON OWUSU, PROSPER MENSAH, MICHAEL AWOTWE-MENSAH, and BOAKYE FELIX

EFFECT OF TEMPERATURE AND RELATIVE HUMIDITY VARIATIONS ON BENDING STRENGTH PROPERTIES OF HYBRID EUCALYPTUS WOOD IN GHANA

The study examines how temperature and relative humidity affect the bending strength properties of hybrid eucalyptus wood from Amantia and Winneba in Ghana. Eucalyptus wood from six trees were tested based on BS 373:1957 under different temperatures and relative humidity levels. The study measured the modulus of elasticity (MOE), modulus of rupture (MOR), and moisture content (MC) of the wood samples. The results showed that MOE and MOR varied significantly across the different conditioning parameters N, T, K and G. MC also influenced the mechanical strength properties of the wood, following the wood-water relation theories. The study concluded that climate and geographical location are important factors to consider when evaluating the mechanical properties of hybrid eucalyptus. This study holds practical implications for optimizing the utilization of eucalyptus wood particularly in the construction and related industries in the three different climatic zones of Ghana

WOOD RESEARCH Volume 68, Number 3, 2023
Dimitrina S. Kiryakova, Antoniya S. Ilieva, and Neli А. Simeonova

Effect of Water Absorption on the Mechanical Properties of Silane-Treated Wood Flour Polypropylene Composites

The behavior of the wood flour-polypropylene composites prepared with various contents of untreated and silane-treated wood flour by immersion in water was studied, as well as the effect of the water absorbed by the samples on their mechanical properties. The highest degree of water absorption was observed for the composites containing 30 – 50 mass% alkali pre-treated wood flour. For the materials with 50 mass% untreated, silane-treated and alkali pre-treated wood flour, the water absorption measured was 8.76%, 7.84% and 13.91%, respectively, after 15 days immersion in water. The value of the thickness swelling calculated for the samples prepared with 50 mass% silane-treated wood flour – polypropylene was the lowest – 1.29%. It was proved that the absorption of water molecules results in change of the tensile profile of the thermoplastic polypropylene composites filled with hygroscopic filler.

WOOD RESEARCH Volume 68, Number 3, 2023
Sumanta Das, Miroslav Gašparík, Anil Kumar Sethy, Peter Niemz, Rastislav Lagaňa, Tomáš Kytka, Martin Sviták, and Gourav Kamboj

Suitability of Aspen (Populus Tremula L.) for Cross-Laminated Timber (CLT)

Cross-laminated timber (CLT) CLT is an excellent material for building and high load-bearing structural applications, but its fabrication and use are limited to softwood only. The suitability of aspen (Populus tremula L) wood for manufacturing CLT was assessed by using two adhesives, one-component polyurethane (1C-PUR) and melamine adhesive (ME). Physical properties like water absorption (WA), thickness swelling (TS), delamination, and mechanical properties like bond shear strength, bending modulus of elasticity, bending strength, and rolling shear strength were evaluated to examine its suitability. Compared to ME-bonded CLT, 1C-PUR bonded CLT panels displayed superior physical characteristics, with 70% passing the delamination test. CLT panels bonded with 1C-PUR adhesive also have better mechanical properties than ME-bonded CLT. CLT panels experienced three types of bending failure: rolling shear, delamination, and tension. Aspen CLT has similar or higher mechanical properties than traditional softwoods, making it suitable for CLT manufacturing.

WOOD RESEARCH Volume 68, Number 3, 2023
HARUNA SEIDU, RÓBERT NÉMETH, FRANCIS WILSON OWUSU, James Korang, Appiah-Kubi Emmanuel, JAMES KUDJO GOVINA, Fath Alrhman A.A Younis, and Safia Ibrahim

Mechanical Properties of PF and MUF Bonded Juvenile Hybrid Eucalyptus Plywoods Produced in Ghana

To obtain the mechanical properties of plywood produced from six yearold hybrid Eucalyptus in Ghana was the objective of this research. The samples for the experiment were prepared and tested according to GS EN 326-1, GS EN 310, GS EN 314-1, and GS EN 314 -2. The data obtained were analysed using the factorial ANOVA analysis. The mean results obtained for the various treatments were MOE (6520 – 7638 N/mm2), MOR (53.29 – 60.56 N/mm2, shear strength (2.47 – 5.51 N/mm2), failure (72 -90%) and density (725 – 748 kg/m3). The orientation of the surface veneer caused variations among treatments whiles the adhesives PF and MUF largely did not cause any variations among treatments. This study has proven that it is possible to produce sufficiently strong and resistant plywood from the juvenile wood of eucalyptus.

WOOD RESEARCH Volume 68, Number 1, 2023
Walter Charles Primus, Faizatul Azwa Zamri, Siti Hashimah Mohamad Hanif, Aaliyawani Ezzerin Sinin, Abdul Halim Shaari, Latifah Omar, and Osumanu Haruna Ahmed

Dependence of polyurethane content on physical and mechanical properties of wood fiber/palm kernel shell composites

Wood-based composites with different ratios of wood fiber (WF)/palm kernel shell (PKS) and polyurethane (PU) content have been prepared using the wet-process method. Samples of WF85/PKS15 and WF75/PKS25 were fabricated where each sample was applied with 20% and 70% of PU contents and its physical and mechanical properties had been studied. The physical results show that the samples with 70% of PU content were denser, had low porosity, low moisture content, and low water absorption. Surface morphology observation shows both series samples with high PU content tend to form tube-like shape with different diameter. In mechanical studies, generally, the sample with high PKS and PU possesses high flexural strength, flexural modulus, tensile strength, tensile modulus, and hardness. However, the increased of PKS content in the composite reduces the tensile strength for both samples with 20% and 70% of PU. The effects of the binder and palm kernel shell in the composite were also explained. Based on the Japanese Industrial Standard (JIS) A 5905 standard, the sample composites meet the requirement under medium density fiberboard (MDF) category and classified as board type 5 which suitable as furniture, house, and automotive interior design and construction materials.

WOOD RESEARCH Volume 67, Number 5, 2022
Kang Chiang Liew and Yu Feng Tan

Densification and effect of compression ratio on mechanical properties of CLT from low-density timber

The mechanical properties of CLT manufactured from densified low-density planted timber, Paraserianthes falcataria were studied in relation to changes in the area of pores for under densification. Conditioned laminas (MC ≤ 15%) underwent two-stage densification using hot-press machine at 105oC, 6 MPa, for 10 min each, with press released for 1 min 40 sec in between the stages, before cooling (< 100oC) to reduce immediate springback. The laminas with thickness 8 mm, 10 mm, and 15 mm were produced using metal stoppers and further manufactured into three-layered CLT of 24 mm, 30 mm, and 45 mm thick. 20 mm undensified laminas with 60 mm CLT as the control. Results shows that modulus of elasticity (MOE), modulus of rupture (MOR), and compression parallel to grain have improved significantly and showed negative correlation with area of pores, except for compression perpendicular to grain.

WOOD RESEARCH Volume 67, Number 4, 2022
Eliška Hřebenářová and František Wald

Comparison of mechanical properties of the eldest larch wood construction with oak wood and spruce wood

The paper discusses mechanical properties of timber for structures – most frequently used spruce wood, historically used oak wood and rarely mentioned larch wood. The main focus is on larch wood extracted from the ceiling of an immovable cultural monument from the 17th century – the determination of its age, its historical importance and mechanical properties. Mechanical properties were obtained by the standard tests in compression parallel and perpendicular to the fibres and in bending. The results of tests are compared to the mechanical properties of oak wood, of commonly used spruce wood and of recently felled larch wood.

WOOD RESEARCH Volume 67, Number 4, 2022
Song Xiaozhou, Liu Guorui, Feng Xuechun, and Zhang Li

Preparation and properties of agglomerated cork panels bound with chitosan binder

In this paper, acidified chitosan was used as an adhesive to prepare aldehyde-free, environmentally-friendly agglomerated cork panels by hot-pressing. After preparation, the physical, mechanical, and the finishing properties of the chitosan-glued agglomerated cork panels were investigated. The optimal mass ratio of acetic acid solution (1 wt.%) to chitosan was determined to be 30:1. The resulting hot-pressed agglomerated cork panels, which featured a density of 0.55 g.cm-3 and a thickness of 4 mm, exhibited a tensile strength of 1.70 MPa and a thermal conductivity of 0.11 W.m-1•K-1. The agglomerated cork panels coated with the oil-based polyurethane and water-based, acrylic-modified polyurethane paints exhibited significantly lower lightness and higher glossiness. The total color differences (ΔE*) of both agglomerated cork panels increased before and after finishing. The oil-based polyurethane paint coating exhibited high adhesion of paint film, reaching a level-0 adhesion, while the water-based, acrylic-modified polyurethane paint coating achieved a level-1 adhesion. The abrasion resistance results showed that the substrates of cork agglomerates coated two types of paint did not expose after undergoing abrasion for 100 revolutions at the turntable speed of 60 rpm.

WOOD RESEARCH Volume 67, Number 3, 2022
Bengang Zhang, Liping Yu, Qiaoyan Zhang, De Li, Yuan Tu, Guoming Xiao, Zhigang Wu, and Jiankun Liang

Effects of fire retardants on mechanical properties and water resistance of Pinus massoniana particleboard

Pinus massoniana Lamb. wood particleboards processed by inorganic and organic fire retardants of two densities were prepared by isocyanate and MUF resin. Variations of internal bonding strength (IB), modulus of rupture (MOR), modulus of elasticity (MOE) and thickness swelling rate (TS) of particleboard were observed. Results demonstrated decreasing of IB from 0.81 MPa to 0.42 MPa and 0.36 MPa, MOR from 17.3 MPa to 12.5 MPa and 12.3 MPa, MOE from 1840 MPa to 1328 MPa and 1117 MPa, and increasing of TS from 5.2% to 15.1% and 11.2%, respectively, for the treated MUF particleboards of density 0.65 g.cm-3. Similarly, decreasing of IB from 0.93 MPa to 0.66 MPa and 0.64 MPa, MOR from 16.2 MPa to 10.6 MPa and 12.1 MPa, MOE from 1246 MPa to 1573 MPa and 1466 MPa, and increasing of TS from 6.7% to 7.1% and 6.0%, respectively, when isocyanate adhesive was used. The similar changes were showed when the density of particleboard was 0.75 g.cm-3. Improving density of particleboard appropriately and decrease density difference between the surface to chip layers could make the profile density curve tend to be stable, which could get a relatively high mechanical strength and water resistance. Synergistic effects between isocyanate and fire retardants was confirmed. The particleboard prepared with isocyanate was obviously superior to that prepared with MUF resin in all performances.

WOOD RESEARCH Volume 67, Number 2, 2022
Vinicius Borges De Moura Aquino, LARISSA SORIANI ZANINI RIBEIRO SOARES, HELOIZA CANDEIA RUTHES, Felipe Nascimento Arroyo, IURI FAZOLIN FRAGA, ANDRÉ LUIS CHRISTOFORO, Herisson Ferreira dos Santos, Eduardo Chahud, Luiz Antonio Melgaço Nunes Branco, and Francisco Antonio Rocco Lahr

Analysis of moisture content variation on strength and stiffness properties of cedrella odorata wood species

In order to analyze the influence of moisture content variation on Cedrella odorata wood specie on strength and stiffness properties, considering 12% moisture content up to fiber saturation point (FSP). Most of strength and stiffness properties analyzed were significantly influenced by moisture content according statistical analysis. ANOVA, Anderson Darling and Multiple comparison tests were used at 5% significance level. Considering that most of properties were affected by moisture content, the equations to estimate wood properties according moisture decrease are quite precise, but most of estimations were higher than experimental values at 12% moisture content, indicating the need of a standard review for such estimators, which may lead to an unsafe timber structure design.

WOOD RESEARCH Volume 67, Number 1, 2022
Darius Albrektas, Simona Gauronskaitė, Vaida Dobilaitė, and Milda Jucienė

Effect of open-holes on mechanical properties of wood composite materials

A few variations of open-holes in wood-based pieces, particle board and plywood were modeled in this article. The modulus of elasticity and the coefficient of damping for these pieces were determined using static and dynamic methods and the effect of holes of different quantity and size on mechanical properties were evaluated. As regards to wood particle boards, it was found that the modulus of elasticity decreased to10% after drilling holes, and the coefficient of damping increased to 13%. With regard to plywood pieces these changes were up to 14.5% and up to 21.5%, respectively.

WOOD RESEARCH Volume 66, Number 5, 2021
Tomasz Ozyhar

Short notes: Application of mineral filler in medium density fiberboard (Mdf) and its effect On material properties as a function of particle size

The addition of inorganic filler material in medium density fiberboard (MDF) and the effect on material properties as a function of particle size was examined. Medium density fiberboard was manufactured in a laboratory scale environment to a target raw density of 750 kgm-3. Wood fibers were replaced by using calcium carbonate at 3 and 10 wt.% using fillers with weighted median particle sizes of d50 = 2.0 μm and d50 = 30 μm, respectively. Urea formaldehyde resin was used as binder in all MDF. The influence of filler addition on the modulus of elasticity, bending and tensile strength, dimensional stability and liquid permeability was investigated. The results demonstrate the effect of filler content and its dependence on particle size. The addition of filler with d50 = 30 μm does not have any influence on material properties up to a filler content of 10 wt.%. Using the finer filler with d50 = 2.0 μm at 10 wt.% filler, the quantity significantly increases the water adsorption and swelling behavior and reduces the strength properties of the MDF.