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.

WOOD RESEARCH Volume 61, Number 6, 2016
Alperen Kaymakci, Nadir Ayrilmis, and Huseyin Akkilic

Utilization of tinder fungus as filler in production of HDPe/wood composite

Selected physical and mechanical properties of high density polyethylene (HDPE) composites filled with various mixtures of wood flour and tinder fungus (Fomes fomentarius) were investigated. For this aim, different mixtures of tinder fungus flour and wood flour (0/40, 10/30, 20/20, and 30/10, and 40/0) (by weight) were compounded with HDPE with a coupling agent (maleic anhydride grafted polyethylene (MAPE) in a twin screw co-rotating extruder. The test specimens were produced by injection moulding machine. The thickness swelling and water absorption of the HDPE/wood composites significantly decreased with increasing content of the tinder fungus flour. The mechanical properties of the composites were negatively affected by increasing amount of tinder fungus flour but there were no significant differences up to 30 wt % tinder fungus content, except for the tensile strength. The optimum physical and mechanical properties for the filled HDPE composites were found to be a 10/30/60/3 formulation of wood flour, tinder fungus, HDPE, and MAPE, respectively.

WOOD RESEARCH Volume 61, Number 6, 2016
ROMAN RÉH and Martin Guoth

Thermoplastic plywood and it’s drawback when moderately heated

GradaTM is new plywood which contains the thermoplastic adhesive. There are so far two material versions 1000 and 2000 which have wide potential in production of wooden products with new perspective of manufacturing. This paper investigates possibilities of including GradaTM material and its versions in skateboard production. Bending strengths at the moderate heat up of this material are presented, specifically at 30, 40°C for both material versions. All increased temperatures are compared to the room temperature (20°C). Mechanical properties that were obtained from the test are modulus of elasticity, modulus of rapture, and stroke strain. The results show the undesirable level of changes present in both versions however version 1000 acts significantly better than 2000.

WOOD RESEARCH Volume 61, Number 6, 2016
Birol Üner, Kenan Kömbeci, and Mehmet Akgül

The utilization of tomato stalk in fiber production: NAOH and CAO pulping process

This study was conducted to explore the utilization of tomato stalk in the paper industry. Fiber morphology of the material was determined according to standard test methods and average fiber length was found to be 980 μm and the width of the fiber was 15 μm. As a result, slenderness ratio was resolved to be around 60. This was considered to be comparable fiber with the most of the hardwood species. Tomato stalks were cooked with soda and lime in a separate process. Screened pulp yield was determined to be 35-45 %. Soda pulp of tomato stalks showed good mechanical properties when temperature raised to 135ºC and low alkali concentration (10 %) and lime pulps showed properties as well as that soda pulp at 135ºC and high alkalinity ratio (30 %).

WOOD RESEARCH Volume 61, Number 6, 2016
Jin Heon Kwon and Nadir Ayrilmis

Short note. effect of hot-pressing parameters on selected properties of flakeboard

Physical and mechanical properties of flakeboards produced from radiata pine flakes under different hot-pressing conditions were investigated in this study. The flakeboard mats were hot-pressed at 2.8 MPa with two different temperatures (170 and 190°C) and three different durations (7, 10, and 15 min). At the 170°C of hot-pressing temperature, the highest bending strength was found in the flakeboards pressed for 7 min while the highest modulus of elasticity was found in the flakeboards pressed for 15 min. The highest internal bond strength was found to be 0.13 MPa for the flakeboards pressed at 190°C for 15 min. The thickness swelling and water absorption of flakeboards pressed at 190°C were lower than those of the flakeboards pressed at 170°C. The control of hot press temperature and duration appears an effective method to enhance serviceability of flakeboard.

WOOD RESEARCH Volume 61, Number 5, 2016
Fatih Yapici, Nurettin Şenyer, and Raşit Esen

Comparision of the multiple regression, ann, and anfis models for prediction of MOe value of OSB panels

This research investigates the prediction of modulus of elasticity (MOE) properties, which is the most important properties in many applications, of the oriented strand board (OSB) produced under different conditions (pressing time, pressing pressure, pressing temperature and adhesive ratios) by multiple regression, artificial neural network (ANN) and adaptive Neurofuzzy inference system (ANFIS). Software computing techniques are now being used instead of statistical methods. It was found that the constructed ANFIS exhibited a higher performance than multiple regression and ANN for predicting MOE.Software computing techniques are very useful for precision industrial applications and, also determining which method gives the highest accurate result.

WOOD RESEARCH Volume 61, Number 2, 2016
Hong Yun, Kaifu Li, Dengyun Tu, and Chuanshuang Hu

Effect of heat treatment on bamboo fiber morphology crystallinity and mechanical properties

This study aimed to investigate the fiber morphology, crystalline structure and mechanical properties of heat-treated bamboo. Moso bamboo was treated by superheated steam at 120, 140, 160, and 180ºC. Fiber morphology and crystalline structure of heat-treated Moso bamboo were researched by transmission electron microscope and X-ray diffraction. The mechanical properties of heat-treated bamboo were tested in the paper. The result showed that the relative crystallinity and length-width ratio of heat-treated bamboo were increased with increased temperature. The elastic modulus of bamboo was increased as the temperature rose from 120 to 140ºC. and then decreased with higher temperature, which was associated with the increase of the crystallinity.