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Ganitri (Elaeocarpus sphaericus (Gaertn.) K. Schum.) and jabon (Anthocephalus cadamba) are fast-growing wood species that have low strength and durability class. One of methods for improving the characteristics of ganitri and jabon woods is impregnation. This study objectives were to analyze the effect of impregnation of Melamine Formaldehyde Furfuryl Alcohol (MFFA) copolymer and 0.5% Nano-SiO2 on the physical, mechanical and durability properties of ganitri and jabon woods. The impregnation process was carried out by applying a 0.5 bar vacuum for 1 hour and followed by 2 bar pressure for 2 hours. The results showed that impregnation with MFFA and Nano-SiO2 could improve optimally the physical and mechanical properties and durability of fast-growing woods

The characteristics of ganitri wood can be improved via wood impregnation. The objective of this research was to analyze the density and dimensional stability of a wood polymer nano-composite, i.e., impregnated ganitri wood with a mixture of melamine formaldehyde furfuryl alcohol and nano-SiO2. The results showed that the impregnation process improved the physical properties of the impregnated ganitri wood. Impregnation with 0.5% melamine-formaldehyde furfuryl alcohol (MFFA)-nano SiO2 had a significant effect on the density, weight percent gain, anti-swelling efficiency, bulking effect (BE), and water uptake (WU). Increased percentage of density and BE values after being treated by MFFA with 0.5% nano-SiO2 were 51.2% and 311.7%, respectively. The percentage decrease in WU was 47.5% (MFFA with 0.5% nano-SiO2). X-ray diffraction analysis verified a decrease in the crystallinity of the wood cellulose. The melamine formaldehyde furfuryl alcohol and nano-SiO2 polymers were found to cover the wood cell walls and lumens (based on scanning electron microscopy images). The formaldehyde emissions of the wood polymer nano-composite decreased. Therefore, it is possible to produce more environmentally friendly materials through wood polymer nano-composites.

Purpose The surface characteristics of thermally and chemically modified wood, such as surface roughness, surface free energy (SFE) and wettability, are important properties that influence further manufacturing processes such as gluing and coating. The aim of this paper was to determine the influence of the surface roughness of thermally and chemically modified teak wood on their SFE, wettability and bonding quality for water-based acrylic and solvent-based alkyd varnishes. In addition, durability against subterranean termites in the field of these modified teak woods was also investigated to give a valuable information for their further application. Design/methodology/approach The woods tested in this study were fast-growing teak woods that were prepared in untreated and treated with furfuryl alcohol (FA), glycerol maleic anhydride (GMA) and thermal. SFE values were calculated using the Rabel method. The wettability values were measured based on the contact angle between varnish liquids and wood surfaces using the sessile drop method, and the Shi and Gardner model model was used to evaluate the wettability of the varnishes on the wood surface. The bonding quality of the varnishes was measured using a cross-cut test based on ASTM 3359-17 standard. In addition, durability against subterranean termites in the field of these modified teak woods was also investigated according to ASTM D 1758-06. Findings The results showed that furfurylated and GMA-thermal 220°C improved the durability of teak wood against termites. The furfurylated teak wood had the roughest surface with an arithmetic average roughness (Ra) value of 15.65 µm before aging and 27.11 µm after aging. The GMA-thermal 220°C treated teak wood was the smoothest surface with Ra value of 6.44 µm before aging and 13.75 µm after aging. Untreated teak wood had the highest SFE value of 46.90 and 57.37 mJ/m2 before and after aging, respectively. The K values of untreated and treated teak wood increased owing to the aging treatment. The K values for the water-based acrylic varnish were lower than that of the solvent-based alkyd varnish. The untreated teak wood with the highest SFE produced the highest bonding quality (grades 4–5) for both acrylic and alkyd varnishes. The solvent-based alkyd varnish was more wettable and generated better bonding quality than the water-based acrylic varnish. Originality/value The originality of this research work is that it provides evaluation values of the durability and SFE. The SFE value can be used to quantitatively determine the wettability of paint liquids on the surface of wood and its varnish bonding quality.

Short rotation teak wood has been produced to overcome the scarcity of long rotation teak. The short rotation teak has low quality, especially in dimensional stability and durability. Glycerol-maleic anhydride (GMA) treatment as non-biocidal wood preservation system was applied to improve technological properties, especially dimensional stability and durability. Impregnation with 10% w/w aqueous solution of GMA followed by thermal modification at 150 and 220 °C under inert conditions was investigated on short rotation teak sapwood. The following technological properties were studied: chemical compound; mass alteration; density; leachability; dimensional stability (volumetric swelling, anti-swelling efficiency (ASE), and water uptake; modulus of elasticity; modulus of rupture; decay resistance; and termite resistance. The results show that chemical modification with 10% GMA combined with thermal modification increased ASE by 62.31% and 73.22% for 150 and 220 °C, respectively, indicating improved dimensional stability. Decay resistances of GMA-thermal treated teak wood against fungal decay of Coriolus versicolor, Pycnoporus sanguineus, and Coniophora puteana were categorized to be class 1 (very durable). Weight loss of GMA-thermal at 220 °C against termite attacks was 0.19%, which presented excellent durability (rating 10) against subterranean termites. Fourier transform infrared and carbon 13 nuclear magnetic resonance analyses indicate that the presence of reaction between GMA polymer with lignin occurred after thermal treatment at 220 °C. Thermogravimetric analysis shows that GMA-thermal treatment also presented better thermal stability than untreated wood. GMA-thermal treatment gave a significant improvement in dimensional stability and resistance to wood-decaying fungi and termite.

Mangium (Acacia mangium Willd.) is a fast-growing wood that is widely grown in Indonesia. The impregnation method is needed to improve the qualities of the wood. In this study, TiO2 nanoparticle (79.17 nm) was produced using the hydrothermal method. The purpose of this study was to analyze the effect of TiO2 nanoparticle impregnation on the density and dimensional stability of mangium and the effectiveness of the presence of TiO2 nanoparticle in wood in degrading pollutants. The mangium samples (2 cm × 2 cm × 2 cm) were placed inside impregnation tube. The impregnation solutions included water (untreated), 1% TiO2 nanoparticle, and 5% TiO2 nanoparticles. The samples were analyzed for density, weight percent gain (WPG) dan bulking effect (BE). Samples were also analyzed by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). TiO2 nanoparticle resulted in an increase in density, WPG, and BE-treated mangium. Based on XRD and FTIR results, TiO2 nanoparticle was successfully impregnated into mangium wood. Scanning electron microscopy–energy-dispersive X-ray spectroscopy analysis indicated that TiO2 nanoparticle covered the surface of the wood cells. The TiO2-impregnated mangium wood has a higher photocatalyst activity than untreated, indicating better protection from UV radiation and pollutants.

An innovative eco-friendly technology, applied to improve the quality of the short rotation teak, was wood modification by heat treatment. The study was to investigate the effects of heat treatment...

Introductions Ultrasonication can be used to synthesize nanosilica from silica derived from betung bamboo sticks and leaves. This study aimed to synthesize nanosilica from betung bamboo sticks and leaves by the use of ultrasonication and to characterize the nanosilica produced. Methods The main materials used in this study were bamboo sticks and leaves. Betung bamboo sticks and leaves were sun-dried and then burned separately without adding fuel to produce charcoal. Then the produced charcoal was burned at a temperature of 700°C for 6 hours in a furnace to produce ash. Silica was extracted from furnace ash using reflux methods. The production of nanosilica from the silica derived from the betung bamboo sticks and leaves was carried out using ultrasonication. Results The yield of silica from sticks and leaves was based on ash dry weight 45.73% and 79.93%, respectively. The nanosilica derived from betung bamboo sticks had a particle size in the range of 169.87-1479.50 nm, with an average size of 502.35 nm and a particle dispersion index value of 0.1420. Nanosilica derived from betung bamboo leaves had a particle size in the range of 234.49-851.36 nm, with an average size of 472.67 nm and a particle dispersion index value of 0.0670. Scanning electron microscopy analysis showed that silica from betung bamboo sticks and leaves still agglomerated. The particle size of silica could minimize through ultrasonication to synthesize nanosilica. Discussions X-ray diffraction analysis showed that the structure of nanosilica differed from that of silica, and it appeared to be semicrystalline. The ultrasonication method for the synthesis of nanosilica derived from betung bamboo sticks and leaves ash can produce nanosilica that has a semicrystalline phase. The use of surfactants in the process can make the size of the nanosilica particles more uniform and reduce the size of the nanoparticles produced.

Jabon (Anthocephalus cadamba) is a fast-growing wood with low quality due to its low density and strength. The quality can be increased by modifying the wood through impregnation with various chemical compounds. In this study, jabon was impregnated with a solution of Fe and immersed in a strong base (NaOH) or a weak base (NH4OH) to form magnetite (Fe3O4) in-situ. This study analysed the use of NaOH and NH4OH in synthesising magnetic jabon wood and evaluated the wood’s characteristics. The impregnation process began with a vacuum of −0.5 bar for 0.5 h and then a pressure of 1 bar for 2 h. The samples subsequently underwent assessment of their dimensional stability, density, and characteristics. The results showed that impregnation with Fe solution followed by NaOH or NH4OH significantly affected the density and dimensional stability of the wood. The polymer weight gain was higher with NaOH, while the anti-swelling efficiency was higher with NH4OH. The density and bulking effect were increased, but the water uptake was decreased. Fourier transform infrared analysis showed the successful synthesis of magnetite. Scanning electron microscopy–energy-dispersive X-ray spectroscopy analysis revealed that magnetite covered the vessel fibre cell walls, and vibrating sample magnetometry analysis showed significant magnetic properties of the wood.

Sengon (Falcataria moluccana Miq.) is one of the fastest growing wood that is broadly planted in Indonesia. Sengon wood has inferior wood properties, such as a low density and dimensional stability. Therefore, sengon wood requires a method to improve its wood quality through wood modification. One type of wood modification is wood impregnation. On the other hand, Betung Bamboo leaves are considered as waste. Betung Bamboo leaves contain silica. Based on several researches, nano-SiO2 could improve fast-growing wood qualities. According to its perfect solubility in water, monoethylene glycol (MEG) is used in the study. The objectives are to evaluate the impregnation treatment (MEG and nano-silica originated from betung bamboo leaves) in regard to the dimensional stability and density of 5-year-old sengon wood and to characterize the treated sengon wood. MEG, MNano-Silica 0.5%, MNano-Silica 0.75%, and MNano-Silica 1% were used as impregnation solutions. The impregnation method was started with 0.5 bar of vacuum for 60 min, followed by 2.5 bar of pressure for 120 min. The dimensional stability, density, and characterization of the samples were studied through the use of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results show that the treatment had a significant effect on the dimensional stability and density of sengon wood. Alterations in the morphology of treated sengon wood were observed through the full coverage of the pits on the vessel walls (SEM analysis results) and the detection of ethylene (FTIR analysis results) and silica (XRD and FTIR analysis results). Overall, the 0.75% MNano-Silica treatment was the most optimal treatment for increasing the dimensional stability and density of 5-year-old sengon wood.

Jabon (Anthocephalus cadamba) is a fast-growing wood species that is widely utilized for light construction and other purposes in Indonesia. The objectives of the current study were to determine the effects of monoethylene glycol (MEG) and SiO2 nanoparticles (nano SiO2) impregnation treatment on the dimensional stability and density of jabon wood and to identify the characteristics of impregnated jabon wood. Wood samples were immersed in water (as untreated), MEG, 0.5% MEGSiO2, then impregnated by applying 0.5 bar of vacuum for 60 min, and then applying 2.5 bar of pressure for 120 min. The results showed that impregnation with MEG and Nano SiO2 had a significant effect on the dimensional stability of jabon wood. Polymers can fill cell walls in wood indicated by increasing weight percentgain, antiswelling efficiency, bulking effect, and density, then decreasing in water uptake value. Jabon wood morphology by using SEM showed that MEG SiO2 polymers can cover part of the pitsin the wood vessel wall of jabon. This finding was reinforced by EDX results showing that the silicon content was increased due to the addition of SiO2 nano. The XRD diffraction pattern indicated that MEG SiO2 treatment increased the degree of crystallinity in wood samples. Overall, treatment with 0.5% MEG SiO2 led to the most improvement in the dimensional stability of 5-year-old jabon wood in this study.

Rahayu I, Laksono GD, Darmawan W, Maddu A, Prihatini E. 2021. Demarcation area between juvenile and mature wood in Elaeocarpus angustifolius. Biodiversitas 22: 2583-2590. Wood for use in building and industrial materials is generally supplied from plantations and natural forests. Timber demand has been increasing as the population grows, but the availability of timber from natural forests is declining. Therefore, to meet timber needs, wood from community forests is becoming a solution. Community forests are widely planted with fast-growing trees, such as Elaeocarpus angustifolius Blume. It offers the advantages of a short cutting cycle and large-diameter wood. This study aimed to determine the demarcation area between juvenile and mature wood on 6-year-old E. angustifolius based on anatomical, physical, and mechanical properties. The parameters used to determine the demarcation area included the following properties: anatomical (fiber length, cell wall thickness, and microfibril angle [MFA]), physical (moisture content and green density), and mechanical (modulus of elasticity [MOE], modulus of rupture [MOR], and hardness). Those parameters were measured from pith to bark. Data analyses were based on segmented linear regression models using PROC NLIN in SAS. Fiber length, cell wall thickness, green density, MOE, MOR, and hardness values increased from pith to bark. Results from the segmented linear regression models on anatomical properties allowed extrapolating that mature wood would begin at the 18 cm (based on fiber length), the 20 cm (based on cell wall thickness), and the 21 cm (based on MFA) distance from the pith. the proportion of juvenile wood in E. angustifolius was 100%. Fiber length, cell wall thickness, and MFA can be used to determine the transition point of juvenile wood and mature wood in E. angustifolius.

Introductions Ultrasonication can be used to synthesize nanosilica from silica derived from betung bamboo sticks and leaves. This study aimed to synthesize nanosilica from betung bamboo sticks and leaves by the use of ultrasonication and to characterize the nanosilica produced. Methods The main materials used in this study were bamboo sticks and leaves. Betung bamboo sticks and leaves were sun-dried and then burned separately without adding fuel to produce charcoal. Then the produced charcoal was burned at a temperature of 700°C for 6 hours in a furnace to produce ash. Silica was extracted from furnace ash using reflux methods. The production of nanosilica from the silica derived from the betung bamboo sticks and leaves was carried out using ultrasonication. Results The yield of silica from sticks and leaves was based on ash dry weight 45.73% and 79.93%, respectively. The nanosilica derived from betung bamboo sticks had a particle size in the range of 169.87–1479.50 nm, with an average size of 502.35 nm and a particle dispersion index value of 0.1420. Nanosilica derived from betung bamboo leaves had a particle size in the range of 234.49–851.36 nm, with an average size of 472.67 nm and a particle dispersion index value of 0.0670. Scanning electron microscopy analysis showed that silica from betung bamboo sticks and leaves still agglomerated. The particle size of silica could minimize through ultrasonication to synthesize nanosilica. Discussions X-ray diffraction analysis showed that the structure of nanosilica differed from that of silica, and it appeared to be semicrystalline. The ultrasonication method for the synthesis of nanosilica derived from betung bamboo sticks and leaves ash can produce nanosilica that has a semicrystalline phase. The use of surfactants in the process can make the size of the nanosilica particles more uniform and reduce the size of the nanoparticles produced.

The quality of finished wood products depends on the quality of its coating layer. An important indicator for evaluating the quality is Adherence of the paint on the wood surface. The purpose of th...

Machining aspects with helical edge router bits (helix angle 15°, 30°, 45°, and 60°) with a cutting circle diameter of 8 mm were studied. The purpose of the research work was to investigate chip formation and surface roughness characteristics in milling pine wood by the straight and helical edge bits. The chips generated could be classified into four types by sieving into spiral chip (5 mesh), flow chip (10 mesh), thin chip (30 mesh), and granule chip (

Falcataria moluccana or sengon is one of the fast-growing wood species widely grown in Indonesia. However, its wood is low quality with low density, and poor strength, durability, and dimensional stability. This study determined the effects of impregnation with monoethylene glycol (MEG) and nano-SiO2 on the characteristics of sengon wood, including its dimensional stability and density. Impregnation with MEG and nano-SiO2 had a significant effects on dimensional stability in terms of the weight percent gain, anti-swelling efficiency, water uptake, bulking effect, and density. The impregnated wood was examined by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction. The results show that MEG and nano-SiO2 were distributed homogeneously into cell walls of wood treated with 0.5% MEGSiO2.

Most of wood industry requires well conformed logs and middle diameter trees to optimize primary processing yields. The raw material, mostly coming from monoculture plantations, contains a considerable proportion of juvenile wood. The objectives of present study were to identify the transition ring between juvenile and mature wood in Douglas-fir and to analyze the effect of juvenility and veneer thickness on bending strength of Douglas-fir laminated veneer lumber (LVL). Microfibril angle (MFA) and tracheid length from five Douglas-fir logs were measured from pith to bark. Veneers peeled with an instrumented lathe to produce LVL. Total of 140 LVL samples were mechanically characterized by measuring modulus of elasticity (MOE) and modulus of rupture (MOR). The results showed that transition rings from juvenile to mature wood at breast height, according to MFA and tracheid length, were at twentieth and twenty-first, respectively. According to analysis of variance, there was a significant effect of juvenility on LVL bending strength. The advantage of using veneers of mature compare to juvenile wood for LVL was due to an improvement of bending strength in the range of 7–22 %. LVL made of 3 mm veneers has lower stiffness (2.2 %) compare to LVL made of 5.25 mm veneers. High correlation between static and dynamic MOE was noted.

Teak wood (Tectona grandis) as an important forest resource in Indonesia has been processed to wood furniture in large quantities to fulfill an increasing need of both local and international consumers. To satisfy the increasing demand for wood products, teak wood has been supplied from the State forests (Perhutani) and Community teak plantations. Community teak has been harvested at shorter age rotations (7–10 years) than Perhutani teak (40–60 years). This paper discusses the occurrence and characteristics of juvenile wood in Perhutani and Community teak based on density, shrinkage, bending strength (modulus of rupture - MOR, modulus of elasticity - MOE), fiber length, and microfibril angle (MFA). A segmented modeling approach was used to find the juvenile mature transition. Fiber length and MFA appear to be good anatomical indicators of radial increment demarcation between juvenile and mature wood, although maturation radial increment varies slightly between the fiber length and MFA. The use of radial increment density, shrinkage, MOR, and MOE were not appropriate, because of low coefficients of determination and a large range of radial increment for transition from juvenile to mature wood. The maturations were estimated to start at radial increments 10 and 14 cm from the pith by fiber length, and 11 and 15 cm from the pith by MFA for Perhutani and Community teak, respectively. The projected figures for the proportion of juvenile wood at breast height for Perhutani and Community teak were 65% and 100%, respectively. The results also indicate that short-rotation Community teak was not remarkably inferior in shrinkage, MOE and MOR compared to Perhutani teak, although it was less dense, less attractive and less durable due to lower heartwood content. Therefore, careful attention should be given to the use of the Community teak in some wood-processing technologies.

Fast growing sengon (Paraserianthes moluccana) is largely rotary-cut to produce veneer for core plywood production. In order to provide better information on veneer production and utilization, in this study the effects of wood juvenility and veneer thickness on lathe checks of rotary-cut sengon veneers were evaluated. Before veneer manufacturing, sengon logs were boiled at 50 oC and 75 oC for 4 and 8 hours respectively. The boiled logs were peeled to produce veneer of 1 mm, 1.5 mm, 2 mm in thickness. Lathe checks of veneers were measured on the loosed side at every 5 mm veneer length under an optical video microscope and their frequency, depth, and length were characterized. Twenty sampling points of 5 mm veneer length were prepared from each segmented ring of 1 cm width from pith to bark. Isocyanate resin adhesive were used to produce laminated veneer lumber (LVL) of 20 mm thick, which consisted of 24-ply of 1 mm veneer thick, 14-ply of 1.5 mm veneer thick, and 11-ply of 2 mm veneer thick, for glue bond and bending strength test. Results showed that wood juvenility and veneer thickness determined the frequency, depth and length of lathe checks for the sengon rotary-cut veneers. In general, the frequency of lathe checks of the veneer increases with increasing veneer thickness, and also increases from pith to bark. Boiling of logs before rotary-cutting could decreases the frequency of lathe check of the veneer. The results indicated that boiling of logs at 50 oC for 8 h and at 75 oC at least 4 h before peeling the logs could minimize the frequency of lathe check in manufacturing rotary cut veneer thickness of 1 mm, 1.5 mm, and 2 mm from juvenile wood of fast growing sengon. The frequency of lathe check affect significantly the glue bond and bending strength, in which the glue bond, Modulus of Elasticity (MOE), and Modulus of Rupture (MOR) decrease as the frequency of lathe checks increases. The authors thank the Directorate for Research and Community Service of the Ministry of National Education for the Republic of Indonesia for the research grant

Key message Lambro, Brenta, Taro, Alcinde and Soligo are new poplar cultivars suitable for laminated veneer lumber (LVL) for structural purposes. While Lena, Koster, Dvina, Mella and Trichobel must be used with careful veneer material selection to obtain high value of mechanical properties. Context In France, the veneer processing industry uses only a very small number of different poplar cultivars. Aims This paper set out to investigate the potential of laminated veneer lumber made from 14 new cultivars for structural purposes, with a focus on juvenility and veneer thickness effects. Methods The mechanical properties of laminated veneer lumber panels made from each cultivar (114 samples per cultivar) were characterized by measuring their density, modulus of elasticity and modulus of rupture. Results A tight correlation was found between destructive and non-destructivemodulus of elasticity tests (R2=0.90, 1,808 samples). Five cultivars had suitable mechanical properties for structural applications (‘Lambro’, ‘Brenta’, ‘Taro’, ‘Alcinde’ and ‘Soligo’). Five cultivars needed to be used with careful sample selection (‘Lena’, ‘Koster’, ‘Dvina’, ‘Mella’ and ‘Trichobel’), and the final four (‘I214’, ‘A4A’, ‘Triplo’ and ‘Polargo’) could not be recommended for structural purposes. Conclusion The advantage of using veneers of mature wood compare to juvenile wood for laminated veneer lumber (LVL) production was due to an improvement of modulus of elasticity and modulus of rupture in the range of 15 to 20 %. The use of thick veneers (5.25 mm compared to 3 mm) did not appear to be detrimental to laminated veneer lumber mechanical performance. This research was carried out at the Laboratoire Bourgogne des Matériaux et des Procédés (LaBoMaP), Ecole Nationale Superieure d’Arts et Metiérs (ENSAM), Cluny, Bourgogne, France. We wish to thank our partners FCBA and CNPF IDF for their active collaboration on this large research programme. We also wish to thank our partners and funders of the Xylomat Technical Platform from the Xylomat Scientific Network funded by ANR-10-EQPX-16 XYLOFOREST.

Jabon (Anthocephalus cadamba Miq.) wood specimens were impregnated for 10, 20, and 30 min with monomer methyl methacrylate (MMA) and polymerized with Co-60 gamma radiation at doses of 10, 20, and 30 kGy. After polymerization process polymer loadings were calculated. For comparison purpose untreated wood as control was also prepared, and all wood specimens were tested for some physical and mechanical properties. The results showed that average polymer loading reached 34 %, and MMA impregnated wood has significantly enhanced physical and mechanical properties. These were indicated by 7 % lower moisture content, 17 % lower volume shrinkage, 12 % higher MOR, and 27 % higher MOE compared to the untreated wood. The impregnation period and radiation doses, and interaction of both the factors did not affect physical and mechanical properties of MMA wood, except impregnation period for moisture content, also radiation doses and the interaction both factors for shrinkage. Impregnation period of 10 min and 10 kGy Co-60 gamma radiation dose were sufficient applying for MMA impregnated process of jabon wood.

Timber as an important forest resource in the tropics has been processed to wood products in large quantity to fulfill an increasing need of both local and international consumers. To satisfy the increasing demand for the wood products, much of the timber has been supplied from fast-growing tree species grown on managed plantations (community forest, industrial plantation forest). The fast-growing wood species have been harvested in short age rotations and could contain higher proportions of juvenile wood. This research article discusses the occurrence and characteristics of juvenility in sengon (Paraserianthes falcataria) and jabon (Anthocephalus cadamba) woods based on density, bending strength (modulus of rupture (MOR), modulus of elasticity (MOE)), fiber length, and microfibril angle (MFA). Segmented modeling approach was used to find juvenile and mature transition, and the SAS non-linear procedure (PROC NLIN) was employed to identify the juvenile to mature transition ring. Fiber length and MFA appear to be the good anatomical indicators of ring demarcation between juvenile and mature wood, although maturation ring varies slightly between the fiber length and MFA. The use of ring density, MOR, and MOE were not appropriate, because of low coefficients of determination and large range of segmented rings for transition from juvenile to mature wood. The maturation rings were estimated to start at segmented rings 17 and 18 by the fiber length, 18 and 20 by the MFA for sengon and jabon respectively. The projected figures for the portion of juvenile wood both in sengon and jabon in the breast height stem at the age of 7 years were 100 %. As a result of this study, the consequent careful attentions should be given for the use of the jabon and sengon woods by some wood-processing technologies.

This article presents the characteristics of delamination wear on the clearance face of newly coated K10 cutting tools when milling particleboard. The K10 cutting tools were multilayer coated with titanium aluminum nitride (TiAlN)/titanium silicon nitride (TiSiN), TiAlN/titanium boron nitride (TiBN), and TiAlN/chromium aluminum nitride (CrAlN). Particleboard with a density of 0.61 g/cm 3 was cut using the multilayer-coated tools and a monolayer-coated (TiAlN) tool. Cutting tests were performed at a high cutting speed of 41.8 m/s and a feed rate of 0.2 mm/rev to investigate the delamination wear on the clearance face of these coated tools. Experimental results showed that the newly multilayer-coated tools experienced a smaller amount of delamination wear than the monolayer-coated tool when milling the particleboard. The best multilayer coating was TiAlN/CrAlN; that tool only suffered a slight chipping on the cutting edge at a cutting length of 1 km. The high hardness, low coefficient of friction, high resistance to oxidation, and high resistance to delamination wear of the multilayercoated TiAlN/CrAlN tool indicate a very promising applicability of this coating for high-speed cutting of abrasive woodbased materials.

Key messageA modelling method is proposed to highlight the effect of cambial age on the effective modulus of elasticity of laminated veneer lumber (LVL) according to bending direction and veneer thickness. This approach is relevant for industrial purposes in order to optimize the performance of LVL products.ContextLVL is used increasingly in structural applications. It is obtained from a peeling process, where product’s properties depend on cambial age, hence depend on radial position in the log.AimsThis study aims to highlight how radial variations of properties and cambial age impact the mechanical behaviour of LVL panels.MethodsAn analytical mechanical model has been designed to predict the modulus of elasticity of samples made from poplar LVL panels. The originality of the model resides in the integration of different data from the literature dealing with the variation in wood properties along the radius of the log. The simulation of the peeling process leads to veneers with different mechanical properties, which are randomly assembled in LVL panels.ResultsThe model shows a correct mechanical behaviour prediction in comparison with experimental results of the literature, in particular with the decrease in MOE in LVL made of juvenile wood. It highlights that the bending direction and veneer thickness have no influence on the average MOE, but affect MOE dispersion.ConclusionThis paper proposed an adequate model to predict mechanical behaviour in the elastic domain of LVL panels based on the properties of raw wood material. ANR xyloforest, région Bourgogne franche-comté

Most of wood industry requires well conformed logs and middle diameter trees to optimize primary processing yields. The raw material, mostly coming from monoculture plantations, contains a considerable proportion of juvenile wood. The objectives of present study were to identify the transition ring between juvenile and mature wood in Douglas-fir and to analyze the effect of juvenility and veneer thickness on bending strength of Douglas-fir laminated veneer lumber (LVL). Microfibril angle (MFA) and tracheid length from five Douglas-fir logs were measured from pith to bark. Veneers peeled with an instrumented lathe to produce LVL. Total of 140 LVL samples were mechanically characterized by measuring modulus of elasticity (MOE) and modulus of rupture (MOR). The results showed that transition rings from juvenile to mature wood at breast height, according to MFA and tracheid length, were at twentieth and twenty-first, respectively. According to analysis of variance, there was a significant effect of juvenility on LVL bending strength. The advantage of using veneers of mature compare to juvenile wood for LVL was due to an improvement of bending strength in the range of 7–22 %. LVL made of 3 mm veneers has lower stiffness (2.2 %) compare to LVL made of 5.25 mm veneers. High correlation between static and dynamic MOE was noted.

For many wood cutting processes, the interest of high-speed tool steels and tungsten carbides remains very important because of their good tool edge accuracy and easy grinding. The wear of high-speed steel and tungsten carbide is an important economic parameter. Wood extractives and silica have a potential adverse effect on tool wear. Rapid chemical wearing due to corrosion and mechanical wearing has been attributed to the presence of extractives and silica in wood and wood composites. This paper presents the wear characteristics of SKH51 high-speed steel and K10 tungsten carbide caused by extractive and abrasive materials present in the lesser-known Tapi-Tapi wood and wood composites of wood cement board, particleboard, MDF, and oriented strand board (OSB). Experimental results showed that wearing of the cutting tools tested was determined by extractives and silica contained in the wood and wood composites. Wood cement board, which is high in silica content, caused severe damage to the cutting edge of the high-speed steel. A corrosion/oxidation mechanism was found to contribute to the wear of SKH51 and K10 when cutting the Tapi-Tapi wood, MDF, particleboard, wood cement board, and OSB. The silica and extractives determined the abrasion and corrosion wear mechanism to a varying degree.