Wood Veneer Research Articles

Enhancing the bending strength, load-carrying capacity and material efficiency of aspen and black alder plywood through thermo-mechanical densification of face veneers

Many research papers highlight the positive impact of wood densification on mechanical properties of solid wood as well as wood veneers. Previous experimental studies comparing densified to non-densified wood materials of the same thickness consistently demonstrated higher strength properties in bending for densified materials. However, these studies often overlooked an important comparison: the strength and load-carrying capacity of non-densified wood material to its densified state, in which the thickness is reduced and thus the material’s moment of inertia. The current study, aims to address this gap for plywood made from low-quality, underutilized hardwood species, encompassing both non-densified and densified veneers. Additionally, these plywood panels are compared with high-quality birch plywood. Plywood samples made from common aspen (Populus tremula L.) and black alder (Alnus glutinosa L.) species, incorporating densified veneers, are compared to conventional silver birch (Betula pendula Roth.) plywood. The study also considers material utilization efficiency. Results showed that plywood made from non-densified aspen and black alder veneers exhibited comparable strength to standard birch plywood, positioning them as competitive alternatives to high-quality wood species. While densified black alder veneers increased strength in average from 83.6 MPa to 126.3 MPa, a loss in load-carrying capacity was observed from 1930 N to 1637 N due to reduced thickness and moment of inertia.

An organic-inorganic dual network built in fast-growing wood veneers to improve the flame retardant and mechanical properties of plywood

Fast-growing wood is widely used in plywood production due to its short growth cycle and low cost. However, its loose fiber structure, inferior material quality, and high flammability significantly limit the application range of plywood products and hinder high-value utilization. This paper reports a simple method for modifying fast-growing wood veneers. We modified phenolic resin with Mg(OH)₂@nano-silica composite particles and impregnated it into the veneers, constructing an organic-inorganic hybrid dual-network structure on both the surface and interior of the veneers. The plywood prepared from the modified veneers exhibited a bending strength of 115.6 MPa, a modulus of elasticity of 9.7 GPa, and a wet shear strength of 2.1 MPa, representing increases of 86.1%, 47.0%, and 90.9%, respectively, compared to plywood made from unmodified veneers. Additionally, the peak heat release rate decreased by 15.3%, and the ignition time was extended to 26 seconds. The uniformly distributed inorganic network effectively mitigated stress concentration and, together with the phenolic resin, formed an efficient thermal insulation layer, enhancing the flame retardancy of the material. This study offers a simple and effective treatment method for reinforcing fast-growing wood veneers, promoting the use of fast-growing wood in high-performance applications.

Programmable and flexible wood-based origami electronics

Natural polymer substrates are gaining attention as substitutes for plastic substrates in electronics, aiming to combine high performance, intricate shape deformation, and environmental sustainability. Herein, natural wood veneer is converted into a transparent wood film (TWF) substrate. The combination of 3D printing and origami technique is established to create programmable wood-based origami electronics, which exhibit superior flexibility with high tensile strength (393 MPa) due to the highly aligned cellulose fibers and the formation of numerous intermolecular hydrogen bonds between them. Moreover, the flexible TWF electronics exhibit editable multiplexed configurations and maintain stable conductivity. This is attributed to the strong adhesion between the cellulose-based ink and TWF substrate by non-covalent bonds. Benefiting from its anisotropic structure, the programmability of TWF electronics is achieved through sequentially folding into predesigned shapes. This design not only promotes environmental sustainability but also introduces its customizable shapes with potential applications in sensors, microfluidics, and wearable electronics.

Application of gas grafting with palmitoyl chloride to manufacture hydrophobic decorative wood veneer

Application of gas grafting with palmitoyl chloride to manufacture hydrophobic decorative wood veneer

Performance Evaluation of Carbon Fiber Fabric-Reinforced Formaldehyde-Free High-Strength Plywood.

Plywood is lightweight, strong, and durable, making it a widely used material in building decoration and furniture areas. In this study, formaldehyde-free, high-strength plywood was prepared through the incorporation of carbon fiber fabrics (CFFs) as reinforcement layers and their bonding with maleic anhydride polyethylene (MAPE) films. Various tests were performed to assess the impact of the carbon fiber fabric positioning on the physical and mechanical properties of plywood, including tensile shear strength, flexural strength, water absorption, thickness swelling, and electro-thermal properties. The results revealed that the plywood with CFFs exhibited significantly higher mechanical properties than plywood without CFFs. Particularly, the addition of CFFs increased the tensile strength of the plywood by nearly 54.43%, regardless of the CFFs' position. The symmetric placement of CFFs near the bottom and upper layers of the plywood resulted in a maximum modulus of rupture of 85.6 MPa. These findings were validated by numerical simulations. Scanning electron microscopy analysis of the plywood microstructures revealed that MAPE penetrated both the vessels and xylem of the wood veneers and the pores of the CFFs, thereby improving the mechanical properties of the plywood. Plywood reinforced with CFFs exhibited increased water absorption and thickness swelling after immersion. Additionally, the placement of CFFs influenced the electro-thermal properties of the plywood. Plywood with CFFs positioned near the bottom and upper surfaces exhibited superior thermal conductivity. Overall, this study presents a feasible method for developing high-performance, formaldehyde-free plywood and sustainable wood-based structural materials with potential applications in geothermal flooring.

The Potential Alternative Antibacterial Activity of Falcata (Falcataria Falcata) Leaf Methanolic Extract against Staphylococcus Aureus and Escherichia Coli

The Potential Alternative Antibacterial Activity Of Falcata (Falcataria falcata) Leaf Methanolic Extract Against Staphylococcus aureus And Escherichia coli  Laliefe B. Arnan; Katherine Joy S. Escueta; Nor Rashida P. Rashid; Elyca M. Tacbobo; Queenie Rose M. Tinoy  Degree: Bachelor of Science in Pharmacy  Thesis Adviser: Junnin Gay L. Garay, RPh, CPh, MS Pharm Falcata is a plant that can be found in the Philippines and is used for the production of wood veneer and plywood. While in Indonesia, it is used as traditional remedy for malaria (Budiarti et al. 2020). They belong to the Fabaceae family, a family known for having great antibacterial effects (Gamo et al. 2015). This study used a percolation extraction method and the percentage yield is calculated to determine the yield from the falcata extract. Disc diffusion method is used for susceptibility testing and determining the zone of inhibition for the different groups. The CLSI guidelines for Staphylococcus aureus and Escherichia coli will be used to determine the antibacterial effect of the extract, in terms of resistance, intermediate, and susceptible results. From the results, the percentage yield of the methanolic crude leaf extract of Falcataria falcata is 2.67%. Leaves from the Falcataria falcata plant were extracted and tested against bacteria. The extracts showed promise in inhibiting the growth of Staphylococcus aureus and Escherichia coli bacteria, with 75% concentration as being more effective. However, these bacteria showed some resistance to all extract concentrations: S. aureus (90% - resistant, 75% - intermediate, 50% - resistant, 25% - resistant); E. coli (90% - resistant, 75% - resistant, 50% - resistant, 25% - resistant). Further study is needed to determine the exact antibacterial properties of the plant.

Unveiling the Potential of Brazilian Eucalyptus for Transparent Wood Manufacturing via the Kraft Pulping Process as a Future Building Material

The emergence of transparent wood as a viable alternative to traditional glass has sparked considerable interest in recent research endeavors. Despite advancements, challenges persist in the delignification methods and wood species utilized in prior studies. Therefore, this study delves into the potential of Brazilian eucalyptus wood for transparent wood production through the kraft pulping process. Delignification was carried out in a laboratory setting, replicating the kraft process with varying reaction times (15, 30, 45, and 60 min). The resulting delignified wood veneers were impregnated with a pre-polymerized PMMA solution. The study encompassed various analyses, including UV-Vis spectroscopy, colorimetry, SEM, optical microscopy, and mechanical property evaluations. The results revealed intriguing trends in terms of transparency, color changes, microstructural modifications, and mechanical properties as a function of delignification time. This work presents valuable insights into the transformative potential of eucalyptus wood, offering a deeper understanding of the interplay between wood modification and PMMA impregnation.

Decorative wood veneers as a medium for contemporary design: A review

The use of decorative wood veneers in contemporary design is increasingly emphasized as society becomes more aware of quality of life and environmental protection. This article explores in detail four key aspects of decorative wood veneers as a contemporary design medium: visual perceptual elements, multisensory interaction, sustainability and environmental impact, and technology and innovation. Through its unique aesthetic attributes and multisensory experience, decorative wood veneers enhance the aesthetics and user experience of interior design, respond to the global trend of sustainability, and promote innovation and environmental responsibility in the design industry through the use of environmentally friendly materials and advanced technologies. This article aims to provide insights for designers, researchers and related industries to stimulate further exploration of the application of decorative wood veneers in design innovation.

Nature-inspired ultrathin wood-based interfacial solar steam generators for high-efficiency water purification

Here, inspired from butterfly wing, novel hierarchical biomimetic structures composed of tunable nano-structured surfaces, rich micro/nanopores and aligned grooves from polythiophene decorated fir wood veneer have been developed to solve it. Nanowire-shaped and button-like nanostructured polythiophenes as light absorption enhanced materials were in situ grown on wood surface by adjustable vapor deposition process (PFW and CPFW). Meanwhile, wood veneer with reversed-tree structure has a unique aligned grooves surface from split tracheids, serving as the substrate for the nanostructured polythiophenes. These ultrathin wood-based solar steam generators (0.6 mm) stand as one of the thinnest reported self-floating photothermal materials based on wood. Meanwhile, high evaporation flux (1.42 and 1.48 kg·m−2·h−1) and solar-to-vapor efficiencies (88.5 % and 92.4 %) for PFW and CPFW are acquired under 1 sun irradiation. Their structure superiority boosting photothermal conversion performance has been further verified by COMSOL simulated results. The synthesized solar steam generator exhibits exceptional capabilities in seawater desalination and wastewater treatment, demonstrating fantastic application potential in water purification.

Controlled Interlayer Binding and Healing Improve the Transverse Properties of Upcycled Disposable Waste Wood.

Recovery and reuse of bulk waste wood are particularly challenging because of usage defects and contaminations. Here, we present a robust and efficient strategy for regenerating used wood veneers into high-performance structural materials through micro/nano interface manipulation. Our approach involves using cellulose-based interlayers to bind together two waste wood plates without an external adhesive by partially dissolving and regenerating the interlayer using a solution of ionic liquids and dimethyl sulfoxide. The mechanical properties of the regenerated wood exceed that of natural wood, displaying over a 16 and 20 times increase in transverse tensile strength and modulus, respectively, and 4-6 times improvement in longitudinal tensile strength and modulus. Nanoscale mechanical analyses show that the improvement is possible as a result of several factors, including the robust network structure of the interlayer, the good adhesion at the wood-interlayer interface, the compacted wood structure, and the low stiffness and deformation gradients between the interlayer and the wood structure. The interlayers can be created from waste papers and wood particles by taking advantage of the nanofibrillar structure of cellulose.

Fabrication and investigation of a novel composite based on waste polyurethane rigid foam and wood veneer

Fabrication and investigation of a novel composite based on waste polyurethane rigid foam and wood veneer

Properties of patula pine plywood using phenolic resin-impregnated veneers

Having observed the need for structural panels for external use, it is important to study methods of treating wood from new forest species, with less harmful products. In this sense, veneers of Pinus patula wood were subjected to immersion treatment in phenolic resin diluted in water at 5% solids content for one minute, and subsequently used to produce plywood panels using phenol-formaldehyde resin, with a weight of 160 g /m² in single line. The experimental design included four types of panels: fresh veneers glued with 35% resin solids content, treated veneers glued with 12%, 23% and 35% resin solids content. The physical-mechanical properties of the panels were compared with the parameters defined by the Brazilian Association of the Mechanically Processed Wood Industry (ABIMCI) and the Brazilian Association of Technical Standards (ABNT). The panels produced presented apparent density and bonding quality results below the minimum recommendations established in these technical parameters, in addition to water absorption higher than the values found in research with other pine species. However, veneer panels treated with phenolic resin showed better bonding quality than untreated panels for the same resin solids content. In less severe conditions, such as in the wet bonding test, the use of 23% resin solids content maintained bonding quality compared to 35% untreated wood. Therefore, further studies are suggested on the use of wood veneers treated with phenol and to reduce the resin solids content for to reduce costs and harmful effects on the environment.

Quercus robur wood veneer with pronounced natural color uniformity and stability by regulating the content of phenolic extractives

Wood is recognized as a promising raw material for house furnishings due to its good mechanical properties, relatively low density and weight and biodegradability. However, the natural color difference of wood veneer always induces value degradation. Therefore, accurate color regulation plays a pivotal role in producing high-value wood-based composites. In this study, a Quercus robur wood exhibiting a pronounced color variation was treated by an alkaline hydrogen peroxide (H2O2) homogenization process to regulate the content of phenolic extractives, and ferric chloride (FeCl3)-induced color modification to optimize the color. In order to minimize the chromatic disparity of the veneer, it simultaneously restores its initial hue and thus enhances its value. The color difference values of natural untreated Quercus robur veneer and homogenized toned veneer were assessed by using color testing based on the CIEL*a*b* 1976 system. The results demonstrated that the levels of lignin, hemicelluloses, and extractives in the toned veneers subjected to homogenization pretreatment exhibited varying degrees of reduction, along with a decrease in their affinity for iron ions. By assessing the colorfastness of homogenized, toned veneer through testing, the water and light resistance of the homogenized pretreated veneer is significantly superior to that of Quercus robur treated exclusively with iron salts. A higher level of color uniformity in the homogenized pretreated toned veneers, with the toned veneers treated with 0.16 mol/L iron salt exhibiting the closest resemblance to natural Quercus robur wood. This study not only reveals a novel methodology for chemically modifying the hue of wooden surfaces to achieve natural color uniformity but also presents a sustainable and facile approach to promote the high value-added utilization of wood.

Linking energy efficiency and waste recovery to improve housing insulation and tackle energy poverty in south-central Chile

Given the environmental impact of the construction industry, sustainable solutions are increasingly needed to minimize the life cycle impacts of buildings by means of reusing renewable industrial waste. Abundant forest and farm waste exist in center-south Chile, with great potential to be used as thermal insulation and, thus, improve the livability of houses located in an area facing air pollution and energy poverty issues. This paper discusses two types of insulation produced and tested jointly with Germany-based Fraunhofer Institute for Wood Research (WKI)– using Chilean agroforestry waste: First, a flakeboard made of wood veneer chips; and second, a flexible substrate and a pressure resistant board made of wheat and oat straw. The main goal of this research is to assess, by means of digital modeling and experimental tests, the thermal characteristics and the resistance to humidity of these new insulation materials and their performance within construction solutions usually used in Chile. The benchmarks used were the most demanding national residential energy efficiency standard implemented to address air pollution and energy poverty, and the most demanding international standard, both for walls and roofing. The results of both insulation materials was promising, as they met the thermal performance and resistance to humidity requirements and show technical feasibility for the insulation market; in addition, they share the potential to be used in different types of buildings and construction solutions both in Chile and abroad, promoting a sustainable approach starting from the raw materials and the manufacturing process, through the buildings’ operations.

Investigating the influence of fabrication parameters, flax fibre reinforcement, and ageing on interlaminar shear strength in thermoplastic-bonded wood veneers

Investigating the influence of fabrication parameters, flax fibre reinforcement, and ageing on interlaminar shear strength in thermoplastic-bonded wood veneers

Progressive Damage Simulation of Wood Veneer Laminates and Their Uncertainty Using Finite Element Analysis Informed by Genetic Algorithms

Within the search for alternative sustainable materials for future transport applications, wood veneer laminates are promising, cost-effective candidates. Finite element simulations of progressive damage are needed to ensure the safe and reliable use of wood veneers while exploring their full potential. In this study, highly efficient finite element models simulate the mechanical response of quasi-isotropic [90/45/0/−45]s beech veneer laminates subjected to compact tension and a range of open-hole tension tests. Genetic algorithms (GA) were coupled with these simulations to calibrate the optimal input parameters and to account for the inherent uncertainties in the mechanical properties of wooden materials. The results show that the continuum damage mechanistic simulations can efficiently estimate progressive damage both qualitatively and quantitatively with errors of less than 4%. Variability can be assessedthrough the relatively limited number of 400 finite element simulations as compared to more data-intensive algorithms utilised for uncertainty quantification.

Perceptual dimensions of wood materials.

Materials exhibit an extraordinary range of visual appearances. Characterizing and quantifying appearance is important not only for basic research on perceptual mechanisms but also for computer graphics and a wide range of industrial applications. Although methods exist for capturing and representing the optical properties of materials and how they vary across surfaces (Haindl & Filip, 2013), the representations are typically very high-dimensional, and how these representations relate to subjective perceptual impressions of material appearance remains poorly understood. Here, we used a data-driven approach to characterizing the perceived appearance characteristics of 30 samples of wood veneer using a "visual fingerprint" that describes each sample as a multidimensional feature vector, with each dimension capturing a different aspect of the appearance. Fifty-six crowd-sourced participants viewed triplets of movies depicting different wood samples as the sample rotated. Their task was to report which of the two match samples was subjectively most similar to the test sample. In another online experiment, 45 participants rated 10 wood-related appearance characteristics for each of the samples. The results reveal a consistent embedding of the samples across both experiments and a set of nine perceptual dimensions capturing aspects including the roughness, directionality, and spatial scale of the surface patterns. We also showed that a weighted linear combination of 11 image statistics, inspired by the rating characteristics, predicts perceptual dimensions well.

Influence of micron-sized oligomeric semisiloxane modification on surface properties of veneer and interfacial adhesion of EVA film/poplar plywood

ABSTRACT Using EVA film as an adhesive to composite with wood veneer can fabricate e formaldehyde-free wood-based panels. In order to improve the interfacial adhesion of the thermoplastic resin plywood, micron-sized oligomeric semisiloxane (MS) solution was prepared and sprayed on the poplar veneer before bonded with the EVA film. The effect of MS solution on the surface properties of poplar and mechanical properties of MS-treated plywood by FTIR, XPS, WCA, and SEM-EDS. The results indicated that MS was successfully grafted onto the surface of veneer by covalent bonding (Si-O-C) and formed a rough hydrophobic coating on the veneer. The WCA of poplar veneer was significantly increased. As a result of the change in surface properties, poplar veneer formed a tight interfacial bonds with EVA film, which improved mechanical performance of plywood. When the MS treatment conditions were 3% silane, 15% neutral silica, and 3 h reaction times, the wet shear tensile strength and dry shear tensile strength reached 1.03 and 1.56 MPa, respectively. Compared with untreated plywood, the wet strength and dry strength were increased by 76% and 39%, respectively. In addition, Reduced gaps between MS-treated poplar veneer and EVA film and formed stronger interlock structures were observed by SEM.

Quality Evaluation of New Types of Layered Composites for Flooring Materials.

The need, or even the obligation, to take care of the natural environment compels a search for new technological solutions, or for known solutions to be adapted to new applications. The maxim is 'don't harm, but improve the world for future generations'. In the wood industry in particular, given that it is based on a natural raw material, we must look for ecological solutions. Trees grow, but the demand for wood exceeds the volume of tree growth. In industrial manufacturing, one of the ways to make full use of wood is through chipless processing, which occurs during rotary cutting (peeling). In addition, wood is a natural material, each fragment of which has a range of properties. In addition, wood defects in quality manipulation generate a lot of waste. The aim of this study was to analyse the quality effect of the tested layered composites for flooring materials on production application. The practical purpose was to exchange actual sawing-based production for chipless production. The composite base layers were made of pine wood (Pinus L.) veneers with differing quality classes. The samples were subjected to three-point bending tests to calculate the moduli of elasticity and stiffness, which are the most important parameters. Because both analysed parameters describe product quality, the analyses were based on the creation of Shewhart control charts for each parameter. In theory, these control charts are tools for analysing whether the production process is stable and yields predictable results. To have full control over the process, five elements have to be applied: central line (target), two types of control lines (upper and lower) and two types of specification lines (upper and lower). New types of layered composites for flooring may be applied to production once verified using Shewhart control charts. It turns out that it is possible to produce the base layer of the flooring materials using the rotary cutting (peeling) method without having to analyse the quality of the raw material. This is a way to significantly increase the efficiency of production in every element of manufacturing.

Enhancing flame retardancy and antibacterial properties of wood veneer by promoting crosslinking in metal-organic framework structures

Decorative veneer, rotary cut from wood, serving as the outermost layer of decorative plates and is exposed to potential risks of fire hazards and bacterial growth. In this study, following the principle of eco-friendly and cost-effective, the polyamino polyether methylene phosphonate (PAPEMP) and magnesium chloride (MgCl2) were sequentially impregnated into the veneer, and then the alkaline environment was employed to facilitate the complexation, leading to the formation of cross-linked chains within the porous wood structure. Consequently, the modified wood veneer, endowed with exceptional flame retardancy, smoke suppression, antibacterial properties, and good wettability was successfully achieved. Through optimization in an alkaline environment, the modified decorative veneer exhibits a remarkable increase in limiting oxygen index from 19.7% in the pure veneer to 36.9%, coupled with a significant reduction of 19.38% in total heat release and 65.22% in total smoke release compared to the pure veneer. Additionally, the peak mass loss rate (PLMR) of the modified veneer was 66.41% lower than that of the pure veneer, and the char residue increased to 46.1%, representing a 149.19% improvement over the pure veneer. Compared with pure veneer, the wettability of modified veneer increased by 37.93%. Additionally, the tensile strength parallel to the grain of the modified veneer was enhanced by 22.09% compared to the veneer without NaOH solution treatment, and exhibits strong inhibitory effects on colony reproduction. The developed flame-retardant and antibacterial treatment processes for decorative veneers offer a novel and environmentally friendly method for utilizing precious tree veneers, suitable for a variety of precious woods, and successfully applied to decorative wooden doors and wooden fire-resistant doors.