Special Issue "Advanced Wood Composites from Renewable Materials"

Submission Deadline: 01 March 2022
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Guest Editors
Antonios N. Papadopoulos, Professor, International Hellenic University, Greek.
Antonios N. Papadopoulos is a specialist in Wood Science, Chemistry and Technology. He is Professor and Head of the Department of Forestry and Natural Environment at the International Hellenic University. He is an M.Sc and Ph.D holder, both from University of North Wales, Bangor. His M.Sc thesis focused on wood composites and his Ph.D thesis on chemical and thermal modification of wood. His main areas of research interests include: chemical and thermal modification of wood, nanotechnology and wood science, composites, wood based panels and adhesives. He has published more than 200 peer reviewed papers, books, and book chapters. He is on various Editorial Boards of journals in the field of wood science and technology.

Summary

Wood, a versatile material, has been used for centuries for many reasons due to its fibrous nature. It varies in color and density and is considered a primary raw material in buildings due to its high strength in combination with its low weight and some durability. It is, therefore, a raw material that can be used in indoor applications and, if treated efficiently, in outdoor application as well. However, two properties restrict its much wider use: dimensional changes when subjected to fluctuating humidity and susceptibility to biodegradation by microorganisms. These drawbacks are mainly due to the cell wall main polymers and, in particular, due to their high abundance of hydroxyl groups. Wood may be modified chemically or thermally, so that selected properties are enhanced in a more or less permanent fashion. Another option to improve the hygroscopicity and the biological durability of both solid wood and wood-based panels is to exploit the solutions that nanotechnology can offer. Employing nanotechnology on wood can result in a next generation of products having hyper-performance and superior service ability when used in severe environments, since it is well known that the cell wall of wood exhibits porosity of molecular scale dimensions due to the partial filling of space between the cellulose microfibrils by lignin, hemicelluloses and extractives. The small size nanoparticles of such nanotechnology compounds can deeply penetrate into the wood, effectively alter its surface chemistry, and result in a high protection against moisture and decay. In addition, the use of lignocellulosic materials for the production of advanced wood composites is an innovative avenue for research. Their growing relevance in the modern industry and science results from the main global trends in industrial development, but also from environmental thinking and nature protection activities, including energy-saving solutions and clean technologies. It must be clearly pointed out that one cannot speak about wood composites without speaking in depth of the polymer binders and adhesives used to hold them together. The history of wood composites themselves is inextricably intertwined with the history and the development of the polymer binders that hold them together and their manufacture. In fact, not only has there been continuous development of new or improved binders that has allowed the development of wood composites but it is the continual renewal, new discovery, and upgrading of such binders that has allowed and allows progress in wood composites. Progress in this fascinating field of primary economic importance has been accelerating, and the number of new ideas, approaches, and new proposed binder systems is continuously increasing, providing a glimpse of an exciting and interesting research future.

 

This Special Issue, Advanced wood composites from renewable materials, seeks high-quality works and topics (not only those) focusing on the latest approaches to the protection of wood and wood composites with chemical or thermal modification technologies, the application of nanomaterials to wood science and the development of new techniques and technologies for production of lignocellulosic materials with enhanced properties and performance. Topics of interest also include mechanical and structural properties of composites as well as their constituent materials; experimental and theoretical studies relating to composites; manipulation of properties through manufacturing and processing; modeling and simulations; microscopic to macroscopic behavior; and performance verification techniques.

 

I deeply believe the collection will become an origin of new ideas for the protection, design, research, and use of sustainable and renewable materials in the fascinating area of wood composites. Laboratories worldwide do innovative research and new challenges, approaches and ideas are continuously increasing letting mirror an exciting and interesting research future.


Keywords
Wood composites, wood, chemical and thermal modification, nanotechnology, lignocellulosic materials, adhesives, sustainable and renewable materials.

Published Papers
  • Analysis of Crack Expansion and Morphology of Cross-Laminated Timber Planar Shear Test
  • Abstract To describe the dynamic cracking process of the CLT vertical layer, the correlation between a load-displacement curve, specimen cracking, and planar shear failure mechanism of the CLT were explored. A three-point bending test and an improved planar shear test are used to evaluate the shear performance of the CLT. In this study, the load-displacement curve is recorded, the experimental part is synchronized with the video, the dynamic process of cracking of the vertical layer is observed and analyzed throughout the test. From the load-displacement curve, the image characteristics of the initial cracking and the sudden increase of the cracking of… More
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  • High Permeability of Boron along the Transverse Direction of Wood under High-Voltage Electrostatic Field (HVEF) Treatment
  • Abstract Permeability of wood preservative is one of the most significant factors for protection of wood construction. Anisotropic flow permeability was involved in different directions of wood with higher flow resistance in the transverse and lower longitudinal directions. In this study, boron acid solution was brushed onto the tangential section of air-dried wood cubes and boron penetration along wood transverse direction was investigated under free diffusion, vacuum and HVEF treatments. Multi-scale boron distribution, FTIR measurement, leaching property, mechanical properties and fungistatic characteristic were investigated for free diffusion, vacuum and HVEF treated samples respectively. The results revealed that boron exhibited high permeability… More
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  • Study on Preparation of Lignin-Containing Nanocellulose from Bamboo Parenchyma
  • Abstract Bamboo vascular bundle fiber and parenchyma (BP) are separated by high-temperature treatment with saturated steam. Bamboo vascular bundle fiber is widely used in the market, but how to develop and utilize parenchyma tissue is a difficult problem. The sulfated cellulose nanofibers (ANFs) were obtained by sulfating BP with a deep eutectic solvent (DES), which provided a theoretical basis for the value-added utilization of BP. Using DES as the reaction medium and reagent, the BP was grafted with a sulfonic acid group to form a gel substance in water, ANFs and nanocellulose gel were obtained by ultrasonic cell crusher. The highest… More
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  • CLT Fabricated with Gmelina arborea and Tectona grandis Wood from Fast-Growth Forest Plantations: Physical and Mechanical Properties
  • Abstract Fabrication and use of Cross Laminated Timber (CLT) using tropical woods is still limited at present. Therefore objective of the present study aims to determine the possibility of using CLT panels of 3 and 5 layers, fabricated with Tectona grandis and Gmelina arborea wood using adhesive of isocyanate polymer emulsion system catalyzed with polymeric isocyanate. Delamination, water absorption, density, flexure test, compression and glue-line shear were evaluated using ANSI/APA PRG320-2012 ASTM D198 and ASTM D4761 standard. The results showed that CLT panels of T. grandis presented higher values of density, less water absorption and lower delamination, with no evident differences… More
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  • Physical and Mechanical Properties of Eco-Friendly Composites Made from Wood Dust and Recycled Polystyrene
  • Abstract The development of alternative wood composites based on the use of waste or recycled materials can be beneficial due to over exploitation of natural resources. Under this frame, an option for the successful utilization of waste polystyrene which avoids environmental problems that formaldehyde adhesives cause and also reduces waste disposal, is its potential application as a binder for the production of value-added environmentally friendly and low cost wood composites. Two types of panel were successfully made, consisting of wood dust and two recycled polystyrene contents, namely, 15% and 30%. Both physical properties, water absorption and thickness swelling, and mechanical properties,… More
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  • Intratree Variation in Viscoelastic Properties of Cell Walls of Masson Pine (Pinus Massoniana Lamb)
  • Abstract In this study, Pinus massoniana Lamb at different heights, across the annual rings, and between earlywood and latewood was measured by X-ray diffraction and the chemical composition was analyzed by chemical treatment. Results indicated that the microfibril angle (MFA) decreased and the chemical composition changed little with the increase in height from 1 m to 9 m. In the radial direction, the MFA decreased and the chemical composition changed little with an increase in annual rings. The cellulose content of latewood was higher than that of earlywood. The viscoelastic changes of wood cell walls at different heights, across the annual rings by… More
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