Wood Modification Technologies: Principles, Sustainability, and the Need for Innovation

Description

The market for durable products using modified wood has increased substantially during the last few years. This is partly because of the restriction on the use of toxic preservatives due to environmental concerns, and to lower maintenance cost and time. Furthermore, as sustainability becomes a greater concern, the environmental impact of construction and interior materials is factored in planning by considering the whole life cycle and embodied energy of the materials used. Wood is modified to improve its intrinsic properties, enhance the range of applications of timber, and to acquire the form and functionality desired by engineers without calling the environmental friendliness into question. Wood modification processes are at various stages of development, and the challenges faced in scaling up to industrial applications differ. 　 The aim of this book is to put together the key elements of the changes of wood constituents and the related changes in wood properties of modified wood. Further, a selection of the principal technologies implemented in wood modification are presented. This work is intended for researchers, professionals of timber construction, as well as students studying the science of materials, civil engineering and architecture. This work is not exhaustive, but intends to deliver an outline of the scientific disciplines necessary to apprehend the technologies of wood modification and its behavior during treatment, as well as during its use. Cover Title Page Copyright Page Preface Table of Contents 1. Wood and Wood Modification 1.1 Wood modification What is wood modification? Wood modification processes 1.2 Wood as a substrate for modification The tree The macrostructure of wood The microstructure of wood Wood cell-wall structure and ultrastructure 1.3 The chemical composition of wood Brief introduction to covalent bonds Chemical reactions of organic compounds The chemistry of wood modification 1.4 The wood-water relationship Determining moisture in wood Wood modification and moisture 1.5 Wood biodegradation Wood as a substrate for microorganisms Biological degradation of wood by fungi Biological degradation of wood by invertebrate organisms Termites 1.6 Weathering of wood Factors contributing to weathering 1.7 Stress-strain response of wood: Considerations in wood modification Elastic behaviour of wood Viscoelastic behaviour of wood Mechano-sorption Stress-strain relationship under longitudinal deformation Stress-strain relationship under transverse compression 1.8 Conclusions on wood and wood modification References 2. Chemical Modification Processes 2.1 Introduction 2.2 Acetylation Material selection and preparation The modification process The modified product Industrial use and application 2.3 The CompregTM process Material selection and preparation The modification process The modified product Industrial use and application 2.4 Impreg Material selection and preparation The modification process The modified product Industrial use and application Comparison between ImpregTM and CompregTM 2.5 Furfurylated wood Material selection and preparation The modification process The modified product Industrial use and application 2.6 DMDHEU Material selection and preparation Modification process The modified product Industrial use and application 2.7 Silicates and silanes Material selection and preparation The modification process The modified product Industrial use and application 2.8 Chitosan Material selection and preparation The modification process The modified product Industrial use and application 2.9 InduriteTM and LigniaTM Material selection and preparation The modifying process Product properties Industrial use and application 2.10 Oil and wax Material selection and preparation Modification process The modified product Industrial use and applications 2.11 Polyethylene glycol (PEG) Material selection and preparation The modification process Product properties Industrial use and application 2.12 Summary and outlook References 3. Thermally-based Modification Processes 3.1 Introduction Thermal degradation of wood 3.2 Charring of wood surfaces Material selection and preparation Industrial charring processes Properties of charred wood Applications for charred wood 3.3 Water as a modification agent for wood Chemistry of TBM treatment 3.4 Thermal modification processes Material selection and preparation Industrial thermal modification processes Properties of thermally modified wood Applications of thermally-modified timber 3.5 Wood ageing Material selection and preparation Industrial wood ageing processes Properties of aged wood Applications of aged wood 3.6 Self-bonding of veneer Material selection and preparation Industrial self-bonding processes Properties of self-bonded veneer Applications for self-bonded veneer 3.7 Frictional wood welding Material selection and preparation Industrial wood-welding processes Properties of the frictional welded bond-line Applications of welded wood 3.8 Wood densification Permanent fixation of compressive deformation Material selection and preparation Industrial densification processes Properties of densified wood Applications of densified wood 3.9 Moulded tubes Material selection and preparation Industrial processes for shaped wood Applications of moulded tubes 3.10 Summary and outlook References 4. The Use of Microwaves, Plasma and Laser Light for Wood Modification 4.1 Introduction Electromagnetic radiation Plasma Laser light 4.2 Wood modification with microwaves Material selection and preparation Wood modification with microwaves: processes, properties, applications 4.3 Wood modification with plasma Corona and plasma treatments: processes properties, applications 4.4 Wood modification with laser light Material selection and preparation Laser modification: processes, properties, applications 4.5 Conclusions on microwaves, plasma and laser-light modification References 5. Other Modification Processes 5.1 Introduction 5.2 Biological treatment of wood Metabolites from wood-destroying organisms to protect wood Fungal incising Enzymatic treatment of wood Bacterial incising Treatment with natural extracts Conclusions regarding biological treatment 5.3 Biomimetics What is biomimetics? Biomimetics in architecture Biomimetics for wood treatment Biomimetics and water repellency Biomimetics and self-cleaning Other potential biomimetic wood modifications 5.4 Mineralisation of wood Mineralisation with silica compounds Mineralisation with nanomaterials Mineralisation with carbonates 5.5 Supercritical fluid treatments Supercritical fluid extraction and liquefaction processes for wood Use of supercritical fluids in wood preservation Other uses of supercritical fluids Overview of supercritical fluids 5.6 Ionic liquids in wood modification What is an ionic liquid? Ionic liquids and wood components Ionic liquids as wood preservatives Chemical modification of wood with ionic liquids Conclusions regarding ionic liquids 5.7 Opportunities for future wood modification Grafting of components to enable polymerisation Click chemistry Rhodium-catalysed reactions of hydroxyl groups Modification of chitosan 5.8 Conclusions on other methods References 6. Modified Wood Beyond Sustainability 6.1 Introduction 6.2 Environmental impact of wood modification processes 6.3 Modified wood in a circular economy 6.4 The use of modified wood in a healthy living environment Environmental assessment of buildings Modified wood as an element of restorative environmental design Volatile organic emissions 6.5 Industry 4.0 in wood supply chain 6.6 Conclusions References Appendix Index