Download or read book Chemical Modification of Wood and Determination of the Resulting Wood Properties written by Carsten Mai and published by . This book was released on 2010 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wood Modification written by Callum A. S. Hill and published by John Wiley & Sons. This book was released on 2007-02-06 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is exclusively concerned with wood modification, although many of these processes are generic and can be applied to other lignocellulosic materials. There have been many rapid developments in wood modification over the past decade and, in particular, there has been considerable progress made in the commercialisation of technologies. Topics covered include: The use of timber in the 21st century Modifying the properties of wood Chemical modification of wood: Acetic Anhydride Modification and reaction with other chemicals Thermal modification of wood Surface modification Impregnation modification Commercialisation of wood modification Environmental consideration and future developments This is the first time that a book has covered all wood modification technologies in one text. Although the book covers the main research developments in wood modification, it also puts wood modification into context and additionally deals with aspects of commercialisation and environmental impact. This book is very timely, because wood modification is undergoing huge developments at the present time, driven in part by environmental concerns regarding the use of wood treated with certain preservatives. There has been considerable commercial interest shown in wood modification over the past decade, with products based upon thermal modification, and furfurylation now being actively being marketed. The next few years will see the commercialisation of acetylation and impregnation modification. This is a new industry, but one that has enormous potential. This book will prove useful to all those with an interest in wood modification including researchers, technologists and professionals working in wood science and timber engineering, wood preservation, and well as professionals in the paper and pulp industries, and those with an interest in the development of renewable materials.
Download or read book Handbook of Wood Chemistry and Wood Composites written by Roger M. Rowell and published by CRC Press. This book was released on 2005-02-18 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: The degradable nature of high-performance, wood-based materials is an attractive advantage when considering environmental factors such as sustainability, recycling, and energy/resource conservation. The Handbook of Wood Chemistry and Wood Composites provides an excellent guide to the latest concepts and technologies in wood chemistry and bio-based composites. The book analyzes the chemical composition and physical properties of wood cellulose and its response to natural processes of degradation. It describes safe and effective chemical modifications to strengthen wood against biological, chemical, and mechanical degradation without using toxic, leachable, or corrosive chemicals. Expert researchers provide insightful analyses of the types of chemical modifications applied to polymer cell walls in wood, emphasizing the mechanisms of reaction involved and resulting changes in performance properties. These include modifications that increase water repellency, fire retardancy, and resistance to ultraviolet light, heat, moisture, mold, and other biological organisms. The text also explores modifications that increase mechanical strength, such as lumen fill, monomer polymer penetration, and plasticization. The Handbook of Wood Chemistry and Wood Composites concludes with the latest applications, such as adhesives, geotextiles, and sorbents, and future trends in the use of wood-based composites in terms of sustainable agriculture, biodegradability and recycling, and economics. Incorporating over 30 years of teaching experience, the esteemed editor of this handbook is well-attuned to educational demands as well as industry standards and research trends.
Download or read book Chemical Modification of Lignocellulosic Materials written by DavidN.-S. Hon and published by Routledge. This book was released on 2017-09-29 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume emphasizes the growing need for wood products with advanced engineering properties. It details the fundamental principles of cellulose technology and presents current techniques to modifying the basic chemistry of lignocellulosic materials. The work: discusses the cost-efficient use of cellulose derivatives in a variety of commodities; highlights the chemical modification of wood by methods such as etherification, esterification and thermoplasticization; considers recent progress in the lignocellulosic liquefaction of wood; and more.
Download or read book Wood Modification Technologies written by Dick Sandberg and published by CRC Press. This book was released on 2021-07-15 with total page 765 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Bondability of modified wood written by Alireza Bastani and published by Cuvillier Verlag. This book was released on 2016-06-30 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigates the bonding properties of modified wood by considering three different aspects: water related characteristics, mechanical performance and optical (fluorescence microscopy and X-ray micro-computed tomography) observation of adhesive penetration into modified wood structure. In recent years, the new wood modifications have become more commercially available in the market for both exterior and interior applications due to improved properties that modification can bring to the wood e.g. the improved biological durability, dimensional stability, hardness and weathering resistance of the wood as well as the environmentally friendly nature of the wood modification processes (Militz and Hill 2005). Besides these advantages, modification can affect some technological aspects of the wood such as its bonding performance. For example, it can alter the strength of adhesion as a result of changes in chemical, physical and structural characteristics of the wood. For example, the less polar and less porous modified wood surfaces can result in reduced adhesion due to formation of less free OH groups for bonding leading to poorer adhesive wetting of the wood surface and weaker chemical bonds between the two adherents (Hunt et al. 2007). As modified wood becomes a more demanded material for different applications, there is a need to study its bonding performance where the challenge is to bond different modified materials as their physical and chemical characteristics are substantially changed by modification. In this thesis, measurements of capillary water uptake, contact angle and surface energy were used to determine the water related properties and hydrophobic behavior of furfurylated (FA40 and FA70, which represent 65 and 75 % WPGs) and N-methylol melamine (NMM) (10, 20 and 30%) modified Scots pine and thermally treated Scots pine and beech (modified through an industrial scale vacuum press dewatering method at 195 and 210 °C). The capillary water uptake results indicated a considerable reduction of water uptake for all modifications in all directions both after short (24 h) and long contact times (168, 336 h). Contact angle measurement data revealed an increased hydrophobicity of modified wood. However, some exceptions were observed, mainly for thermally treated wood. Modifications provided radial and tangential surfaces with a non-polar character. Penetration of adhesives into the wood structure plays an important role in the production of glued wood-based panels and products by affecting the bond quality (Frihart 2005, Kamke and Lee 2007). The gross penetration of emulsion polymer isocyanate (EPI), polyurethane (PU) and polyvinyl acetate (PVAc) adhesives into modified wood, both with and without pressure, were determined by using fluorescence microscopy based on measurements of effective (EP) and maximum penetration (MP). Without application of pressure, the EP of EPI adhesive reduced after NMM modification and furfurylation (FA70) and also PU adhesive after NMM modification while the EP of PVAc adhesive increased into furfurylated and NMM modified (10 and 20%) wood. For thermally treated Scots pine, increasing the treatment temperature improved EP of all adhesives. Among used adhesives, PU penetrated much deeper into thermally treated wood for both treatment temperatures. Comparison of penetration of adhesive with and without pressure revealed that with the exception of EP of PU and EPI adhesives into NMM-modified wood and PVAc into thermally treated beech at 195°C, application of pressure led to rather different results as compared to the EP data when no pressure was applied. Visual observation and analysis of fluorescence microscopy photomicrographs provided more detailed information on modality of penetration. Due to the large and deep penetration of PU adhesive into thermally treated Scots pine observed in both studies (with and without pressure), the 3D pattern of penetration of this adhesive was obtained by X-ray micro- computed tomography indicating the pathways which were used by this adhesive for penetration. In another study, the bonding shear strength of the same modified wood materials glued with the same adhesives was also investigated. For all adhesives used, the shear strength significantly reduced after furfurylation and NMM modification of Scots pine samples, mainly due to the brittle nature of the wood after modification rather to the failure of the bondline. Bonding strength of both Scots pine and beech was also negatively affected by thermal modification and the bondline was found to be the weakest link in thermally modified wood. The EP of adhesives and the bondline thickness did not relate to the shear strength of all modified wood materials. It was indicated that the lower shear strength of modified wood could be attributed to other factors, such as the decreased chemical bonding or mechanical interlocking of adhesives, and the reduced strength of brittle modified wood substrate. The effect of two important bonding variables, wood moisture content and open assembly time on penetration of PU adhesive into thermally modified wood (195 and 210 °C) was also studied. The equilibrium moisture content (EMC) level of 8.6% was found to be the optimum for an effective penetration of PU adhesive in thermally modified Scots pine treated at 195°C. In most of the cases, penetration of PU adhesive did not change significantly by increasing the open assembly time, which suggested using a shorter open assembly time of 15 min than 30 min for bonding of thermally modified Scots pine with PU adhesive, in order to save time and reducing the production costs. For samples treated at both treatment temperatures and after shorter open assembly time, the highest MP values observed at moderate EMC levels of 8.6 and 8.2% and the lowest at the higher EMC levels of 13.2 and 12.5%. In another study, the effect of phenol formaldehyde (PF) treatment on bonding performance of beech glued with PVAc and phenol resorcinol formaldehyde (PRF) adhesives was also investigated. The results of both dry and wet conditions indicated higher shear strength for samples bonded with PRF than PVAc. With the exception of 25% PF treated wood bonded with PVAc, the PF modified wood can be glued with both adhesives satisfactorily under dry condition, while under wet condition only the 25% PF modified samples bonded with PRF provided acceptable bonding. For both adhesive systems, PF modification caused a reduction of adhesive penetration into wood structure, especially in the case of higher load treatment. The development of bonding strength of modified birch veneers glued with hot curing phenol formaldehyde (PF) adhesive was investigated in different pressing (20 s , 160s) and open assembly times (20s , 10 min). Generally, the bonding strength improved by extending the pressing time. In 20 s pressing, increasing assembly time did not change the bonding strength in most of the cases while at 160 s pressing, prolongation of assembly time developed a better bonding for controls, NMM modified and thermally treated veneers at 180°C. The combination of 10 min assembly time and 160 s pressing time provided the highest bonding strength for controls, NMM modified and thermally treated veneers at 180°C while furfurylated samples achieved the highest values in 20 s assembly and 160 s pressing times. In general, modification affected negatively the bonding performance of the veneers, especially for furfurylated and NMM modified samples. In General, the overall results obtained in this thesis showed that modified wood has lower bonding ability and performance than unmodified wood as result of the decreased water related properties, less penetration of adhesive into wood structure and decreased bonding strength after modification. However, the increased dimensional stability and low water uptake of modified wood might lead to better performance in long term.
Download or read book Chemical Modification of Wood written by Christopher P. Gabrielli and published by . This book was released on 2008 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tendency of wood to shrink and swell with changing moisture content remains as one of the most significant challenges to using wood in its many applications. Viscoelastic Thermal Compression (VTC) has been shown to significantly increase the density, strength and stiffness of wood. However, dimensional stability is still a concern. Active and passive chemical modifications have been developed which impart dimensional stability by chemically altering the wood substrate or physically blocking the vital pathways of water through the wood microstructure. The efforts of this research have been to develop an approach which combines the VTC process with a chemical modification process resulting in a novel wood-based product that exhibits improved structural properties, as well as a high degree of dimensional stability. Low-grade, plantation-grown hybrid poplar (Populus spp.) was impregnated with low molecular weight phenol-formaldehyde resin, acetic anhydride or tung oil and then densified in the VTC process. Water soak and boil tests were performed to investigate the influence of each treatment on thickness swell, antiswelling efficiency (ASE), irreversible swelling, and thickness recovery. Modulus of elasticity (MOE) was also examined for each treatment. Fluorescence microscopy was applied to determine the physical location and distribution of the impregnating reagents to better understand their role in imparting dimensional stability. PF and acetylation treatments were shown to increase the stability of VTC treated samples. ASE values for both PF and acetylation treatments were high, with a maximum value of 86% for the PF treatment and 56% for the acetylation treatment. Two different low molecular weight PF resins were tested and it was found that the higher MW resin was retained within the cellular structure to a greater degree and imparted greater dimensional stability. MOE was positively correlated to density but negatively correlated to weight percent gain for PF treated samples. All chemically modified samples had lower increases in MOE than unmodified control specimens compressed to the same final thickness. A sub-sample of higher density PF treated specimens had significantly higher MOE values and similar stability values compared to lower density samples. Tung oil treated samples showed no ability to swell the wood cell wall and remained in the cell lumens. Although dimensional stability may have increased on a very short-term basis due to physical obstruction of moisture, long-term stability was not improved with tung oil treatments.
Download or read book Impact of process conditions in open and closed reactor systems on the properties of thermally modified wood written by Michael Altgen and published by Cuvillier Verlag. This book was released on 2016-12-05 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various thermal wood modification technologies have been developed in Europe during the past decades that differ notably in the process conditions applied. However, the changes in wood properties by thermal modification, the underlying modes of action and their link to the process conditions are still not fully understood. This thesis investigates the influence of different process conditions in open and closed reactor systems on the resulting properties of thermally modified wood. In closed reactor systems, elevated water vapor pressure accelerates the thermal degradation of wood polymers and results in high mass loss levels even at mild treatment temperatures. However, in addition to the loss in wood mass, a strong influence of drying and softening of wood at elevated temperatures as well as an increased cell wall matrix stiffness by modification of the lignin carbohydrate complex under dry heat conditions influences the wood properties, i.e. water sorption. For wood thermally modified in open reactor systems at different peak temperatures and durations, the surface performance is investigated with regard to the susceptibility to surface cracking, photodegradation and coatability. The results provide explanations why the performance of thermally modified wood in exterior applications does not always meet the expectations derived from its enhanced resistance against decay fungi.
Download or read book Wood Properties and Processing written by Miha Humar and published by MDPI. This book was released on 2020-05-23 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wood-based materials are CO2-neutral, renewable, and considered to be environmentally friendly. The huge variety of wood species and wood-based composites allows a wide scope of creative and esthetic alternatives to materials with higher environmental impacts during production, use and disposal. Quality of wood is influenced by the genetic and environmental factors. One of the emerging uses of wood are building and construction applications. Modern building and construction practices would not be possible without use of wood or wood-based composites. The use of composites enables using wood of lower quality for the production of materials with engineered properties for specific target applications. Even more, the utilization of such reinforcing particles as carbon nanotubes and nanocellulose enables development of a new generation of composites with even better properties. The positive aspect of decomposability of waste wood can turn into the opposite when wood or wood-based materials are exposed to weathering, moisture oscillations, different discolorations, and degrading organisms. Protective measures are therefore unavoidable for many outdoor applications. Resistance of wood against different aging factors is always a combined effect of toxic or inhibiting ingredients on the one hand, and of structural, anatomical, or chemical ways of excluding moisture on the other.
Download or read book Handbook of Wood Chemistry and Wood Composites Second Edition written by Roger M. Rowell and published by CRC Press. This book was released on 2012-09-06 with total page 707 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wood has played a major role throughout human history. Strong and versatile, the earliest humans used wood to make shelters, cook food, construct tools, build boats, and make weapons. Recently, scientists, politicians, and economists have renewed their interest in wood because of its unique properties, aesthetics, availability, abundance, and perhaps most important of all, its renewability. However, wood will not reach its highest use potential until we fully describe it, understand the mechanisms that control its performance properties, and, finally, are able to manipulate those properties to give us the desired performance we seek. The Handbook of Wood Chemistry and Wood Composites analyzes the chemical composition and physical properties of wood cellulose and its response to natural processes of degradation. It describes safe and effective chemical modifications to strengthen wood against biological, chemical, and mechanical degradation without using toxic, leachable, or corrosive chemicals. Expert researchers provide insightful analyses of the types of chemical modifications applied to polymer cell walls in wood. They emphasize the mechanisms of reaction involved and resulting changes in performance properties including modifications that increase water repellency, fire retardancy, and resistance to ultraviolet light, heat, moisture, mold, and other biological organisms. The text also explores modifications that increase mechanical strength, such as lumen fill, monomer polymer penetration, and plasticization. The Handbook of Wood Chemistry and Wood Composites concludes with the latest applications, such as adhesives, geotextiles, and sorbents, and future trends in the use of wood-based composites in terms of sustainable agriculture, biodegradability and recycling, and economics. Incorporating decades of teaching experience, the editor of this handbook is well-attuned to educational demands as well as industry standards and research trends.
Download or read book Treatments that Enhance Physical Properties of Wood written by Roger M. Rowell and published by . This book was released on 1987 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wood Modification Technologies written by Dick Sandberg and published by CRC Press. This book was released on 2021-07-14 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes how to Improvement of wood products Describes Sustainable development Covers Environmental industrial processing
Download or read book Chemistry in the Utilization of Wood written by R. H. Farmer and published by Elsevier. This book was released on 2013-10-22 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemistry in the Utilization of Wood deals with the chemistry of wood and its technical and practical applications. It shows how the chemical nature of wood influences its properties and utilization, both as a constructional material and as the raw material for the manufacture of secondary products such as pulp and paper, cellulose derivatives, and board materials. Comprised of 12 chapters, this volume begins with an introduction to the chemical nature of wood, including a brief treatment of its anatomical structure. The discussion then turns to the chemistry of wood cell wall components such as cellulose, hemicellulose, and lignin; the principles of the methods employed in wood analysis, with emphasis on the determination of moisture content and extractives, cellulose, pentosan, and other polysaccharides; the influence of extractives on the properties and utilization of wood; and the use of timber in conjunction with chemicals. Other chapters deal with the conversion of wood into chemical products; corrosion of metals in association with wood; and the relationship between wood and water. The chemical aspects of wood attack by fungi and insects are also considered, along with destructive distillation of wood. This book is primarily intended for technical men in the wood-using industries who have an interest in wood and some knowledge of chemistry, and for students entering any field of wood technology.
Download or read book Determination of The Mechanisms of Effectiveness Against Decay of Nontoxic Chemical Modification of Wood written by Roger M. Rowell and published by . This book was released on 1976 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Natural and Wood Fibre Reinforcement in Polymers written by A. K. Bledzki and published by iSmithers Rapra Publishing. This book was released on 2002 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report examines the different fibre types available and the current research. The authors have cited several hundred references to the latest work on properties, processing and applications. The different methods of fibre pretreatment are examined, together with fibre properties, chemistry and applications. This review is accompanied by summaries of papers from the Rapra Polymer Library database.
Download or read book Research Paper FPL written by and published by . This book was released on 1983 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanotechnology in Paper and Wood Engineering written by Rajeev Bhat and published by Elsevier. This book was released on 2022-01-21 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology in Paper and Wood Engineering: Fundamentals, Challenges and Applications describes recent advances made in the use of nanotechnology in the paper and pulp industry. Various types of nano-additives commonly used in the paper industry for modification of raw material to enhance final products are included, with other sections covering the imaging applications of nano-papers and nano-woods in pharmaceuticals, biocatalysis, photocatalysis and energy storage. This book is an important reference source for materials scientists and engineers who are looking to understand how nanotechnology is being used to create more efficient manufacturing processes in for the paper and wood industries. Provides information on nano-paper production and its applications Explains the major synthesis techniques and design concepts of cellulosic or wooden nanomaterials for industrial applications Assesses the major challenges of creating nanotechnology-based manufacturing systems for wood and paper engineering
