Download or read book Characterization of Modified Wood in Relation to Wood Bonding and Coating Performance written by COST Action FP0904 Thermo-Hydro-Mechanical Wood Behaviour and Processing and published by . This book was released on 2013 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 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 Environmental Impacts of Traditional and Innovative Forest based Bioproducts written by Andreja Kutnar and published by Springer. This book was released on 2016-03-21 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive description of traditional and innovative forest-based bioproducts, from pulp and paper, wood-based composites and wood fuels to chemicals and fiber-based composites. The descriptions of different types of forest-based bioproducts are supplemented by the environmental impacts involved in their processing, use, and end-of-life phase. Further, the possibility of reusing, recycling and upgrading bioproducts at the end of their projected life cycle is discussed. As the intensity of demand for forest biomass is currently changing, forest-based industries need to respond with innovative products, business models, marketing and management. As such, the book concludes with a chapter on the bioproducts business and these products’ role in bioeconomies.
Download or read book Wood Protection and Preservation written by Christian Brischke and published by MDPI. This book was released on 2020-12-10 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wood is an advantageous building material in many respects, but it is biodegradable and therefore requires protection when used in highly hazardous applications. This Special Issue comprises 19 papers by authors from 14 countries in Asia, North America and Europe. They represent a wide range of aspects related to wood protection and wood preservation, and give timely examples of research activities that can be observed around the globe. Several authors reported on the processes of thermal modification and different chemical wood modification techniques, which are among the latest alternative wood protection methods without the use of biocides. New preservatives and assessment methods of preservative-treated wood products are presented, as well as studies on the natural durability of wood, fire-retardant treated wood, the effect of concrete on wood durability and different novel surface modification techniques using plasma. In addition to biological durability, the mechanical properties, moisture performance, bonding properties, weathering stability and the corrosiveness of differently treated wood are investigated and reported within this Special Issue. Examples of research on fungal biology, service life planning with wood and test methodology are also included and complete the Special Issue.
Download or read book Progress in Adhesion and Adhesives written by K. L. Mittal and published by John Wiley & Sons. This book was released on 2015-07-27 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on the 13 review articles written by subject experts and published in 2014 in the Journal Reviews of Adhesion and Adhesives. The rationale for publication of this book is that currently the RAA has limited circulation, so this book provides broad exposure and dissemination of the concise, critical, illuminating, and thought-provoking review articles. The subjects of the reviews fall into 4 general areas: 1. Polymer surface modification 2. Biomedical, pharmaceutical and dental fields 3. Adhesives and adhesive joints 4. General Adhesion Aspects The topics covered include: Adhesion of condensed bodies at microscale; imparting adhesion property to silicone material; functionally graded adhesively bonded joints; synthetic adhesives for wood panels; adhesion theories in wood adhesive bonding; adhesion and surface issues in biocomposites and bionanocomposites; adhesion phenomena in pharmaceutical products and applications of AFM; cyanoacrylate adhesives in surgical applications; ways to generate monosort functionalized polyolefin surfaces; nano-enhanced adhesives; bonding dissimilar materials in dentistry; flame treatment of polymeric materials—relevance to adhesion; and mucoadhesive polymers for enhancing retention of ocular drug delivery.
Download or read book Wood Modification written by Anna Sandak and published by Mdpi AG. This book was released on 2021-12-10 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue of Coatings presents the newest research outcome in the field of the enhancement of native wood properties through a wide range of chemical, biological, and physical agents. The broad spectrum of topics provides a comprehensive update regarding ongoing research in this field. Such a compilation can be an inspiration for the further development of multifunctional and sustainable coatings, revolutionizing the wood sector of the future.
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 2012-09-06 with total page 703 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 perha
Download or read book Wood Modification written by Anna Malgorzata Sandak and published by . This book was released on 2021 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue of Coatings presents the newest research outcome in the field of the enhancement of native wood properties through a wide range of chemical, biological, and physical agents. The broad spectrum of topics provides a comprehensive update regarding ongoing research in this field. Such a compilation can be an inspiration for the further development of multifunctional and sustainable coatings, revolutionizing the wood sector of the future.
Download or read book Isolation Modification and Characterization of the Constituents Cellulose Hemicellulose Lignin et al in Biomass and Their Bio based Applications written by Caoxing Huang and published by Frontiers Media SA. This book was released on 2022-05-31 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Material Characterization of Wood Adhesive and Coating of Cultural Heritage Under Various Climatic Conditions written by Erik Valentine Bachtiar and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of ICDMC 2019 written by Lung-Jieh Yang and published by Springer Nature. This book was released on 2020-06-01 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises select proceedings of the International Conference on Design, Materials, Cryogenics and Constructions (ICDMC 2019). The chapters cover latest research in different areas of mechanical engineering such as additive manufacturing, automation in industry and agriculture, combustion and emission control, CFD, finite element analysis, and engineering design. The book also focuses on cryogenic systems and low-temperature materials for cost-effective and energy-efficient solutions to current challenges in the manufacturing sector. Given its contents, the book can be useful for students, academics, and practitioners.
Download or read book Coating Performance on Preservative Treated Wood written by Mojgan Nejad and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Characterization of Chemically Modified Wood written by Samuel O. Olaniran and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Green Chemistry for Surface Coatings Inks and Adhesives written by Rainer Höfer and published by Royal Society of Chemistry. This book was released on 2019-06-06 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many modern surface coatings and adhesives are derived from fossil feedstocks. With fossil fuels becoming more polluting and expensive to extract as supplies dwindle, industry is turning increasingly to nature, mimicking natural solutions using renewable raw materials and employing new technologies. Highlighting sustainable technologies and applications of renewable raw materials within the framework of green and sustainable chemistry, circular economy and resource efficiency, this book provides a cradle-to-cradle perspective. From potential feedstocks to recycling/reuse opportunities and the de-manufacture of adhesives and solvents, green chemistry principles are applied to all aspects of surface coating, printing, adhesive and sealant manufacture. This book is ideal for students, researchers and industrialists working in green sustainable chemistry, industrial coatings, adhesives, inks and printing technologies.
