Wood Modification Hill, Callum A. S
2007, 2006, 2007-02-06, Volume:
5
eBook
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 centuryModifying the properties of woodChemical modification of wood: Acetic Anhydride Modification and reaction with other chemicalsThermal modification of woodSurface modificationImpregnation modificationCommercialisation of wood modificationEnvironmental consideration and future developmentsThis 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.
Companies in the wood industry are constantly developing their outdoor products. The possibility of using bio-based chemicals as an alternative to traditional wood preservatives—regulated in Europe ...by The Biocidal Products Regulation No 528/2012—has been considered, but chemical leaching from the wood decreases its effectiveness and may negatively affect the environment. This study aims to compare the effectiveness of bio-based chemicals with potential use in wood preservation to commercially available preservatives, to investigate their fixation to wood and their ecotoxicity and to quantify the potentially toxic elements leached from the wood. Pyrolysis distillates of tree bark, organic acids found in distillates, Colatan GT10 tannin extract and log soaking liquid as a hardwood veneer process residue were tested and compared with commercial pine oil and a copper-based wood preservative. In the wood decay test of impregnated pine sapwood specimens, Colatan GT10 extract performed as well as the commercial wood preservatives. The same decay trial with leached specimens significantly reduced the performance of the bio-based chemicals. The results of the ecotoxicity test with photoluminescent Aliivibrio fischeri bacteria showed that many bio-based chemicals with potential use in wood preservation have markedly lower ecotoxicity than commercially available wood preservatives, but the ecotoxicity of some bio-based chemicals is higher, as in the case of some of the pyrolysis distillates. The wood preservation efficiency and the ecotoxicity of the studied chemicals had a poor correlation, implying that other factors besides treatment agent toxicity play a role in deterring fungal growth on treated wood. The amount of elemental toxins in the leachates was low. These results emphasize the importance of the chemical ecotoxicity of bio-based preservative compounds, as their detrimental effect on the environment can be higher than that of the traditional preservatives unless effectively linked to wood to prevent leaching.
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•Antifungal activity of bio-based preservatives decreased significantly after leaching.•Bio-based chemicals had generally lower ecotoxicity than the commercial products.•Some bio-based chemicals had higher ecotoxicity than the commercial products.•Fixation of preservative components to wood is needed to reduce their ecotoxicity.
The wood preservation industry has taken large leaps to develop and produce chemicals that protect wood from microorganisms and weathering degradation with no or low environmental impact. These ...improvements occurred after concerns of federal and public agencies about the release of toxic components into atmosphere, soil, and water. These days, reduction in use of non-renewable resources is a crucial concern. Wood and wood-based products are generally low in CO 2 emissions and can be gained from sustainable forest resources. Therefore, they can play a significant role as renewable resources. In comparison to other building materials, wood has numerous advantages, such as suitable thermal insulation, high strength to weight ratio, easy machinability, and attractive esthetics. Wood as a valuable building and industrial material requires to be protected due to its biodegradable properties especially when it is submitted to harsh conditions. Wood durability can be improved through wood protection which include wood preservatives and modification systems. Wood protection should be safe to use, efficient, cost-effective, permanent, and should not corrode metal or degrade wood components. Numerous reviews of wood protection can be found in the scientific literatures, but until now a review of a combination of wood preservation and wood modification has not been studied. It should be considered that the latest research projects in wood protection in academia not always reflect the most current developments in the industry due to exclusive rights. The findings reported in academia contribute to the safe use of preservatives, advancement of wood modification techniques, as well as recycle and disposal of treated material. Therefore, in this study, the most current research and advancements promoted in the wood protection in academia are discussed which including an overall summary of the recent developments on wood preservatives, different types of preservatives, natural preservative compounds, and modification technologies in academia.
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•Solve the defect of cinnamaldehyde that are easy to volatile and lose during use.•Fixing cinnamaldehyde essential oils on wood using Schiff base reaction.•The treated wood is ...resistant to decay while being environmentally friendly.
Environmental concerns over organic chemicals used for protecting wood and wood products from biological degradation have prompted the development of natural wood preservatives with lower health risks and prolonged efficacy. In this study, mixing chitosan and cinnamaldehyde to prepare an emulsion as natural wood preservative can effectively infuse cinnamaldehyde in the treated wood, enhancing the ability of the wood to resist decay fungi. Wood decay fungi were cultivated in emulsion with various molar ratios of cinnamaldehyde to chitosan emulsion. The antifungal property of the emulsion was compared according to its growing colony diameter and the mycelial morphology. The preservative emulsion was also impregnated into poplar (Populusnigra L.) with vacuum-pressure cycle. The decay resistance was evaluated by wood decay resistance test and electron microscope observation. The results showed that the cinnamaldehyde chitosan emulsion severely impacted the normal growth of the decay fungi and changed the mycelium morphology of the decay fungi. The Schiff base was formed in treated wood, and the decay resistance of treated wood was improved. Its decay resistance against brown-rot fungi Gloeophyllum trabeum was better than that of white-rot fungi Trametes versicolor. This study suggests the cinnamaldehyde chitosan emulsion can be effectively used as environmentally friendly wood preservative.
The properties of wood influence its use as a final product, so it is essential to know their relation and influence on the quality of preservation. In this sense, for the present study we aim at the ...determination of the physical properties of Corymbia citriodora Eucalyptus citriodora Hook; Eucalyptus camaldulensis Dehnh. and Eucalyptus camaldulensis Dehn. x Eucalyptus grandis, and the quality of the preservative treatment with CCA-C in an autoclave. We determined diameter, heartwood and sapwood percentages, and their relationship, as well as the basic density for the three genetic materials. The quality of the preservation was evaluated through the area treated and not treated by CCA, besides its penetration and retention. The highest proportion of sapwood, treated area, and highest density value was found in C. citriodora, whereas the hybrid E. camaldulensis x E. grandis presented the highest level of CCA retention. The diameter and density showed the highest correlation with CCA retention in wood, the length and moisture of the small logs also shown to be influential. All clones presented satisfactory chemical treatment quality for use as fence posts.
Developing natural preservatives for wood protection is of great interest in sustainable construction and green building industries. This study was designed to determine the feasibility of using ...methyl-β-cyclodextrin-essential oils (MβCD-EOs) complexes as potential bio-based preservatives for wood protection. Four essential oils (EOs) with proven antifungal properties, eugenol (EG), trans-cinnamaldehyde (CN), thymol (TM) and carvacrol (CV), were complexed with methyl-β-cyclodextrin (MβCD) by a co-precipitation method. The inclusion of EOs in MβCD and the corresponding inclusion yield of the MβCD-EOs complexes were determined by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and ultraviolet-visible spectroscopy (UV/Vis), respectively. The maximum inclusion yields in MβCD-EG, MβCD-CN, MβCD-CV, and MβCD-TM were estimated to be almost 100%. MβCD-EOs complexes were impregnated into southern pine wood blocks and exposed to two brown rot fungi, Gloeophyllum trabeum and Postia placenta, following procedures described in AWPA Standard E22 and E10. The penetration of MβCD-EOs complexes in wood was confirmed by fluorescence microscopic analysis after the selective dyeing of EOs encapsulated in MβCD. In comparison to the control wood samples, MβCD-EOs complexes treated wood exhibited a significant reduction in the mass loss from 16–36% to 2–18%, accompanied by improvement in radial compression strength loss from 81–92% to 29–67% after four-week fungi exposure.
•Methyl-β-cyclodextrin (MβCD) was used as a carrier for antifungal essential oil (EO) compounds.•The inherent instability of EOs was improved through the MβCD encapsulation process.•MβCD-EOs treatment on wood significantly reduces mass and compression strength loss against fungi.•MβCD-EOs complexes show potential for bio-based wood preservatives.
Heavy metal concentrations of Cd, Cr, Cu, Ni, Pb and Zn were investigated for 127 urban soil samples collected from business area (BA), classical garden (CG), culture and education area (CEA), public ...green space (PGS), residential area (RA) and roadside area (RSA) in Beijing. The distribution of Cd, Cu, Pb and Zn was mainly affected by anthropogenic sources, with their mean concentrations much higher than the background values of Beijing, while Cr and Ni were from natural sources. Among the 6 types of land use, the concentrations of Cd, Cu, Pb and Zn in CG were significantly higher than those in the other 5 types of land use (p<0.05), which were due to their historical use such as pigments, wood preservation and brassware. For the other 5 types of land use except CG, the mean concentration of Cd in RSA was significantly higher than those in BA, CEA, PGS and RA (p<0.05), suggesting Cd was mainly from traffic sources. The distribution maps revealed that the concentrations of Cu, Pb and Zn showed decreasing trends from the center to the suburb of Beijing, they increased with the age of the urban area.
In recent times, mass timber products have encouraged renewed interest in wood as raw material for more sustainable building and construction. However, durability concerns due to wood susceptibility ...to biodegradation could curtail this interest. Hence, there is a need for more durable wood products in emerging structural applications including the use of preservative-treated wood for composite and mass timber products. This is particularly crucial in tropical and subtropical environments where wood products are highly vulnerable to biodeterioration. Unfortunately, preservation treatment often adversely affects other wood properties such as the surface adhesion characteristics and adhesive-bond performance. Therefore, this review focused on the adhesion characteristics of wood, the impact of preservative impregnation, and the resultant effect on adhesive-bond performance. The aim is to draw attention to the challenges with bonding preservative-treated wood, and possible areas for research targeting bonding improvements.
ABSTRACT CLT (Cross Laminated Timber) is a pre-fabricated engineered wood panel, generally made from conifer woods, mainly pine and spruce. Due to the low natural resistance of this species to ...deteriorating organisms attack, the Brazilian standard ABNT NBR 7190:1 (2022) orients the treatment of structural elements before being used. This study aimed to evaluate the resistance of woods from Pine and Spruce species, with different preservative treatments and retentions, against wood termite (Cryptotermes brevis) attack. Different species of Pine and Spruce (Pinus abies, Pinus sylvestris, Pinus elliottii e Pinus taeda) were evaluated, as well as different preservatives such as Impralit KDS-B, CCA (Chromated Copper Arsenate), CCB (Copper Borate Chromated), MCA-C (Micronized Copper Azol type C) and HQC 791 (fire retardant for wood), usually used in Brazil, the United States and Europe. The results demonstrated that the fire retardant induced greater resistance to attack by xylophagous organisms, with total insect mortality and no surface deterioration after 45 days of testing. The CCA preservative also demonstrated efficiency in wood treatment with high resistance to termite attack, high mortality and only superficial wear of the specimen. It was concluded, therefore, that preservative treatments are recommended to guarantee the durability of the constructive system so that the so-called engineered wood elements can be used as structural systems.
RESUMO CLT (Cross Laminated Timber) é um painel de madeira engenheirado pré-fabricado, geralmente feito de madeiras de coníferas, principalmente pinus e abeto. Devido à baixa resistência natural desta espécie ao ataque de organismos deteriorantes, a norma brasileira ABNT NBR 7190:1 (2022) orienta o tratamento de elementos estruturais antes de serem utilizados. Este trabalho teve como objetivo avaliar a resistência de madeiras das espécies Pinus e Spruce, com diferentes tratamentos conservantes e retenções, ao ataque do cupim xilófago (Cryptotermes brevis). Diferentes espécies de pinus e abeto (Pinus abies, Pinus sylvestris, Pinus elliottii e Pinus taeda) foram avaliadas, bem como diferentes conservantes como Impralit KDS-B, CCA (Chromated Copper Arsenate), CCB (Copper Borate Chromated), MCA- C (Azol de Cobre Micronizado tipo C) e HQC 791 (retardante de fogo para madeira), normalmente utilizados no Brasil, Estados Unidos e Europa. Os resultados demonstraram que o retardante de fogo induziu maior resistência ao ataque de organismos xilófagos, com mortalidade total dos insetos e sem deterioração da superfície após 45 dias de teste. O conservante CCA também demonstrou eficiência no tratamento da madeira com alta resistência ao ataque de cupins com alta mortalidade e desgaste apenas superficial do corpo de prova. Concluiu-se, portanto, que para garantir a durabilidade do sistema construtivo são recomendados tratamentos preservativos para que os chamados elementos de madeira engenheirada possam ser utilizados como sistemas estruturais.
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