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Improvement on dimensional stability and mold resistance of wood modified by tannin acid and tung oil
Holzforschung
Abstract
In this study, two plant derived compounds, namely tannin acid (TA) and tung oil (TO) were used to modify southern yellow pine wood (Pinus spp.) to enhance its durability. Wood samples were firstly impregnated with aqueous TA solutions at 5, 10 and 15%, respectively, and then impregnated with TO. Samples treated by TA or TO alone were also prepared. The dimensional stability, hydrophobicity, mold resistance, and thermal stability of both treated and untreated wood were evaluated. The results showed that the dimensional stability and hydrophobicity of wood treated with 10% TA and TO (T10+TO group) improved significantly. Compared with control group, the water absorption of T10+TO group decreased by 80.0% after 192 h immersion, and the anti-swelling efficiency reached up to 90.7%, with the contact angle of 118°at 50 s. The mold resistance of wood after 5% TA and TO treatment presented an effectiveness of 87.5%. Meanwhile, T10+TO group presented better thermal stability. Overall, this study revealed that wood impregnated by TA and TO exhibited excellent dimensional stability and anti-mold properties, which could be applicable to indoor environment.
... In the first stage, TG curves in the range of 100-220 °C are considered as a degradation of unstable components such as hemicellulose and a bond breaking of complex components [56,57]. Subsequently, temperatures ranging from 220 to 450 °C result in a significant reduction in mass loss by approximately 80%, which encompasses both thermal decomposition (220-290 °C) and carbonization phases (260-450 °C) [35,58]. The control sample exhibited a peak at 342 °C, which can be ascribed to the decomposition of cellulose resulting in wood mass loss. ...
... In the first stage, TG curves in the range of 100-220 • C are considered as a degradation of unstable components such as hemicellulose and a bond breaking of complex components [56,57]. Subsequently, temperatures ranging from 220 to 450 • C result in a significant reduction in mass loss by approximately 80%, which encompasses both thermal decomposition (220-290 • C) and carbonization phases (260-450 • C) [35,58]. The control sample exhibited a peak at 342 • C, which can be ascribed to the decomposition of cellulose resulting in wood mass loss. ...
Rubber wood often exhibits dimensional instability during use, which seriously hinders its widespread application. In order to enhance the dimensional stability of rubber wood, a two-step method was employed in this study to modify rubber wood using two plant-derived compounds, namely sucrose and tung oil. Samples treated alone with sucrose or tung oil were also prepared. The water absorption, dimensional stability, and thermal stability of modified and untreated wood were evaluated. The results show that wood samples treated with 30% sucrose and tung oil had excellent water resistance and dimensional stability based on the synergistic effect of sucrose and tung oil. After 384 h of immersion, the 30% sucrose and tung oil group presented a reduction in water absorption by 76.7% compared to the control group, and the anti-swelling efficiency was 57.85%, which was 66.81% higher than that of the tung oil treatment alone. Additionally, the leaching rate of the 30% sucrose and tung oil group decreased by 81.27% compared to the sample modified with the 30% sucrose solution alone. Simultaneously, the 30% sucrose and tung oil group showed better thermal stability. Therefore, this study demonstrates that the synergistic treatment of modified rubber wood by sucrose and tung oil is an eco-friendly, economical, and highly efficient approach with the potential to expand the range of applications of rubber wood products.
... Tannins irreversibly bind to active proteins, leading to the formation of precipitates. Alternatively, tannins can interact with enzymes and potentially act as inhibitors [216]. Voda et al. [217], in their study, indicated that thymol and carvacrol are the essential oil phenols with the most antifungal activity and that the mechanism of the toxicity of phenolic compounds to fungi is mainly based on the inhibition of fungal enzymes containing -SH groups in the active site [197]. ...
Extractives, which naturally evolve as fundamental defense mechanisms in wood against environmental stresses, hold an essential place in the field of wood conservation science. Despite their low content in woody substrates, extractives are chemically complex and can be extracted accurately by solvents with different polarities, covering key components such as aliphatic, terpenoid, and phenolic compounds. The application of solvent extraction allows for the effective recovery of these extracts from forestry waste, thereby creating new opportunities for their reuse in wood modification and enhancing the economic value and potential applications of forestry waste. In the wood industry, extractives not only act as efficient preservatives and photo-stabilizers, significantly improving the decay resistance and photodegradation resistance of wood, but also serve as ideal dyes for fast-growing wood due to their abundant natural colors, which lend the product a distinct aesthetic appeal. The aim of this paper is to provide a comprehensive review of the origin and distribution characteristics of wood extractives and to examine the impact of solvent selection on extraction efficiency. At the same time, the mechanism of extractives in enhancing wood decay resistance and slowing down photodegradation is deeply analyzed. In addition, specific examples are presented to illustrate their wide utilization in the wood industry. This is intended to provide references for research and practice in related fields.
Thermal treatment is an effective method for improving the dimensional stability of wood; however, it typically requires high temperatures. To achieve low-temperature heat treatment, this study employed wood samples impregnated with 10 % tannin acid (TA) and examined their changes in dimensional stability and chemical components after heat treatment at various initial moisture content levels. The results revealed that the TA-10 %-HT group exhibited enhanced dimensional stability. Specifically, both the tangential and radial moisture swelling decreased by 21.7 % and 11.8 %, respectively. FTIR and XRD analysis indicated that the presence of tannin acid catalytically facilitated the degradation of hemicellulose. Moreover, an increase in moisture content resulted in the ionization of TA, amplifying acidity and further affecting cellulose degradation. TGA demonstrated that TA impacted the thermal stability of heat-treated materials by lowering the initial decomposition temperature of wood components and increasing the residual weight of wood. Overall, pretreatment with TA impregnation and moisture content significantly improved the dimensional stability of Chinese fir wood and altered its chemical composition. This approach holds considerable potential for enhancing wood properties through a low-energy consumption method during the heat treatment process, expanding the practical application of wood.
A method is proposed for approximating of the internal friction of wood based on the Boltzmann superposition principle, which describes the complex viscoelastic behavior of the system by a linear combination of components. Prepared samples of natural and modified wood, sawn from the stem part of drooping birch (Betula pendula ROTH) trees growing in the Khlevensky Forestry (52.184130, 39.110463, ASL 157m), were exposed to radial and tangential directions with ultrasound (frequency 24.5 kHz, exposure 0 -20 minutes, step 5 minutes) and pulsed magnetic field (strength - 0.3 T, exposure 0-2 minutes, step 0.5 minutes). Next, the internal friction of the samples was studied on an experimental setup using the logarithmic damping decrement based on free-bending vibrations. The absolute values of the dimensionless viscosity coefficient κ included in the model as the main structural parameter for samples of natural and modified wood were obtained at a significance level of p=0.95: for moisture content from 4.3 to 15; for ultrasound 4.6 to 20; for a pulsed magnetic field from 3.6 to 7.7. The absolute values of the dimensionless scaling factors μ for natural and modified wood samples range from 1.92 to 3.91. The highest approximation value was achieved when testing natural wood samples of silver birch (Betula pendula ROTH): R2=0.98 for the radial direction, the influence of the humidity factor, and R2=0.85 for the tangential direction, the influence of the ultrasonic factor, as well as for a sample of modified wood brand "Destam" in the radial direction R2=0.96, the influence of the factor of the pulsed magnetic field.
The modern society pays growing attention on global environmental issues, public safety, and individual health, which highlights the necessity of exploring sustainable, energy-saving, flame-retardant, and anti-mildew materials for building applications. Herein, by in-situ preparing copper phytate-hierarchically porous MOF-199 hybrid (PCuM) in natural wood (W) via simple phytate induced defect engineering strategy, we reported a multifunctional low fire-hazard wood composite (PCuM-W). The
phytate anion not only acted as a modulator to generate hierarchical porosity in MOF-199, but also offered high flame retardancy due to its six phosphorus groups. The copper phytate anchored on the cell wall exhibited charring and graphitizing effects and enhanced the flame retardancy and smoke suppression performance of wood. By pyrolysis, a hierarchically porous MOF-199-derived carbon formed and offered a considerably enhanced catalytic activity towards the conversion of CO. With a weight percent gain of only 13.5%, the fire growth index, total smoke production, and maximum CO production rate of PCuM-W were 74.2%, 85.4%, and 33.3% lower than that of W, respectively, showing outstanding fire-hazard-reducing efficiency that surpassed most of its counterparts. Furthermore, due to the hierarchical porosity and antimicrobial property of PCuM, PCuM-W showed excellent moisture-buffering ability and mildew resistance. This work brings guidelines for fabricating hierarchically porous MOFs to realize multifunctional materials via phytate induced defect engineering.
Poor dimensional stability restricts the commercial utilization of fast-growing wood. In this study, fast-growing poplar ( Populus cathayana ) was treated by removing hemicellulose with hydrothermal treatment and impregnating alkali lignin via full-cell process, synergistically, for enhanced dimensional stability. After modification, hydroxyl groups were reduced in hemicellulose removed wood (DHC), alkali lignin was observed to fill in the cell lumens of vessels and wood fibers in the impregnated wood (AL) and in the wood modified by hemicellulose removal with alkali lignin impregnation (DHCAL). Compared with untreated wood, the volumetric swelling ratio of DHC and AL decreased by 11 % and 21 % under relative humidity (RH) of 89 %, respectively. The volumetric swelling ratio of DHCAL decreased by over 50 %, indicating a positive synergistic effect. The combination of hemicellulose removal and alkali lignin impregnation treatment improved the dimensional stability of wood significantly by reconstructing wood chemical components with various levels of hygroscopicity. This work could meaningfully contribute to the efficient utilization of fast-growing wood and promote the added value of industrial alkali lignin.
Eugenol in water nanoemulsions loaded with tebuconazole appear as a very promising alternative formulations for wood protection against xylophagous fungi that are the main species responsible for different rots in wood structures. The dispersions as prepared and upon dilution (impregnation mixtures) were characterized by the apparent hydrodynamic diameter distribution of the oil droplets loaded with tebuconazole and their long-term stability. The impregnation mixtures were applied on wood of Populus canadensis I-214 clone by using a pressure-vacuum system, and the effectiveness against fungal degradation by Gloeophyllum sepiarium and Pycnoporus sanguineus fungi was determined. The retention of tebuconazole in wood was about 40% of the amount contained in the impregnation mixtures. The results showed that the impregnation process leads to a long-term antifungal protection to the wood, with the mass loss after 16 weeks being reduced more than 10 times in relation to the control (untreated poplar wood) and the reference wood (untreated beech wood).
Organic acids are present in many bio-based chemicals suggested as active ingredients for wood preservative formulations, but their effects in wood have not been studied. However, an understanding of their effect in wood is necessary. The aim of this study was to determine the antifungal and wood-preserving activities in vitro of acetic, formic, and propionic acids against the wood-decaying fungi Coniophora puteana, Rhodonia (Poria) placenta, Gloeophyllum trabeum, and Trametes versicolor. Mixes of these three acids were also tested for possible synergetic effects. All the acids and mixtures showed antifungal activity against the pure cultures of wood-decaying fungi. Propionic acid by itself had the best performance, inhibiting at 1 g/L concentration the growth of all the decay fungi by 99-100%. Despite the antifungal activity of the organic acids, the pine sapwood specimens treated with 3% and 6% acid solutions and exposed to decay by C. puteana and G. trabeum did not differ significantly from the untreated pine. Leaching of the sapwood specimens caused an incremental mass loss of the sapwood specimens. In addition, the leached specimens had a lower mass than the same specimens before the acid impregnation, indicating that they were damaged by the acidic chemicals. The presence and acidity of organic acids in wood-derived bio-based chemicals need to be assessed before they are used as wood preservatives.
Wood is a renewable, versatile material with multiple applications and the largest terrestrial pool of sequestered carbon. However, it is susceptible to degradation, mainly caused by wood-decaying fungi. Since several traditional wood preservatives have been banned owing to their detrimental effects on humans and the environment, extending the lifespan of wood products using new generation natural preservatives is an imperative from the perspectives of human health and environmental protection. Several natural compounds of plant and animal origin have been tested for their fungicidal properties, including essential oils, tannins, wood extractives, alkaloids, propolis or chitosan; and their enormous potential in wood protection has been shown. Although they are not free of limitations, the potential methods to overcome their drawbacks and enhance their bioactivity already exist, such as co-impregnation with different polymers, cross-linkers, metal chelators or antioxidants. The presence of the discrepancies between laboratory tests and the field performance, as well as legislation-related problems resulting from the lack of standards defining the quality and performance of natural protective formulations, however, create an urgent need for further thorough research and arrangements. The collaboration with other industries interested in the utilisation of natural active compounds will reduce the associated costs, thus, will facilitate the successful implementation of alternative antifungal agents.
Drying oils provide exquisite bio-based finishes for wood products but their application is restricted by their time-consuming polymerization. Research and industrial development are impeded by a lack of scientific methods to follow the polymerization progress of oils applied on wood. We investigated the drying behavior of linseed oil, tung oil, and their 1:1 mixture both with and without the addition of a drier. Liquid samples revealed faster polymerization of the mainly conjugated and highly unsaturated tung oil than of non-conjugated linseed oil. Recurring water contact angle measurements of oil finishes applied on beech and oak wood showed clear differences in wetting. Tung oil provided hydrophobicity to all wood samples soon after its application, even when used without drier. Linseed oil required longer drying times and was more susceptible to substrate influences but ultimately reached the highest contact angles when equipped with a drier. Further, we observed a relationship between drying time and contact angle stability. As a new and straightforward tool to characterize the drying progress of applied oil-based finishes, we propose the calculation of a contact angle reduction factor, that takes into account both the initial water contact angle as well as its stability over measurement time.
In this study, modification of European beech wood (Fagus sylvatica) through in situ esterification of sorbitol and citric acid (SorCA) was investigated at two curing temperatures, 140 and 160 °C. In order to determine the optimum condition for modification, an aqueous solution of SorCA at varying concentrations was evaluated (10, 20, 30, and 55% w/w). Physical, mechanical, chemical, and durability properties of the modified wood were examined. Results have disclosed that among different SorCA concentrations, treatment with SorCA at 30% w/w was considered as the optimum concentration independent of the curing temperature. Under these conditions, anti-swelling efficiency increased to approx. 55% and modulus of elasticity increased slightly with approx. 9% in comparison with untreated wood. Decay resistance against white-rot (Trametes versicolor), brown-rot (Coniphora puteana), and soft-rotting microfungi classified the SorCA-30%-modified wood as very durable. In addition, thermogravimetric study evidenced that SorCA 30%-modified wood has a lower thermal decomposition temperature in comparison with untreated wood/wood control by 20 °C difference, indicating that the SorCA-modified wood possibly has fire-retardant properties. However, due to the acidic properties of the SorCA solution, modulus of rupture (MOR) and mainly work to maximum load in bending decreased considerably.
Natural wood is susceptible to moisture during its practical use, limiting not only service life but also the range of uses. In this study, plant extracts, specifically linseed oil and carnauba wax (both environmentally friendly and water-repellent substances), were examined as a means to mitigate limitations of natural wood. Stable and homogenous epoxidized linseed oil/carnauba wax emulsions with an average particle size less than 230 nm were used as a modifier to enhance the performance of wood. Weight percentage gain, bulking coefficient, micromorphology, chemical structure, moisture adsorption, contact angle, water repellency, and dimensional stability of treated wood were measured. Using a scanning electron microscope (SEM), it was observed that carnauba wax and epoxidized linseed oil acted as a mechanical barrier and could partially cover or block vessels, pits, and wood rays. Furthermore, the hydrophobicity of wood increased significantly after emulsion impregnation. However, there was no obvious chemical reaction between epoxidized linseed oil and the main components of wood in the Fourier transform infrared spectroscopy (FTIR) results. The combined effect of epoxidized linseed oil and carnauba wax was apparent in both decreased water absorption and dimensional deformation. Poplar wood impregnated with an epoxidized linseed oil/carnauba wax complex emulsion shows potential for improving water-related properties. Thus, the complex emulsion modification can improve the inherent shortcoming of poplar wood effectively.
The search for green and sustainable modification method to produce durable bamboo materials remains a challenge in industry. Here, heat treatment in tung oil at 100–200 °C was employed to modify bamboo materials. Oil permeation and distribution in the structure of bamboo samples during heat treatment were explored. The synergistic effects of tung oil and heat treatment on the chemical, physical and mechanical properties of bamboo materials, and their mutual relationships were also investigated in detail. Results showed that the tung oil heat treated bamboo not only had an enhanced hydrophobic property and dimensional stability, improved fungi resistance, but also displayed good mechanical performance. Compared with the untreated sample, the water-saturated swelling reduced from 3.17% to 2.42% for the sample after oil heat treatment at 200 °C, and the contact angles of the sample after oil heat treatment at 200 °C can keep >100° after 300 s in radial direction. Such improvement can be attributed to changes of chemical components, increased crystallinity structure, and the formation of oily films inside or over the bamboo surface. Therefore, tung oil heat treatment can be a highly promising technology for bamboo modification in the industry.
The decay resistance of modified fast-growing poplar lumber with ion-based preservative and thermosetting resins were determined in laboratory and field stake tests. Commercial alkaline copper quat-type D (ACQ-D), thermosetting phenol–formaldehyde (PF) resin with varying concentrations, and urea–formaldehyde (UF) resin were used to improve decay resistance of low-grade fast-growing poplar. The results indicated that the concentrations of PF and weight gains of resin-modified specimens were highly correlated, and target resin retains can be achieved from resin concentration. The retention rates of ACQ of 1.1% concentration, UF of 41.5% concentration and PF of 10% concentration were 6.72, 18.43, and 7.31 kg/m³, respectively. For PF, the retention rate is linearly related to concentration. The mass losses (ML) for the untreated, ACQ-treated, and UF-treated specimens were 26.34%, 8.91%, and 11.66% after 12 wk of incubation in laboratory, respectively. The ML for the treated specimens were 9.74%, 7.32%, 3.14%, 2.38%, and 2.41% for PF impregnated wood at concentrations of 10%, 15%, 20%, 25%, and 40%, respectively, after 12 wk of incubation in the laboratory. After 24-mo field tests, the loss and damage rates of the treated specimens were 83%, 67%, 50%, and 100% for the ACQ-D, UF, PF, and untreated specimens, respectively. The specimens modified with thermosetting resin have very good decay resistance.
Tannins, an abundant group of plant secondary compounds, raise interest in different fields of science, owing to their unique chemical characteristics. In chemical ecology, tannins play a crucial role in plant defense against pathogens, herbivores, and changing environmental conditions. In the food industry and in medicine, tannins are important because of their proven positive effect on human health and disease treatment. Such wide interests fueled studies on tannin chemistry, especially on their flagship ability to precipitate proteins. In this Review, we expand the basic knowledge on tannin chemistry to the newest insights from the field. We focus especially on tannin reactions with different non-protein organic N compounds, as well as the complex interactions of tannins with enzymes, resulting in either an increase or decrease in enzyme activity.
The unsteady-state diffusion of boron through southern pine (Pinus spp.) was investigated at various moisture contents, temperatures, and treatment conditions. The fastest rates of diffusion were observed in the longitudinal direction, followed by the radial and the tangential directions. The diffusion rate increased with time in all directions. The longitudinal diffusion rate increased rapidly with moisture content (MC), while a slow increase in the radial diffusion rate was observed at MCs above 90%. Moisture content did not affect the rate of tangential diffusion within the range of MCs in this study (70-110%). The effect of temperature on boron diffusion rates was more pronounced than the effect of MC. The diffusion rate increased with temperature, although slight direction-dependent differences were observed. A repeated dip-treatment increased the rate of diffusion in the tangential direction, but only small differences were found in the longitudinal and the radial directions. No other data were found in the literature for comparison. Average values of the diffusion coefficients were calculated to predict the concentration profile of boron in wood under various conditions. The longitudinal diffusion coefficients were 10 to 20 times larger than the radial diffusion coefficients, and the radial diffusion coefficients were two to four times larger than the tangential diffusion coefficients. The use of the average boron diffusion coefficients caused some differences between real and predicted values in the early stages of diffusion, but the potential for practical use was demonstrated.
The chemical nature of the polyphenols of cashew kernel testa has been determined.
Testa contains tannins, which present large molecular complexity and has an ancient
use as tanning agents. The use of tannins extracted from cashew testa, considered in
many places as a waste, grants an extra value to the cashew. In this work we have
analysed through high performance liquid chromatography, infrared spectroscopy (FTIR)
and thermo gravimetric analysis the average molecular weight, main functional
groups and thermal properties of tannins extracted from Anacardium occidentale L.
The results of these analyses are compared with the commercial grade tannic acid. The
FT-IR spectra showed bands characteristic of CvC, CZC and OH bonds. This
important bioactive compound present in the cashew nut kernel testa was suggested as
an interesting economical source of antioxidants for use in the food and nutraceutical
industry.
In this study, the effect of mass loss on mechanic properties of Paulownia (Paulownia elongata) wood was investigated. For this study, three different temperatures (160, 180, and 200 degrees C) and durations (3, 5, and 7 hours) were carried out. After heat treatment, the mass loss of the heat-treated samples were found and then it is determined how affected on mechanic properties of Paulownia wood The data obtained were analyzed using variance analysis, and then Tukey's test was used to determine the effect on mechanic properties of mass loss during heat treatment. The results show that mechanic properties were occurred decreasing in variation ration in relate with mass loss. While the maximum mass loss found was 9,78% at 200 degrees C and 7 hour, the compression strength, modulus of elasticity, bending strength and impact strength decreased about 17, 19, 78 and 88%, respectively. Hence, it is determined that the mass loss on mechanic properties of Paulownia wood significantly affected.
"Wood Coatings" addresses the factors responsible for the performance of wood coatings in both domestic and industrial situations. The term 'wood coatings' covers a broad range of products including stains, varnishes, paints and supporting ancillary products that may be used indoors or outdoors. Techniques for coating wood go back many centuries but in recent decades there has been a move towards more environmentally-friendly materials, for example, the use of water-borne rather than solvent-borne chemicals. A major objective of "Wood Coatings" is to explain the underlying factors that influence selection, application and general operational issues. Basic information on the chemistry and technology of coatings is included for the benefit of students and laboratory technicians. Additionally, the book includes individual chapters of interest to architects, specifiers, and industrial users. It offers up-to-date guidance on current availability and usage of wood coatings. It provides the reader with a basic understanding of both coating and substrate interactions. It covers both architectural (trade and DIY) and industrial sectors.
Most European wood species do not have durable wood. In order to be used in outdoor conditions, non-durable material must be protected. Non-biocidal solutions for wood protection are attracting a lot of attention nowadays, particularly in class 2 and 3 applications. One non-biocidal technique is treatment of wood with water repellents, such as wax emulsions and oils. Linseed oil and tung oil are frequently used water repellents. In the present research, the performance of linseed and tung oil treated Norway spruce and beech wood against wood decay fungi is reported. Additionally, short term hydrophobic properties (with tensiometer) and long-term hydrophobic properties (soaking in water) in laboratory and outdoor conditions (electrical resistance measurements) were determined. Tung oil performed better than linseed oil in all tests.
Adhesive wettability of wood is usually evaluated by contact angle measurement. Because of liquid penetration and spreading on the wood surface, the contact angle changes as a function of time. In this study, a wetting model was developed to describe the dynamic contact angle process in which a parameter (K) can be used to quantify the adhesive penetration and spreading during the adhesive wetting process. By applying the wetting model, the adhesive wettability of sapwood and heartwood of southern pine and Douglas-fir was studied. Liquid wettability along and across the wood grain direction was also compared. Two resin systems, polymeric diphenylmethane diisocyanate (PMDI) and phenol-formaldehyde (PF), were evaluated. It was learned from this study that the wetting model could accurately describe the dynamic adhesive wetting process on wood surfaces. Through applying this model, it is shown that PMDI resin exhibited a better wettability on wood than PF resin. The adhesive is more easily wetted along the grain direction than across the grain direction. Species and drop location have no significant effect on the spreading and penetration rate (K-value). However, the interaction term between species and resin type shows a significant effect for the K-value. PMDI exhibits a greater K-value on the Douglas-fir surface, while PF resin shows a greater K-value on the southern pine surface. Heartwood shows a lower instantaneous contact angle than sapwood. Douglas-fir has a greater instantaneous contact angle than southern pine. The effect of species on the equilibrium contact angle is strongly dependent on the location of the drop on the wood surface. The equilibrium contact angle of Douglas-fir is smaller than that of southern pine for sapwood, but is greater for heartwood.
In the last decades, many wood preservatives have been prohibited for their ecotoxicity. The present article is focusing on the conifer-derived condensed tannins as environment-friendly options for the substitution of artificial wood preservatives. Eight different tannin fractions were extracted from spruce cones, spruce barks, and pine cones. The parameters of tannin extraction, such as the methods of purification and concentration of active components in the extracts, have been investigated. The cone and bark extracts were tested for the growth inhibition of eight brown-rot fungi, three white-rot fungi, and four soft-rot fungi in liquid cultures. The cone tannins provided a more efficient fungal growth inhibition than bark tannins. Purification increased the antifungal properties of the extracts. The growth of brown-rot fungi was inhibited by the tannins already at low concentrations. However, the extracts were not effective against the white-rot or soft-rot fungi. More investigation is needed concerning the tannin source and the purification procedure of the extracts before tannins can be considered as an ecologically benign wood preservative.
The remarkable biological properties of tannin-boron wood preservatives for outdoor applications have been investigated recently (Thevenon et al. in Eur. J. Wood Prod. 67:89, 2009). In the present paper mechanical and fire-proofing attributes of these formulations are determined. Mechanical properties of Scots pine and beech specimens treated with tannin-based formulations were examined in compression and bending strength tests and surface hardness was determined. The tannin-hexamine formulations reticulated into the wood structure improve the strength of the treated specimens. The treated samples which underwent compression, bending, hardness and gluing tests showed improvements of on average 20%.
Fire tests have been monitored regarding short and long flame exposure time. Short tests such as ignition, flame and ember time have allowed the ignition of the fire to be simulated, while the weight loss tests have provided a good overview of the behavior of the specimens during prolonged fire. A positive effect on fire-resistance is shown when wood is treated with tannin formulations. The fire-proofing properties of the resin have been upgraded adding boron and phosphorus. The ember time of the pieces treated using this method can be reduced by up to ten times.
Heat treatment is often applied to some wood species to improve dimensional stability. This study evaluated the effect of heat treatment on some physical and mechanical properties and colour of Eucalyptus wood (Eucalyptus camaldulensis Dehn.), which has industrially high usage potential and large plantations in Turkey. Wood specimens from Tarsus, Turkey were subjected to heat treatment in varying temperatures and durations. After the heat treatment, hardness, swelling, ovendry density, and colour change of the wood specimens were tested in comparison with untreated specimens. The results showed that density, swelling, and hardness decreased with increasing treatment temperature and durations while heat treatment made the colour of the wood specimens darker.
Tung oil is favoured in applications such as historic wood consolidation or as varnish component that require a rapid-drying medium compared with linseed oil and other analogues such as walnut oil and poppy seed oil. The Raman spectra of tung oil and artificially aged specimens have been obtained and indicate that severe degradation of the C = C unsaturation sites occurs compared with the slower-drying linseed oil. Characteristic spectral signatures of fresh tung oil have been identified which provide diagnostic discrimination between this oil and others used in the preparation and preservation of artworks. Mid-infrared spectra of aged tung oils have served to identify the formation of acidic functionalities which could affect associated pigments and substrates in artwork. Comparative spectra are also reported for a range of other oils such as walnut seed, poppy and sunflower seed oils.
In this study, two kinds of plant origin substances, namely tannin acid (TA) and tung oil (TO), were used to treat wood to improve their durability during outdoor applications. For this purpose, southern yellow pine wood was firstly impregnated with TA solution and then immersed in TO at atmospheric pressure. The samples treated with TA or TO alone, as well as untreated wood, were also prepared for comparison. The performance of the different samples during accelerated UV weathering and brown-rot decay tests were evaluated. The results showed that TO imparted wood with excellent color stability against weathering, while samples treated with TA alone experienced more obvious discoloration. The presence of TO built a barrier for the penetration of UV light and water on wood surface. TA acted as a good UV absorber and free-radical scavenger during UV exposure. It also successfully prohibited the colonization of brown-rot fungi (Gloeophyllum trabeum) on wood owing to its strong antioxidation activity. Overall, wood treated with both TA and TO exhibited the best durability during photo-degradation and biodeterioration process.
It is commonly known that wood is a limited renewable material, and its low dimensional stability characteristics limit its ability to be more widely used. Tung oil, which is characterized by environmentally friendly and water-repellent features, is used in this study as a modifier to improve the properties of wood. Wood is impregnated with Tung oil at room temperature, and the effects of Tung oil on the dimensional stability, moisture absorption, chemical structure, thermostability, and morphological characteristics of the wood are studied. The results show that Tung oil treatment is an effective technique to improve wood dimensional stability. The weight percentage gain was found to attain up to 60.56%, and Tung oil treatment decreased the wood tangential and radial swelling coefficients by 30.8% and 29.6%, respectively. Tung oil treatment also decreased the moisture absorption by 51.53%. Specimens treated with Tung oil presented two sharp peaks of decomposition around 376 °C and 421 °C, while the control specimens exhibited a more common DTG curve with a sharp peak at 376 °C. Tung oil can be impregnated into wood and occluded pits, and solidifies at the internal surface of wood to prevent moisture absorption. This method can be implemented in buildings, furniture, and landscape architecture to broadly expand the application of wood products.
This review article provides an overview of air-drying binders and chemical processes responsible for their solidifica-tion and hardening. It is focused not only on binders derived from plant oils but also on oriental lacquers and their syn-thetic congeners as their curing is also based on chemical reactions with air-oxygen. The main aim of this article is to bring a critical view on mechanism of autoxidation process relevant to paint technology and highlight the previous misinterpretation, remaining open questions and gaps in current state of knowledge. Such objective was achieved by utilization of the latest knowledge appearing in various areas of the chemical research, e.g. organic chemistry, bio-chemistry, physical chemistry, computational chemistry and inorganic chemistry. Considerable attention is also given to recent developments in the field of transition metal driers and additives including clarification the role of cobalt-based driers and updated overview of cobalt replacement.
Penicillium digitatum is a destructive post-harvest pathogen of citrus fruit during storage and marketing. The aim of this study is to evaluate the activity of the natural polyphenolic compounds, tannins, on P. digitatum. Tannins acted against P. digitatum by inhibiting its mycelial growth and spore germination. In vivo tests showed that tannins significantly (P < 0.05) decrease the disease symptoms of P. digitatum in artificially inoculated citrus fruit. Storage tests also showed that tannins reduce the disease severity of green mold on citrus fruit by 70 %. To determine the antifungal mechanism of tannins on P. digitatum, we evaluated the integrity of the cell wall and the permeability of the membrane. The disruption of cell wall and the plasma membrane caused leakage of the intracellular contents, such as sugars. These findings suggest that the cell wall of P. digitatum is the target for tannins and that they can potentially be used as an alternative to control citrus green mold.
Tannins as herbal extracts are a good alternative for green chemistry. They are found aplenty in some plant species and can be extracted by simple methods. The tannins main feature and advantage is their phenolic structure which is very similar to synthetic phenols. Another key feature of tannins is their actions as antioxidants. The use of tannins is often connected to one of these features. They are now actively used in leather
tanning, adhesive making (especially wood adhesives), fisheries, beverages manufacturing, animal feed and many others. Considerable amounts of research has also been recently conducted on the possibility of using tannins in the manufacture of biosourced foams, wood preservatives, corrosion inhibitors, polyurethane surface
coatings, epoxy adhesives, binders for Teflon coatings and etc. This paper deals with different uses of tannins and with the latest research which has been done on this subject.
In this study, low-temperature thermally-modified (at 140°C) Scots pine (Pinus sylvestris L.) wood samples were impregnated with either one or more modifying agents, including the brown colorant, paraffin wax emulsion (PWE), and an organic preservative (4,5-dichloro-2-octyl-2H-isothiazol-3-one, DCOIT) microemulsion. All wood samples were assessed in dimensional stability, water absorption, the modulus of rupture (MOR), decay and mold resistance, and their weathering performance under both lab-scale and outdoor exposure. The results showed that 1) the treating groups with PWE showed obvious lower water absorption, and the lowest value appeared in the group treated with brown colorant and PWE (BC-PWE); 2) thermal modification improved the dimensional stability of wood, whereas all the further treatments except the group impregnated with PWE slightly counteracted the effect of thermal modification on dimensional stability after water soaking; 3) the MOR of thermally-modified sample showed little change after further treatments; 4) and thermally-modified wood treated with BC-PWE-DCOIT showed the optimal weathering performance with the least color change and the best mold resistance.
The paper describes the obtaining of new epoxy derivatives and their influence on wood thermal and fungi stability. Epoxy derivatives were thermally and photochemically crosslinked. The softwood samples, modified with succinic anhydride, were impregnated individually or in the mixture with glycidyl methacrylate, diglycidyl ether of bisphenol A, epoxidized grapeseed oil and crosslinked afterwards. The samples impregnated with glycidyl methacrylate were firstly exposed to UV at 254 nm 30 minutes on all surfaces and thermal crosslinking 5 hours at 130 oC and 30 minutes at 150 oC. The samples were characterized by thermogravimetric analysis and decay resistance to fungi. The untreated samples exhibited the most significant mass losses. Evolved gases analysis was undertaken. The sample containing epoxy grapeseed oil exhibited a superior thermal stability and decay resistance to Penicillium chrysogenum and Cladosporium cladosporioides.
Fast-growing plantation wood normally possesses some undesirable intrinsic properties, such as dimensional instability, inferior mechanical strength, and flammability, limiting its usage as an engineering material. Herein, we report a green and facile approach for upgrading the low-quality poplar wood via a combined treatment with biomass-derived furfuryl alcohol (FA) and ammonium dihydrogen phosphate (ADP) acting as a flame-retardant additive. Wood/PFA/ADP composites were prepared by impregnation of the FA precursor solutions into the wood matrix, followed by in situ polymerization upon heating to form a hydrophobic FA resin/ADP network within the wood scaffold. In-depth scanning electron microscopy coupled with enregy-dispersive X-ray spectroscopy (SEM-EDX) and confocal laser scanning microscopy (CLSM) analyses reveal the wide distribution of the FA resin/ADP complexes inside the cell walls and also in the cell lumens. The incorporation of hydrophobic FA resin into wood results in reduced water uptake and remarkably enhanced dimensional stability, as well as generally improved mechanical properties. The addition of a small amount of ADP greatly enhances the flame retardancy of the modified wood and also effectively suppresses smoke generation during its combustion by reducing the heat-release rate and promoting char formation, as proven by cone calorimetry. The FA resin/ADP complexes increase phosphorus fixation in wood and reduces its leaching into water, suggesting a long-term fire protection of wood in service. Such modified poplar wood with overall enhanced properties could be potentially utilized as a reliable engineering material for structural applications.
Heat treatment is an eco-friendly and efficient way to improve the defective properties of woods, such as hygroscopic nature, lack of dimensional stability, and low resistance against biological degradation, and to produce a green and sustainable wood material for construction and buildings. The aim of this study is to investigate the thermal degradation of a hardwood (poplar, Populus nigra) and a softwood (fir, Abies pectinata) in a semi-industrial scale reactor in which a vacuum environment is adopted to intensify the thermal degradation process. Four different stages of thermal degradation during wood heat treatment are defined, based on the intensity of differential mass loss (DML). Meanwhile, a number of analyses on untreated and treated woods are performed to evaluate their thermal degradation characteristics and compositional change during treatment. The FTIR analysis clearly demonstrates the thermal degradation through dehydration, deacetylation, depolymerization, and condensation reactions during the heat treatment. In addition, the XRD analysis indicates an increase in relative crystallinity of cellulose. The correlation of devolatilization index (DI) with respect to mass loss of the two wood species is strongly characterized by linear distribution, which is able to provide a simple and useful tool in predicting mass loss of wood treated in wood industry.
Biomass pyrolysis is one of the most important means to realize effective treatment and efficient utilization of biomass wastes and materials. Therefore, it has great practical significance to research the process and mechanism of biomass pyrolysis. Wood, as a renewable material with a rich source, is a kind of pyrolysis raw material among lots of biomass. As we all know, because of the difference of composition and other aspects, pyrolysis characteristics of different tree species have obvious differences. However, even the same kind of wood such as the heartwood and sapwood of lumber show different pyrolysis characteristics and products in the process of pyrolysis, due to the significant differences in such aspects as microstructure, chemical composition and the amount of each component, which is studied feild in this paper. In the experiment, sabina chinensis, a kind of common landscaping, are taken as test material, whose heartwood and sapwood are clearly distinct. In order to research the pyrolysis differences between heartwood and sapwood, TG-FTIR method is used to obtain the thermogravimetric curves and volatile spectrograms during the process. Results elucidated that the content of cellulose, hemicellulose, lignin and extracts have a remarkably effect on both heartwood and sapwood. On account of higher content of hemicellulose and lignin, the heartwood of sabina chinensis showed higher weight loss ratio than sapwood during the early and late stages. What's more, higher content of extracts increased the weight loss ratio of heartwood in the medium stage, which reduced the differences between heartwood and sapwood. On contrary, sapwood with more cellulose had more obvious weight loss during 300~380 ℃ and higher weight loss ratio in the DTG curve. In addition, the infrared spectrum indicated that both heartwood and sapwood produced almost same volatiles, but there were differences in amount. And when the pyrolysis came to the maximum weight loss velocity, volatiles produced increased significantly. Moreover, sapwood produced more organic compounds, while heartwood produced more water and CO2.
In this study, the water sorption and diffusion properties of wood/plastic composites (WPCs) as a function of formulation design were investigated. Composites with different amounts of wood, coupling agent and high density polyethylene (HDPE) were produced by profile extrusion method. The time required to reach saturation point, moisture contents at saturation point, diffusion coefficients and thickness swelling were measured for all composites. The results showed that the response of WPCs towards water exposure is heavily dependent on formulation design. The time required to reach saturation point varied between four weeks and 84 weeks. Such a big difference reflected magnitude of formulation design on water resistance of WPCs. Composites with large particles demonstrated weak performance towards water. Any increase in wood content led to an increase in water absorption. Coupling agent reduced water absorption. Diffusion coefficients and thickness swelling were also affected by wood and coupling agent contents, and wood particle size. The highest diffusion coefficients and thickness swelling were found in composites with high wood contents and large particles. Studying the water sorption process in WPCs showed that the process follows kinetics and mechanisms described by Fick’s law.
Wood plastic composites (WPCs) were produced from thermally treated beech (Fagus orientalis L.) wood and polypropylene (PP) polymer with coupling agent, by using injection molding. The wood chips were thermally treated for 30 or 120 min at three different temperatures (120 °C, 150 °C, or 180 °C) under saturated steam in a digester and then grounded (40-mesh size) by wood mill. Long-term water absorption kinetics of the composites were investigated with water immersion test. It was found that the water absorption decreased with increasing severity of the thermal-treatment and water immersion time as compared to the control composites. Furthermore, the composites produced with wood treated at 180 ºC for 120 min exhibited the least water absorption. Microstructures of the composites were examined by SEM analysis to understand the mechanisms for the wood-plastic interaction which affected the water absorption. Further studies were conducted to model the water diffusion of the composites. Diffusion coefficient parameter in the models was obtained by fitting the model predictions with the experimental data. Water absorption of the studied composites was proved to follow the kinetics of a Fickian diffusion process.
In this study the water sorption and diffusion properties of wood/plastic composites (WPCs) as a function of formulation design were studied. Composites with different amounts of wood, coupling agent and high density polyethylene (HDPE) were produced by extrusion. The time required to reach saturation point, moisture contents at saturation point, diffusion coefficients and thickness swelling were measured for all composites. The results show that the response of WPCs towards water exposure is strongly dependent on formulation design. The time required to reach saturation point varies between 4 weeks and 86 weeks depending on the formulation of WPCs. Composites with large particles demonstrated weak performance towards water. Any increase in wood content led to an increase in water absorption. Coupling agent reduced water absorption. Diffusion coefficients and thickness swelling were also affected by wood content, coupling agent content, and wood particle size. The highest diffusion coefficients and thickness swelling were found in composites with high wood contents and large particles. The study of the water absorption process in WPCs has shown that the process follows the kinetics and mechanisms described by Fick`s law.
In this paper, Tung oil from the south of Shaanxi province was assayed, and the behavior of its thermal decomposition was investigated by thermogravimetry. The pyrolysis characteristics of Tung oil experimentally studied using thermo-gravimetric analyzer (TGA).The TG curves and DTG curves were examined under different operating conditions such as heating rate and different atmospheres. The mechanism equation of pyrolysis reaction, activation energy (E) and frequency factor (A) were obtained by using differential method to fit experimental data. The experimental results shown that there are two temperature ranges in the organic matter pyrolysis period: 350-420°C and 420-500°C in air, but 350-450°C in nitrogen. The effects on Tung oil pyrolysis of different heating rates were indistinct. The activation energy in the first period was more than that in the second period.
The hygroscopicity of woody materials results in moisture absorption into wood-based composites, including wood–plastic composites (WPC). The objective of this research was to improve the water resistance and mold resistance of WPC by extraction of hemicelluloses from the wood raw material. The treatment may also eliminate extractives such as free sugars, starches, and lipids that can serve as food for fungi. Liquid hot water extraction was performed on southern yellow pine flakes under different temperatures (140, 155, and 170 °C) and over a period of 60 min. Wood flour from extracted or control flakes was compounded with isotactic polypropylene in an extruder, both with and without a coupling agent. Injection molding was used to make tensile test samples. Wood–plastic composite samples were immersed for 5, 10, and 15 wk in water and the water absorption and tensile properties of the samples were measured. The susceptibility of the WPCs to mold was evaluated also. The water absorption of samples decreased after extraction; this resulted in higher mechanical properties of WPCs from extracted wood flour after different periods of soaking in water. Extraction also resulted in improvement in mold resistance of the WPC.
Eprint: http://www.tandfonline.com/eprint/UitwwEqd2MNXrFwr4kkb/full
A review of vibrational frequencies reported for tannin molecules is provided to create a database with typical fingerprints for different types of tannins. This will provide researchers working on vibrational spectroscopy applications and technicians a fast, easy and reliable method to assess the quality and authenticity of these compounds, both extracted in laboratories and provided from commercial sources. The widespread use of these compounds has highlighted the need for a systematic characterization of the vibrational frequencies and molecular fingerprints for their identification and discrimination. According to our knowledge, this is the first systematic collection of typical peak frequencies for tannins, which can be applied in several research fields and technological applications.
"Wood and Tree Fungi" provides an up-to-date overview of the various wood and tree fungi that damage trees, lumber, and timber, with special focus given to identification, prevention, and remediation techniques. First, the fundamentals of cytology and morphology, growth and reproduction, formal genetics, and enzymatic wood decay are addressed. Causative factors are then analyzed, followed by descriptions of interactions like antagonism, succession, and mycorrhiza. The more practical section describes damages by viruses on trees and by bacteria on the xylem of trees and on structural timber, wood discoloration caused by molds and stain fungi, wood decays by rot fungi, and preservation methods. The habitats of wood fungi are described as well as tree care. Important tree pathogens and wood decay fungi are characterized for prevention and identification. The final section focuses on the positive effects of wood-inhabiting microorganisms, covering past and classical methods like myco-wood, mushroom cultivation, biological pulping, and "palo podrido", as well as recent biotechnological processes.
Thermal modification of wood produces a wood material with many interesting properties, such as enhanced dimensional stability, lower equilibrium moisture content and increased biological durability. Changes in the chemical structure of pine (Pinus sylvestris) caused by thermal treatment were investigated by studying various components of wood using C-13 CPMAS NMR spectroscopy. Electron spin resonance (ESR) spectroscopy on the same set of samples was used to study the formation and stability of free radicals formed during the treatment. The most remarkable changes revealed by solid state NMR were the increase in relative crystallinity of cellulose and destruction and deacetylation of hemicelfuloses. Changes in the lignin fraction were mostly registered as diminishment in the methoxyl content, although the intensity of the aromatic region increased relative to the carbohydrate fraction during the treatment. Increase in the intensities of the ESR signals from thermally treated wood samples proves the formation of stable free radicals. In addition, radical formation is believed to take part in condensation reactions leading to crosslinks within the lignin and possibly between lignin and other wood components. Both of the methods used indicate that the changes are most remarkable when the treatment temperature is over 200 degreesC.
The thermal degradation behavior at 350 C of poly(hydroxybutyric acid), Biopol'', has been studied by pyrolysis-GC using a microthermocouple-controlled filament. The overall pyrolysis mechanism--an array of parallel and consecutive processes--has been elucidated by a novel method. This involves the measurement of product yields as a function of sample thickness, for samples in the microgram range, pyrolyzed for a chosen duration (5 s was used in the present study). This approach provides indirect control of the residence time of primary products in the melt and thereby facilitates the detection of secondary reactions. From quantitative measurements of bonus yields and deficit yields, it is shown, for example, that only trans isomers are formed as primary products; trans-cis isomerizations then occur as secondary reactions. Moreover, although monomeric, dimeric, and trimeric products are formed by primary processes, there is evidence that a trimeric product is also formed by a consecutive reaction mechanism. Somewhat unexpectedly, the tetrameric products are formed exclusively by secondary reactions. This observation casts some doubt on the view that the pyrolysis products from this polymer can be accounted for entirely in terms of random ([beta]-elimination) scissions.
Tebuconazole, didecyldimethylammonium chloride (DDAC), and boric acid are co-biocides frequently added to copper-based wood preservative systems. Although the performance thresholds of these biocides are well known, there is currently little information on the effects of subthreshold loadings of the co-biocides on common wood decay fungi. We tested five strains of Postia placenta on white pine cubes (Pinus strobus) treated with subthreshold retentions of tebuconazole, DDAC, or boric acid. No stimulatory effects were observed on blocks treated with DDAC or boric acid. Decay stimulation, as measured by weight loss, occurred between loadings of 1.0 x 10(-5) to 1.0 x 10(-3) kg m(-3) on blocks treated with tebuconazole. This effect should be taken into account during the design and use of wood preservative systems containing this fungicide.
A major consumer concern regarding lumber in above-ground exposure Such as decking is the poor dimensional stability that leads to warping, splitting, and checking. One method to increase dimensional stability is to treat lumber with a water repellent. A waterborne water repellent made from the resin acid abietic acid or a commercial source of resin acids, tall oil rosin or TOR, was tested using southern pine sapwood. In laboratory water-swelling tests, the waterborne abietic acid provided water repellency that was almost equivalent to that provided by wax, while no water repellency was observed with solventborne resin acid. Wood treated with waterborne TOR also provided good water repellency in laboratory tests and fair water repellency at up to 13 months of outdoor exposure, but the laboratory efficacy was partially reduced by a water leach. The dimensional stability (cupping and checking) and mold growth on TOR-treated lumber in above-ground exterior exposure was better than for untreated boards, but not as good as for wax-treated lumber. Analysis of the wood in southern pine tree trunks of 14 or 29 years of age of various diameters and sampled at the bottom, middle and top showed that the resin acid content in southern pine wood is quite variable. This may explain the wide variation in natural water repellency and decay resistance previously observed with untreated southern pine sapwood.
HPLC-FTIR was investigated for the qualitative determination of catechins and methyl xanthines present in green tea extracts. A reversed phase separation of the green tea components was performed on a C-18 column equilibrated at 30°C using an isocratic mobile phase of acetonitrile: 0.1% formic acid (15 : 85), prior to introduction to the deposition interface linked to the FTIR detector. The solvent was evaporated at 130°C and spectra were collected every six seconds during the run. Six catechins, (+)-catechin, gallocatechin, (−)-epicatechin, (−)-epigallocatechin and (−)-epigallocatechin gallate, and (−)- epicatechin" gallate, as well as two methyl xanthines, caffeine and theobromine, were separated and positively identified in a sample of Chinese green tea. The catechins and methyl xanthines were matched to the respective standards by both retention time and the measured infrared spectrum.
The effect of the filler volume fraction on the tensile behavior of injection-molded rice husk-filled polypropylene (RH–PP) composites was studied. Hygrothermal aging behavior was also investigated by immersing the specimens in distilled water at 30 and 90°C. The kinetics of moisture absorption was studied from the amount of water uptake by specimens at regular interval times. It was found that the diffusion coefficient and the maximum moisture content are dependent on the filler volume fraction and the immersion temperatures. Incorporation of RH into the PP matrix has led to a significant improvement in the tensile modulus and a moderate improvement in the tensile strength. Elongation at break and energy at break, on the other hand, decreased drastically with the incorporation of the RH filler. The extent of deterioration incurred by hygrothermal aging was dependent on the immersion temperature. Both the tensile strength and tensile modulus deteriorated as a result of the combined effect of thermal aging and moisture attack. Furthermore, the tensile properties were not recovered upon redrying of the specimens. Scanning electron microscopy was used to investigate the mode of failure of the RH–PP composites. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 742–753, 2001
In this study the effects of heat treatment on compression strength (CS) of spruce wood (Picea orientalis) were examined and changes in the chemical structure of the treated wood were determined by analyzing contents of cellulose, hemicellulose and lignin.Heat treatment was applied on the test samples in an oven at four different temperatures (130, 150, 180 and 200 °C) and three different durations (2, 6 and 10 h) under atmospheric pressure.The results indicate that the effects of heat treatment on CS values generally exhibited a decrease with increased duration and temperature. It was seen that hemicelluloses were the wood-cell components most degraded by the heat treatment.
In this study the weathering behavior of lime wood (Tillia cordata Mill.) has been examined using FT-IR and 2D IR correlation spectroscopy, which evidenced chemical changes induced by exposure to weathering conditions. It was showed that lignin is most sensitive component to the photodegradation processes as indicated by considerable decreases in the intensities of the characteristic aromatic lignin band at 1505cm(-1) and other associated bands. By 2D correlation spectroscopy has been demonstrated that the moment of CO from carboxyl and acetyl groups in hemicelluloses is changing first, followed by the CC of aromatic skeletal, CO in non-conjugated ketones, carboxyl groups and lactones, absorbed O-H and conjugated C-O groups in quinones. The carbonyl formation corresponded well with lignin degradation, indicating a close relationship between them. Comparing the rate of carbonyl formation and lignin decay clearly showed that the former is remarkably higher than the latter, indicating the formation of carbonyl bands at 1738cm(-1) probably resulted from not only lignin oxidation but also from reactions occurring in other components of the wood. Quinine formation is combined with the decay of aromatic structures and the formation of conjugated carbonyl groups.