- TEI of Thessaly, School of Technological Sci.
Dept of Wood & Furniture Design and Technology, Griva 11, GR 43100
Karditsa - Greece - +306947300585
- TEI of Thessaly, Wood and Furniture, Design and Technology, Faculty Memberadd
- Dr. George I. Mantanis is a faculty member in the University of Thessaly, at the Lab of Wood Science and Technology, ... moreDr. George I. Mantanis is a faculty member in the University of Thessaly, at the Lab of Wood Science and Technology, Karditsa campus, Greece. Dr. G. Mantanis holds a PhD in wood science from the University of Wisconsin-Madison, USA (1994). He has worked at the Forest Products Lab (FPL) - Madison (1994), Forest Research Inst. of Thessaloniki (1996-97) and in the industrial company CHIMAR HELLAS S.A. (former ACM Wood Chemicals Plc) in years 1998-2002. Currently, he is Co-Editor in the referred journal 'Wood Material Science & Engineering' (Taylor & Francis).edit
The market for new durable products of modified wood has increased substantially during the last few years, especially in Europe. This increased interest depends partly on the restricted use of toxic preservatives due to increased... more
The market for new durable products of modified wood has increased substantially during the last few years, especially in Europe. This increased interest depends partly on the restricted use of toxic preservatives due to increased environmental concern, as well as the need for reduced maintenance for wood products that are mainly for exterior use. Furthermore, as sustainability becomes a greater concern, the environmental impact of construction and interior materials should be included in planning by considering the entire life cycle and embodied energy of the materials used. As a result, wood modification has been implemented to improve the intrinsic properties of wood, widen the range of sawn timber applications, and acquire the form and functionality desired by engineers, without bringing environmental friendliness into question. The different wood modification processes are at various stages of development , and the challenges that must be overcome to expand to industrial applications differ amongst them. In this paper, three groups of wood modification processes are discussed and exemplified with modified wood products that have been newly introduced to the market: (i) chemical processing (ace-tylation, furfurylation, resin impregnation etc.); (ii) thermo-hydro processing (thermal treatment); and (iii) thermo-hydro-mechanical processing (surface densification). Building on these examples, the paper will discuss the environmental impact assessment of modification processes and further development needs.
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In this work, the adhesive systems used today in the European industries of particleboard, medium density fibreboard (MDF), and oriented strand board (OSB) are discussed. The structure of particleboard, MDF and OSB markets in Europe in... more
In this work, the adhesive systems used today in the European industries of particleboard, medium density fibreboard (MDF), and oriented strand board (OSB) are discussed. The structure of particleboard, MDF and OSB markets in Europe in relation to the types of adhesives and product specifications are presented as well. It is noticeable that new markets for wood-based panels like particleboard and fibreboard, known as non-furniture markets, are growing in Europe at a fast rate. It was concluded that most of the technological changes concerning the adhesive systems applied and additives have been realised from the need for niche panel products, the obligation to reach even lower formaldehyde emissions, and the necessity to decrease production costs due to the stringent competition in the market of wood-based panels.
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Significant developments in the area of wood modification have been achieved during the last three decades. These developments can be attributed to increased environmental concerns, the escalating demand for a high and constant quality of... more
Significant developments in the area of wood modification have been achieved during the last three decades. These developments can be attributed to increased environmental concerns, the escalating demand for a high and constant quality of wood products, and the rising prices of the durable tropical timber as well as its very limited availability, as affected by illegal logging. As a consequence, a number of wood modification techniques such as chemical and impregnation modifications or heat treatments have been introduced, and some of these technologies have reached the industrial level. This review paper deals with two successful technologies, that is, wood acetylation and wood furfurylation. It briefly discusses the advantages of the new modified products and presents in short their improved properties. Published findings indicate that chemical modification of wood, to a full or partial degree, by means of acetylation or furfurylation, offers a way to transform low durability wood species to new 'green' wood materials having advanced qualities and properties.
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This study identified the wood species and evaluated the degree of weathering and biological degradation of a historical timber construction element originating from the Great Metéoron monastery in Metéora, Greece. The wood material was... more
This study identified the wood species and evaluated the degree of weathering and biological degradation of a historical timber construction element originating from the Great Metéoron monastery in Metéora, Greece. The wood material was provided from the interior side of a balcony that was fully covered with a roof and exposed to outdoor conditions for more than 400 years. The species was identified as Quercus spp. of the white oak group. In the timber element, the physical, morphological, and chemical changes were studied to assess the type and extent of degradation using light microscopy and Fourier transform infrared (FT-IR) spectroscopy. To examine the degree of biological degradation and weathering, the surface layer and inner parts of the specimen were studied separately and compared with a recent wood specimen of the same species. The FT-IR analysis revealed remarkable differences between the surface layer and the inner parts of the historical wooden element. Macroscopic and microscopic investigation indicated that multiple types of degradation caused by weathering, fungi, and insect attacks had occurred in the wood structure. It was finally concluded that the historical timber construction element was in better condition than was expected before the study.
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The field of wood protection is currently changing due to the restrictions imposed by the Biocidal Products Regulation. The need for development of new wood protection technologies is therefore growing. In this work, the resistance of... more
The field of wood protection is currently changing due to the restrictions imposed by the Biocidal Products Regulation. The need for development of new wood protection technologies is therefore growing. In this work, the resistance of European beech (Fagus sylvatica L.) wood impregnated with nano-dispersions of zinc oxide (nano-ZnO) and zinc borate (nano-ZnB) against the termite Reticulitermes grassei Clement was investigated. Three different concentrations (0.5%, 1%, 2%) of
the nanocompounds were tested. The effects of water leaching were also investigated. A severe effect in terms of termite workers mortality was induced by both dispersions, even at the lowest concentration. In terms of termite feeding, nano-ZnO dispersions appeared to be more efficient than nano-ZnB as they induced significant improvement at concentrations as low as 0.5%. Nano-ZnB was applied at 1% or higher concentrations in order to impart similar changes. Nano-ZnB
dispersions were efficient in terms of termite resistance for a concentration at least 1%. Further increasing concentration to 2% resulted in a respective increase of wood efficacy against termites.
For both tested nanocompounds, water leaching did not result in any significant increase of termite feeding.
the nanocompounds were tested. The effects of water leaching were also investigated. A severe effect in terms of termite workers mortality was induced by both dispersions, even at the lowest concentration. In terms of termite feeding, nano-ZnO dispersions appeared to be more efficient than nano-ZnB as they induced significant improvement at concentrations as low as 0.5%. Nano-ZnB was applied at 1% or higher concentrations in order to impart similar changes. Nano-ZnB
dispersions were efficient in terms of termite resistance for a concentration at least 1%. Further increasing concentration to 2% resulted in a respective increase of wood efficacy against termites.
For both tested nanocompounds, water leaching did not result in any significant increase of termite feeding.
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In this work, the biological resistance of Scots pine (Pinus sylvestris L.) wood impregnated with nano-sized zinc oxide and zinc borate against the fungi Daedalea quercina, Poria placenta and Serpula lacrymans was evaluated. It can be... more
In this work, the biological resistance of Scots pine (Pinus sylvestris L.) wood impregnated with nano-sized zinc oxide and zinc borate against the fungi Daedalea quercina, Poria placenta and Serpula lacrymans was evaluated. It can be concluded that nano-sized zinc oxide inhibited the biological degradation of pine wood against Serpula lacrymans, while it was ineffective against the brown-rot fungus Poria placenta. Pine wood treated with nano-sized zinc borate exhibited higher biological resistance against the fungi Serpula lacrymans and Poria placenta.
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In this work, the colour changes of pine and fir wood treated with several nano‐compounds were investigated. Surface treatments with titanium‐ and zinc‐ oxide based nanocompounds clearly retarded lightness reduction to a certain extent in... more
In this work, the colour changes of pine and fir wood treated with several nano‐compounds were investigated. Surface treatments with titanium‐ and zinc‐ oxide based nanocompounds clearly retarded lightness reduction to a certain extent in both pine and fir wood tested. The maximum lightness improvement was obtained with the nano‐compound B (titanium oxide based; rutile), which was improved by 57.8% for fir and 44.8% for pine wood, respectively. On the other hand, the treated samples showed the least redness (Δa*) and yellowness (Δb*) reduction in both wood species. Moreover, the same compound was considerably more effective in reducing the rate of lightness decrease in fir wood, whereas compound A (titanium oxide based; 75% anatase, 25% rutile) was more effective in reducing the rate of lightness decrease in pine wood against ultraviolet irradiation. The highest lightness improvement occurred in fir (47.9%) with compound B, while the highest lightness improvement took place in pinewood (56.5%) with compound A. In addition, the marked effect of whiteness and yellowing colour protection with the nanocompound based coatings tested against natural and UV irradiation weathering was shown in the work. The surface coating agents typically resulted in a colour reduction improvement (ΔE) of 12.2 value units for naturally weathered fir wood, and of 10.3 value units for UV irradiated fir wood. It was shown that nanocompound B was considerably more effective in reducing the rate of total colour decrease in fir wood both in natural weathering and artificial UV‐chamber weathering.
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At the end of their service life, wood-based panels become eventually waste wood. Deploying in landfills is no longer considered as an acceptable solution for their handling due to the high organic load included. The recycling of this... more
At the end of their service life, wood-based panels become eventually waste wood. Deploying in landfills is no longer considered as an acceptable solution for their handling due to the high organic load included. The recycling of this waste to be employed as raw material for the wood panel industry, which traditionally makes use of wood processing residues, has hence
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Furfurylation is a modifi cation process carried out in order to improve the biological resistance and dimensional stability of wood. In this research work, a three-year outdoor weathering test of furfurylated wood was performed using the... more
Furfurylation is a modifi cation process carried out in order to improve the biological resistance and dimensional stability of wood. In this research work, a three-year outdoor weathering test of furfurylated wood was performed using the following wood materials: a deck of furfurylated radiata pine (Pinus radiata), a deck of furfurylated maple (Acer spp.), a deck of furfurylated southern yellow pine (Pinus spp.), and a control deck of Ipê wood (Handroanthus spp.) that was used for comparative reasons. The decks, without any protection or finishing, were exposed for 36 months in Karditsa, Greece in order to evaluate some physical and structural properties of wood such as colour, staining, distortion, surface cracking and end splitting. All tested decks exhibited colour changes that were perceptible by the naked eye and much higher during the fi rst twelve months of weathering. The three furfurylated wood decks showed smaller total colour changes as compared to those of Ipê control deck. In respect to surface cracking, furfurylated radiata pine deck generally showed minor surface cracks, while furfurylated maple deck presented the lowest degree of surface and end splitting. In overall, the furfurylated wood
decks tested performed very well and showed no signs of black staining (except for the southern yellow pine deck)
and no fungal or mould decay after three years of outdoor exposure.
decks tested performed very well and showed no signs of black staining (except for the southern yellow pine deck)
and no fungal or mould decay after three years of outdoor exposure.
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"In this work, the brown rot resistance of black pine (Pinus nigra L.) wood, pressure-treated in an autoclave with nano-sized zinc borate and zinc oxide dispersions, was investigated. The two formulations based on zinc borate have given... more
"In this work, the brown rot resistance of black pine (Pinus nigra L.) wood, pressure-treated in an autoclave with nano-sized
zinc borate and zinc oxide dispersions, was investigated. The two formulations based on zinc borate have given encouraging
results, indicating fungicide effects of the metal nanoparticles on Coniophora puteana. In specific, mean weight losses for P.
nigra sapwood exposed to this fungus (one without and one with the addition of a binder) were negligible, that is 0.54% and
0.34%, respectively. On the contrary, the impregnation of pine wood with nano-sized zinc oxide resulted in minimal
protection, i.e. 35.9% weight loss. Therefore, nano-sized zinc borate can be utilised in new formulations to impart resistance
to wood against the brown rot C. puteana."
zinc borate and zinc oxide dispersions, was investigated. The two formulations based on zinc borate have given encouraging
results, indicating fungicide effects of the metal nanoparticles on Coniophora puteana. In specific, mean weight losses for P.
nigra sapwood exposed to this fungus (one without and one with the addition of a binder) were negligible, that is 0.54% and
0.34%, respectively. On the contrary, the impregnation of pine wood with nano-sized zinc oxide resulted in minimal
protection, i.e. 35.9% weight loss. Therefore, nano-sized zinc borate can be utilised in new formulations to impart resistance
to wood against the brown rot C. puteana."
Two Greek red wines (Syrah and Cabernet) were artificially aged with different wood chips (white oak, red oak, Turkey oak, chestnut, Bosnian pine, cherry, common juniper, common walnut, white mulberry, black locust and apricot). The... more
Two Greek red wines (Syrah and Cabernet) were artificially aged with different wood chips (white oak, red oak, Turkey oak, chestnut, Bosnian pine, cherry, common juniper, common walnut, white mulberry, black locust and apricot). The influence of each wood species was tested for up to 20 days. The optimum duration for the extraction of total polyphenols was 20 days (Syrah) or 10 days (Cabernet) when chips of white oak, chestnut, cherry, white mulberry, black locust and apricot where used. Resveratrol and catechin concentrations ranged within the limits previously reported in literature. A high antioxidant activity was established after 10 days of artificial aging. The sensory evaluation showed that the best results were produced by the apricot chips after 5 days (Syrah) or black locust and apricot after 5 days (Cabernet). Colour was seen to increase with both time of aging and number of wood chips added.
This work aimed at evaluating the indoor concentrations of formaldehyde in twenty five new apartments in the city of Drama, Northern Greece. By means of a formaldehyde meter, two series of measurements were made in September 2009 and... more
This work aimed at evaluating the indoor concentrations of formaldehyde in twenty five new apartments in the city of Drama, Northern Greece. By means of a formaldehyde meter, two series of measurements were made in September 2009 and September 2010. Early morning measurements were made in the living rooms, bedrooms, kitchen rooms and child rooms. Initial measurements showed that average concentrations of formaldehyde exceeded by far the limit of 0.1 ppm set in most of the European countries for formaldehyde concentration in residential environments. After a 30-minute natural ventilation in the apartments, formaldehyde concentrations remained at the levels higher than 1.0 ppm only in three apartments. In the following months (September 2009 to September 2010), a systematic ventilation by opening windows took place not only in the morning but also in the late afternoon. In September 2010, measurements were performed in the same apartments indicating that all apartments investigated had formaldehyde concentrations much lower than 1.0 ppm and obviously the indoor air environment was much cleaner.
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This work reports on the colour changes in wood surfaces, namely from the species European pine, fir, Bosnian pine, chestnut and cherry, which have been modified by a new nanoparticulate treatment. Colour values (CIE L*, a*, b*) for both... more
This work reports on the colour changes in wood surfaces, namely from the species European pine, fir, Bosnian pine, chestnut and cherry, which have been modified by a new nanoparticulate treatment. Colour values (CIE L*, a*, b*) for both control and treated wood samples have been studied for each of the five different species. The results have shown a certain effectiveness of the anti-UV surface treatment used, while lower effects were due to ultraviolet light induced photodecolouration. The largest improvements against discolouration were observed with cherry wood. It was observed that anti- UV compound applied on chestnut was particularly less effective (ΔL= -4.64) in respect to other species. It appears that the yellowness show systematic trends with anti-UV treated samples. However, the UV irridation appears to change surface yellowness of coniferous species more than hardwood species. The anti-UV treated hardwood surfaces (chestnut and cherry) yielded higher gloss than the anti-UV treated softwoods (pine and fir).
The chemical composition of the essential oil obtained by steam distillation from the wood of P. heldreichii, collected from north Greece area was determined by GC and GC/MS for the first time. Forty constituents (corresponding to 96.3%... more
The chemical composition of the essential oil obtained by steam distillation from the wood of P. heldreichii, collected from north Greece area was determined by GC and GC/MS for the first time. Forty constituents (corresponding to 96.3% of the total weight) were identified. The main components were: limonene, cembrene, longifolene, α-pinene, methyl chavicol, kaurene and cembrene A. The antimicrobial activity of the oil was evaluated against six Gram positive and Gram negative bacteria and three human pathogenic fungi, using the agar dilution technique. Strong activities against most of the tested microorganisms were exhibited. Moreover, the oil showed a very promising antioxidant activity through Rancimat method.
The aim of this work was to determine the main physical and mechanical properties of athel wood (Tamarix aphylla), one of the least studied non-commercial wood species. Wood samples of Tamarix aphylla were harvested from a small tree... more
The aim of this work was to determine the main physical and mechanical properties of athel wood (Tamarix aphylla), one of the least studied non-commercial wood species. Wood samples of Tamarix aphylla were harvested from a small tree stand in Molyvos coastal area (Lesvos, Greece) and standard test methods were followed on small green specimens. Athel wood’s air- and oven dry densities were determined at 0.73 and 0.66 g/cm3, while maximum tangential shrinkage and swelling were approximately 10.8 and 12.1%, respectively. The volumetric shrinkage and swelling were estimated at 14.0 and 15.5%, respectively. Modulus of rupture, modulus of elasticity, compression strength parallel to grain and Janka hardness (perpendicular to grain) values were found to be 88.5 N/mm2, 7,533 N/mm2, 40.9 N/mm2 and 33.7 N/mm2, respectively.
Keywords: Wood; Tamarix aphylla; Mechanical properties; Density; Shrinkage; Swelling
Keywords: Wood; Tamarix aphylla; Mechanical properties; Density; Shrinkage; Swelling
"The rate and maximum swelling of several North American wood species in water have been obtained with a computer interfaced linear variable displacement transformer. Since wood swells extremely fast in water even at room temperature,... more
"The rate and maximum swelling of several North American wood species in water have been obtained with a computer interfaced linear variable displacement transformer. Since wood swells extremely fast in water even at room temperature, this apparatus made it possible for the first time, to obtain accurate rate data on the swelling of wood in water. The strict linear dependence of swelling on the temperature suggests a chemical mechanism.
The activation energies obtained from Arrhenius plots ranged from 32.2 KJ/ mole for sitka spruce to 47.6 KJ/ mole for sugar maple. Although the two hardwoods exhibited greater maximum tangential swelling compared with the two softwoods, the maximum swelling appears to be correlated with the wood density. Generally both the rate and maximum swelling of the woods were increased by removal of extractives and the activation energies were reduced."
The activation energies obtained from Arrhenius plots ranged from 32.2 KJ/ mole for sitka spruce to 47.6 KJ/ mole for sugar maple. Although the two hardwoods exhibited greater maximum tangential swelling compared with the two softwoods, the maximum swelling appears to be correlated with the wood density. Generally both the rate and maximum swelling of the woods were increased by removal of extractives and the activation energies were reduced."
"The rate and maximum swelling of several North American wood species in 40 organic liquids have been obtained with a computer interfaced linear variable displacement transformer. Since wood swells very fast in some organic liquids, even... more
"The rate and maximum swelling of several North American wood species in 40 organic liquids have been obtained with a computer interfaced linear variable displacement transformer. Since wood swells very fast in some organic liquids, even at room temperature, this apparatus made it possible to obtain
accurate rate data on the swelling of wood in organic liquids. It was found that many similarities existed between wood and cellulose maximum swelling within various solvent chemical classes. Hence, it appears that cellulose is the primary wood polymer responsible for the major amount of swelling of wood. In general, all the liquids, with a molar volume greater than 100 cc or with a small hydrogen bonding parameter, caused very little equilibrium swelling. The logarithm of the rate of wood swelling
(In k) in the liquids was inversely correlated with the solvent molecular weight as well as with the molar volume of the solvent, that is, the larger the solvent molecular size, the slower the rate of swelling. The Ink also was strongly correlated with the maximum tangential swelling of wood. The maximum tangential swelling for all wood species was linearly correlated with the solvent basicity (donor number). Other solvent properties such as volubility parameter, dipole moment, dielectric constant, and surface tension showed very weak correlations with the maximum tangential swelling of wood in organic liquids."
accurate rate data on the swelling of wood in organic liquids. It was found that many similarities existed between wood and cellulose maximum swelling within various solvent chemical classes. Hence, it appears that cellulose is the primary wood polymer responsible for the major amount of swelling of wood. In general, all the liquids, with a molar volume greater than 100 cc or with a small hydrogen bonding parameter, caused very little equilibrium swelling. The logarithm of the rate of wood swelling
(In k) in the liquids was inversely correlated with the solvent molecular weight as well as with the molar volume of the solvent, that is, the larger the solvent molecular size, the slower the rate of swelling. The Ink also was strongly correlated with the maximum tangential swelling of wood. The maximum tangential swelling for all wood species was linearly correlated with the solvent basicity (donor number). Other solvent properties such as volubility parameter, dipole moment, dielectric constant, and surface tension showed very weak correlations with the maximum tangential swelling of wood in organic liquids."
Thermodynamic work of adhesion, contact angle, wettability and acidbase contributions of the wetting of four North American wood species were determined using the Wilhelmy technique. The wetting angles with water varied from 60 ° for... more
Thermodynamic work of adhesion, contact angle, wettability and acidbase contributions of the wetting of four North American wood species were determined using the Wilhelmy technique. The wetting angles with water varied from 60 ° for Sitka spruce to 74 ° for Douglas-fir. The wood surfaces had a strong acidic character since the greatest interactions for all the wood pecies occurred with formamide (basic probe) while lesser interactions were obtained withethylene glycol (acidic probe). In addition, dispersive and polar surface free energies of wood, 7 d and 7 p respectively, were determined using Wu's simultaneous equations. In general, 75 to 80% of the total surface free energy of wood was due to dispersion forces. Specific wettabilities of wood and advancing contact angles in thirty various organic liquids were also evaluated.
"The conventional strawboard technology employing MDI binders has shown technical and economical disadvantages,specifically, high resin costs and additional costs related to release agents required to avoid sticking of panels to press... more
"The conventional strawboard technology employing MDI binders has shown technical and economical disadvantages,specifically, high resin costs and additional costs related to release agents required to avoid sticking of panels to press plates. The adhesion of urea formaldehyde (UF) resin to the straw fiber has been demonstrated in a previous research project using an innovative chemi-thermo-mechanical (CTM) pre-treatment of the straw. This work focuses on the joint efforts to develop a strawboard technology based on UF resins. Three different straw preparation systems, a twin-screw extruder, a pressurized refiner and a combined extruder-refiner treatment, have been chosen to apply intensive shear forces to straw chips in order to overcome the wax and silica layer. With the first two technologies, one-layer panels exclusively bonded with UF have been produced. The board characteristics included excellent appearance, surface smoothness, machinability, edge appearance as well as good bending properties. The internal bond strength values achieved were compatible to particleboard standards. The swelling characteristics did not meet the European standard requirements. With the combined extruder-refiner technology, the UF bonded boards produced showed similarly excellent visual characteristics, bending and internal bond strength values exceeding the MDF standard requirements and swelling figures close to particleboard and MDF standards. By bonding with UF resins, good mat stability, a pressing
process without sticking problems and significant resin cost savings can be achieved. The forthcoming development work will be focused on further improvement of the adhesion of straw fibers to produce even higher quality strawboards."
process without sticking problems and significant resin cost savings can be achieved. The forthcoming development work will be focused on further improvement of the adhesion of straw fibers to produce even higher quality strawboards."
"Research efforts enabled the development of a new process for the recycling of end-use wood panels into new marketable fiberboards. This patent-pending process is based on refiner techniques and allows the use of mixtures of fresh... more
"Research efforts enabled the development of a new
process for the recycling of end-use wood panels into
new marketable fiberboards. This patent-pending
process is based on refiner techniques and allows the
use of mixtures of fresh wood and waste panel chips
as a raw material for dry-process fiberboard production.
The process is applicable in existing fiberboard
plants with only minor operation modifications. At
the refining stage, chemical agents are employed and
the process enables the use of significant amounts of
waste material replacing over 20 percent of the wood
feed and providing significant savings.The aim of the
present work was to validate the industrial applicability
of the new process in the recycling of waste fiberboards.
The new fiberboards obtained during the industrial-
scale trials were of acceptable quality.Testing
results revealed that under conventional gluing and
pressing conditions, the process effectively recycles
the waste boards at a wood substitution level of at
least 25 percent. Further validation and optimization
work is presently underway in the direction of using
other waste panel types and also increasing the level
of waste in the feed material."
process for the recycling of end-use wood panels into
new marketable fiberboards. This patent-pending
process is based on refiner techniques and allows the
use of mixtures of fresh wood and waste panel chips
as a raw material for dry-process fiberboard production.
The process is applicable in existing fiberboard
plants with only minor operation modifications. At
the refining stage, chemical agents are employed and
the process enables the use of significant amounts of
waste material replacing over 20 percent of the wood
feed and providing significant savings.The aim of the
present work was to validate the industrial applicability
of the new process in the recycling of waste fiberboards.
The new fiberboards obtained during the industrial-
scale trials were of acceptable quality.Testing
results revealed that under conventional gluing and
pressing conditions, the process effectively recycles
the waste boards at a wood substitution level of at
least 25 percent. Further validation and optimization
work is presently underway in the direction of using
other waste panel types and also increasing the level
of waste in the feed material."
Maximum liquid-holding capacities of various compressed fibers in water and in a series of various organic liquids have been investigated. The maximum liquid-holding capacity versus bulk density relationships gave polynomial curves,... more
Maximum liquid-holding capacities of various compressed fibers in water and in a series of various organic liquids have been investigated. The maximum liquid-holding capacity versus bulk density relationships gave polynomial curves, generally with a peak. Good relative correlations for cellulose, compressed fiber pellets and wood were found for the series of liquids tested. In general, liquids that swelled wood to a low to medium range (up to 6%) did not swell appreciably a -cellulose and sulfite pulp, while good to excellent wood-swelling agents swelled all the fibers very significantly. It was also found that the hydrogen-bonding parameter of the swelling liquid was the most important factor. The swelling rate of various compressed fiber systems in organic liquids was dramatically increased by raising the temperature. Activation energies and molar volume of the swelling liquid were linearly correlated.
A fire retardant composition that is halogen-free comprises an aqueous solution of an amine, a borate and a phosphate. The claimed composition is effective in providing wood-based panels like medium- or high-density fibreboards with high... more
A fire retardant composition that is halogen-free comprises an aqueous solution of an amine, a borate and a phosphate. The claimed composition is effective in providing wood-based panels like medium- or high-density fibreboards with high fire resistance without a diminution in their physical and mechanical properties.
"In this work, the adhesives used in the European particleboard and MDF industry are presented. The structure of the particleboard and MDF market in Europe in relation to the adhesive type and product application is discussed as well. It... more
"In this work, the adhesives used in the European particleboard and MDF industry are presented. The structure of the particleboard and MDF market in Europe in relation to the adhesive type and product application is discussed as well. It is notable that new markets for particleboard and MDF - known as non-furniture markets - are developing in Europe at a very fast
rate. Newly developed resin systems and trends affecting the industry are also presented."
rate. Newly developed resin systems and trends affecting the industry are also presented."
The swelling of wood in organic liquids at elevated temperatures has been investigated with the use of a computerized linear variable displacement transformer (LVDT). Wood swelled extremely fast at high swelling temperatures. The rate of... more
The swelling of wood in organic liquids at elevated temperatures has been investigated with the use of a computerized linear variable displacement transformer (LVDT). Wood swelled extremely fast at high swelling temperatures. The rate of wood swelling in organic liquids showed a strong dependence on temperature which closely obeyed the classical Arrhenius equation. This strict linear dependence of wood swelling on the temperature clearly suggests a chemical mechanism. Activation energies for wood swelling (Ea) in several chemical classes of organic liquids have been obtained from Arrhenius equation plots. A strong linear relationship was found to exist between Ea and solvent molecular weight. Removal of extractives greatly enhanced the maximum tangential swelling of wood, especially for sugar maple. There was also a significant increase in the wood swelling rate after removal of extractives.
A continuous process for the extraction, decontamination and defibration of waste creosote-, chromated copper aresenate- or pentachlorophenol-treated wood has been developed, which is based on a one-step chemical-thermal-mechanical... more
A continuous process for the extraction, decontamination and defibration of waste creosote-, chromated copper aresenate- or pentachlorophenol-treated wood has been developed, which is based on a one-step chemical-thermal-mechanical treatment that allows the production of fibres suitable for the formation of lignocellulosic composite materials.
A statistical model for prediction of the maximum extent of the swelling of wood in organic liquids is proposed in this work. Solvent basicity, solvent molecular volume, and density of wood appeared to be the most important parameters in... more
A statistical model for prediction of the maximum extent of the swelling of wood in organic liquids is proposed in this work. Solvent basicity, solvent molecular volume, and density of wood appeared to be the most important parameters in the proposed model. The addition of the hydrogen bonding capability parameter did not significantly improve the model.
The subject of agricultural lignocellulosic residues produced in Greece is reviewed in this work. An estimation of the annual overall amounts of the agricultural residues is made, and the rational utilization prospects for these not... more
The subject of agricultural lignocellulosic residues produced in Greece is reviewed in this work. An estimation of the annual overall amounts of the agricultural residues is made, and the rational utilization prospects for these not exploited biomass residues are discussed.
"At the end of their service life, wood-based panels become eventually waste wood. Deploying in landfills is no longer considered as an acceptable solution for their handling due to the high organic load included. The recycling of this... more
"At the end of their service life, wood-based panels become eventually waste wood. Deploying in landfills is no longer considered as an acceptable solution for their handling due to the high organic load included. The recycling of this waste to be employed as raw material for the wood panel industry, which traditionally makes use of wood processing residues, has hence gained more importance and been examined from earlier times.
Technical problems and the lack of enforcing legislative regulations have delayed, however, the industrial implementation of the new technologies proposed. Recent research efforts
enabled the development of a new process for the recycling of end-use wood panels into new marketable fibreboards. This patent pending process is based on the refiner technique and
allows the use of mixtures of fresh wood and waste panel chips as a raw material for dry process fibreboard production. The process is applicable in existing fibreboard plants with only minor operation modifications and therefore, there is no need of major capital investment in additional equipment to effect the recycling. At the refining stage, chemical agents are employed and the process enables the use of significant amounts of waste
material replacing over 20% of the wood feed and providing significant savings. The aim of the present work was to validate the industrial applicability of the new process in the recycling of waste medium-density fibreboards. The new fibreboards obtained during the industrial scale tests were of acceptable quality, and the testing results revealed that under
conventional gluing and pressing conditions, the process effectively recycles the waste boards into new ones at least at 25% wood substitution level. Further validation and
optimisation work is underway in the direction of using other waste panel types and also increasing the level of waste in the feed material."
Technical problems and the lack of enforcing legislative regulations have delayed, however, the industrial implementation of the new technologies proposed. Recent research efforts
enabled the development of a new process for the recycling of end-use wood panels into new marketable fibreboards. This patent pending process is based on the refiner technique and
allows the use of mixtures of fresh wood and waste panel chips as a raw material for dry process fibreboard production. The process is applicable in existing fibreboard plants with only minor operation modifications and therefore, there is no need of major capital investment in additional equipment to effect the recycling. At the refining stage, chemical agents are employed and the process enables the use of significant amounts of waste
material replacing over 20% of the wood feed and providing significant savings. The aim of the present work was to validate the industrial applicability of the new process in the recycling of waste medium-density fibreboards. The new fibreboards obtained during the industrial scale tests were of acceptable quality, and the testing results revealed that under
conventional gluing and pressing conditions, the process effectively recycles the waste boards into new ones at least at 25% wood substitution level. Further validation and
optimisation work is underway in the direction of using other waste panel types and also increasing the level of waste in the feed material."
This research work presents a study on the properties of finger jointing green oak wood (Quercus conferta L.) using a one-component polyurethane adhesive. The effect of finger joint orientation (vertical or horizontal fingers) was also... more
This research work presents a study on the properties of finger jointing green oak wood (Quercus conferta L.) using a one-component polyurethane adhesive. The effect of finger joint orientation (vertical or horizontal fingers) was also examined. In general, the results from the measurements of modulus of rupture and modulus of elasticity of green glued finger-jointed specimens indicated that the green gluing of a high density species such as oak wood is feasible.
The potential of improving the thickness swelling of commercial wood based panels by applying a new nanotechnology compound was investigated. The application of the compound SurfaPoreTM W, an aqueous wood-water repellent resulted in a... more
The potential of improving the thickness swelling of commercial wood based panels by applying a new nanotechnology compound was investigated. The application of the compound SurfaPoreTM W, an aqueous wood-water repellent resulted in a significant improvement in the thickness swelling of the panels tested.
The potential of improving the hygroscopicity of solid wood by applying a new nanotechnology compound was investigated. The sorption isotherms were analysed using the Hailwood-Horrobin model. The experimental analysis of the sorption... more
The potential of improving the hygroscopicity of solid wood by applying a new nanotechnology compound was investigated. The sorption isotherms were analysed using the Hailwood-Horrobin model. The experimental analysis of the sorption isotherms showed that the treatment affected total, polymolecular and monomolecular sorption. The application of the compound reduced the total sorption by 26.5%, polymolecular sorption by 23.9% and monomolecular sorption by 33.1%, at saturation.
"(Original paper in Greek) - Abstract Nowadays, the determination of formaldehyde release from composite wood products is deemed necessary both for technical and most importantly for health protection reasons. The methods used to... more
"(Original paper in Greek) - Abstract
Nowadays, the determination of formaldehyde release from composite wood products is deemed necessary both for technical and most importantly for health protection reasons. The methods used to determine the formaldehyde emission or formaldehyde content evolved during the years and they were adapted to the prevailing conditions each time. In this review work, the results from studies for the determination of formaldehyde according to standard methods used internationally are presented. A comparison of such methods was also performed. Specifically, a) the Perforator method (European standard ΕΝ 120), b) the Chamber method (European standard ΕΝ 717-1 and N. American standard ASTM E1333), c) the Gas Analysis method (European standard EN 717-2), d) the Flask method (European standard EN 717-3), e) the small chamber method (Japanese standard JIS-A-1901) and f) the Desiccator method (mostly based on the Japanese standards JIS-A-1460 και JAS-233) were compared. The advantages and drawbacks of each one of these methods are presented too together with the results of correlation studies done on these methods. "
Nowadays, the determination of formaldehyde release from composite wood products is deemed necessary both for technical and most importantly for health protection reasons. The methods used to determine the formaldehyde emission or formaldehyde content evolved during the years and they were adapted to the prevailing conditions each time. In this review work, the results from studies for the determination of formaldehyde according to standard methods used internationally are presented. A comparison of such methods was also performed. Specifically, a) the Perforator method (European standard ΕΝ 120), b) the Chamber method (European standard ΕΝ 717-1 and N. American standard ASTM E1333), c) the Gas Analysis method (European standard EN 717-2), d) the Flask method (European standard EN 717-3), e) the small chamber method (Japanese standard JIS-A-1901) and f) the Desiccator method (mostly based on the Japanese standards JIS-A-1460 και JAS-233) were compared. The advantages and drawbacks of each one of these methods are presented too together with the results of correlation studies done on these methods. "
In this work, the effects of the impregnation with nano-ZnO and nano-ZnB dispersions on the termite resistance of European beech wood were investigated. Three different concentrations (namely 0.5%, 1% and 2%) of the above two materials... more
In this work, the effects of the impregnation with nano-ZnO and nano-ZnB dispersions on the termite resistance of European beech wood were investigated. Three different concentrations (namely 0.5%, 1% and 2%) of the above two materials were tested. Water leaching effect was also investigated. It was concluded that a severe effect in terms of termite workers mortality is induced by the use of both dispersions even at the lowest concentration. In terms of termite feeding, Nano-ZnO dispersions seem more efficient than nano-ZnB because they induce significant improvement at concentrations as low as 0.5% while nano-ZnB should be used at concentrations at least 1% in order to induce similar changes. Nano-ZnB dispersions are efficient in terms of termite resistance for concentrations at least 1%. Further increasing concentration to 2% resulted to a respective increase of termite durability. For both tested dispersions and for all tested concentrations water leaching did not induce significant increase of termite feeding.