Sotirios Karastergiou - Academia.edu (original) (raw)

Papers by Sotirios Karastergiou

The purpose of this paper is to show the effects of level of substitution with a linear chain anh... more The purpose of this paper is to show the effects of level of substitution with a linear chain anhydride (propionic anhydride) on dimensional stability and decay resistance of modified Scots pine sapwood. The work described herein has demonstrated that chemically modified Scots pine sapwood with propionic anhydride afforded substantial bioprotection against Coniophora puteana. It required a weight gain of approximately 16-18% following reaction to ensure complete protection. The dimensional stability of propionic anhydride modified wood was greatly improved.

European Journal of Wood and Wood Products, Mar 1, 2004

This article validates the technical feasibility of making one layer experimental particleboard f... more This article validates the technical feasibility of making one layer experimental particleboard from bamboo chips bonded with UF resin. Bamboo chips were characterised by having higher length to thickness and length to width ratios and lower bulk density than industrial wood chip particles. The rate of heat transfer to the core was approximately the same in the two mats, probably reflecting the same values of bulk density between bamboo and wood chips. The results obtained in this study showed that bamboo chips can be successfully used, as an alternative lignocellulosic raw material, to manufacture P3 boards for interior fitments using a relatively low resin dosage (10% UF). The more stringent ANSI criteria, however, required 14% UF resin and 1% wax to satisfy the 8% TS criteria. Combinations of bamboo chips with industrial wood chips and application of other resin systems may be an avenue for exploration in further investigations.

Journal of composites science, Mar 31, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Finger jointing has been in use in production for many years, yet it is only with the decline in ... more Finger jointing has been in use in production for many years, yet it is only with the decline in resource quality that interest in it for furniture has increased. Beech wood is one of the most important species for the furniture production in Europe. It is used mainly as steamed as well as unsteamed wood as raw material in many furniture applications. In this work, the utilization of small dimensions steamed and unsteamed beech wood (Fagus silvatica) was studied for the manufacture of finger jointed furniture lumber. Particularly, it was investigated the effect of the two most common used finger lengths (4mm and 10mm) on static bending strength (modulus of rupture and modulus of elasticity) of the finger jointed beech wood that was connected across the grain with a polyvinyl-acetate based glue (D1, D2, D3 durability classes) (EN 204:2001). Modulus of rupture (MOR) of unsteamed wood joints ranged from 33.51 N/mm to 82.24 N/mm, which corresponds to a percentage of 30.8% to 75.7% respe...

Epistēmonikē Epetērida Tou Tmēmatos Dasologies Kai Fusikou Periballontos Aristoteleio Panepistēmio Thessalonikēs, 2000

In this work various lignocellulosic materials of annual plants such as kenaf (Hibiscus cannabicu... more In this work various lignocellulosic materials of annual plants such as kenaf (Hibiscus cannabicus), mischanthus (Miscanthus sinensis 'giganteus'), reed (Arundo donax L.) and agricultural residues of cotton were evaluated as alternative raw material for the production of particleboards of low toxicity (low emission of formaldehyde). The results showed that the above materials if properly treated could be used satisfactorily in admixtures with poplar wood to manufacture both low and high density particleboards. Also, low density boards of the above materials proved to behave satisfactorily as basic components for manufacturing of building materials with good thermo-sound insulating properties.

Journal of Applied Polymer Science, 2006

Beech wood is one of the most important species used in furniture production in Europe. In this w... more Beech wood is one of the most important species used in furniture production in Europe. In this work, the effects of poly(vinyl acetate) (PVAc) bonding [durability classes D1, D2, and D3 according to EN 204 : 2001), finger length (4 and 10 mm), and finger orientation on the bending strength of finger-jointed steamed and unsteamed beech wood (Fagus sylvatica) were studied. Specimens were prepared according to EN 385 (2001) and modulus of rupture (MOR) and modulus of elasticity (MOE) tests were performed according to the procedures detailed in the ISO 10983 (1999) and DIN 52186 (1978) standards. The MOR of unsteamed wood joints ranged from 33.51 to 82.24 N/mm 2 , whereas the MOR of the steamed wood joints fluctuated from 34.9 to 80.27 N/mm 2. In both steamed and unsteamed wood the specimens with a finger length of 10 mm showed higher MOR than the specimens with a finger length of 4 mm. The MOE of the unsteamed specimens was not affected by finger jointing, whereas, the MOE of the steamed specimens increased slightly (by 5.4%) compared to the control solid wood. It was concluded that it was better to use a 10-mm finger length and the D3 durability class of PVAc adhesives when fingerjointed furniture lumber is produced.

Holz als Roh- und Werkstoff, 2004

Holz als Roh- und Werkstoff, 2005

Proceedings of The First International Conference on “Green” Polymer Materials 2020, 2020

The objective of this study was to examine oil-retention, adsorption, swelling and tensile streng... more The objective of this study was to examine oil-retention, adsorption, swelling and tensile strength of lap joints of wood treated with hot rape oil. Wood specimens of two species (Fagus sylvatika and Pinus nigra) were impregnated in a steel vessel using the empty cell process (Lowry method). Several impregnated specimens were additionally surface treated with turpentine. Rape oil retention ranged between 124 and 189 kg/m3 for pine wood specimens and between 187 and 285 kg/m3 for beech wood specimens. For both species, the impregnated specimens had an adsorption of about 20%, while the untreated near 60%. Total swelling of specimens was not affected by the impregnation but the rate of swelling was decreased. The impregnated specimens had a little lower tensile strength mostly when glued with polyurethane (PU). Surface treatment with turpentine slightly improved tensile strength of lap joints.

The objective of this study was to examine oil-retention, swelling, adsorption, static bending pr... more The objective of this study was to examine oil-retention, swelling, adsorption, static bending properties and tensile strength of lap joints of black pine (Pinus nigra Arn.) wood treated with hot r ...

The objective of this study was to examine the retention (kg/m³) and the penetration depth (mm) a... more The objective of this study was to examine the retention (kg/m³) and the penetration depth (mm) as well as the impregnated area of cross sections (%) along the hole length, in fir (Abies borisii re ...

Fir and spruce wood specimens, 2×2 cm in cross section and 34 cm long, were pre-pared with true r... more Fir and spruce wood specimens, 2×2 cm in cross section and 34 cm long, were pre-pared with true radial and tangential surfaces. All lateral surfaces of the wood specimens were drilled by laser beams to a depth of 0,4 cm (1/5 of specimen thickness) with two drilling patterns (distance between holes 1×1 cm and 1×2 cm) in order to improve the wood permea-bility of these refractory to impregnation species. After drilling and assessing the drilling ef-fect on mechanical properties of wood, wood specimens, 10 cm long, were impregnated with oil and CCB preservatives by using vacuum (0,6 mmHg) and pressure (1,5 bar) for 15 minutes and 30 minutes, respectively. The effects of the two laser drilling patterns on impreg-nability of fir and spruce wood specimens were measured and assessed. The results showed that both drilling patterns created by laser beams on all lateral surfaces of fir and spruce wood specimens at 0,4 mm depth improved the retention and penetration of preservatives in fir and...

Journal of Renewable Materials, 2021

Materials, methods & technologies, 2015

The objective of this study was to examine bending and tensile strength of beech wood (Fagus sylv... more The objective of this study was to examine bending and tensile strength of beech wood (Fagus sylvatica) joints (basic mortise and tenon) along with the effect of wood impregnation with rapeseed oil and type of glue (PVA or PU). The wood specimens were impregnated with the empty-cell treatment (Lowry process). Retention of rape oil was about 273 kg/m 3 . Beech wood impregnation led to some reduction of the bending and tensile strength. Bending strength of the specimens reduced from 9,9% up to 25,9% while tensile strength reduced from 19,7 up to 35,2% for joints glued with PVA and from 2,1 up to 16,7% for joints glued with PU. Joints glued with PU had higher bending and tensile strength in most cases. Joints constructed from wood impregnated before mortise and tenon construction had generally higher mechanical strength. Joints constructed from impregnated wood that primarily treated with turpentine, had lower mechanical strength, than the non treated with turpentine joints.

International Wood Products Journal, 2020

ABSTRACT This work examined the enhancement of bending strength properties of two wood species, n... more ABSTRACT This work examined the enhancement of bending strength properties of two wood species, namely fir and pine, reinforced with two carbon fibre fabrics (CFF) of different areal weight, in two different layouts. CFF applied in the bottom surfaces of the specimens (‘F’-type) and in the second wrapped in the bottom surfaces and up to the half of the lateral surfaces (‘U’-type).The results indicated that samples which are reinforced with CCF show higher MOR and MOE values than the controls and this improvement was found to be significantly different. The reinforcement layout affected the bending properties of both pine and fir wood, since the corresponding values are higher in U-shaped reinforcement than in F-type reinforcement, at identical CFF areal weights. In the case of fir wood, the CFF areal weight did not significantly affect the bending properties.

Πρακτικά 12ου Πανελληνίου Δασολογικού Συνεδρίου Δάσος Και Νερό Προστασία Φυσικού Περιβάλλοντος, Jan 7, 2010

Fir and spruce wood specimens, 20 × 20 mm in cross section and 340 mm long, were prepared with tr... more Fir and spruce wood specimens, 20 × 20 mm in cross section and 340 mm long, were prepared with true radial and tangential surfaces. All lateral surfaces of the specimens were drilled by laser beams to a depth of 0.4 cm (1/5 of specimen thickness) with two drilling patterns (distance between holes 1 × 1 cm and 1 × 2 cm). After drilling, MOE and MOR in static bending, axial compression and toughness were determined and compared with non-drilled controls. MOE was not affected by the laser drilling but MOR was significantly increased. The increase in MOR was 12-13% for the drilled fir specimens as compared to controls and was significant only for the 1 × 2 cm pattern, while for spruce it was noted an even higher increase of 21-24% significant for both drilling patterns. Toughness strength of drilled fir and spruce specimens was lower than the non-drilled but the differences were not significant. Laser drilling had a positive significant impact in axial compression strength with an incre...