lnu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Adamopoulos, StergiosORCID iD iconorcid.org/0000-0002-6909-2025
Alternative names
Publications (10 of 139) Show all publications
Balducci, F., Adamopoulos, S., Pettinari, C., Canti, E., Di Nicola, C., Tombesi, A., . . . Gabbani, C. (2020). A formaldehyde-free adhesive for particleboards based on soy flour, magnesium oxide, and a plant-derived enzymatic hydrolysate. BioResources, 15(2), 3087-3102
Open this publication in new window or tab >>A formaldehyde-free adhesive for particleboards based on soy flour, magnesium oxide, and a plant-derived enzymatic hydrolysate
Show others...
2020 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 15, no 2, p. 3087-3102Article in journal (Refereed) Published
Abstract [en]

An adhesive for particleboards based on natural materials was prepared. Soy flour (38.9 wt%), magnesium oxide (MgO) (2.8 wt%), and a hydrolysate from an agricultural crop (13.9 wt%) were mixed with water and ground in a ball mill at 44% solids. The solubility and interaction of the soy flour proteins and the proteins contained in the plant hydrolysate were triggered by the strong basic environment created by MgO in the presence of water. The natural adhesive appeared to be thermally stable at temperatures from 130 °C to 240 °C, with unchanged mass and no major signals in the thermal analysis curves. These results, together with a viscosity of 510 Pa·s at 25 °C, suggested a good operability of the adhesive. Three-layered particleboards were manufactured with weight combinations of natural adhesive and polyamidoamine-epichlorohydrin (PAE) of 0%:100%, 33%:67%, 50%:50%, 67%:33%, and 100%:0%. The natural adhesive showed inferior internal bond strength and poor water resistance compared with urea-formaldehyde-bonded boards. Addition of the PAE significantly improved the internal bond and swelling, and for all the combinations these properties were comparable or, in most cases, better than in the urea-formaldehyde controls. All boards were formaldehyde-free, while the natural adhesive itself released no dangerous volatile substances

National Category
Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-92984 (URN)
Available from: 2020-03-18 Created: 2020-03-18 Last updated: 2020-03-23Bibliographically approved
van Blokland, J., Olsson, A., Oscarsson, J., Daniel, G. & Adamopoulos, S. (2020). Crack formation, strain distribution and fracture surfaces around knots in thermally modified timber loaded in static bending. Wood Science and Technology, 1-28
Open this publication in new window or tab >>Crack formation, strain distribution and fracture surfaces around knots in thermally modified timber loaded in static bending
Show others...
2020 (English)In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, p. 1-28Article in journal (Refereed) Epub ahead of print
Abstract [en]

The effect of thermal modification (TM) on the chemistry, anatomy and mechanical properties of wood is often investigated using small clear samples. Little is known on the effect of growth-related and processing defects, such as knots and checks, on the bending strength and stiffness of thermally modified timber (TMT). Nine boards of Norway spruce with different combinations of knot types were used to study the combined effects of checks and knots on the bending behaviour of TMT. Digital image correlation (DIC) measurements on board surfaces at sites of knots subjected to bending allowed to study strain distribution and localise cracks prior to and after TM, and to monitor development of fracture (around knots) in TMT to failure. DIC confirmed that checking in knots was increased after TM compared to kiln-dried timber, specifically for intergrown knots and intergrown parts of encased knots. Effects appear local and do not affect board bending stiffness at these sites. Bending failure in TMT initiated mainly at knot interfaces or besides knots and fractures often propagated from checks. Scanning electron microscopy analyses of fracture surfaces confirmed this, and fractures were typically initiated around knots and at knot interfaces due to crack propagation along the grain in the longitudinal–radial plane (TL fracture) under mixed mode I and II loading, such that boards failed in simple tension like unmodified timber. Images of fracture surfaces at the ultrastructural level revealed details of the brittle behaviour of TM wood. This was especially apparent from the smooth appearance of transwall failure under mode I loading across the grain.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
checks, digital image correlation (DIC), Norway spruce, scanning electron microscopy (SEM), ThermoWood®
National Category
Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-95388 (URN)10.1007/s00226-020-01190-5 (DOI)
Funder
Swedish Research Council Formas, 942-2015-722
Note

Bibliografiskt granskad

Available from: 2020-06-03 Created: 2020-06-03 Last updated: 2020-06-03
Kumar, A., Adamopoulos, S., Jones, D. & Amiandamhen, S. (2020). Forest biomass availability and utilization potential in Sweden: A review. Waste and Biomass Valorization, 1-16
Open this publication in new window or tab >>Forest biomass availability and utilization potential in Sweden: A review
2020 (English)In: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265X, p. 1-16Article in journal (Refereed) Epub ahead of print
Abstract [en]

In recent years, there has been a growing interest in many parts of the world for more effective biomass utilization due tolegislative and public interest in sustainable development. Whilst much of the effort has been on energy generation frombiomass, there is considerable interest on biomass availability and utilization for other end uses. With about 1% of the world’scommercial forest areas, Sweden provides about 10% of the sawnwood, and pulp and paper that is traded on the global market.The Swedish agricultural sector also contributes to biomass availability, not only by production of sustainable food crops, butalso by utilizing side streams and underutilized land for biomaterial purposes. To meet the challenges that climate changepresents, there has to be a shift to sustainable biomass production and increased interest in promoting a circular bioeconomy.This review presents a systematic assessment on the availability of biomass and its utilization potential in Sweden. Thereview also focuses on biomass production and trade in the Swedish forest industry. In addition, the environmental impactof biomass utilization is discussed

Place, publisher, year, edition, pages
Springer, 2020
National Category
Forest Science Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-92279 (URN)10.1007/s12649-020-00947-0 (DOI)000515731400002 ()
Available from: 2020-02-20 Created: 2020-02-20 Last updated: 2020-05-07
Kumar, A., Ryparovà, P., Kasal, B., Adamopoulos, S. & Hajek, P. (2020). Resistance of bamboo scrimber against white-rot and brown-rot fungi. Wood Material Science & Engineering, 15(1), 57-63
Open this publication in new window or tab >>Resistance of bamboo scrimber against white-rot and brown-rot fungi
Show others...
2020 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 15, no 1, p. 57-63Article in journal (Refereed) Published
Abstract [en]

Bamboo scrimber is one of the most emerging structural materials for future building applications andit possesses properties comparable to other natural wood-based engineered materials such as glulam,laminated veneer lumber and cross-laminated timber. The goal of this work was to study the decayresistance of bamboo scrimber against white-rot (Trametes versicolor) and brown-rot fungi (Serpulalacrymans). Bamboo scrimber samples were incubated in petri dishes with the wood-decaying fungiand the weight loss after 12 weeks was measured. The surface morphology of fungal-degradedbamboo scrimber was evaluated using optical microscopy. Based on the percentage weight loss,bamboo scrimber could be classified as highly resistant against bio-deterioration by white andbrown-rot fungi.

Place, publisher, year, edition, pages
Taylor & Francis, 2020
National Category
Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-74431 (URN)10.1080/17480272.2018.1475420 (DOI)000510012600006 ()
Available from: 2018-05-21 Created: 2018-05-21 Last updated: 2020-02-21Bibliographically approved
Taghiyari, H. R., Esmailpour, A., Adamopoulos, S., Zereshki, K. & Hosseinpourpia, R. (2020). Shearn strenght of heat-treated solid wood bonded with polyvinyl-acetate reinforced by nanowollastonite. Wood research, 65(2), 183-194
Open this publication in new window or tab >>Shearn strenght of heat-treated solid wood bonded with polyvinyl-acetate reinforced by nanowollastonite
Show others...
2020 (English)In: Wood research, ISSN 1336-4561, Vol. 65, no 2, p. 183-194Article in journal (Refereed) Published
Abstract [en]

This study investigated the shear strength of heat-treated solid wood of three species (beech, poplar, and fir) bonded with polyvinyl-acetate (PVA) adhesive reinforced by nanowollastonite (NW). Wood specimens were heat-treated at 165°C and 185°C, and then bonded using PVA reinforced by 5% and 10% of NW. Shear strength tests parallel to the grain of bonded specimens were performed according to ASTM D143-14 (2014). The results demonstrated that the shear strength was significantly dependent upon the density of the specimens. Heat treatment decreased the shear strength of the bonded specimens considerably. This was attributed to several factors, such as a reduction in polar groups in the cell wall, increased stiffness of the cell wall after heat treatment, and a reduction in the wettability of treated wood. However, NW acted as a reinforcement agent or extender in the complex, and eventually improved the shear bond strength. Moreover, the density functional theory (DFT) proved the bond formation between calcium atoms in the NW and hydroxyl groups of cell wall polymers. The overall results indicated the potential of NW to improve the bonding strength of heat-treated wood.

Place, publisher, year, edition, pages
Slovak Forest Products Research Institute, 2020
Keywords
Heat treatment, nano-suspensions, polyvinyl-acetate adhesive (PVA), shear bond strength, wollastonite
National Category
Wood Science Polymer Technologies
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-94771 (URN)000530092600001 ()
Available from: 2020-05-15 Created: 2020-05-15 Last updated: 2020-06-03Bibliographically approved
Hemmilä, V., Adamopoulos, S., Hosseinpourpia, R. & Ahmed, S. A. (2019). Ammonium Lignosulfonate Adhesives for Particleboards with pMDI and Furfuryl Alcohol as Crosslinkers. Polymers, 11(10), 1-17, Article ID 1633.
Open this publication in new window or tab >>Ammonium Lignosulfonate Adhesives for Particleboards with pMDI and Furfuryl Alcohol as Crosslinkers
2019 (English)In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, no 10, p. 1-17, article id 1633Article in journal (Refereed) Published
Abstract [en]

Tightening formaldehyde emission limits and the need for more sustainable materials have boosted research towards alternatives to urea-formaldehyde adhesives for wood-based panels. Lignin residues from biorefineries consist of a growing raw material source but lack reactivity. Two crosslinkers were tested for ammonium lignosulfonate (ALS)—bio-based furfuryl alcohol (FOH) and synthetic polymeric 4,4′-diphenylmethane diisocyanate (pMDI). The addition of mimosa tannin to ALS before crosslinking was also evaluated. The derived ALS adhesives were used for gluing 2-layered veneer samples and particleboards. Differential Scanning Calorimetry showed a reduction of curing temperature and heat for the samples with crosslinkers. Light microscopy showed that the FOH crosslinked samples had thicker bondlines and higher penetration, which occurred mainly through vessels. Tensile shear strength values of 2-layered veneer samples glued with crosslinked ALS adhesives were at the same level as the melamine reinforced urea-formaldehyde (UmF) reference. For particleboards, the FOH crosslinked samples showed a significant decrease in mechanical properties (internal bond (IB), modulus of elasticity (MOE), modulus of rupture (MOR)) and thickness swelling. For pMDI crosslinked samples, these properties increased compared to the UmF. Although the FOH crosslinked ALS samples can be classified as non-added-formaldehyde adhesives, their emissions were higher than what can be expected to be sourced from the particles. 

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
biorefinery lignin; wood panels; sustainable adhesives; adhesive penetration; particleboard properties; formaldehyde emissions
National Category
Polymer Technologies
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-89556 (URN)10.3390/polym11101633 (DOI)000495382700102 ()31658588 (PubMedID)
Available from: 2019-10-14 Created: 2019-10-14 Last updated: 2019-11-21Bibliographically approved
Hemmilä, V., Hosseinpourpia, R., Adamopoulos, S. & Eceiza, A. (2019). Characterization of Wood-based Industrial Biorefinery Lignosulfonates and Supercritical Water Hydrolysis Lignin. Waste and Biomass Valorization, 1-11
Open this publication in new window or tab >>Characterization of Wood-based Industrial Biorefinery Lignosulfonates and Supercritical Water Hydrolysis Lignin
2019 (English)In: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265X, p. 1-11Article in journal (Refereed) Epub ahead of print
Abstract [en]

Understanding the properties of any particular biorefinery or pulping residue lignin is crucial when choosing the right lignin for the right end use. In this paper, three different residual lignin types [supercritical water hydrolysis lignin (SCWH), ammonium lignosulfonate (A-LS), and sodium lignosulfonate (S-LS)] were evaluated for their chemical structure, thermal properties and water vapor adsorption behavior. SCWH lignin was found to have a high amount of phenolic hydroxyl groups and the highest amount of beta-O-4 linkages. Combined with a low ash content, it shows potential to be used for conversion into aromatic or platform chemicals. A-LS and S-LS had more aliphatic hydroxyl groups, aliphatic double bonds and C=O structures. All lignins had available C-3/C-5 positions, which can increase reactivity towards adhesive precursors. The glass transition temperature (T-g) data indicated that the SCWH and S-LS lignin types can be suitable for production of carbon fibers. Lignosulfonates exhibited considerable higher water vapor adsorption as compared to the SCWH lignin. In conclusion, this study demonstrated that the SCWH differed greatly from the lignosulfonates in purity, chemical structure, thermal stability and water sorption behavior. SCWH lignin showed great potential as raw material for aromatic compounds, carbon fibers, adhesives or polymers. Lignosulfonates are less suited for conversion into chemicals or carbon fibers, but due to the high amount of aliphatic hydroxyl groups, they can potentially be modified or used as adhesives, dispersants, or reinforcement material in polymers. For most value-adding applications, energy-intensive purification of the lignosulfonates would be required. [GRAPHICS] .

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Ammonium lignosulfonate, Sodium lignosulfonate, Hydrolysis lignin, Phenolics, Aromatics
National Category
Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-90318 (URN)10.1007/s12649-019-00878-5 (DOI)000496201800001 ()
Note

Bibliografiskt granskad

Available from: 2019-11-29 Created: 2019-11-29 Last updated: 2020-06-02
Kumar, A., Ryparová, P., Hosseinpourpia, R., Adamopoulos, S., Prošek, Z., Žigone, J. & Petrič, M. (2019). Hydrophobicity and resistance against microorganisms of heat and chemically crosslinked poly(vinyl alcohol) nanofibrous membranes. Chemical Engineering Journal, 360, 788-796
Open this publication in new window or tab >>Hydrophobicity and resistance against microorganisms of heat and chemically crosslinked poly(vinyl alcohol) nanofibrous membranes
Show others...
2019 (English)In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 360, p. 788-796Article in journal (Refereed) Published
Abstract [en]

Poly(vinyl alcohol) (PVA) is a water-soluble, semi-ionic and biocompatible polymer with excellent chemical and thermal stability. The chemical crosslinking of PVA membrane improve its stability towards humidity and water. In the present work, PVA nanofibrous membranes were fabricated using roller electrospinning techniques. The prepared membranes were crosslinked by heat treatment, glutaraldehyde dipping, and glutaraldehyde vapour. Furthermore, octadecyltrichlorosilane (OTS) treatment was used for hydrophobization of the crosslinked membranes. The prepared crosslinked membranes were analysed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The hydrophobization of PVA nanofibrous membranes were analysed by employing optical goniometer and auto-dynamic vapour sorption (AVS) techniques. Further, the PVA membranes were tested against algae and mould growth at in-vitro laboratory conditions. The SEM and FTIR results revealed significant differences in the morphology of the PVA nanofibrous membranes and in chemical bond formation due to crosslinking treatments. Water contact angle and AVS data confirmed a hydrophobization of PVA membranes by the treatments.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Polymer Technologies Other Materials Engineering
Research subject
Chemistry, Organic Chemistry
Identifiers
urn:nbn:se:lnu:diva-79195 (URN)10.1016/j.cej.2018.12.029 (DOI)000460964000079 ()2-s2.0-85058096376 (Scopus ID)
Available from: 2018-12-13 Created: 2018-12-13 Last updated: 2019-08-29Bibliographically approved
Hemmilä, V., Meyer, B., Larsen, A., Schwab, H. & Adamopoulos, S. (2019). Influencing factors, repeatability and correlation of chamber methods in measuring formaldehyde emissions from fiber- and particleboards. International Journal of Adhesion and Adhesives, 95, 1-9, Article ID 102420.
Open this publication in new window or tab >>Influencing factors, repeatability and correlation of chamber methods in measuring formaldehyde emissions from fiber- and particleboards
Show others...
2019 (English)In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 95, p. 1-9, article id 102420Article in journal (Refereed) Published
Abstract [en]

Recently, there has been focus on lowering emission levels of wood-based boards. However, the accuracy and correlationbetween EN 717-1 and ASTM D 6007 chamber methods at emission levels below 0.05 ppm are not wellinvestigated, and information about their correlation to the EN 16516 method is limited. In this paper, the lowemission level of interest was determined by measuring emissions from particles, fibers and pressed boards withoutglue. The effect of analytical methods and edge-sealing on chamber emissions was determined, and accuracies andcorrelations of the EN 717-1 and ASTM D 6007 chambers were defined at low emission levels (< 0.05 ppm). Inaddition, some emission values were compared to those obtained with EN 16516. The EN 717-1 and ASTM D 6007methods had high accuracy. The acetyl acetone and 2.4-dinitrophenylhydrazine analytical methods showed lowstandard deviations (< 5%), except at emission levels below 0.02 ppm. This could be counteracted by using a directreagent absorber solution. Opening 5% of the edge of boards affected emissions and was dependent on board type.ASTM D 6007 and EN 717-1 methods were highly correlated for both particleboards (r2=0.9167) and fiberboards(r2=0.9443) at emission levels below 0.05 ppm. EN 16516 emissions were 2.6 times greater than those of EN 717-1 at emission range<0.05 ppm, exceeding the conversion factor of two given in the German legislation. The EN 717-1 to EN 16516 correlation needs to be further evaluated for different board types and emission ranges

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-88576 (URN)10.1016/j.ijadhadh.2019.102420 (DOI)000499734000023 ()
Available from: 2019-08-22 Created: 2019-08-22 Last updated: 2019-12-19Bibliographically approved
Foti, D., Adamopoulos, S., Voulgaridou, E., Voulgaridis, E., Passialis, C., Amiandamhen, S. & Daniel, G. (2019). Microstructure and compressive strength of gypsum-bonded composites with papers, paperboards and Tetra Pak recycled materials. Journal of Wood Science, 65(1), 1-8, Article ID 42.
Open this publication in new window or tab >>Microstructure and compressive strength of gypsum-bonded composites with papers, paperboards and Tetra Pak recycled materials
Show others...
2019 (English)In: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 65, no 1, p. 1-8, article id 42Article in journal (Refereed) Published
Abstract [en]

The incorporation of recycled papers, paperboards and Tetra Pak as filling materials in brittle matrices presents aninteresting approach in the utilization of waste materials for building construction. This paper examines the compressivestrength and microstructure of gypsum-bonded wastepaper-based composites. Recycled wastepaper of varioustypes (office paper, magazine paper and newspaper), cardboards, paper boxes and Tetra Pak were shredded to shortlength strips of about 4 × 18 mm. The shredded materials were used as filling materials in natural gypsum in a ratioof 1:3 (v/v), and water was added to the mix. The paste was formed in cylindrical samples measuring 10 cm in lengthand 5 cm in diameter. Seven different types of composites were produced depending on the material used. Thecomposite products with newspaper and magazine paper had significantly lower density and compressive strength(p < 0.05) than the others. However, the differences were small to have any practical importance. The density valuesranged between 1.26 and 1.34 g/cm3, and compressive strength was the lowest (4.48 N/mm2) in the gypsum–magazinepaper composites and the highest (6.46 N/mm2) in the gypsum–Tetra Pak I composites. Since the samplesproduced in this study exhibited adequate compressive strength, the products could be suitable for such applicationsas interior walls in building constructions. Scanning electron microscopy (SEM) examination of the fractured surfacesrevealed needle-like structures of gypsite crystals surrounding the fibers, which indicates good adhesion between thehydrophobic matrix and lignocellulosic fibers.

Place, publisher, year, edition, pages
Springer, 2019
National Category
Wood Science Composite Science and Engineering
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-89175 (URN)10.1186/s10086-019-1821-5 (DOI)000483579900001 ()
Funder
Swedish Research Council, 942-2016-2Swedish Research Council Formas, 2017-21The Kamprad Family Foundation, 20160052The Kamprad Family Foundation, 2017-19
Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-09-25Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6909-2025

Search in DiVA

Show all publications