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Adamopoulos, StergiosORCID iD iconorcid.org/0000-0002-6909-2025
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Publications (10 of 133) Show all publications
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), 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, 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. 

Keywords
biorefinery lignin; wood panels; sustainable adhesives; adhesive penetration; particleboard properties; formaldehyde emissions
National Category
Polymer Technologies
Identifiers
urn:nbn:se:lnu:diva-89556 (URN)10.3390/polym11101633 (DOI)
Available from: 2019-10-14 Created: 2019-10-14 Last updated: 2019-10-14
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
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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 inmeasuring formaldehyde emissions from fiber- and particleboards. International Journal of Adhesion and Adhesives, 95, Article ID 102420.
Open this publication in new window or tab >>Influencing factors, repeatability and correlation of chamber methods inmeasuring formaldehyde emissions from fiber- and particleboards
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2019 (English)In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 95, 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)
Available from: 2019-08-22 Created: 2019-08-22 Last updated: 2019-10-14Bibliographically 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
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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
van Blokland, J., Olsson, A., Oscarsson, J. & Adamopoulos, S. (2019). Prediction of bending strength of thermally modified timber using high-resolution scanning of fibre direction. European Journal of Wood and Wood Products, 77(3), 327-340
Open this publication in new window or tab >>Prediction of bending strength of thermally modified timber using high-resolution scanning of fibre direction
2019 (English)In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 77, no 3, p. 327-340Article in journal (Refereed) Published
Abstract [en]

The market share of thermally modified wood (TMW) has increased in Europe during the past few years as an environmentally friendly and durable building product. However, TMW products of today are not permitted for use in structural applications, because the reduction in strength that is caused by thermal treatment cannot be accounted for. The purpose of this paper was to investigate the bending properties of thermally modified timber (TMT) of Norway spruce, and to explore possibilities to predict the bending properties of TMT. A sample of 100 boards from a 2X-log sawing pattern of 100 logs was thermally modified according to the ThermoWood® process, while the mirror 100 boards served as an unmodified control sample. Two non-destructive methods were employed: (1) a novel method based on scanning of fibre directions to obtain the lowest edgewise bending modulus of elasticity (MOE) along a board, and (2) a conventional excitation method to determine the first axial resonance frequency used to calculate the axial dynamic MOE. Finally, the boards were bent to failure according to European standard EN 408. Despite the fact that bending strength was reduced by 42% due to thermal treatment, the type and location of failure in TMT remained related to the presence of knots. Prediction of bending strength based on local fibre direction and axial dynamic MOE, gave coefficients of determination of 0.51 for the thermally modified boards and 0.69 for the control boards, whereas axial dynamic MOE alone gave 0.46 and 0.57, respectively. These results indicate that although Norway spruce TMT has lower bending strength compared to unmodified timber, predictions of the bending strength can be made with good accuracy.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
axial dynamic excitation, fibre angle, four-point bending, grade determining properties, machine strength grading, ThermoWood®, tracheid effect
National Category
Building Technologies Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-80374 (URN)10.1007/s00107-019-01388-w (DOI)000463863700001 ()2-s2.0-85064163799 (Scopus ID)
Funder
Swedish Research Council Formas, 942-2015-722Stora Enso
Available from: 2019-02-11 Created: 2019-02-11 Last updated: 2019-10-17Bibliographically approved
Hosseinpourpia, R., Adamopoulos, S., Mai, C. & Taghiyari, H. R. (2019). Properties of medium-density fibreboards bonded with dextrin-based wood adhesive. Wood research, 64(2), 185-194
Open this publication in new window or tab >>Properties of medium-density fibreboards bonded with dextrin-based wood adhesive
2019 (English)In: Wood research, ISSN 1336-4561, Vol. 64, no 2, p. 185-194Article in journal (Refereed) Published
Abstract [en]

This study focuses on manufacturing of medium density fibreboard (MDF) panels bonded with dextrin-based wood adhesive and crosslinked in situ with various weight ratios of synthetic (e.g., polymeric-methane diphenyl-diisocyanate, pMDI) or bio-based (e.g., glyoxal) crosslinkers. The physical and mechanical properties of the panels were evaluated and compared with those from panels without crosslinker (control). Modulus of rupture (MOR) and internal bond (IB) strength of the MDF panels were considerably increased by increasing the crosslinkers’ content. While, slight improvements were observed in modulus of elasticity (MOE) of the panels as a function of crosslinker type and content. Addition of crosslinkers clearly reduced the thickness swelling (TS) and water absorption (WA) of the panels, whereas, the panels with pMDI showed superior performances than the control and glyoxal added ones within 4 h and 24 h immersion in water. The results indicate the potential of dextrin as wood panel adhesive along with the use of appropriate crosslinkers.

Place, publisher, year, edition, pages
SDVÚ, 2019
Keywords
Crosslinker, dextrin adhesive, glyoxal, mechanical properties, pMDI, thickness swelling
National Category
Composite Science and Engineering Wood Science Polymer Technologies
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-82474 (URN)000467016100001 ()
Funder
Vinnova, 2015-04825The Kamprad Family Foundation, 20160052
Available from: 2019-05-08 Created: 2019-05-08 Last updated: 2019-05-28Bibliographically approved
Hosseinpourpia, R., Adamopoulos, S. & Eceiza, A. (2019). Thermal stability and water vapor sorption of wheat starch modified with isocyanate functional groups. In: 7th International Conference on Biobased and Biodegradable Polymers (BIOPOL), 17-19th June 2019, Stockholm, Sweden: . Paper presented at 7th International Conference on Biobased and Biodegradable Polymers (BIOPOL), 17-19th June 2019, Stockholm, Sweden. KTH
Open this publication in new window or tab >>Thermal stability and water vapor sorption of wheat starch modified with isocyanate functional groups
2019 (English)In: 7th International Conference on Biobased and Biodegradable Polymers (BIOPOL), 17-19th June 2019, Stockholm, Sweden, KTH , 2019Conference paper, Published paper (Refereed)
Abstract [en]

Wheat starch polymer was modified through the unequal reactivity of isocyanate groups in isophorone diisocyanate (IPDI) monomer. Fourier transform infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (13C NMR) confirmed the presence of both urethane and isocyanate functionalities in the modified polymer. Thermal stability and water vapor sorption properties of the modified polymer were evaluated by means of thermogravimetric analysis (TGA) and auto-dynamic vapor sorption (AVS) method, respectively. The results indicated that the modified starch polymer showed a better thermal stability (e.g. higher temperature at maximum weight loss) compared to the unmodified one. Water vapor sorption of starch polymer was considerably reduced after modification with IPDI monomer.

Place, publisher, year, edition, pages
KTH, 2019
National Category
Textile, Rubber and Polymeric Materials Polymer Chemistry
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-85788 (URN)
Conference
7th International Conference on Biobased and Biodegradable Polymers (BIOPOL), 17-19th June 2019, Stockholm, Sweden
Projects
Lantmännen project
Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-08-28Bibliographically approved
Hosseinpourpia, R., Adamopoulos, S. & Parsland, C. (2019). Utilization of different tall oils for improving the water resistance of cellulosic fibers. Journal of Applied Polymer Science, 136(13), Article ID 47303.
Open this publication in new window or tab >>Utilization of different tall oils for improving the water resistance of cellulosic fibers
2019 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 136, no 13, article id 47303Article in journal (Refereed) Published
Abstract [en]

This study was conducted to assess the effect of the pulping by-products crude tall oil (CTO), distilled tall oil (DTO), andtall oil fatty acid (TOFA) on dynamic water vapor sorption behavior, interfiber strength, and thermal stability of cellulosic paper-sheets.The results were compared against those obtained in cellulose papers treated with the conventional petroleum-derived hydrophobicagent hydrowax and in untreated ones. The tall oil treatments caused strong reduction in equilibrium moisture content of the paper-sheets during adsorption and desorption runs. The same trend was noticed for the hydrowax-treated papers, however, it was lesspronounced than the CTO-treated and DTO-treated samples in the relative humidity range of 75–95%. The sorption hysteresis was con-siderably decreased after the treatments. The ultimate dry-tensile strengths of the paper-sheets were significantly reduced by TOFA andhydrowax treatments, while CTO and DTO showed comparable strength as that of untreated control. The ultimate wet-strengths of thepaper-sheets were improved after the treatments. The thermal stability of the specimens was improved by the tall oil treatments, and thehydrowax-treated samples illustrated lower degradation temperature than the untreated control. The results are promising for the use oftall oils as alternative hydrophobic agents of cellulosicfiber-based products, such as wood panels and paper packaging.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2019
National Category
Wood Science Composite Science and Engineering Paper, Pulp and Fiber Technology Bio Materials Polymer Chemistry
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-78872 (URN)10.1002/app.47303 (DOI)000454418300034 ()2-s2.0-85056707222 (Scopus ID)
Funder
Vinnova, 2015‐04825The Kamprad Family Foundation, 20160052
Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2019-08-29Bibliographically approved
Adamopoulos, S., Ahmed, S. A. & Lankveld, C. (2018). Acoustic properties of acetylated wood under different humid conditions and its relevance for musical instruments. In: Jos Creemers, Thomas Houben, Bôke Tjeerdsma, Holger Militz and Brigitte Junge (Ed.), Proceedings of the 9th European Conference on Wood Modification 2018, Arnhem, The Netherlands: . Paper presented at 9th European Conference on Wood Modification (ECWM9), September 17-18, Arnhem, The Netherlands (pp. 236-243). The Netherlands: Practicum
Open this publication in new window or tab >>Acoustic properties of acetylated wood under different humid conditions and its relevance for musical instruments
2018 (English)In: Proceedings of the 9th European Conference on Wood Modification 2018, Arnhem, The Netherlands / [ed] Jos Creemers, Thomas Houben, Bôke Tjeerdsma, Holger Militz and Brigitte Junge, The Netherlands: Practicum , 2018, p. 236-243Conference paper, Published paper (Refereed)
Abstract [en]

In musical instrument making, less expensive wood species and materials with good characteristics and acoustical properties can provide potentials to find alternatives to the traditional exotic wood species used today. Modified wood could be such a choice if shows similar sound characteristics to wood coming from endangered and expensive tropical species with problematic commercial availability. In musical instruments, the overall functionality depends on the contribution of wood to different material performance indexes like sound radiation coefficient (R), characteristic impedance (z) and acoustic conversion efficiency (ACE). In this study, the performance indexes were measured for acetylated beech, maple and radiata pine and compared with these obtained for the reference wood materials maple, mahogany, alder and ash. A non-destructive free-free flexural vibration test method was used at constant temperature (20oC) but in different humid conditions- dry (35% RH), standard (65% RH) and wet (85% RH). Dimensional changes in the different humid conditions were also taken in account. Acetylated wood showed lower EMC with higher dimensional stability at each humidity level as compared with the reference wood materials. These properties are considered important factors for making quality musical instruments. Based on the acoustical properties, acetylated wood materials, especially radiata pine, showed good potential for use for musical instruments where specific characteristics of sound are required. However, the other types of acetylated wood can also be used for specific musical instruments.

Place, publisher, year, edition, pages
The Netherlands: Practicum, 2018
Keywords
Acoustic conversion efficiency, damping, equilibrium moisture content, free-free flexural vibration, volumetric shrinkage
National Category
Wood Science Chemical Engineering Polymer Technologies
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-84630 (URN)
Conference
9th European Conference on Wood Modification (ECWM9), September 17-18, Arnhem, The Netherlands
Available from: 2019-06-05 Created: 2019-06-05 Last updated: 2019-06-18Bibliographically approved
Ahmed, S. A. & Adamopoulos, S. (2018). Acoustic properties of modified wood under different humid conditions and their relevance for musical instruments. Applied Acoustics, 140, 92-99
Open this publication in new window or tab >>Acoustic properties of modified wood under different humid conditions and their relevance for musical instruments
2018 (English)In: Applied Acoustics, ISSN 0003-682X, Vol. 140, p. 92-99Article in journal (Refereed) Published
Abstract [en]

In musical instrument making, there is a strong need to find alternatives to the traditional endangered and expensive tropical wood species used today. The present study examined whether different commercial and experimental modified wood materials have the necessary acoustic qualities under different humid conditions (dry, standard and wet) to contribute to the use of raw materials for wooden musical instruments. The materials were thermally-modified wood (ash, aspen and birch), acetylated wood (beech, maple and radiata pine), melamine- and phenol formaldehyde-treated beech and furfurylated Scots pine (Kebony Scots pine). Investigations involved physical (density ρ, Equilibrium moisture content EMC, volumetric shrinkage) and dynamic elastic testing by a free-free flexural vibration method to determine various acoustic characteristics: specific dynamic modulus (MOEdyn/ρ), damping coefficient (tanδ), speed of sound (c), specific acoustic impedance (z), sound radiation coefficient (R) and acoustic conversion efficiency (ACE). The modified materials and especially acetylated wood showed low EMC values and high dimensional stability at each humidity level, which are considered important factors for making quality musical instruments. Based on the obtained value ranges of all acoustical properties, the different modified wood materials could find uses in musical instruments where specific characteristics of sound are required. Furthermore, most of the modified materials showed an excellent acoustic performance in the three humid conditions based on a high ACE and low tanδ. Furfurylated Scots pine and phenol formaldehyde-treated beech showed an inferior acoustic quality with the lowest ACE and the highest tanδ, which is a less favourable combination for most of the musical instruments.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Wood modification; Dimensional stability; Free-free flexural vibration; Dynamic elastic modulus; Damping; Sound velocity; Sound radiation; Acoustic impedance; Acoustic conversion efficiency
National Category
Wood Science
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-74511 (URN)10.1016/j.apacoust.2018.05.017 (DOI)000440121900010 ()2-s2.0-85047306125 (Scopus ID)
Available from: 2018-05-24 Created: 2018-05-24 Last updated: 2019-08-29Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-6909-2025

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