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Scharf, A., Švajger, Č., Lin, C.-F., Humar, M., Sandberg, D. & Jones, D. (2024). Effect of fire-retardant treatment of wood prior to thermo-mechanical densification. Wood Material Science & Engineering, 19(3), 1-4
Open this publication in new window or tab >>Effect of fire-retardant treatment of wood prior to thermo-mechanical densification
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2024 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 19, no 3, p. 1-4Article in journal (Refereed) Epub ahead of print
Abstract [en]

Wood densification itself does not, in general, improve the fire-retardant properties sufficiently to reach the standard requirements. The object of this study was to enhance the fire-retardant properties of thermo-mechanically densified wood without any loss of moisture stability and hardness. Scots pine sapwood was pretreated before densification by impregnation with a fire retardant (FR) consisting of ammonium dihydrogen phosphate and urea and then cured in-situ by hot pressing at 150 °C or 210 °C. Densified specimens without FR were used as a control. Set-recovery, fire retardancy in an open flame test, and Brinell hardness were determined. The set-recovery was slightly reduced as a result of the FR treatment, but the pressing temperature and time had a much greater influence. In the open flame test, specimens without FR-treated ignited within 15-50s of exposure to the flame, whereas all the FR-treated specimens exhibited ignition resistance over the 10 minutes duration of the test. Water-soaking cycles had no impact on the ignition resistance in these groups, indicating a strong resistance to water leaching of FR after pressing at 210 °C for 60 minutes. The hardness increased due to the presence of FR after pressing at 210 °C, but sharply decreased after water immersion.

Place, publisher, year, edition, pages
Taylor & Francis, 2024
Keywords
Wood compression, open flame, urea, ammonium dihydrogen phosphate
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-104919 (URN)10.1080/17480272.2024.2329734 (DOI)
Note

Full text license: CC BY-NC-ND

Available from: 2024-03-28 Created: 2024-03-28 Last updated: 2024-04-05
Lin, C.-F., Karlsson, O., Jones, D. & Sandberg, D. (2024). Kraft lignin-glyoxal, phase-change material modified wood for enhancing thermal-energy storage capability. Wood Material Science & Engineering, 19(3), 821-824
Open this publication in new window or tab >>Kraft lignin-glyoxal, phase-change material modified wood for enhancing thermal-energy storage capability
2024 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 19, no 3, p. 821-824Article in journal (Refereed) Published
Abstract [en]

The rise in energy consumption and the increase in the use of bio-based materials in the building sector, has led to the need to investigate the possibilities to use wood as a porous support material for phase change materials (PCMs), and thereby creating a thermal regulative wood-based product. This study investigated the influence of Kraft lignin-glyoxal prepolymer on the thermal-energy storage properties of wood modified with paraffin-type of PCM. The implementation of the modified wood involves preparing PCM emulsions, synthesising lignin-glyoxal prepolymer, and modifying wood with the PCM-Kraft lignin-glyoxal emulsion through vacuum-pressure impregnation. The infrared imaging suggested the ability of PCM-modified wood to delay the temperature changes, even with the introduction of Kraft lignin-glyoxal prepolymer. In conclusion, it is feasible to introduce thermal-energy storage property into wood with the addition of Kraft lignin-glyoxal prepolymer. Further studies will focus on the long-term thermal storage performance properties when this PCM system is subjected to repeated heating/cooling cycles. 

Place, publisher, year, edition, pages
Taylor & Francis, 2024
Keywords
Encapsulation, paraffin, thermal-regulated wood
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-105332 (URN)10.1080/17480272.2024.2344050 (DOI)001217231100001 ()2-s2.0-85192186364 (Scopus ID)
Funder
Swedish Research Council FormasLuleå University of Technology, CT WOOD; SUN
Note

Validerad;2024;Nivå 2;2024-07-02 (hanlid);

Funder: Swedish Wood Industry;

Full text license: CC BY-NC-ND

Available from: 2024-05-03 Created: 2024-05-03 Last updated: 2024-07-02Bibliographically approved
Lin, C.-F., Karlsson, O., Myronycheva, O., Das, O., Mensah, R. A., Mantanis, G. I., . . . Sandberg, D. (2024). Phosphorylated and carbamylated Kraft lignin for improving fire- and biological-resistance of Scots pine wood. International Journal of Biological Macromolecules, Article ID 133734.
Open this publication in new window or tab >>Phosphorylated and carbamylated Kraft lignin for improving fire- and biological-resistance of Scots pine wood
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2024 (English)In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, article id 133734Article in journal (Refereed) In press
Abstract [en]

In this study, Kraft lignin was modified by ammonium dihydrogen phosphate (ADP) and urea for achieving phosphorylation and carbamylation, aiming to protect wood against biological and fire attack. Scots pine (Pinus sylvestris L.) sapwood was impregnated with a water solution containing Kraft lignin, ADP, and urea, followed by heat treatment at 150 °C, resulting in changes in the properties of the Kraft lignin as well as the wood matrix. Infrared spectroscopy, 13C cross-polarisation magic-angle-spinning (MAS) nuclear magnetic resonance (NMR), and direct excitation single-pulse 31P MAS NMR analyses suggested the grafting reaction of phosphate and carbamylate groups onto the hydroxyl groups of Kraft lignin. Scanning electron microscopy with energy dispersive X-ray spectroscopy indicated that the condensed Kraft lignin filled the lumen as well as partially penetrating the wood cell wall. The modified Kraft lignin imparted fire-retardancy and increased char residue to the wood at elevated temperature, as confirmed by limiting oxygen index, microscale combustion calorimetry, and thermogravimetric analysis. The modified wood exhibited superior resistance against mold and decay fungi attack under laboratory conditions. The modified wood had a similar modulus of elasticity to the unmodified wood, while experiencing a reduction in the modulus of rupture.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Lignin valorization, Phosphorylation, Fire-retardancy
National Category
Wood Science Organic Chemistry
Research subject
Wood Science and Engineering; Structural Engineering; Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-108336 (URN)10.1016/j.ijbiomac.2024.133734 (DOI)
Funder
Luleå University of TechnologySwedish Research Council Formas, 2021 -00818The Kempe Foundations
Available from: 2024-07-12 Created: 2024-07-12 Last updated: 2024-07-12
Scharf, A., Sandberg, D. & Jones, D. (2024). The influence of chemical content and pressing temperature on the properties of citric acid-bonded particleboards from softwood sawmilling residues. Wood Material Science & Engineering
Open this publication in new window or tab >>The influence of chemical content and pressing temperature on the properties of citric acid-bonded particleboards from softwood sawmilling residues
2024 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280Article in journal (Refereed) Epub ahead of print
Abstract [en]

Citric acid can be used as a bio-based binding agent in composites made from lignocellulosic material due to its crosslinking ability with hydroxyl groups via ester formation. Even though plenty of research has investigated diverse manufacturing conditions, with a focus on citric acid content and pressing temperature, an apparent knowledge gap persists regarding their effect on the properties of particleboards made from softwood sawdust. Furthermore, the optimal temperature for particleboards crafted from mostly non-wood lignocellulosic materials was found to be 180–200°C which is lower than that observed for softwood material in a prior study. This study aimed to systematically examine the effects of citric acid content and pressing temperature on particleboards derived from softwood sawdust. Results highlighted a positive correlation of both citric acid content and pressing temperature with mechanical and hygroscopic properties of the particleboards, the best results being achieved at 20 wt% citric acid and 220°C, exhibiting a thickness swelling of 9%, internal bonding strength of 0.77 MPa and a modulus of rupture of 4.3 MPa. This study served as a foundational framework for future investigations into the addition of other chemicals, offering a comprehensive understanding of their interactions with citric acid in particleboard manufacturing.

Place, publisher, year, edition, pages
Taylor & Francis, 2024
Keywords
Citric acid, natural adhesive, particleboard, sawdust
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-108226 (URN)10.1080/17480272.2024.2367608 (DOI)
Funder
Vinnova, 2022-00998Swedish Research Council Formas, 2022-00998Swedish Energy Agency, 2022-00998
Note

Full text license: CC BY-NC-ND 4.0; 

Available from: 2024-07-01 Created: 2024-07-01 Last updated: 2024-07-01
Sarvašová Kvietková, M., Dvořák, O., Kalábová, M., Šimůnková, K., Štěrbová, I., Pastierovič, F., . . . Jones, D. (2024). The influence of the type of coating on thermally modified wood and the resulting durability of the surface treatment on a facade. Journal of Building Engineering, 91, Article ID 109629.
Open this publication in new window or tab >>The influence of the type of coating on thermally modified wood and the resulting durability of the surface treatment on a facade
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2024 (English)In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 91, article id 109629Article in journal (Refereed) Published
Abstract [en]

Many architects choose wooden façades to clad modern buildings, and Thermowood® is a popular choice for such applications. This study focuses on methods to prolong the “fresh” appearance of Thermowood® façades, specifically Thermo-ash (Fraxinus excelsior L.), Thermo-spruce (Picea abies (L.) Karst.) and Thermo-pine (Pinus silvestris L.). The study involves exposing three groups to natural weathering: one reference untreated group, one group with a thin-layer alkyd coating, and another with a thick-layer acrylate coating. The results indicated that a thick-layer acrylate coating was the most suitable treatment for Thermowood® surfaces, as this coating retained a better appearance and demonstrated superior coating durability. Furthermore, cost-benefit analysis (CBA) suggested a thick-layer acrylate coating proved to be the most suitable and cost-effective choice, based on architects’ desires, to maintain a “fresh/original” appearance.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Wood-façade, Thermowood®, Exterior, Durability, Cost-benefit analysis (CBA)
National Category
Wood Science Building Technologies
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-105507 (URN)10.1016/j.jobe.2024.109629 (DOI)2-s2.0-85193581226 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-06-12 (hanlid)

Available from: 2024-05-17 Created: 2024-05-17 Last updated: 2024-06-12Bibliographically approved
Borko, D., Scharf, A., Lin, C.-F., Karlsson, O., Humar, M., Sandberg, D. & Jones, D. (2024). The potential of citric acid and glucose enhancing the reaction of wood with bicine and tricine. Wood Material Science & Engineering
Open this publication in new window or tab >>The potential of citric acid and glucose enhancing the reaction of wood with bicine and tricine
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2024 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280Article in journal (Refereed) Epub ahead of print
Abstract [en]

To improve the resistance of wood to biological decay the Maillard reaction between introduced amines and wood cell-wall polymers can be utilised. However, initial studies in wood modification showed almost complete leaching of bicine and tricine from treated wood and the loss of beneficial effects. The objective of this study was to assess whether possible reactions of bicine or tricine with wood could be further enhanced and reaction products stabilised through the addition of glucose and/or citric acid. Thus, Scots pine sapwood specimens were impregnated with tricine or bicine, with or without glucose and citric acid, and then heated to a temperature of 160°C. The dimensional stability, degree of chemical leaching and mechanical properties were assessed. Overall, it was concluded that neither the presence of glucose nor citric acid did appear to enhance the reactivity of tricine or bicine. Anti-swelling efficiency (ASE) of 50% was observed for combined treatments of bicine/tricine and citric acid but the leaching resistance originated mainly from citric acid and glucose, with no indication for the retention of bicine or tricine. The presence of citric acid led to a strongly reduced modulus of rupture. 

Place, publisher, year, edition, pages
Taylor & Francis, 2024
Keywords
Maillard reaction, thermal/chemical treatment, mechanical properties, wood modification
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-105914 (URN)10.1080/17480272.2024.2357632 (DOI)
Note

Full text: CC BY-NC-ND License

Available from: 2024-06-07 Created: 2024-06-07 Last updated: 2024-06-07
Lin, C.-F., Myronycheva, O., Karlsson, O., Jones, D. & Sandberg, D. (2023). A new wood-modification process based on grafted urethane groups: Durability of carbamated Scots pine (Pinus sylvestris L.) wood.. In: C. Crestini; H. Lange; M. Gigli; M. Sgarzi (Ed.), 21st ISWFPC Conference Proceedings: Vol. II Poster presentations. Paper presented at 21st International Symposium on Wood, Fiber and Pulping Chemistry (ISWFPC 2023), Venice, Italy, June 4–7, 2023 (pp. 78-81). Ca’ Foscari University of Venice, Department of Molecular Sciences and Nanosystems,, 2
Open this publication in new window or tab >>A new wood-modification process based on grafted urethane groups: Durability of carbamated Scots pine (Pinus sylvestris L.) wood.
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2023 (English)In: 21st ISWFPC Conference Proceedings: Vol. II Poster presentations / [ed] C. Crestini; H. Lange; M. Gigli; M. Sgarzi, Ca’ Foscari University of Venice, Department of Molecular Sciences and Nanosystems, , 2023, Vol. 2, p. 78-81Conference paper, Poster (with or without abstract) (Refereed)
Place, publisher, year, edition, pages
Ca’ Foscari University of Venice, Department of Molecular Sciences and Nanosystems,, 2023
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-103166 (URN)
Conference
21st International Symposium on Wood, Fiber and Pulping Chemistry (ISWFPC 2023), Venice, Italy, June 4–7, 2023
Projects
Advanced research supporting the forestry and wood-processing sector’s adaptation to global change and the 4th industrial revolutionBiobased fire protection of wood panel for exterior conditions by using phosphorylated lignin from wheat straw
Funder
Swedish Research Council Formas, 2021-00818
Note

Funder: OP RDE (CZ.02.1.01/0.0/0.0/16_019/0000803); CT WOOD; Swedish wood industry

ISBN for host publication: 9788831461580

Available from: 2023-12-01 Created: 2023-12-01 Last updated: 2023-12-21Bibliographically approved
Lin, C.-f., Myronycheva, O., Karlsson, O., Mantanis, G. I., Jones, D. & Sandberg, D. (2023). A new wood-modification process based on in situ grafting of urethane groups: biological resistance and dimensional stability of carbamylated Scots pine wood. Wood Material Science & Engineering, 18(3), 1160-1162
Open this publication in new window or tab >>A new wood-modification process based on in situ grafting of urethane groups: biological resistance and dimensional stability of carbamylated Scots pine wood
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2023 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, no 3, p. 1160-1162Article in journal (Refereed) Published
Abstract [en]

Chemical modification of wood typically requires the impregnation of wood with reactive compounds capable of undergoing covalent bonding to functional groups present in the cell wall. Creating such reactive agents in situ, with the use of low-priced chemicals, would prove more attractive for commercial applications. In this study, Scots pine (Pinus sylvestris L.) sapwood was impregnated with an aqueous solution of urea (30%), dried at 40°C for 24 h, and subsequently heat treated in an oven at 150°C for 24 h to produce the reactive isocyanic acid. By using accelerated fungal tests under laboratory conditions, provisional tests demonstrated a high biological resistance against selected moulds and rots. Migration of urea into the wood structure and grafting to its polymers during subsequent heat treatment, led to a bulked cell wall and enhanced resistance to water swelling, even after cycling water treatments. The bending strength (MOR) of modified pine wood was reduced by the treatment applied, while its modulus of elasticity (MOE) remained unchanged.

Place, publisher, year, edition, pages
Taylor & Francis, 2023
Keywords
Biological durability, distortion, sawn timber, thermal modified timber, Wood protection
National Category
Wood Science Composite Science and Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-97268 (URN)10.1080/17480272.2023.2207541 (DOI)000991623500001 ()2-s2.0-85159810327 (Scopus ID)
Projects
Biobased fire protection of wood panel for exterior conditions by using phosphorylated lignin from wheat straw
Funder
Luleå University of Technology, CT-WOODSwedish Research CouncilSwedish Research Council Formas, 2021-00818
Note

Validerad;2023;Nivå 2;2023-06-30 (joosat);

Licens fulltext: CC BY-NC-ND License

Available from: 2023-05-22 Created: 2023-05-22 Last updated: 2023-06-30Bibliographically approved
Lin, C.-F., Scharf, A., Karlsson, O., Sandberg, D. & Jones, D. (2023). Biobased adesive derived from citric acid and sorbitrol for wood-composite manufacture.. In: Morwenna Spear, Simon Curling, Athanasious Dimitriou, Rob Elias, Ceri Loxton (Ed.), Proceedings of the International Panel Production Symposium 2023: . Paper presented at International Panel Production Symposium 2023 (IPPS23), Llandudno, Wales, United Kingdom, October 3-4, 2023 (pp. 183-187). The BioComposite Centre, Bangor University, UK
Open this publication in new window or tab >>Biobased adesive derived from citric acid and sorbitrol for wood-composite manufacture.
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2023 (English)In: Proceedings of the International Panel Production Symposium 2023 / [ed] Morwenna Spear, Simon Curling, Athanasious Dimitriou, Rob Elias, Ceri Loxton, The BioComposite Centre, Bangor University, UK , 2023, p. 183-187Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
The BioComposite Centre, Bangor University, UK, 2023
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-103637 (URN)
Conference
International Panel Production Symposium 2023 (IPPS23), Llandudno, Wales, United Kingdom, October 3-4, 2023
Funder
Swedish Research Council Formas, 2021-00818
Note

Funder: OP RDE (CZ.02.1.01/0.0/0.0/16_019/0000803), CT WOOD

ISBN for host publication: 978-1-84220-200-5

Available from: 2024-01-14 Created: 2024-01-14 Last updated: 2024-03-23Bibliographically approved
Kim, I., Ross, L., Alfredsson, G., Karlsson, O., Jones, D., Mantanis, G. I. & Sandberg, D. (2023). Durability of wood modified with maleic anhydride and sodium hypophosphite.. In: Larnøy, E (Ed.), 19th Annual Meeting of the Northern European Network for Wood Science and Engineering (WSE 2023): 19th Annual Meeting of the Northern European Network for Wood Science and Engineering (WSE 2023), Ås and Oslo, Norway, October 10-12, 2023. Paper presented at 19th Annual Meeting of the Northern European Network for Wood Science and Engineering (WSE 2023), Ås and Oslo, Norway, October 10-12, 2023 (pp. 22-24). Ås: NIBIO
Open this publication in new window or tab >>Durability of wood modified with maleic anhydride and sodium hypophosphite.
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2023 (English)In: 19th Annual Meeting of the Northern European Network for Wood Science and Engineering (WSE 2023): 19th Annual Meeting of the Northern European Network for Wood Science and Engineering (WSE 2023), Ås and Oslo, Norway, October 10-12, 2023 / [ed] Larnøy, E, Ås: NIBIO , 2023, p. 22-24Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Ås: NIBIO, 2023
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-103449 (URN)
Conference
19th Annual Meeting of the Northern European Network for Wood Science and Engineering (WSE 2023), Ås and Oslo, Norway, October 10-12, 2023
Available from: 2024-01-02 Created: 2024-01-02 Last updated: 2024-01-12Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5565-6651

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