@article{stolze_determination_2023,
	title = {Determination of the {Bonding} {Strength} of {Finger} {Joints} {Using} a {New} {Test} {Specimen} {Geometry}},
	volume = {0},
	abstract = {In this study, a specimen geometry for testing finger joints was developed using finite element simulation and proofed by experimental testing. Six different wood species and three adhesives were used for finger-jointing specimens. With the test specimen geometry, the bonding strength of the finger joints was determined without the usual self-locking of the joint. Under load, the test specimen geometry introduces maximum stress at the beginning of the bond line (adhesive zone). However, the test specimen geometry does not generate a symmetric stress state. The main difficulty here is the flank angle of the finger joint geometry. The wood species and adhesives significantly influenced the performance of the finger joints.},
	language = {en},
	number = {0},
	journal = {Process},
	author = {Stolze, Hannes and Gurnik, Michael and Kegel, Sebastian and Bollmus, Susanne and Militz, Holger},
	year = {2023},
	file = {Stolze et al. - 2023 - Determination of the Bonding Strength of Finger Jo.pdf:C\:\\Users\\maicher\\Zotero\\storage\\SRKKQCZA\\Stolze et al. - 2023 - Determination of the Bonding Strength of Finger Jo.pdf:application/pdf},
}

In this study, a specimen geometry for testing finger joints was developed using finite element simulation and proofed by experimental testing. Six different wood species and three adhesives were used for finger-jointing specimens. With the test specimen geometry, the bonding strength of the finger joints was determined without the usual self-locking of the joint. Under load, the test specimen geometry introduces maximum stress at the beginning of the bond line (adhesive zone). However, the test specimen geometry does not generate a symmetric stress state. The main difficulty here is the flank angle of the finger joint geometry. The wood species and adhesives significantly influenced the performance of the finger joints.

@article{alade_improved_2022,
	title = {Improved adhesive-bond performance in copper azole and disodium octaborate tetrahydrate-treated {Eucalyptus} grandis laminates},
	volume = {0},
	issn = {2042-6445},
	url = {https://doi.org/10.1080/20426445.2022.2058277},
	doi = {10.1080/20426445.2022.2058277},
	abstract = {The prospect of manufacturing durable structural laminated wood with copper and boron-based preservative-impregnated Eucalyptus grandis wood was previously investigated but revealed adhesive-bond performance below standard requirements. In this study, bonding process factors, viz. mechanical pretreatment (surface planing) and bonding pressure in conjunction with wood preservative and adhesive compatibility for improved bond performance in preservative-treated E. grandis laminates were investigated. The results obtained showed significant and satisfactory improvement in shear strength and delamination resistance of E. grandis laminates based on EN 14080:2013 [Timber structures — Glued laminated timber and glued solid timber — Requirements, BSI Stand. Publ. (2014) 1–110] requirements. The suitability of polyurethane, melamine-urea-formaldehyde, and phenol-resorcinol-formaldehyde adhesives for bonding copper azole (CA) and disodium octaborate tetrahydrate (DOT)-impregnated E. grandis wood was established. Satisfactory pathways, including greener process routes for manufacturing CA and DOT-impregnated E. grandis laminates for structural applications in tropical and subtropical climes were achieved. The established processes could be readily adopted industrially to enhance the global implementation of solid wood composites and promote hardwood bonding.},
	number = {0},
	urldate = {2022-04-11},
	journal = {International Wood Products Journal},
	author = {Alade, Adefemi Adebisi and Wessels, Coenraad Brand and Stolze, Hannes and Militz, Holger},
	month = apr,
	year = {2022},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/20426445.2022.2058277},
	keywords = {adhesion, E. grandis, hardwood bonding, bond durability, bond quality, solid wood composites, water-borne preservatives, Wood preservation},
	pages = {1--9},
}

The prospect of manufacturing durable structural laminated wood with copper and boron-based preservative-impregnated Eucalyptus grandis wood was previously investigated but revealed adhesive-bond performance below standard requirements. In this study, bonding process factors, viz. mechanical pretreatment (surface planing) and bonding pressure in conjunction with wood preservative and adhesive compatibility for improved bond performance in preservative-treated E. grandis laminates were investigated. The results obtained showed significant and satisfactory improvement in shear strength and delamination resistance of E. grandis laminates based on EN 14080:2013 [Timber structures — Glued laminated timber and glued solid timber — Requirements, BSI Stand. Publ. (2014) 1–110] requirements. The suitability of polyurethane, melamine-urea-formaldehyde, and phenol-resorcinol-formaldehyde adhesives for bonding copper azole (CA) and disodium octaborate tetrahydrate (DOT)-impregnated E. grandis wood was established. Satisfactory pathways, including greener process routes for manufacturing CA and DOT-impregnated E. grandis laminates for structural applications in tropical and subtropical climes were achieved. The established processes could be readily adopted industrially to enhance the global implementation of solid wood composites and promote hardwood bonding.

@article{stolze_non-destructive_2022,
	title = {Non-{Destructive} {Evaluation} of the {Cutting} {Surface} of {Hardwood} {Finger} {Joints}},
	volume = {22},
	copyright = {http://creativecommons.org/licenses/by/3.0/},
	issn = {1424-8220},
	url = {https://www.mdpi.com/1424-8220/22/10/3855},
	doi = {10.3390/s22103855},
	abstract = {In this study, the surface parameters wettability, roughness, and adhesive penetration, which are important for wood bonding, were investigated and evaluated utilizing non-destructive methods after different mechanical processing. For this purpose, beech and birch finger joints were prepared with different cutting combinations (three cutters with different sharpness levels and two feed rates) in an industrial process. Effects and interactions on the surface parameters resulting from the different cutting combinations were evaluated using three Full Factorial Designs. The various cutting parameters had a predominantly significant influence on the surface parameters. The effects and identified interactions highlight the complexity of the cutting surface and the importance of wood bonding. In this respect, a new finding is that with sharper cutters, higher contact angles of the adhesives occur. The methods (contact angle measurement, laser scanning microscopy, and brightfield microscopy) used were well suited to make effects visible and quantifiable, which can be of interest for the quality control of the wood processing industry. The results can help to better understand and evaluate the design of wood surfaces via machining and the bonding of hardwoods. Possibly the results can contribute to further standardizing the production of load-bearing hardwood finger joints and making them more efficient.},
	language = {en},
	number = {10},
	urldate = {2022-05-19},
	journal = {Sensors},
	author = {Stolze, Hannes and Gurnik, Michael and Koddenberg, Tim and Kröger, Jonas and Köhler, Robert and Viöl, Wolfgang and Militz, Holger},
	month = jan,
	year = {2022},
	note = {Number: 10
Publisher: Multidisciplinary Digital Publishing Institute},
	keywords = {wettability, hardwood, roughness, non-destructive evaluation, adhesive penetration, cutting surface, finger-jointing, wood characterization},
	pages = {3855},
	file = {Full Text PDF:C\:\\Users\\maicher\\Zotero\\storage\\H4WWF56G\\Stolze et al. - 2022 - Non-Destructive Evaluation of the Cutting Surface .pdf:application/pdf;sensors-22-03855.pdf:C\:\\Users\\maicher\\Zotero\\storage\\J6S2BUM3\\sensors-22-03855.pdf:application/pdf},
}

In this study, the surface parameters wettability, roughness, and adhesive penetration, which are important for wood bonding, were investigated and evaluated utilizing non-destructive methods after different mechanical processing. For this purpose, beech and birch finger joints were prepared with different cutting combinations (three cutters with different sharpness levels and two feed rates) in an industrial process. Effects and interactions on the surface parameters resulting from the different cutting combinations were evaluated using three Full Factorial Designs. The various cutting parameters had a predominantly significant influence on the surface parameters. The effects and identified interactions highlight the complexity of the cutting surface and the importance of wood bonding. In this respect, a new finding is that with sharper cutters, higher contact angles of the adhesives occur. The methods (contact angle measurement, laser scanning microscopy, and brightfield microscopy) used were well suited to make effects visible and quantifiable, which can be of interest for the quality control of the wood processing industry. The results can help to better understand and evaluate the design of wood surfaces via machining and the bonding of hardwoods. Possibly the results can contribute to further standardizing the production of load-bearing hardwood finger joints and making them more efficient.

@article{alade_characterizing_2022,
	title = {Characterizing surface adhesion-related chemical properties of copper azole and disodium octaborate tetrahydrate-impregnated {Eucalyptus} grandis wood},
	volume = {0},
	issn = {0169-4243},
	url = {https://doi.org/10.1080/01694243.2022.2125208},
	doi = {10.1080/01694243.2022.2125208},
	abstract = {In-depth knowledge of the interaction effects of wood and preservative chemicals on surface adhesion characteristics is crucial for developing pathways to improve the adhesive bonding of treated woods. Therefore, this study investigated fundamental changes in the surface adhesion-related chemical characteristics of E. grandis sapwood and heartwood impregnated with copper azole (CA) and disodium octaborate tetrahydrate (DOT) wood preservatives. The characterization techniques employed include scanning electron microscopy integrated with energy-dispersive X-ray spectroscopy and Fourier transformed infrared spectroscopy. The results obtained revealed that CA and DOT impregnations significantly altered the acidity and reduced the polar functional groups on E. grandis sapwood and heartwood surfaces. The effect was more pronounced with DOT impregnation and on the sapwood. The observed modifications signal that the CA- and DOT-treated wood adhesion could be inhibited due to reduced opportunity for chemical bonding between the treated wood and adhesive molecules. Furthermore, there is a high likelihood of the hindrance of adhesion via mechanical interlocking as a result of chemical deposits, particularly in copper azole-impregnated wood. Considering the observed changes in the surface chemical characteristics of the CA and DOT-impregnated E. grandis, adhesive compatibility and adapting bonding parameters, such as assembly time and bonding pressure could be vital in ensuring adequate bonding of the treated E. grandis wood.},
	number = {0},
	urldate = {2022-09-26},
	journal = {Journal of Adhesion Science and Technology},
	author = {Alade, Adefemi Adebisi and Naghizadeh, Zahra and Wessels, Coenraad Brand and Stolze, Hannes and Militz, Holger},
	month = sep,
	year = {2022},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/01694243.2022.2125208},
	keywords = {adhesion, FTIR, Eucalyptus grandis, Wood preservation, SEM-EDS, surface modification},
	pages = {1--24},
}

In-depth knowledge of the interaction effects of wood and preservative chemicals on surface adhesion characteristics is crucial for developing pathways to improve the adhesive bonding of treated woods. Therefore, this study investigated fundamental changes in the surface adhesion-related chemical characteristics of E. grandis sapwood and heartwood impregnated with copper azole (CA) and disodium octaborate tetrahydrate (DOT) wood preservatives. The characterization techniques employed include scanning electron microscopy integrated with energy-dispersive X-ray spectroscopy and Fourier transformed infrared spectroscopy. The results obtained revealed that CA and DOT impregnations significantly altered the acidity and reduced the polar functional groups on E. grandis sapwood and heartwood surfaces. The effect was more pronounced with DOT impregnation and on the sapwood. The observed modifications signal that the CA- and DOT-treated wood adhesion could be inhibited due to reduced opportunity for chemical bonding between the treated wood and adhesive molecules. Furthermore, there is a high likelihood of the hindrance of adhesion via mechanical interlocking as a result of chemical deposits, particularly in copper azole-impregnated wood. Considering the observed changes in the surface chemical characteristics of the CA and DOT-impregnated E. grandis, adhesive compatibility and adapting bonding parameters, such as assembly time and bonding pressure could be vital in ensuring adequate bonding of the treated E. grandis wood.

@inproceedings{stolze_self-locking_2022,
	address = {Sopron, Hungary},
	title = {Self-locking of finger joints - {Influence} of density and moisture content},
	isbn = {978-963-334-446-0},
	language = {EN},
	booktitle = {Hardwood {Conference} {Proceedings}},
	publisher = {University of Sopron Press},
	author = {Stolze, Hannes and Trautwein, Jan-Frederik and Mayer, Aaron Kilan and Theis, Viorica and Bollmus, Susanne and Militz, Holger},
	year = {2022},
	pages = {317--323},
}

@article{stolze_monitoring_2021,
	title = {Monitoring of {Beech} {Glued} {Laminated} {Timber} and {Delamination} {Resistance} of {Beech} {Finger}-{Joints} in {Varying} {Ambient} {Climates}},
	volume = {12},
	copyright = {http://creativecommons.org/licenses/by/3.0/},
	url = {https://www.mdpi.com/1999-4907/12/12/1672},
	doi = {10.3390/f12121672},
	abstract = {In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.},
	language = {en},
	number = {12},
	urldate = {2022-01-17},
	journal = {Forests},
	author = {Stolze, Hannes and Schuh, Mathias and Kegel, Sebastian and Fürkötter-Ziegenbein, Connor and Brischke, Christian and Militz, Holger},
	month = dec,
	year = {2021},
	note = {Number: 12
Publisher: Multidisciplinary Digital Publishing Institute},
	keywords = {adhesives, delamination, beech glulam, finger-joint bonding, monitoring experiment},
	pages = {1672},
	file = {Full Text PDF:C\:\\Users\\maicher\\Zotero\\storage\\PTR39CZS\\Stolze et al. - 2021 - Monitoring of Beech Glued Laminated Timber and Del.pdf:application/pdf;Snapshot:C\:\\Users\\maicher\\Zotero\\storage\\8BNTBW9V\\1672.html:text/html},
}

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

@article{alade_compatibility_2021,
	title = {Compatibility of preservative with adhesive in {Eucalyptus} grandis laminates},
	volume = {13},
	issn = {2042-6445},
	url = {https://doi.org/10.1080/20426445.2021.2018101},
	doi = {10.1080/20426445.2021.2018101},
	abstract = {The fundamental factors responsible for the complexities in adhesive bonding of preservative-treated wood are predominantly wood species, preservative composition, and adhesive system. It is post-effect of these factors that process variables such as assembly times and bonding pressure exert secondary influences on adhesive-bond development in preservative-treated laminates. Hence, this study investigated the effect of copper azole (CA) and disodium octaborate tetrahydrate (DOT) impregnations on E. grandis heartwood (HW) and sapwood (SW) bonding with melamine–urea–formaldehyde and polyurethane adhesives. Based on the adhesives and bonding conditions investigated, the CA and DOT-treated E. grandis laminates do not satisfy at least one of the shear strength and delamination requirements according to EN 14080:2013. Contrary to delamination, shear strength was significantly affected by the HW–SW difference. This study established the basis for further considerations on adapting bonding conditions for improved adhesive-bond performance in CA and DOT-treated E. grandis laminates towards manufacturing durable hardwood composite for tropical and subtropical environments.},
	number = {1},
	urldate = {2021-12-23},
	journal = {International Wood Products Journal},
	author = {Alade, Adefemi Adebisi and Naghizadeh, Zahra and Wessels, Coenraad Brand and Stolze, Hannes and Militz, Holger},
	month = dec,
	year = {2021},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/20426445.2021.2018101},
	keywords = {adhesion, wood composites, E. grandis, hardwood bonding, Wood durability treatment},
	pages = {57--69},
	file = {Alade et al. - 2021 - Compatibility of preservative with adhesive in Euc.pdf:C\:\\Users\\maicher\\Zotero\\storage\\XFVIY46R\\Alade et al. - 2021 - Compatibility of preservative with adhesive in Euc.pdf:application/pdf},
}

The fundamental factors responsible for the complexities in adhesive bonding of preservative-treated wood are predominantly wood species, preservative composition, and adhesive system. It is post-effect of these factors that process variables such as assembly times and bonding pressure exert secondary influences on adhesive-bond development in preservative-treated laminates. Hence, this study investigated the effect of copper azole (CA) and disodium octaborate tetrahydrate (DOT) impregnations on E. grandis heartwood (HW) and sapwood (SW) bonding with melamine–urea–formaldehyde and polyurethane adhesives. Based on the adhesives and bonding conditions investigated, the CA and DOT-treated E. grandis laminates do not satisfy at least one of the shear strength and delamination requirements according to EN 14080:2013. Contrary to delamination, shear strength was significantly affected by the HW–SW difference. This study established the basis for further considerations on adapting bonding conditions for improved adhesive-bond performance in CA and DOT-treated E. grandis laminates towards manufacturing durable hardwood composite for tropical and subtropical environments.

@techreport{stolze_spezifische_2016,
	address = {Göttingen},
	type = {Bachelorarbeit},
	title = {Spezifische {Sortierung} von {Prüfkörpern} aus {Buchen}- und {Kiefernsplintholz} nach {Kriterien} zur {Prüfung} von elasto-mechanischen {Eigenschaften} - {Specific} sorting of beech and pine sapwood according to the criteria for testing the elasto-mechanical characteristics},
	language = {deutsch},
	institution = {Georg-August-Universität Göttingen, Fakultät für Forstwissenschaften und Waldökologie, Abteilung Holzbiologie und Holzprodukte},
	author = {Stolze, Hannes},
	year = {2016},
	note = {1. Prüfer: Dr. Antje Gellerich
2. Prüfer: Prof. Dr. Holger Militz},
}