Interaction between Thermal Modification Temperature of Spruce Wood and the Cutting and Fracture Parameters

Hlásková, Luďka; Procházka, Jiří; Novak, V. R.; Čermák, Petr; Kopecký, Zdeněk

doi:10.3390/ma14206218

Cited by 8 publications

(4 citation statements)

References 65 publications

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“…128 Due to the degradation of cell wall polymers and the formation of cross-links, thermally modified wood is a stiff but brittle material, with reduced water uptake and swelling properties. 129 Compared to unmodified wood, thermally modified wood is darker in color and has improved dimensional stability and microbial resistance. An advantage of this technique is that it enhances the durability, so that wood products with higher durability can be obtained out of nondurable species and sapwood (durability classes according to European Standard EN 350-2).…”

Section: Thermal Wood Modificationmentioning

confidence: 99%

“…Thermal modification results in weight loss, usually accompanied by macroscopic dimensional changes, to an extent which depends from the wood species and whether dry or wet conditions are employed . Due to the degradation of cell wall polymers and the formation of cross-links, thermally modified wood is a stiff but brittle material, with reduced water uptake and swelling properties . Compared to unmodified wood, thermally modified wood is darker in color and has improved dimensional stability and microbial resistance.…”

Section: Conventional Approaches To Reduce Wood Diversity In Manufact...mentioning

confidence: 99%

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Sustainability in Wood Products: A New Perspective for Handling Natural Diversity

2022

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Wood is a renewable resource with excellent qualities and the potential to become a key element of a future bioeconomy. The increasing environmental awareness and drive to achieve sustainability is leading to a resurgence of research on wood materials. Nevertheless, the global climate changes and associated consequences will soon challenge the wood-value chains in several regions (e.g., central Europe). To cope with these challenges, it is necessary to rethink the current practice of wood sourcing and transformation. The goal of this review is to address the intrinsic natural diversity of wood, from its origin to its technological consequences for the present and future manufacturing of wood products. So far, industrial processes have been optimized to repress the variability of wood properties, enabling more efficient processing and production of reliable products. However, the need to preserve biodiversity and the impact of climate change on forests call for new wood processing techniques and green chemistry protocols for wood modification as enabling factors necessary for managing a more diverse wood provision in the future. This article discusses the past developments that have resulted in the current wood value chains and provides a perspective about how natural variability could be turned into an asset for making truly sustainable wood products. After briefly introducing the chemical and structural complexity of wood, the methods conventionally adopted for industrial homogenization and modification of wood are discussed in relation to their evolution toward increased sustainability. Finally, a perspective is given on technological potentials of machine learning techniques and of novel functional wood materials. Here the main message is that through a combination of sustainable forestry, adherence to green chemistry principles and adapted processes based on machine learning, the wood industry could not only overcome current challenges but also thrive in the near future despite the awaiting challenges.

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Section: Thermal Wood Modificationmentioning

confidence: 99%

Section: Conventional Approaches To Reduce Wood Diversity In Manufact...mentioning

confidence: 99%

Sustainability in Wood Products: A New Perspective for Handling Natural Diversity

2022

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“…Over the years, to improve of technological properties of LVL as a construction material, reinforcement of LVL, wood and adhesive type and methods have been carried out by many researchers [22][23][24][25][26][27][28][29][30][31][32][33] . When previous studies are analyzed, many of the researchers have been focused effect of reinforcement material on tension of glulam or timber in bending, modulus of rupture (MOR), and modulus of elasticity (MOE), however reinforcing LVL has not been commonly reported.…”

Section: Introductionmentioning

confidence: 99%

Influence of carbon fibre layers on the strength of thermally modified laminated veneer lumber

Perçin

Ülker

2023

Polímeros

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Thermally modification of wood is an environment-friendly alternative method for improving several properties of wood without the use of chemicals. The compressive strength (CS) parallel to the grain of reinforced laminated veneer lumber (LVL) manufactured from heat treated beech (Fagus orientalis) veneers and carbon fibre was determined. Thermally modification was performed at 140°C, 160°C, 180°C, and 200 °C according to thermal treatment process. Carbon fibre were added as a reinforcement layer between wood veneers bonded with phenol-formaldehyde (PF), polyvinyl acetate (PVAc) polyurethane adhesives (PU) to improve properties of LVL. Results showed that reinforcing LVL panels with carbon fibre increased both density and CS. The PF adhesive showed better results for reinforced LVL panels with carbon fibre. The anatomical structure and density of the wood material significantly affect its mechanical properties, including compressive strength parallel to the grains. Wood density had a strong significant linear relationship with CS.

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“…An important factor determining the course of the modification process and consequently the properties of wood is the temperature [9,10]. Environmental is also important factor.…”

Section: Introductionmentioning

confidence: 99%

Influence of Thermal Modification in Nitrogen Atmosphere on Physical and Technological Properties of European Wood Species with Different Structural Features

et al. 2022

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The wood of five European species: black poplar (Populus nigra L.), European beech (Fagus sylvatica L.), European ash (Fraxinus excelsior L.), European oak (Quercus robur L.), and Scots pine (Pinus sylvestris L.) was subjected to thermal modification in nitrogen atmosphere at 190 °C during 6 h. Native and modified wood was varnished and oiled in industrial conditions. Thermally modified (TM) wood was characterized by a greater absorption of varnish and oil when applying the first layer to the surface, which finally resulted in higher application values compared to native wood. In particular, after varnishing, there was a significant increase in gloss and radical change of colour. Regardless of the wood species, finishing process (varnishing, oiling), the ΔE values were close to or higher than 6, which proves high colour changes. Modified poplar, ash, and oak after varnishing had a different colour (ΔE higher than 12). The surface colour changes as a result of UV photoaging was individual, depending on the wood species and the method of finishing. In the case of the thickness of varnish coatings, the wood structure was important, i.e., on ring-porous hardwood and softwood they were thicker. In the case of wood species with a lower density, i.e., black poplar and pine, the thermal modification in nitrogen atmosphere process did not reduce the resistance of the varnish coat, and in the case of species with a higher density (oak, ash, beech) it decreased by one level. Thermal modification reduced the Brinell hardness of wood with wide rays (oak and beech) by 11%. The applied process of surface finishing by double varnishing or oiling did not significantly change the hardness of tested wood.

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Interaction between Thermal Modification Temperature of Spruce Wood and the Cutting and Fracture Parameters

Cited by 8 publications

References 65 publications

Sustainability in Wood Products: A New Perspective for Handling Natural Diversity

Sustainability in Wood Products: A New Perspective for Handling Natural Diversity

Influence of carbon fibre layers on the strength of thermally modified laminated veneer lumber

Influence of Thermal Modification in Nitrogen Atmosphere on Physical and Technological Properties of European Wood Species with Different Structural Features

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