Surface modification of wood using friction

Rautkari, Lauri; Properzi, M.; Pichelin, Frédéric; Hughes, Mark

doi:10.1007/s00226-008-0227-0

Cited by 56 publications

(59 citation statements)

References 12 publications

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“…To create a high-density wood surface, an adequate volume of wood beneath the surface must be softened (Rautkari et al 2009). Due to the low heat conductivity of wood, local moistening improves the heat transfer into the wood; this helps to soften the moistened region of the wood and improve its compressibility, while the rest of the wood continues to resist compressive deformation (Wang & Cooper 2005, Lama-iForest 10: 895-908 903…”

Section: Surface Densificationmentioning

confidence: 99%

“…Pizzi et al (2005) used a friction-welding machine to densify two pieces of wood at the same time, separated by a layer of oil to avoid bonding. A similar approach was adopted by Rautkari et al (2009), only using one piece of sawn timber at a time to vibrate on the other, fixed heated steel plate. The vast majority of further studies used a rather simple surface densification process in a hot press.…”

Section: Surface Densificationmentioning

confidence: 99%

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Wood modification technologies - a review

Sandberg¹,

Kutnar²,

Mantanis³

2017

iForest

350

197

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The market for new durable products of modified wood has increased substantially during the last few years, especially in Europe. This increased interest depends partly on the restricted use of toxic preservatives due to increased environmental concern, as well as the need for reduced maintenance for wood products that are mainly for exterior use. Furthermore, as sustainability becomes a greater concern, the environmental impact of construction and interior materials should be included in planning by considering the entire life cycle and embodied energy of the materials used. As a result, wood modification has been implemented to improve the intrinsic properties of wood, widen the range of sawn timber applications, and acquire the form and functionality desired by engineers, without bringing environmental friendliness into question. The different wood modification processes are at various stages of development, and the challenges that must be overcome to expand to industrial applications differ amongst them. In this paper, three groups of wood modification processes are discussed and exemplified with modified wood products that have been newly introduced to the market: (i) chemical processing (acetylation, furfurylation, resin impregnation etc.); (ii) thermo-hydro processing (thermal treatment); and (iii) thermo-hydro-mechanical processing (surface densification). Building on these examples, the paper will discuss the environmental impact assessment of modification processes and further development needs.

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Section: Surface Densificationmentioning

confidence: 99%

Section: Surface Densificationmentioning

confidence: 99%

Wood modification technologies - a review

Sandberg¹,

Kutnar²,

Mantanis³

2017

iForest

350

197

View full text Add to dashboard Cite

show abstract

“…Wood can be densified by applying a thermo-mechanical (TM) or thermo-hydromechanical (THM) treatment, or viscoelastic thermal compression (VTC) (Kutnar et al 2009), using the linear vibration friction technology (LVFT) (Rautkari et al 2009). Wood can be densified in its whole volume (Ülker et al 2012; İmirzi et al 2014) or on the surface (Belt et al 2013;Laine et al 2013b;Rautkari et al 2013;Kariz et al 2017).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Process Parameters on the Density Profile and Hardness of Surface-densified Birch Wood (Betula pendula Roth)

Laskowska¹

2017

BioResources

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This study examined the influence of temperature and time of treatment on the density profile and hardness of surface-densified birch wood (Betula pendula Roth). An analysis of the wood density profile was conducted on the basis of the following parameters: thickness, maximum density, and the distance between the maximum density and the wood surface. Depending on the technological parameters' values, the degree of compression of the wood was 13% to 22%, and its maximum density was 808 kg/m 3 to 994 kg/m 3 . As a result of the modification of birch wood at a temperature of 100 °C and 125 °C, the wood was densified on one side. As the temperature of the thermo-mechanical treatment was raised from 150 °C to 200 °C, the wood became densified on both sides. The maximum density of the wood increased gradually with the increase of the temperature of the press plate. The longer the time of thermomechanical treatment, the more distant the maximum density area was from the wood surface. Depending on the temperature and the time of treatment, the hardness of the surface-densified birch wood was 1.4 to 2.2 times greater than the hardness of non-densified wood.

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“…Wood densification is one of the most common methods for the modification of mechanical properties. It works with the principle that these properties are directly dependent on changes in wood density and has been confirmed by a number of authors dealing with either surface densification (Lamason and Gong 2007;Gong et al 2010;Rautkari et al 2009Rautkari et al , 2011Laine et al 2013Laine et al , 2014 One of the most important properties for dynamic loading is the impact bending strength (IBS). It is the ability to resist immediate maximal loading, which means absorbing and dissipating energy through impact bending (Požgaj et al 1997;Bal and Bektaş 2012).…”

Section: Peer-reviewed Articlementioning

confidence: 89%

Impact Bending Strength and Brinell Hardness of Densified Hardwoods

et al. 2016

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The objective of this research was to determine the influence of wood species (Fagus sylvatica L. and Populus tremula L.), thickness (4, 6, 10, 18 mm), and degree of densification (0%, 10%, and 20%) on the impact bending strength (IBS) and Brinell hardness (BH) in the radial direction. Three-factor analysis of variance confirmed that the difference in IBS was significantly related to the wood species and wood thickness. Wood densification did not have a significant effect on IBS. In addition, beech wood exhibited higher IBS values than aspen wood. The IBS values increased proportionally with increasing thickness. All factors affecting Brinell hardness were statistically significant, although thickness had the smallest influence overall. The Brinell hardness values were substantially higher in beech wood than aspen wood, and in some cases were more than three times greater. On the other hand, densification exhibited a more positive effect on increasing Brinell hardness for aspen wood than beech wood. Keywords INTRODUCTIONWood is generally recognized as one of the most important renewable resources and among the most versatile and widely used materials. On the other hand, much of its uses depend on the species, because while some tree species are used almost everywhere, others have limited application. The application of wood is directly influenced by its physical and mechanical properties.European beech (Fagus sylvatica L.) is a native wood that grows throughout Europe (Eilmann et al. 2014). Beech is one of the most commonly used hardwoods in Europe (Pöhler et al. 2006;Gryc et al. 2008) for furniture, floors, toys, veneer products, and musical instruments, as well as for the production of stairs, cladding, and glued loadbearing elements in construction (Ohnesorge et al. 2010;Aicher and Ohnesorge 2011;Guntekin et al. 2014). On the other hand, European aspen (Populus tremula L.) wood has only occasional uses. In the woodworking industry, aspen is used in the manufacturing of wood-based materials (plywoods, particle, and flakeboards), in the furniture industry for underlying veneers or surface veneers for backside or nonvisible surfaces (Kärki 2001), and for the facings of ceilings or saunas where high strength or hardness are not necessary (Möttönen et al. 2015). In the past, aspen was primarily used for the production of matches; currently, it has application in the production of biomass fuel, paper, and pulp (Kärki 2001; Heräjärvi and Junkkonen 2006). PEER-REVIEWED ARTICLEbioresources.com Gašparík et al. (2016). "IBS and BH of hardwoods," BioResources 11(4), 8638-8652. 8639The uses for these wood species are closely related to their mechanical properties. Mechanical properties differ by wood type because they depend not only on the type of loading (tension, pressure, and bending), but also on the loading's character (static or dynamic loading) (Bal and Bektaş 2012). In general, wood can resist static loading to a greater extent than dynamic loading. Static loading is characterized by an increasing loading forc...

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Surface modification of wood using friction

Cited by 56 publications

References 12 publications

Wood modification technologies - a review

Wood modification technologies - a review

The Influence of Process Parameters on the Density Profile and Hardness of Surface-densified Birch Wood (Betula pendula Roth)

Impact Bending Strength and Brinell Hardness of Densified Hardwoods

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