Use of computed tomography to determine penetration paths and the distribution of melamine resin in thermally-modified beech veneers after plasma treatment

Wascher, Richard; Bittner, Florian; Avramidis, Georg; Bellmann, M.P.; Endres, Hans‐Josef; Militz, Holger; Viöl, Wolfgang

doi:10.1016/j.compositesa.2020.105821

Cited by 11 publications

(5 citation statements)

References 28 publications

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“…In other applications, like the impregnation of veneers, permeability ceases to be a limiting factor as the dimensions through which fluid is required to flow have been radically reduced. This led to the adoption of plywood-based systems by Millett et al (1943) in Compreg and to more recent advances in this re-emerging field (Fleckenstein et al 2018;Bliem et al 2020;Wascher et al 2020). Aspects other than the permeability and availability of timber are rarely considered in the choice of wood species, and the literature lacks a comparative study that investigates how wood species with different chemical compositions and cell structures behave in the same treatment.…”

Section: Introductionmentioning

confidence: 99%

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Kupfernagel

Spear

Pitman³

et al. 2022

Eur. J. Wood Prod.

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Wood modification is an excellent way to improve material properties, prolong service life, and pave the way for new applications for timber in the built environment. The aim of this study is to establish the influence of wood species in the modification process with phenol urea formaldehyde resin. Seven hardwoods and four softwoods were compared in an identical treatment. Since the wood species is the main variable, the study provides a clear insight as to its influence on modification—something not previously investigated. Small wood blocks of all eleven species were impregnated with low-molecular weight phenol urea formaldehyde resin and were subsequently heat-cured at 150 °C. Mass and dimensions of specimens were carefully monitored throughout three cycles of oven-drying and water-soaking to determine anti-swelling efficiency, bulking coefficient, and swelling coefficient. The results showed a clear relationship between density, bulking-, and swelling coefficients. Beyond this well-known relationship it was observed that species with similar density (e.g., lime and sycamore) had significantly different bulking coefficients and anti-swelling efficiencies. Reasons for these differences, which are independent of density, are discussed. The soaking solution was analysed to determine the nature of leached substances showing a correlation between the amount of leachate and the UV-absorbance (272 nm) of the solution.

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Section: Introductionmentioning

confidence: 99%

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Kupfernagel

Spear

Pitman³

et al. 2022

Eur. J. Wood Prod.

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“…In contrast, the same amount of melamine resin is transported to the deeper layers in the plasma-treated samples (1 s soaking time) due to the plasma-induced increase in surface energy of the affected areas inside the wood (e.g., cavity walls). Another effect of the plasma treatment could be an increased diffusion of the melamine resin into the cell walls [14].…”

Section: Resultsmentioning

confidence: 99%

“…As a consequence, plywood samples made from beech veneers treated with plasma and subsequently impregnated with melamine resin showed higher shear strength than the reference [13]. Recent studies [9,13,14] on the comparability of plywood samples made from plasma-pretreated and non-pretreated beech veneers raise the following question: how do plywood specimens perform with respect to dimensional stability and mechanical properties when the individual (non-plasma-pretreated) veneers of these specimens have the same melamine resin uptake-with a correspondingly longer immersion time-as the plywood made from plasma-pretreated veneers (impregnation time 1 s)? Although this question has already been briefly touched upon in Reference [13], there is a lack of systematic investigation and discussion on this issue.…”

Section: Introductionmentioning

confidence: 97%

Plywood Made from Plasma-Treated Veneers: Investigation of Performance Differences between Plasma-Pretreated and Untreated Beech Veneers at Comparable Melamine Resin Load

Wascher¹,

Avramidis²,

Viöl

2021

Forests

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In this study, the dimensional stability and mechanical properties of plywood made from untreated and plasma-pretreated beech veneers were compared. The wood veneers used (native and thermally modified) were impregnated with melamine resin in a simple dipping process prior to plywood production. The duration of the impregnation process was adjusted to give the same melamine resin loading for the different veneer types, with the plasma-pretreated veneers requiring only a fraction of the impregnation time compared with non-plasma-pretreated veneers. With comparable melamine loading, testing of the mechanical properties of the plywood for the different specimen collectives showed significant differences in some cases with respect to compressive strength, bending strength and tensile strength (with the associated moduli of elasticity). For example, it was shown that plywood made from plasma-pretreated native beech veneers shows an increase in bending strength of about 8%, and from plasma-pretreated and thermally modified beech veneers, there is an increase of about 10% compared to the reference.

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“…More recently, Wascher et al . used micro-CT to study the impregnation volume, penetration paths, and distribution of melamine resin in beech veneer, and Koddenberg and Militz used the tool for quantitative studies of the cellular structure in European ash (Fraxinus excelsior L.) . In another study, micro-CT was used for anatomical structures of willow ( Salix sp.)…”

Section: Introductionmentioning

confidence: 99%

The Accessibility of the Cell Wall in Scots Pine (Pinus sylvestris L.) Sapwood to Colloidal Fe₃O₄ Nanoparticles

et al. 2021

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This work presents a rapid and facile way to access the cell wall of wood with magnetic nanoparticles (NPs), providing insights into a method of wood modification to prepare hybrid bio-based functional materials. Diffusion-driven infiltration into Scots pine ( Pinus sylvestris L.) sapwood was achieved using colloidal Fe 3 O 4 nanoparticles. Optical microscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray powder diffraction analyses were used to detect and assess the accessibility of the cell wall to Fe 3 O 4 . The structural changes, filling of tracheids (cell lumina), and NP infiltration depth were further evaluated by performing X-ray microcomputed tomography analysis. Fourier transform infrared spectroscopy was used to assess the chemical changes in Scots pine induced by the interaction of the wood with the solvent. The thermal stability of Fe 3 O 4 -modified wood was studied by thermogravimetric analysis. Successful infiltration of the Fe 3 O 4 NPs was confirmed by measuring the magnetic properties of cross-sectioned layers of the modified wood. The results indicate the feasibility of creating multiple functionalities that may lead to many future applications, including structural nanomaterials with desirable thermal properties, magnetic devices, and sensors.

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Use of computed tomography to determine penetration paths and the distribution of melamine resin in thermally-modified beech veneers after plasma treatment

Cited by 11 publications

References 28 publications

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Plywood Made from Plasma-Treated Veneers: Investigation of Performance Differences between Plasma-Pretreated and Untreated Beech Veneers at Comparable Melamine Resin Load

The Accessibility of the Cell Wall in Scots Pine (Pinus sylvestris L.) Sapwood to Colloidal Fe₃O₄ Nanoparticles

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Use of computed tomography to determine penetration paths and the distribution of melamine resin in thermally-modified beech veneers after plasma treatment

Cited by 11 publications

References 28 publications

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Plywood Made from Plasma-Treated Veneers: Investigation of Performance Differences between Plasma-Pretreated and Untreated Beech Veneers at Comparable Melamine Resin Load

The Accessibility of the Cell Wall in Scots Pine (Pinus sylvestris L.) Sapwood to Colloidal Fe3O4 Nanoparticles

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The Accessibility of the Cell Wall in Scots Pine (Pinus sylvestris L.) Sapwood to Colloidal Fe₃O₄ Nanoparticles