Magnus E P Wålinder

Magnus E P Wålinder
KTH Royal Institute of Technology | KTH · Department of Civil and Architectural Engineering, Building Materials

Professor Docent PhD LicEng MSc
Teaching and research about biobased building materials from renewable resources

About

84
Publications
25,217
Reads
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1,760
Citations
Introduction
Since June 1, 2011: Professor in Building materials at KTH (Stockholm, Sweden, www.kth.se/profile/walinder). Focus is on biobased building materials. Senior lecturer (Docent) in Wood & wood composites. PhD in Wood technology & processing. M.Sc. in Mechanical engineering. 2002–2011: Centre Manager of EcoBuild Institute Excellence Centre, Head of Materials and Products group, researcher, SP Technical Research Institute of Sweden, Wood Technology. 2000–2002: Postdoc at Univ. of Maine, AEWC, USA.
Additional affiliations
May 2011 - present
KTH Royal Institute of Technology
Position
  • Professor (Full)
Description
  • www.kth.se/profile/walinder/
April 2000 - May 2002
University of Maine
Position
  • PostDoc Position
Description
  • Worked in the research group lead by Professor Douglas J. Gardner
August 2002 - December 2011
RISE Research Institutes of Sweden
Position
  • Centre Manager, researcher
Description
  • www.ecobuild.se

Publications

Publications (84)
Article
Full-text available
This paper focuses on a particular application of birch plywood in adhesively bonded connections, namely, a node of a timber truss. The aim is to investigate the influence of the plywood's additional width and the load-to-face grain angles on its load-bearing capacity in tension (tensile capacity). The experimental tests started from the case with...
Article
Full-text available
This study investigates frame corner joints built of birch plywood plates and glulam elements connected via self-tapping screws. Analytical calculations based on the fastener group's torsional moment resistance, the proposed fastener group's elastic and post-elastic load-bearing criteria, and the design formulas in Eurocode 5 were performed to pred...
Article
Full-text available
There is growing interest recently in reducing the usage of metals in timber structures. Birch plywood possesses satisfactory mechanical properties compared to other wood-based panels and is promising to be utilized in timber connections as a substitute for the more conventional slotted-in metal plate. There are essentially two possibilities to con...
Article
Full-text available
The design of timber connections is of vital importance in timber structures. Bonded connections exhibit the advantages of lower cost, higher load-bearing capacity, and higher stiffness compared to conventional mechanical connections. However, the potential of the bonded connections has yet to be fully exploited, not only due to their sensitivity t...
Article
Full-text available
Birch plywood has superior mechanical properties compared with that made from most softwoods. However, durability-related issues still limit the application of birch plywood in outdoor structures. A means to enhance its durability is to acetylate birch veneers before processing them into plywood. An earlier study showed that such acetylated birch p...
Conference Paper
Full-text available
Compared to steel plates, plywood plates are competitive in structural connections due to their low carbon footprint, high tolerance during assembly, relatively low cost, and less prefabrication demand (Kromoser et al. 2021). During the last few decades, plywood depicts its imprint as connections in timber structures such as truss connections, beam...
Article
Full-text available
This study presents the feasibility of constructing moment joints using birch plywood plates and glulam beams. Beam-beam joints consisting of birch plywood gussets and glulam beams connected by self-tapping screws were built and tested in the four-point bending regime. Analytical calculations based on the fastener group's torsional moment resistanc...
Article
Full-text available
Birch plywood has superior mechanical properties compared with plywood made from most softwood species, which makes it suitable for structural application. Plywood is also more environmentally friendly, cost-efficient, and less prefabrication demanding than steel plates. For a proper design of birch plywood as joint plates in timber-timber connecti...
Article
Full-text available
Due to the increasing interest in reducing the usage of metals in the construction sector, birch plywood has shown good potential in structural engineering and timber connections as a substitute for the more conventional slotted-in metal plate solutions. However, a proper way of bonding birch plywood with other timber parts that results in adequate...
Article
Full-text available
Birch is a short-lived hardwood species widespread in the Northern Hemisphere. Plywood made from birch has superior mechanical properties compared with that made from most softwoods, which makes it suitable for structural application. In this study, the feasibility of using birch plywood as gusset plates in timber-timber connections is presented. T...
Article
Full-text available
Birch plywood exhibits outstanding mechanical properties with regards to tensile, compressive, and shear behaviors, making this wood engineered product promising in timber connection applications. However, the edgewise bending strength and stiffness, which are often critical for the design of gusset plates, have not been investigated thoroughly. Mo...
Conference Paper
Full-text available
Plywood made from birch has superior mechanical properties compared with that made from most softwoods, which makes it suitable for structural application. Several previous studies have addressed birch plywood’s structural usage and angle-dependent mechanical properties (Crocetti et al. 2021; Furuheim et al. 2021; Wang et al. 2021, 2022a; Kromoser...
Article
Full-text available
Proper surface pre-treatment plays an important role for good compatibility between the wood and the coating. The present study aimed to determine the correlations between the type of surface pre-treatment and the wettability for unmodified and thermally modified beech (Fagus sylvatica L.) wood with water and water-based coatings. A new approach to...
Article
Full-text available
There is an increasing demand for engineered wood products (EWPs) due to the flourish of modern timber structures during recent years. However, the durability-related issues are still unignorable limitations when applying timber to outdoor structures. Therefore, treatment measures are still needed to enhance the durability of timber. The acetylatio...
Article
Full-text available
There is an increasing demand for engineered wood products in modern structures. Birch plywood is promising in structural applications, due to the combined advantages of its superior mechanical properties and the cross lamination configuration. However, the off-axis mechanical properties of birch plywood have not been thoroughly investigated. The a...
Conference Paper
Full-text available
The outstanding mechanical properties of birch plywood make it promising to be applied for structural purposes. However, the poor durability of birch against biodeterioration limits its outdoor uses. Chemical modification, e.g., acetylation, is one of the potent ways to mitigate the durability issues. Embedment strength is one of the main parameter...
Article
The effect of prolonged ultraviolet (UV) irradiation on the performance of superhydrophobized birch and acetylated birch wood was investigated. The surface modification of the wood was based on a newly developed method using silicone nanofilaments. The combination of surface modification and acetylation of wood showed good wetting resistance also a...
Conference Paper
Full-text available
An innovative timber-steel hybrid system, composed of glulam beams reinforced by means of steel rods with shear keys as connectors, was proposed to improve glulam structural performance in terms of strength, stiffness, and ductility. This hybrid system can be used for both reinforcing prefabricated timber members and retrofitting existing timber me...
Conference Paper
Full-text available
The acetylation process involves chemical reaction between acetic anhydride and wood, which results in esterification of accessible hydroxyl groups in the cell wall, with formation of the by-product acetic acid. Acetylation of wood has been widely studied during the past decades, and several experimental studies have proven it to be effective in re...
Article
Full-text available
In this work, a non-fluorinated surface treatment, i.e., hydrophobized silicone nanofilaments, was applied on both birch and acetylated birch wood samples via a gas-phase based reaction. A superhydrophobic behavior was observed on both the surface-modified samples as revealed by the static water contact angles (CAs) greater than 160°, also valid fo...
Article
Full-text available
There is an increasing interest in large-dimensional timber structural elements within the construction sector in order to fulfil the combined demand of sustainability, open spaces and architectural flexibility. Current timber technology allows for efficient production of long-size beams, but many problems are related to their overall high costs du...
Conference Paper
Full-text available
In recent years, large-dimensional structural timber elements are highly demanded for the construction of high-rise timber buildings as well as large-span structures. However, long-span wooden products are not easy to handle during transportation and erection phases, making them particularly expensive. To meet this challenge, an innovative timber-s...
Article
Full-text available
The increasing utilization of wood-based products raises new demands for improved durability, for example an enhanced liquid repellence. Superhydrophobic or superamphiphobic surfaces have been widely fabricated. Less attention has been paid to such modifications on wood and the changes of its hygroscopic or solvoscopic properties. In this work, woo...
Article
Full-text available
The overall aim of this work was to gain more insight on the potential of modified wood (TMW) components for use in wood–thermoplastic composites (WPCs). Laboratory-scale TMWPCs were produced, and the effects of severe water soaking–drying cycles on the samples were studied. Water sorption behavior and resulting dimensional and micromorphological c...
Article
Full-text available
The moisture sorption behaviour of wood strongly influences the durability of exterior-coated wood. Wood characteristics are known to influence the water sorption of uncoated wood. Despite this, the majority of the research on coated wood has been focused on the coating properties. This study aims to investigate the impact of heartwood, sapwood and...
Article
Full-text available
This paper investigates ways in which weathering-related site conditions can be allowed to inform the design process in order to improve a building's geometry and performance. Providing a building design with the capacity to remember past experiences and anticipate future events can provide substantial gains to the architectural configuration and e...
Article
The objective of this work is to study the water vapor sorption and surface energy properties of thermally modified wood (TMW) components, ie wood processing residuals in the form of sawdust. The thermal modification was performed on spruce wood components using a steam-pressurized laboratory-scale reactor at two different temperature (T) and relat...
Article
Full-text available
A multicycle Wilhelmy plate method was applied to study the water and octane sorption behaviour of small Norway spruce veneers. Dry heart- and sapwood samples of varying density were investigated. The results showed a correlation between the porosity and the sorption of octane for all samples, i.e. a higher wood porosity resulted in higher octane s...
Article
Full-text available
A variety of climate mitigation strategies is available to mitigate climate impacts of buildings. Several studies evaluating the effectiveness of these strategies have been performed at the building stock level, but do not consider the technological change in building material manufacturing. The objective of this study is to evaluate the climate mi...
Article
The effect of extractives removal on liquid sorption, swelling and surface energy properties of unmodified wood (UW) and thermally modified Scots pine heartwood (hW) (TMW) was studied. The extraction was performed by a Soxtec procedure with a series of solvents and the results were observed by the multicycle Wilhelmy plate method, inverse gas chrom...
Article
Full-text available
Poplar wood was modified by a combination of thermo-mechanical densification (TMD) and heat treatment (HT) process at five temperatures ranging from 170 to 210°C. A new two-step conditioning method (CM) is suggested, in the course of which the modified wood is submitted to 50°C/99% RH→25°C/65% RH, where RH means relative humidity in the climate cha...
Article
Full-text available
The mechanical properties of wood can be improved by compressing its porous structure between heated metal plates. By adjusting the process parameters it is possible to target the densification only in the surface region of wood where the property improvements are mostly needed in applications, such as flooring. The compressed form is, however, sen...
Article
Full-text available
X-ray computed tomography (XCT) was utilized to visualize and quantify the 2D and 3D microstructure of acetylated southern yellow pine (pine) and maple, as well as furfurylated pine samples. The total porosity and the porosity of different cell types, as well as cell wall thickness and maximum opening of tracheid lumens were evaluated. The wetting...
Article
Full-text available
The density of wood can be increased by compressing the porous structure under suitable moisture and temperature conditions. One aim of such densification is to improve surface hardness, and therefore, densified wood might be particularly suitable for flooring products. After compression, however, the deformed wood material is sensitive to moisture...
Conference Paper
Full-text available
An Automatic Bond Evaluation System (ABES) hot press was employed to manufacture a self-bonded joint between two veneers of rotary-cut birch (Betula pendula Roth). The hot-pressing conditions were 220 °C and 5.0 MPa, with press times ranging from 180 s to 600 s with 60 s intervals. Additionally, the log-soaking temperature (20 °C and 70 °C) and the...
Article
A superamphiphobic coating on a biobased material shows extreme liquid repellency with static contact angles (CA) greater than 150° and roll-off angles less than 10° against water, ethylene glycol, diiodomethane and olive oil, and a CA for hexadecane greater than 130°. The coating consisting of titania nanoparticles deposited by liquid flame spray...
Article
The objective of this work was to study the hygroscopicity and surface chemical composition of thermally modified (TM) spruce. An effort was also made to study if those features were influenced by a previous exposure to a significant increase in relative humidity (RH). TM and unmodified Norway spruce (Picea abies Karst) samples, both in solid and g...
Article
During fibre processing, wood fibres are subjected to a range of physical and chemical conditions sufficient to slightly alter their chemical composition and hence their ultimate performance when used in the manufacture of wood fibre-based composites. In order to better understand the effects of refiner conditions on material performance, wood fibr...
Article
The surface energy of unmodified and thermally modified spruce wood components was researched at dry and moist conditions using inverse gas chromatography. The results indicate a more pronounced heterogeneous nature of the thermally modified wood surfaces in terms of the dispersive (nonpolar) component of the surface energy, compared with that of t...
Conference Paper
Full-text available
Development of material science and of products for the building industry constantly provides new options, new possibilities. But what is the most realistic and sustainable way to go, when technology enables mankind to produce almost anything thinkable while nature is crying out for reduced consumption of natural resources and decreased environment...
Article
The wetting, dimensional stability and sorption properties of a range of modified wood samples obtained either by acetylation or furfurylation were compared with those of unmodified samples of the same wood species via a multicycle Wilhelmy plate method. Wettability measurements were performed with water and octane as the swelling and non-swelling...
Article
The hydrophilic nature of wood surfaces is a major cause for water uptake and subsequent biological degradation and dimensional changes. In the present paper, a thin transparent superhydrophobic layer on pine veneer surfaces has been created for controlling surface wettability and water repellency. This effect was achieved by means of the liquid fl...
Conference Paper
Full-text available
Wood fibres were produced on the pilot scale refiner at the BioComposites Centre, Bangor University, from a commercially sourced mix of chipped wood. The fibres were produced at refiner pressure 4, 6, 8 and 10 bar and dried in the associated flash drier. Surface energy characterization of the refined fibres was performed using inverse gas chromatog...
Article
Scots pine (Pinus sylvestris L.) wood was surface densified in its radial direction in an open press with one heated plate to obtain a higher density on the wood surface whilst retaining the overall thickness of the sample. This study investigated the effect of temperature (100, 150 and 200 °C) and press closing speed (5, 10 and 30 mm/min, giving c...
Article
The wettability of Scots pine veneers was investigated with different approaches using the Wilhelmy plate method. The probe liquids were water and octane, which differ; in that, water is able to swell the wood sample, whereas octane does not. Novel approaches based on the Wilhelmy plate method to study wettability, liquid penetration, and swelling...
Article
A multi-cycle Wilhelmy plate method has been developed to investigate wetting properties, liquid sorption and swelling of porous substrates such as wood. The use of the method is exemplified by studies of wood veneers of Scots pine sapwood and heartwood, which were subjected to repeated immersion and withdrawal in a swelling liquid (water) and in a...
Article
The aim of this work was to achieve a better understanding of the wettability, i.e. liquids wetting and sorption characteristics (or penetrability), of acetylated Southern yellow pine (SYP) including probable differences in such characteristics between early- or latewood. Matched samples of acetylated and untreated SYP boards were prepared. The wet...
Conference Paper
Full-text available
The objective of this work is to characterize surface energetics of thermally modified wood. Such information may be useful for a better understanding and predictions of adhesion properties between the modified wood and other material systems, e.g. coatings, adhesives or matrices in composites. Inverse gas chromatography (IGC) was used to study the...
Article
Micromorphological studies of wood-plastic composites (WPC) are crucial for deeper understanding of their physical, mechanical, and durability properties. The objective of this study was to examine process-related mechanical degradation of the wood component in an extruded high-wood-content WPC. WPC with 70% wood content and three distinctly differ...
Article
Full-text available
Moisture sorption in wood-plastic composites (WPCs) affects their durability and dimensional stability. In certain outdoor exposures, the moisture properties of WPCs are altered due to e.g. cracks induced by swelling and shrinkage of the components, as well as UV degradation or biological attack. The aim of this work was to study the effect of diff...
Article
The main objective of this work was to study the chemical composition of surfaces and ageing effects on acetylated pine (Pinus sylvestris), heat treated spruce (Picea abies), and furfurylated radiata pine (Pinus radiata) in comparison to unmodified wood. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-...
Article
The main objective of this work was to apply contact angle analysis to predict work of adhesion (W a) between some modified wood materials and certain thermoplastics and adhesives. Wetting properties, i.e., contact angles, were measured by the Wilhelmy method on both freshly prepared and aged veneer samples of unmodified and acetylated Scots pine,...
Article
The objective of this paper is to demonstrate an ultraviolet (UV) laser ablation technique as a tool for sample preparation in microscopy studies of modified wood. Improved techniques for studying the microstructure of modified wood are crucial for a deeper understanding of many of their physical, mechanical and durability properties. The surface p...
Article
Recent advances in spectroscopic methods used in the surface science field may provide new valuable information about the surface chemical composition of engineering materials. Such methods, combined with wettability analyses, have been applied in the development of well-designed adhesives and coating systems for newly developed and commercially av...
Article
The purpose of this study was to evaluate the dimensional stability and strength properties of compressed laminated veneer lumber (LVL) produced using a closed hot pressing system. LVL specimens were produced with varying number of veneers using either diphenylmethane diisocyanate (MDI) or a water-soluble phenol formaldehyde (PF) resin at varying t...
Article
There is a great incentive and motivation in the building and wood research communities as well as in the industry to develop more eco-efficient and durable wood-based products with better performances. In this context, eco-efficient products refer to “green” sustainable products where both economical and ecological aspects have to be balanced. Thi...
Article
One of the major issues in a long-term perspective for the use of wood-plastic composites (WPCs) in outdoor applications is the moisture sensitivity of the wood component and the consequent dimensional instability and susceptibility to biological degradation of the composite. In this work, the effects of using an acetylated wood component and a cel...
Article
The objective of this research was to use inverse gas chromatography (IGC) to infer fiber–matrix interactions for predicting practical adhesion between cellulose fibers and polystyrene matrix polymer. IGC experiments were performed on polystyrene, untreated, alkyl- and amino-silanated cellulose (lyocell) fibers. The fiber–matrix acid–base interacti...
Article
The edge and face gluing of green timber using a one-component polyurethane adhesive was investigated. Knot free and straight grained lamellae of dimensions were prepared for this purpose. The relationship between final shear strength and wood failure percentage after kiln drying of the edge green glued specimens was shown. A slight increase of the...
Article
Wood composites should be protected against microbial and insect attack when used outdoors, especially in construction applications with prolonged exposure to moisture. Preservative systems and treatment processes affect composite properties, especially adhesive/wood bonding and mechanical properties. Several common systems for preservation of comp...