Andreas Treu
Avdelingsleder/forskningssjef
Biografi
Dr. Andreas Treu has been a research scientist at NIBIO (formerly the Norwegian Forest and Landscape Institute) since 2006 and works in the Department of Wood Technology. He graduated from the University in Göttingen, Germany, with a doctoral degree in Forest Sciences and Forest Ecology. He works on wood protection, modification, and anatomy.
Sammendrag
Modifying natural polymers with silicones gives new possibilities for packaging products and waste management. In this study, the innovative papers produced were altered following the reaction of polysaccharides and organosilicon compounds. The susceptibility of the studied material to biodegradation caused by a brown-rot fungus was assessed. Strength properties by tensile strength and dynamic mechanical analysis and hydrophobic properties by water uptake test and water contact angle analysis were evaluated. Moreover, elemental analysis by ICP method was controlled. The durability against fungi and the hydrophobic properties were increased by the modification. The fungal decay resistance of the silanized paper was reduced by water storage, which allows for managing paper waste. Cellulose-based paper treated with starch-modified methyltrimethoxysilane showed potential as a packaging material due to its reduced water uptake. Possible application areas could be corrugated boxes, cellulose thermoformed products for electronics, and food packaging. However, the water-repellent effect is limited to short-term exposure in humid conditions.
Sammendrag
Wood modification using polyesterification of sorbitol and citric acid is a novel environmentally friendly strategy for wood protection improving its dimensional stability and acts against fungal deterioration. Inelastic Raman scattering is sensitive to the molecules of high polarizability and both lignocellulose and aliphatic esters formed during the treatment are polar. Therefore, in the present study, the quality control of the treatment using a handheld Raman spectrometer equipped with 830 nm laser is suggested as a rapid and reliable approach. Raman spectra from six wood modification levels (resulting in different weight percent gain, WPG) of three different wood species (Silver birch, Scots pine and Norway spruce) as well as three sample preparation strategies (intact, sanded and milled wood samples) were collected, and further analyzed using a chemometric method. Best performing models based on Powered Partial Least Squares Regression predicted the WPG level at R2 = 0.85, 0.95 and 0.98 for birch, pine and spruce, respectively. In addition, a clear separation between hard and soft wood species was also captured. Especially for softwood species, the sample preparation method affected the model accuracy, revealing the best performance in milled material. It is concluded that by using handheld Raman spectrometer it is possible to perform accurate quality control of wood modified by polyesterification of citric acid and sorbitol.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Andreas Treu Katrin Zimmer Christian Brischke Erik Larnøy Lone Ross Foued Aloui Simon M. Cragg Per-Otto Flæte Miha Humar Mats Westin Luisa Borges John WilliamsSammendrag
Timber structures in marine applications are often exposed to severe degradation conditions caused by mechanical loads and wood-degrading organisms. This paper presents the use of timber in marine environments in Europe from a wood protection perspective. It discusses the use of wood in coastline protection and archeological marine wood, reviews the marine borer taxa in European waters, and gives an overview of potential solutions for protection of timber in marine environments. Information was compiled from the most relevant literature sources with an emphasis on new wood protection methods; the need for research and potential solutions are discussed. Traditionally, timber has been extensively utilized in a variety of marine applications. Although there is a strong need for developing new protection systems for timber in marine applications, the research in this field has been scarce for many years. New attempts to protect timber used in marine environments in Europe have mainly focused on wood modification and the use of mechanical barriers to prevent colonization of marine wood borers. The importance of understanding the mechanisms of settlement, migration, boring, and digestion of the degrading organisms is key for developing effective systems for protecting timber in marine environments.
Sammendrag
Non-destructive and rapid analysis of adhesive penetration in engineered wood products ensures bond integrity, enabling the development of novel adhesives and quality manufacturing. The present study evaluated the X-ray densitometry method for studying the adhesive penetration in birch plywood. In this approach, it was quantified as a function of distance by measuring the X-ray density profile section where the adhesive bond-line density was above the baseline wood density. Accordingly, untreated and esterified birch veneers were pressed into plywood using both liquid and solid-type phenolic adhesives, resulting in four types of five-layered plywood of 7-8 mm in thickness. Optimization of X-ray beam attenuation through the plywood was done by preliminary trials and identified the specimen dimensions as 50 mm in height and 25 mm in width using a scanning speed of 0.5 mm min $$^{-1}$$ . The X-ray densitometry measured densities of cured phenolic adhesive to be 1150 ± 50 kg m $$^{-3}$$ and esterification-modified birch plywood to be 750 ± 25 kg m $$^{-3}$$ . These density values are consistent with gravimetric density measurements. Density profile observations indicate that both liquid and solid forms of phenolic adhesives exhibited similar levels of adhesive penetration in plywood. X-ray densitometry analysis determined a total interphase thickness ranging from 0.50 to 0.75 mm, encompassing the central adhesive bond-line and the effective adhesive penetration into both adjacent veneers. These values are comparable with those measurements obtained from microscopy imaging analysis. Therefore, X-ray densitometry could be a swift method for quantifying adhesive penetration, although further studies are needed to validate its accuracy and reliability.
Forfattere
Petri Widsten Marc Borrega Miriam Kellock Mariem Zouari Anita Wronka Grzegorz Kowaluk Matthew Schwarzkopf Andreas TreuSammendrag
Abstract Indoor air quality can be improved by coatings that adsorb harmful volatile organic compounds (VOCs). In the present work, bio-based and VOC-adsorbing wood coatings were fabricated from polyphenols extracted from spruce bark, biochar produced from mixtures of spruce and pine bark, and a polyamine crosslinker. The bark-based biochar was doped with a catalyst (MnO 2 ) to enable continuous elimination of the adsorbed VOCs so that the coatings would not become saturated. The coatings formed a homogenous and smooth layer that covered the whole surface of the wood and showed excellent adhesion to the substrate, while their VOC removal efficiency was dependent on the pollutant type and the coating weight. The best performance was achieved toward formaldehyde, followed by chloroform and methyl ethyl ketone. Thick coatings (200–220 g/m 2 ) reached a formaldehyde removal of 62%, with the coating base and the biochar contributing nearly equally to the VOC removal. Overall, the bark-based coatings showed good potential for improving indoor air quality, but the surface wettability of the coated spruce wood was high. Despite the presence of biochar and nitrogen-containing aromatic compounds, the coatings did not appear to improve the reaction to fire of the wood.
Sammendrag
Wood has many attractive material qualities, but it is susceptible to biological degradation by wood-decaying fungi. Moisture is one of the critical requirements for wood decay, but much remains unknown about moisture dynamics in decaying wood. To fill this knowledge gap, this study investigated moisture in Scots pine sapwood during decay caused by the brown rot fungus Coniophora puteana. Samples were exposed to decay in two time-series experiments; mass loss and moisture content were recorded over the course of decay, and the bound and free water populations in the samples were analysed using low-field nuclear magnetic resonance (LFNMR) relaxometry in both the decaying state and at full water saturation. Selected samples were also used for water vapour sorption measurements. The time-series decay tests showed that moisture content initially increased due to fungal activity but decreased over time when corrected for mass loss, contrary to the general belief that moisture content increases with decay. LFNMR revealed that bound water content increased on a decayed-mass basis in the decaying state and at saturation, but no increase was seen after correction for mass loss. Free water content followed gravimetric moisture content in the decaying state, but the saturated state measurements revealed an initial increase and subsequent decrease with mass loss. Degradation caused changes in hygroscopicity, but our data show that overall moisture content is regulated by fungal activity rather than by material properties. These findings highlight the complexity of water interactions during fungal degradation, offering valuable new insights into wood degradation mechanisms.
