Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2007
Abstract
The effectiveness against soft rotting micro fungi and other soil inhabiting micro-organisms was tested according to ENV 807 using different treated Scots pine sapwood and beech wood samples. The treatments differed in basic material, solvent, depolymerization agent, viscosity and post treatment. The chitosan treated Scots pine samples showed improved performance against soft rot, whereas a large amount of untreated pines sapwood samples failed during the test. The different chitosan treatments showed only slight differences in performance during the test.Further results of ongoing field tests should give more information about the life performance of the treated samples.
Abstract
Furfurylated wood has shown to have promising properties for a wood modification agent during the last years. In this paper, an alternative curing method for furfuryl alcohol modified pine sapwood by means of microwave radiation was investigated. Different process parameters of microwave treatment such as output power, exposure time to microwave radiation, initial wood moisture content and evaporation during treatment, were tested. The weight percent gain of pine wood samples due to polymerised furfuryl alcohol was investigated by means of thermo gravimetric analysis. Leaching of furfuryl treated and differently cured samples gave information about the degree of fixation. No distinct influence of initial moisture content could be stated. A slight tendency of improving the degree of fixation by increasing the consumption energy of wood samples due to microwave energy was found. Changing the evaporation ability of samples during microwave treatment by using plastic foil had no distinct influence. Fixation of furfuryl alcohol could be improved by microwave treatment, and a degree of fixation above 90 % was calculated. However, the fixation was lower than in oven cured samples.
Abstract
The aim of this study was to use Energy-Dispersive X-ray Spectroscopy (EDS) to localize chitosan in the cell wall of chitosan impregnated Scots pine. It is of both general and specific interest to investigate the concentration of chitosan in the wood matrix to gain further knowledge and understanding of chitosan as a wood protective system.After deacetylation, chitosan was re-acetylated with chloroacetic anhydride to achieve a covalent bonding of chloride to the chitosan polymer. Chloride labeled chitosan was measured by EDS using a Scanning Electron Microscope (SEM) and described in apparent concentration of chloride. Analysis for free chloride anions was tested by dialysis and ion chromatography.There was a significant correlation between the molecular weight of chitosan and the apparent concentration of covalent bonded chloride to the chitosan polymer. High molecular weight chitosan showed a better interaction with the cell wall structure than low molecular chitosan.
Abstract
Furfurylated wood is an environmentally friendly, chemically treated, wood product with improved characteristics. Quality control of furfurylated wood is still performed manually by subtracting the initial weight of a treated sample from its final weight, then dividing the result by the initial weight. Expressed as a percentage, this results in a value that represents the weight percent gain (WPG) of the treated sample and thus the degree of modification. The major disadvantage of this quality control method is that the production parameters are needed to determine WPG, since the initial weight cannot be deduced from a treated wood sample. In this paper the use of ThermoGravimetric Analysis (TGA) is presented as a potential quality control method for furfurylated Scots pine (Pinus sylvestris L.). The technique is independent of production parameters and, therefore, enables third parties to determine the WPG of any furfurylated wood product. Three validation trials have been performed with the same validation samples, but varying TGA settings and with different Partial Least Square regression models (PLS-models). Although the method needs further improvement, it has shown good accuracy and precision. Therefore, it is con
Abstract
Furfurylated wood (wood modified by furfuryl alcohol) has over the last years gained marked shares from both tropical wood and conventional preservative treated wood and this has, in turn, generated several research projects concerning process development. The impregnation of spruce is well known from literature to be a difficult task. Furthermore, the sapwood of Scandinavian grown Scots pine is also known to be difficult to fully impregnate from time to time. The primary objective of the study was to evaluate whether the Oscillating Pressure Method (OPM) could be used to impregnate green and dry Norway spruce wood (Picea abies) with a Furfuryl alcohol (FA) - mixture. The secondary objective of the study was to evaluate if OPM could improve the penetration of FA in Scots pine (Pinus sylvestris) as compared to conventional full cell (Bethell) treatment. Impregnation tests were carried out on boards and planks as well as 300 mm and 500 mm clear wood samples. Samples were removed for MC measurement and the initial weight of the test samples was determined. Four different impregnation schemes were tested. The results indicate that Norway spruce can be impregnated by the OPM method to produce a protective shell of treated wood around a core of untreated wood. The penetration in Spruce showed great variation between different boards and between different parts of the individual boards. This is in part expected, but can also be caused by uncontrolled pre drying of the test material which was stacked uncovered after sawing. For Scots pine, the OPM improved the penetration of both sapwood and, to some extent, the outer heartwood.
Abstract
The objective was to evaluate whether Lowry-impregnation of Scots pine with FA100-mix, instead of the FA40-mix, would lead to similar or slightly higher WPGs and to investigate any potential changes in penetration pattern. The results indicate that the penetration was better, also penetrating the outer zone of the heartwood. Furthermore, it was possible to reduce the WPG-levels for pine down to 50-70% (corresponding to PFA retentions of 260- 315 kg/m³) from 120% (approx. 550 kg/m³) with full-cell impregnation using FA100-mix. Using the Lowry process with FA100-mix would probably be a possible treating schedule for products aimed for use in ground contact. The reduced content of hygroscopic salts in the furfurylated wood product would also further reduce hygroscopisity compared with FA-40 mix. However, more trials are needed in order to optimize penetration while still keeping the final WPG low.
Abstract
In Norway exterior wood structures have traditionally nearly exclusively been made of treated and untreated Picea abies and Pinus sylvestris. In recent years there has been a tendency that other tree species, like various domestic hardwoods and imported species have been used in exterior above ground applications, often unfinished. For several wood species, especially hardwoods, information regarding the durability in use class 3 is lacking. The main objective of this paper is to evaluate natural durability of Norwegian wood species for above ground applications comparing two non-standard above ground tests with the European standard tests for soil contact (EN 252) and lab performance against basidiomycetes (EN 113). The European standard tests EN 113 and EN 252 gave quite similar results, and they also corresponded well with the natural durability classification in EN 350-2. The two non-standard above ground tests differed to some extend from EN 113, EN 252 and EN 350-2. The results indicate that natural durability classification for one single wood species can change depending on use class. However, the field trials need a longer period of time before a final classification can be performed. Four species not included in EN 350-2 were classified in this study: Juniperus communis (1), Salix caprea (5), Sorbus aucuparia (5) and Populus tremula (5).
Abstract
No abstract has been registered
Authors
Kristoffer Segerholm Roger Rowell Pia Larsson-Brelid Magnus Wålinder Mats Westin Gry AlfredsenAbstract
No abstract has been registered
Abstract
The area of wood protection is in a period of change. New tools are needed to understand the mode of action, and to further improve the new wood protection systems. A set of useful tools are found among the molecular methods. This paper presents an overview of some of the tools available, and the methods are exemplified by papers within the frame of wood protection issues. However, there is still a great unexplored potential within the field of wood protection by the use of various molecular methods. The majority of the work using molecular methods has been performed on species identification issues and within species variation. This paper lists some new promising molecular methods for wood protection issues and a presentation of a new project. The new project will help to gain some new knowledge about how the fungal decay processes are affected by different wood modification systems.