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.
2016
Abstract
The aim of this study was to determine the efficacy of chitosan and methoxysilane in the prevention of surface mold growth on rubberwood. Three different chitosan samples were tested; C1 (Mw 37 kDa), C2 (Mw 5.4 kDa) and C3 (Mw 3.5 kDa). Radial growth inhibition assay of the chitosan samples was investigated at concentrations ranging from 0.063 to 0.5 %w/v against Aspergillus niger BAM 4 and Penicillium decumbens CBS 121928. Chitosan samples C1 and C3 exhibited strong antifungal activity against both molds. Rubberwood samples were either vacuum or dip treated with varying concentrations of chitosan or silane solution. The content of chitosan in wood showed that after the leaching test, chitosan was well retained in both vacuum and dip treated wood. The concentration of silicon in wood showed similar results. The vacuum treated wood samples with chitosan C1 and C3 at 1 %w/v concentration had strong resistance against A. niger BAM 4. However, dip treated rubberwood samples with 2 %w/v chitosan solutions showed lower resistance against A. niger BAM 4. On the other hand, both vacuum and dip treated rubberwood samples with chitosan had no resistance against P. decumbens CBS 121928. The silane treated wood samples showed no resistance to fungal growth.
Abstract
The aim of cell wall modification is to keep wood moisture content (MC) below favorable conditions for decay organisms. However, thermally modified, furfurylated, and acetylated woods partly show higher MCs than untreated wood in outdoor exposure. The open question is to which extent decay is influenced by the presence of liquid water in cell lumens. The present paper contributes to this topic and reports on physiological threshold values for wood decay fungi with respect to modified wood. In total, 4200 specimens made from acetylated, furfurylated, and thermally modified beech wood (Fagus sylvatica L.) and Scots pine sapwood (sW) (Pinus sylvestris L.) were exposed to Coniophora puteana and Trametes versicolor. Piles consisting of 50 small specimens were incubated above malt agar in Erlenmeyer flasks for 16 weeks. In general, pile upward mass loss (ML) and MC decreased. Threshold values for fungal growth and decay (ML ≥ 2%) were determined. In summary, the minimum MC for fungal decay was slightly below fiber saturation point of the majority of the untreated and differently modified materials. Surprisingly, T. versicolor was able to degrade untreated beech wood at a minimum of 15% MC, and growth was possible at 13% MC. By contrast, untreated pine sW was not decayed by C. puteana at less than 29% MC.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Anna Komasa Anna Klementyna Przybył Piotr Barczynski Izabela Ratajczak Kinga Szentner Magdalena Wozniak Pawel Kowalewski Waldemar Perdoch Grzegorz Cofta Patrycja Kwaśniewska-Sip Joanna Siuda Wojciech Grzeskowiak Krystofiak Tomasz Lone Ross Janka Dibdiakova Magdalena Broda Bartłomiej MazelaAbstract
No abstract has been registered
Abstract
Due to more restrictive toxicological requirements and increased ecological awareness of consumers, wood preservatives containing harmful biocides are no longer desired on the market. Therefore, research on new environmentally friendly formulations is of great importance. One of the possible solutions is to develop new preservatives based on natural substances, which are harmless to humans, animals and the environment, while biologically active. The aim of the study was to develop new biocide-free preservative systems which increase wood resistance to wood-decaying fungi. The following silanes: [3-(2-Aminoethylamino)propyl]trimethoxysilane (AATMOS), (Aminopropyl)triethoxysilane (APTEOS), and (Aminopropyl)trimethoxysilane (APTMOS); caffeine, natural oils and potassium carbonate were chosen as components of new protective formulations, which were planned to be an alternative for traditionally used biocides. Samples of three different wood species (pine, spruce, and poplar) were treated with the new preservative systems and exposed to the brown-rot fungus Coniophora puteana and the white-rot fungus Coriolus versicolor according to EN-113 and EN-839 standards. The obtained results show that wood treated with the water-based formulation consisting of silanes and caffeine (2% caffeine + 5% AATMOS, 2% caffeine + 5% APTEOS) demonstrated the highest resistance to the test fungi. Wood mass loss after exposure to the decay fungi was 1%. All wood species treated with this formulation achieved index 1 (“very resistant”) within durability class acc. to the EN350 standard.
Abstract
Understanding the influence of weathering factors and the material degradation mechanisms are fundamental for modelling the weathering process of wood. The goal of this work was to investigate the combined effect of time and exposure on the physical-chemical mechanisms of wood weathering. Four exposure directions (North, South, East and West) were investigated. Experimental tests were performed for 28 days through July, which according to previous research is considered as the most severe period for weathering of wood micro-sections. Measurements of samples included: photogrammetry, near and mid infrared spectroscopy, colour measurement, SEM observation and visual assessment. Parameters obtained by measuring the weathered surfaces with various sensors were compared with the subjective visual assessment by an expert evaluator. Algorithm based on multi sensor data fusion allowing calculation of the “weathering indicator” was developed. It was concluded that the progress of degradation is clearly correlated to the solar radiation and the exposure direction seems to have a clear effect on the degradation intensity.
Abstract
Growth of dark moulds enables the use of a decorative and protective biofinish for wood, showing advantages compared to traditional wood-coatings in terms of sustainability and selfrepair. Based on the formation of a uniform mould covering on oil treated wood during outdoor exposure, the utilisation of a biofinish is in development. Basic information is lacking on the correlation between exposure site and biofinish formation on wood. To evaluate the impact of different locations, a biofinish assessment method was applied on different combinations of wood species and vegetable oil types after outdoor exposure in the Netherlands and Norway. Biofinishes were detected on wood samples made of spruce, pine sapwood and ilomba that were treated with olive oil and on pine sapwood treated with raw linseed oil after one and a half year of outdoor exposure in the Netherlands. More time was needed for biofinish formation on multiple wood-oil combinations for samples exposed in Norway. After two years of outdoor exposure three out of five wood-oil combinations that contained biofinishes in the Netherlands, showed similar results with the samples in Norway. Biofinish formation was not detected at all on untreated wood samples, regardless the wood species or exposure site. Loose fibres were observed on the surface of all untreated samples. It is likely that biofinish formation was prevented by the removal of stained fibres. Analysis of the stain coverage development on the wood samples, including initial stages of biofinish formation, showed a significant effect of exposure time and (oil) treatment on the stain coverage.
Authors
Lone RossAbstract
No abstract has been registered
Abstract
In order to determine the relation between the structural properties and fungistatic activity of quinolizidine and bisquinolizidine alkaloids, the bioactive derivatives of cytisine, sparteine and lupanine were tested for the inhibitory activity against the microfungus causing mould growth phenomenon (Aspergillus niger van Tieghem ATCC 6275). The compounds tested were screened for antifungal properties using the bioautography-TLC. According to the results, the following cytisines showed an inhibiting effect on mould; spirocytisine, 3,5-dibromocytisine, bromo-N-boccytisine, N-Boccytisine, 3-bromobenzylocytisine, 4-bromo-benzylcytisine, 3-iodobenzylcytisine, 4-iodobenzylcytisine.