Hopp til hovedinnholdet

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.

2019

To document

Abstract

When exposed to moisture, wood undergoes swelling and is susceptible to fungal degradation. Chemical modification via oligomeric lactic acid (OLA) treatment has been found to be a promising environmentally friendly solution to this disadvantage. In this study, wood was impregnated with OLA and then variously heat treated to polymerize the OLA in situ. The effect of curing temperature and time on OLA polymerization has been determined chemically. Dimensional stability was examined by water immersion and hygroscopicity measurements and biological decay resistance also evaluated. OLA impregnation followed by heat treatment enhanced wood properties. OLA cure at 160 °C for 48 h resulted in treated wood with greater dimensional stability and biological resistance.

To document

Abstract

No abstract has been registered

To document

Abstract

This study addresses changes in visual appearance of unpainted wood materials exposed outdoors. Specimens of aspen (Populus tremula), Norway spruce (Picea abies), untreated Scots pine (Pinus sylvestris), DMDHEU-modified Scots pine and acetylated Radiata pine (Pinus radiata) were exposed facing south in Ås, Norway for 62 weeks. During this period, mould growth coverage, lightness (L*) and the uniformity of the weather grey colour were assessed. Mould growth coverage was evaluated visually using a rating system. L* and the uniformity were evaluated using image analysis. The increase in mould rating of the wood materials developed in varying speed, but all specimens had reached the maximum rating after 42 weeks. Until then, the changes in L* correlated significantly with the mould rating. However, the specimens continued to darken after they had reached maximum mould rating. DMDHEU was the only material that obtained a more uniform colour as a consequence of the weathering.