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This paper aims to discover how organic wood preservatives containing different fungicides and insecticides used to protect wood against fungal and insect pests affect the fire performance and combustion properties of wood materials commonly used in the domestic wood and construction industry. The aim of this article was to investigate the charring depth. From the point of view of the loss of load-bearing capacity of the wood, only the charring depth matters, since the reduction of the load-bearing capacity will be determined by the reduction of the cross section of the wood. We examined the effects of wood preservatives applied to undamaged samples of Scots pine and Norway spruce conditioned under normal climate conditions. The test samples underwent a second treatment application after which we examined the effect of different preservative combinations. Seven treatment mixtures were selected from the organic solvent and water-based wood preservatives available on the domestic market. The soaking experiments demonstrated that the preservative impregnation of Norway spruce differs significantly from that of Scots pine, which affected the comparability of the test results. We have experimentally investigated the moisture content, the loss of mass and we have calculated the char depth. Adhering to the MSZ 9607–1:1983 standard, the Linder method was performed to analyze the wood and wooden-based construction products used in construction. The effect of the different treatment materials was more significantly detectable when analyzing the size of the surface burn patterns. The Scots pine specimens suffered much greater surface burn than the Norway spruce specimens did, regardless of the type of preservative used. The higher body density, resin content (1–10%) and higher initial moisture content of Scots pine caused it to bend and, therefore, to burn better.

AbstractNatural constituents of wood cell-wall layers are affected in various ways by thermal treatment. This study investigated the effect of high-temperature treatment on the properties of cell-wall layers. The properties were studied using PeakForce quantitative nanomechanical mapping and Fourier-transform infrared spectroscopy (FTIR). European beech wood was thermally treated at 200 °C for 1, 3, and 5 h in an oxidizing atmosphere. Modulus of elasticity, adhesion force, and roughness of the secondary S2 layer and the compound middle lamella (CML) were determined using atomic force microscopy (AFM). Results showed that both the S2 layer and CML were affected by thermal treatment. Stiffening of the S2 layer was caused by increased crystallinity of the cellulose-dominated component, having peaked after 1 h of treatment. The degradation thereafter resulted in a decrease of the S2 as well as the CML stiffness. An increase of CML roughness after 3 h of treatment was associated with the effect of thermal degradation on CML integrity. The analysis suggested that the reduction in syringyl lignin is potentially associated with an increase in adhesion of cell-wall layers.

In Hungary, large stocks of plantation poplar reached their cutting age. The present paper is a part-time report of the OTKA project on the wettability of Pannónia poplar samples originating from two Hungarian plantations: Győr and Solt. The main question was whether the different sites of origin have a significant influence on the properties of the boards. Samples from the two plantation sites were collected from different trunks, and laboratory samples with tangential cut were prepared by planing. Wettability was measured by sessile drop method, both with distilled water and diiodomethane, using a PGX goniometer. Surface tension was calculated according to the Fowkes method.

Thermally treated and ground poplar bark was used as the raw material for pressed bark insulation panels. Bark chips were treated for one, two, and three hours at 180 °C after a slow warming, drying process. The physical and mechanical properties of the pressed panels were investigated and compared to each other and to the control panel made of untreated bark chips. Thermal conductivity showed slight deviations and ranged from 0.064 – 0.067 W·m−1·K−1. The MOR and MOE showed a significant increase of 100%. The internal bond increased by 27% while the water absorption and thickness swelling decreased by 53.8% and 69.1% respectively. Panel density did not change significantly because the target density was the same for every panel type. The mechanical and physical properties of thermal insulation panels made of heat-treated chips increased significantly.