The Biological Durability of Thermally- and Chemically-Modified Black Pine and Poplar Wood Against Basidiomycetes and Mold Action

Abstract

Wood of black pine and poplar species were subjected to thermal modification under variant conditions, while subsequently, a number of the thermally-modified black pine specimens were subjected to surface modification with organosilane solutions, and the biological resistances of the different materials were examined using laboratory agar block tests against the action of basidiomycetes and microfungi. Thermally-modified pine specimens were exposed to the brown rot fungi Coniophora puteana and Oligoporus placenta, whereas poplar wood was exposed to the white rot fungus Trametes versicolor and O. placenta. Regarding the biological durability of thermally-chemically-treated pine wood with organosilanes, it was tested against the action of C. puteana. Additionally, both of the thermally-treated wood species, as well as thermally-chemically-treated pine wood were exposed to a microfungi mixture, so that the wood treatments efficacy would be evaluated through a visual assessment of fungal growth on the specimen’s surface The thermal treatments seem to increase the biological resistance of black pine against C. puteana by 9.65–36.73% compared to unmodified wood. The most significant increase in biological durability among all the thermally-treated wood categories was recorded by O. placenta, with 28.75–68.46% lower mass losses in treated pine specimens and 31.98–64.72% in thermally-treated poplar, respectively, compared to unmodified wood. The resistance of treated poplar against T. versicolor was also found increased (13.25–46.08%), compared to control. Thermal modification affected positively the biological resistance of both species, though it did not manage to protect effectively pine and poplar wood from the microfungi action. The combination of thermal and organosilanes treatment revealed a significant improvement of the durability of pine wood compared to? control (45.68–87.83% lower mass losses against C. puteana), as well as against the microfungi action, with the presence of benzin to have a positive effect on the silanes solutions performance and protective action.

Natural weathering performance of thermally treated poplar and black pine wood

“…According to the results of both species, the duration of over 5 hours, of thermal treatment (under the specified conditions), presented a negative impact on the integrity of wood tissue and smoothness of the surface, probably attributed to the changes induced by the thermal treatment in the chemical components and morphological characteristics of wood (Kamperidou 2019). The loss of volatile extractives, hemicelluloses and part of amorphous cellulose, due to the thermal treatment, contribute to the reduction of wood density and therefore, may increase the surface roughness.…”

“…Only defect-free material was used in the tests. The present study investigates only the resistance of the modified materials to weathering factors, but since it constitutes a part of experimental work, other critical properties of the materials, such as their physical (EMC, density, biological durability among others), hygroscopic (tangential and radial swelling, adsorption) and mechanical properties (static bending strength, modulus of elasticity, impact bending strength, hardness, compression strength among others) have already been investigated (Kamperidou and Barboutis 2017, Kamperidou and Barboutis 2018, Kamperidou et al 2013, Kamperidou 2019.…”

Chemical and Structural Characterization of Poplar and Black Pine Wood Exposed to Short Thermal Modification

“…ML -Mass loss, % M 0 -Initial oven-dry mass of the specimen before thermal treatment, g M 1 -Oven-dry mass of the same specimen after thermal treatment, g Thermal treatment of poplar wood under the above mentioned conditions induced mass losses in the range of 11.24 % -18.88 %, of which 10.50 % corresponds to moisture, generated by the drying and thermo-degradation process, whereas thermally-treated black pine wood recorded a little lower mass losses of 10.63 % -15.25 %, of which the 11.44 % refers to moisture content loss. Additionally, the wood of black pine contains a significant amount of resin, and the mass loss could also be partly attributed to the evaporation of the resin during the thermal treatment, as well as other volatile compounds and unstable components (Kamperidou, 2019).…”

The Action Difference of Lasiodiplodia theobromae on Infecting and Dyeing Poplar Wood in Spatial Growth

“…The better dyeing effect can be observed from the cross-sectional infection of fungi due to the longitudinal infection channels [34,39]. In this study, the methods of cross-sectional infection in a vertical and horizontal direction were used to achieve microbial staining.…”