Ways to improve the properties of natural wood when using waste vegetable oils

The article is devoted to the development and study of new compositions based on spent sunflower oil for the protective treatment of natural wood. Samples of birch and aspen wood were selected as the subjects of the study. The processing of wood samples was carried out by the method of “hot-cold impregnation”. Refined sunflower oil was used as the oil base of the propearized compounds developed. Plant oil fillers were chosen wood flour, stearic acid, canifol and sikkativ based on metal salts. The use of developed compounds can improve the hydrophobic properties of wood, increase its water and water resistance, as well as reduce swelling in tangential and radial directions. The optimal compositions on the basis of spent vegetable oil for protective processing of birch wood have been selected. The difference in the modifying capacity of the developed compositions for different types of wood is shown on the example of birch and aspen. Propiary compounds based on spent vegetable oil have environmental safety and their use allows the disposal of food waste.

Investigation of the use of old railroad ties (Fagus orientalis) and citrus branches (orange tree) in the particleboard industry

Effects of two widely available and underutilized lignocellulosic materials on the mechanical and physical properties of particleboards were investigated in this work. The ratio of mixtures lignocellulosic flakes at four levels (100% aspen wood), (50% aspen wood: 25% citrus: 25% old railroad ties), (50% aspen wood: 50% citrus), and (50% aspen wood: 50% old railroad ties), and the percentage of resin in two levels (8 and 12%) were considered as variable factors. The 100% aspen wood (Populus tremula) was mixed as a control board (100% aspen wood). Then the mechanical and physical properties of the samples including modulus of rupture, modulus of elasticity, internal bond, water absorption, and thickness swelling after 2 h and 24 h of immersion (EN 310-319) and fire resistance (ISO 11925-2) were measured. The results showed that with increasing poplar wood in mixtures, modulus of rupture, modulus of elasticity, internal bond increased, while water absorption and thickness swelling decreased. Also, in comparison with the control boards, the boards that were made by mixing 50% poplar and 50% citrus branches with 12% glue had the highest mechanical strength. The results also showed that increasing the amount of old railroad ties chips in mixing caused a significant decrease in the fire retardancy of the boards.

DIVERSITY OF THE BIBIONOMORPHA AND TIPULOMORPHA (DIPTERA) FROM DEAD ASH AND ASPEN WOOD IN THE FORESTS OF LITHUANIA

The aim of this study was to investigate the biodiversity of nematoceran flies associated with dead wood in a forest ecosystem. Although wood is a primary habitat for a vast amount of Diptera species, no effort has previously been made to study saproxylic flies in Lithuania. During this research, emergence traps were used on aspen (Populus tremula) and ash (Fraxinus excelsior) trees in Dūkštų Ąžuolynas forest and Būda Botanical-Zoological Reserve during the period 2014–2019. In total, 672 individuals of the Bibionomorpha and Tipulomorpha collected from fallen tree trunks were identified to species. Seventy-four species represented nine families, with the Sciaridae, Anisopodidae and Mycetophilidae being most abundant. The Sciaridae family has barely studied in Lithuania and its diversity is still poorly known. During the research 23 nematoceran species, of which 19 belonging to the Sciaridae family, are first reported from Lithuania. Key words: nematoceran, saproxylic species, emergence traps.

Study of the Porous Structure and High Adsorption Capacity of Biomass-Based Activated Carbon Prepared from Aspen Wood by Ferric Nitrate III Activation

In this study, aspen wood sawdust was used as the raw material, and Fe(NO3)3 and CO2 were used as activators. Activated carbon powder (ACP) was produced by the one-step physicochemical activation method in an open vacuum tube furnace. The effects of different mass ratios of Fe(NO3)3 and aspen wood sawdust on the pore structure of ACP were examined under single-variable experimental conditions. The mass ratio was 0–0.4. The detailed characteristics of ACP were examined by nitrogen adsorption, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption capacity of ACP was established by simulating volatile organic compounds (VOCs) using ethyl acetate. The results showed that ACP has a good nanostructure with a large pore volume, specific surface area, and surface functional groups. The pore volume and specific surface area of Fe-AC-0.3 were 0.26 cm3/g and 455.36 m2/g, respectively. The activator played an important role in the formation of the pore structure and morphology of ACP. When the mass ratio was 0–0.3, the porosity increased linearly, but when it was higher than 0.3, the porosity decreased. For example, the pore volume and specific surface area of Fe-AC-0.4 reached 0.24 cm3/g and 430.87 m2/g, respectively. ACP presented good VOC adsorption performance. The Fe-AC-0.3 sample, which contained the most micropore structures, presented the best adsorption capacity for ethyl acetate at 712.58 mg/g. Under the action of the specific reaction products nitrogen dioxide (NO2) and oxygen, the surface of modified ACP samples showed different rich C/O/N surface functional groups, including C-H, C=C, C=O, C-O-C, and C-N.

How clonal differences and within-tree heterogeneity affect pore properties of hybrid aspen wood and biochar?

Production of applicable and homogeneous biochar for soil amendment purposes would benefit from knowledge on how feedstock heterogeneity impacts key biochar pore properties and how the properties are transformed due to pyrolysis. This study aimed (1) to quantify how clonal differences and within-tree heterogeneity of a hybrid aspen feedstock (wood) impact biochar pore properties and (2) to estimate how pore properties of non-pyrolysed wood materials are transformed when pyrolysed into biochar. The study was conducted by collecting samples from a hybrid aspen (Populus tremula L. × Populus tremuloides Michx.) clonal field trial. Key pore properties of non-pyrolysed and pyrolysed wood samples were quantified with 3D X-ray imaging and quantitative image analyses. The results demonstrated how pyrolysis shifted distinctively bi-modal pore size distributions of the wood samples towards smaller pore size regions. The bi-modal wood tissue structure controlled the pore structure also in the biochars. Due to decreasing cell wall thicknesses, the pyrolysis increased the porosity of the materials. While the thermal process homogenized differences in the wall thicknesses, the thicknesses of the feedstock were also shown to control the resulting thicknesses in the biochars. Mechanisms of biochar pore property formation can be considered important when designing applicable biochars for a chosen purpose. Clonal differences and within-tree heterogeneity had a direct impact only on the wall thicknesses and the pore diameters of vessels. These impacts can be of interest when planning feedstock utilization in biochar production. However, the results suggest that relatively homogeneous biochar can be produced from hybrid aspen feedstocks.

Effect of Lignin Modifier on Engineering Performance of Bituminous Binder and Mixture

Lignin accounts for approximately 30% of the weight of herbaceous biomass. Utilizing lignin in asphalt pavement industry could enhance the performance of pavement while balancing the construction cost. This study aims to evaluate the feasibility of utilizing lignin as a bitumen performance improver. For this purpose, lignin derived from aspen wood chips (labeled as KL) and corn stalk residues (labeled as CL) were selected to prepare the lignin modified bituminous binder. The properties of the lignin modified binder were investigated through rheological, mechanical and chemical tests. The multiple stress creep recovery (MSCR) test results indicated that adding lignin decreased the Jnr of based binder by a range of 8% to 23% depending on the stress and lignin type. Lignin showed a positive effect on the low temperature performance of asphalt binder, because at −18 °C, KL and CL were able to reduce the stiffness of base binder from 441 MPa to 369 MPa and 378 MPa, respectively. However, lignin was found to deteriorate the fatigue life and workability of base binder up to 30% and 126%. With bituminous mixture, application of lignin modifiers improved the Marshall Stability and moisture resistance of base mixture up to 21% and 13%, respectively. Although, adding lignin modifiers decreased the molecular weight of asphalt binder according to the gel permeation chromatography (GPC) test results. The Fourier-transform infrared spectroscopy (FTIR) test results did not report detectable changes in functional group of based binder.

Enhancing Thermally Modified Wood Stability against Discoloration

Thermal modification of wood has gained its niche in the production of materials that are mainly used for outdoor applications, where the stability of aesthetic appearances is very important. In the present research, spectral sensitivity to discoloration of thermally modified (TM) aspen wood was assessed and, based on these results, the possibility to delay discoloration due to weathering by non-film forming coating containing transparent iron oxides in the formulation was studied. The effect of including organic light stabilizers (UVA and HALS) in coatings as well as pretreatment with lignin stabilizer (HALS) was evaluated. Artificial and outdoor weathering was used for testing the efficiency of different coating formulations on TM wood discoloration. For color measurements and discoloration assessment, the CIELAB color model was used. Significant differences between the spectral sensitivity of unmodified and TM wood was observed by implying that different strategies could be effective for their photostabilization. From the studied concepts, the inclusion of the transparent red iron oxide into the base formulation of the non-film forming coating was found to be the most effective approach for enhancing TM wood photostability against discoloration due to weathering.

Evaluating the impact of stand composition and competition on white spruce and aspen wood attributes in the boreal mixedwood

I evaluated how intra- and inter-specific competition affects the development of eleven wood attributes of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) over 34 years. My analysis was conducted in a mixedwood trial site in Northern British Columbia, Canada, that included treatments consisting of 0, 1000, 2000, 5000, and 10000 stems per hectare of aspen. Competition was found to negatively influence wood attribute development in aspen and positively impact spruce (at low levels of competition). Plot level competition indices were the best predictor of variation in aspen wood attributes, while stand level competition (population density) best explained the majority of spruce wood attributes. Maintaining aspen at lower densities in intimate mixture can have a positive effect on spruce wood quality, while incurring relatively small reductions in spruce volume production and also retaining the ecological benefits associated with managing for mixed stands.