INVESTIGATION OF THE DENSITY OF A FIBROUS CELLULOSE MATRIX FOR A HEAT-INSULATING POLYMER COMPOSITE MATERIAL AT LOW PRESSING PRESSURES

Для теплоизоляционных полимерных композиционных материалов (ПКМ) с наполнителем из целлюлозных волокон одним из актуальных вопросов является изменение плотности волокнистой матрицы под действием внешних механических нагрузок. Предметом экспериментального исследования явились образцы разрыхленной небелёной древесной сульфитной целлюлозы из хвойной древесины в воздушно-сухом состоянии. Цель исследования – оценка изменения насыпной плотности разрыхленной целлюлозы от величины давления прессования при малых давлениях прессования. В экспериментальных исследованиях использован метод денсиметрии. Из целлюлозной папки в лабораторных условиях получены образцы разрыхленной целлюлозы путём механического разволокнения. Использован лабораторный колковый рыхлитель роторного действия. Разрыхление проведено при окружной скорости ротора 50 м/с. Давление прессования варьировалось от 0 до 7,5 кПа. Получены образцы разрыхленноё целлюлозы с насыпной плотностью от 11,1 до 100,0 кг/м3. Эксперименты проведены с трёхкратным повторением. Показано, что при увеличении давления прессования насыпная плотность целлюлозы стабильно возрастает. В исследованном диапазоне давлений прессования уплотнение целлюлозы проходит в два этапа. На первом этапе при давлении прессования от 0 до 5 кПа насыпная плотность возрастает от 11,1 до 87,5 кг/м3. На втором этапе, при давлении прессования свыше 5 кПа, насыпная плотность возрастает с 87,5 до 100 кг/м3. На втором этапе замедление нарастания насыпной плотности при росте давления прессования может быть обусловлено деформацией элементарных волокон целлюлозы. Результаты экспериментального исследования могут быть применены для создания теплоизоляционных ПКМ на основе целлюлозных волокон. For heat-insulating polymer composite materials (PCM) with a cellulose fiber filler, one of the topical issues is the change in the density of the fiber matrix under the influence of external mechanical loads. The subject of the experimental study was samples of loosened unbleached wood sulfite cellulose from coniferous wood in an air-dry state. The aim of the study is to assess the change in the bulk density of loosened pulp from the value of the pressing pressure at low pressing pressures. In experimental studies, the method of densimetry was used. Samples of loosened cellulose were obtained from the pulp folder under laboratory conditions by mechanical de-fibration. A laboratory rotary chopper was used. Loosening was carried out at a circumferential rotor speed of 50 m / s. The pressing pressure varied from 0 to 7.5 kPa. Samples of loosened cellulose with a bulk density from 11.1 to 100.0 kg/m3were obtained. The experiments were carried out in three-fold repetition. It is shown that with an increase in the pressing pressure, the bulk density of cellulose steadily increases. In the studied range of pressing pressures, the pulp compaction takes place in two stages. At the first stage, at a pressing pressure of 0 to 5 kPa, the bulk density increases from the initial value 11.1 to 87.5 kg / m3. At the second stage, when the pressing pressure exceeds 5 kPa, the bulk density increases from 87.5 to 100 kg/ m3. At the second stage, the slowdown in the increase in bulk density with an increase in the pressing pressure can be caused by the deformation of the elementary cellulose fibers. The results of the experimental study can be used to create heat-insulating PCM based on cellulose fibers.

STADY OF SURFACE TENSION OF MODIFIED WOOD

The study of the surface tension of wood of various tree species impregnated with used sunflower oil was carried out. Samples of birch, pine and linden wood were used for oil treatment. Impregnation of wood materials was carried out by the method of “hot-cold baths”. As an impregnating material, used refined fryer oil was used. In more detail, the paper examines the effect of an impregnating composition based on used fryer oil, with a filler and a desiccant on birch wood. Wood flour of coniferous wood species and a metal salt-based drier were used as a filler. The surface tension for all images was determined by the edge angle of wetting. For this purpose, the method of a liquid drop on the surface of a solid body was used. It was found that the impregnation of untreated wood with deep-frying oil leads to an increase in the surface tension on all samples, to a greater extent this is typical for pine wood. The introduction of a 1% siccative in the impregnating composition together with wood flour reduces the drying time and improves the water-repellent properties of birch wood.

CONTINUOUS IMPREGNATION OF WOOD FROM THE END FACE UNDER PRESSURE WITH VARIOUS COMPOSITIONS

Modern impregnating compositions for wood can significantly improve its characteristics. Water-soluble and oily antiseptics, flame retardants, strengthening and plasticizing modifiers, and dyes are used as impregnating compositions. By means of impregnation, substances are introduced into the wood that increase its characteristics such as plasticity, hydrophobicity, bio- fire resistance and shape stability. But, the indicator of certain properties after impregnation of wood with a certain composition depends on the depth of impregnation, on the uniformity of the distribution of the impregnating composition over the entire volume of wood, on the concentration of the impregnating composition in the wood, on the chosen method of impregnation. It also affects which group of impregnability a particular wood belongs to, according to the breed composition, the division is made into 3 groups: 1-easily nourished rocks (birch, alder, beech, aspen sapwood, poplar, pine); 2-moderately impregnated rocks (cedar, oak, ash, maple, linden, pine core); 3-hard- to-impregnate rocks (spruce, larch, fir). Spruce and larch are considered to be almost impervious to deep impregnation of the rocks, because of their clogged pores with resin. In the autoclave method of impregnation with water solutions, the wood must be dried to a humidity of 40% before impregnation, and to a humidity of 30% when impregnated with oily liquids. After impregnation, a re-drying operation follows. Another significant disadvantage of autoclave impregnation is its uneven distribution of the absorbed liquid in the workpieces, in some workpieces too much impregnating liquid penetrates, and in others not enough. In order to avoid two dries and to be able to set the volume of liquid that the wood will absorb, as well as to ensure the uniformity of impregnation over the entire volume of wood, it is proposed to develop a technology and equipment for end-to-end impregnation of coniferous wood from the end under pressure of raw, rounded logs with a diameter of 15-35 cm and a length of 3 m.

CREATION OF A COMPOSITE COMPOSITION FOR IMPREGNATING RAILWAY SLEEPERS

This paper shows the stages of developing an eco-friendly composite composition (PKS) for impregnating railway sleepers made of birch wood, which has high water and moisture resistance. Used oils were selected for the study: mineral engine oil, transmission oil, sunflower oil, corn oil. The used oils were compared with the oil liquid ZHTK-2, which is widely used for impregnating railway sleepers, according to the following indicators: the content of the impregnating composition; water absorption and swelling of the impregnated wood after 30 days of standing in water in the radial and tangential directions. According to the sum of the obtained indicators, the spent mineral engine oil (OMM) was chosen as the basis of the PKS, flour of various types of wood (coniferous or deciduous), flour of oak, birch or pine bark was proposed as a filler. The greatest effect was obtained when introducing coniferous wood flour (MDH) in the amount of 1% of the mass of the OMM into the OMM. At the same time, the content of the impregnating composition in the wood increases from 43 to 70%, water absorption decreases (by 63.8%) and the swelling of the wood in the tangential and radial directions. When comparing the target values for the oil composition (OMM+MDX) and the oil liquid ZHTK-2, it was found that the content of the impregnating composition is 10.6% higher than for ZHTK-2, water absorption is reduced by 6.8%.

Genome of Ganoderma Species Provides Insights Into the Evolution, Conifers Substrate Utilization, and Terpene Synthesis for Ganoderma tsugae

Ganoderma tsugae is an endemic medicinal mushroom in Northeast China, providing important source of pharmaceutical product. Comparing with other Ganoderma species, wild G. tsugae can utilize coniferous wood. However, functional genes related to medicinal component synthesis and the genetic mechanism of conifer substrate utilization is still obscure. Here, we assembled a high-quality G. tsugae genome with 18 contigs and 98.5% BUSCO genes and performed the comparative genomics with other Ganoderma species. G. tsugae diverged from their common ancestor of G. lingzhi and G. sinense about 21 million years ago. Genes in G. tsugae-specific and G. tsugae-expanded gene families, such as salh, phea, cyp53a1, and cyp102a, and positively selected genes, such as glpk and amie, were functionally enriched in plant-pathogen interaction, benzoate degradation, and fanconi anemia pathway. Those functional genes might contribute to conifer substrate utilization of G. tsugae. Meanwhile, gene families in the terpene synthesis were identified and genome-wide SNP variants were detected in population. Finally, the study provided valuable genomic resources and offered useful hints for the functional gene mapping and investigation of key gene contributing to conifer cultivation substrate utilization and medicinal component biosynthesis.

Super interesting black hole? The micromorphology of organic materials in a Mesolithic hearth pit feature from the site of Soest-Staringlaan (the Netherlands)

A series of thin sections from a Mesolithic hearth pit from the site of Soest-Staringlaan (the Netherlands) were studied to assess the variability of the charred and non-charred organic remains inside them. Non-charred remains included plant roots; fungal fruiting bodies and hyphae; mesofauna coprolites; and podzolization-related polymorphic humus and monomorphic humus coatings. Charred remains included charcoal of coniferous wood, charred non-woody plant material and fragments of wood. However, a large proportion of the charred material consists of fine, powdery fragments. This may at least partly be due to trampling and/or eluviation of disintegrating charcoal. Most of the micromorphological features in the Soest pit are similar to those found in pits from previously investigated Mesolithic sites. Common features include the presence of large fragments of charcoal in the lower parts of hearth pits, tar, charred humus and evidence for charcoal disintegration and eluviation. The combined results first and foremost demonstrate the strong variability between samples within the same feature. This implies that multiple samples from a pit are necessary in order to at least attempt to try to capture this variability. It is also clear from the results that sampling should include layers or deposits that macroscopically seem to be outside the feature proper. These may contain parts of the phenomenon studied that are difficult to recognize with the naked eye. These observations add to the notion that Mesolithic hearth pits are generally formed by the same human activities, formation processes and taphonomy. However, they make clear that intense sampling is needed for any research to better understand the formation of these pits and that supplemental chemical analyses may be needed to better interpret the observed features and get a better idea of the potential use of these common Mesolithic features.

CP MAS 13C NMR SPECTROSCOPY IN DETERMINATION OF SPECIFIC DIFFERENCES IN COMPOSITION OF WOOD

In recent years solid-state 13C NMR spectroscopy using the technique of cross-polarization (CP) and sample rotation at a magic angle (MAS) has been used in the analysis of plant materials, including wood. Knowledge of the composition, structure and behavior of wood components in different conditions is of great importance, since the properties of wood materials depend on this. In this work differences in the composition of various tree species wood in central Russia (birch, aspen, spruce, and larch) were revealed using CP MAS 13C NMR spectroscopy. Assignment of various peaks in CP MAS 13C NMR spectra with the main components of wood was carried out. It was shown that cellulose is presented in amorphous and crystalline forms, the presence of lignin is unambiguously confirmed by signals of aromatic carbon atoms, and hemicellulose is detected by signals from carbon atoms of methyl groups of acetylxylose and L-rhamnose. According to the integral intensities, the total proportion of cellulose and hemicellulose in relation to lignin was determined: the largest amount of lignin was found in coniferous wood (spruce, larch), and the smallest amount of lignin was detected in deciduous species (aspen and birch).

The Timber Footprint of the German Bioeconomy—State of the Art and Past Development

The article gives a comprehensive overview of the roundwood equivalents (RE) consumed in the German bioeconomy from Germany and abroad between 1995 and 2015, i.e., the Timber Footprint of final Consumption (TFPcon). The calculation is based on an adapted version of Exiobase 3.4. The sustainability of roundwood procurement for the TFPcon is assessed. A systematic embedding of the tree compartments considered in the TFP in the context of national forest inventories and material flow analysis is presented. The results show that, in 2015, the total volume of the TFPcon of Germany is 90 Mm3 (slightly above the 1995 level) and is composed of 61% coniferous and 39% non-coniferous wood. Germany is strongly dependent on roundwood sourced from abroad and thus was a net importer of RE in 2015. Among the 17 countries with the largest supply of RE for the TFPcon, around one third very likely include large shares of roundwood procured from deforestation or clear-cutting. The self-sufficiency rate in 2015 was only 76%. It would be possible to increase domestic roundwood production by 8–41% (mainly in the hardwood sector) without exceeding the sustainability limits as defined in the WEHAM scenarios.

USE OF CONIFEROUS WOOD BIOCHAR AS A SUBSTITUTE FUEL IN AN IRON ORE SINTERING PROCESS

The article presents the results of tests carried out at Łukasiewicz – IMŻ, in cooperation with the Institute for Chemical Processing of Coal, on the use of biochar from coniferous wood as a substitute fuel in the iron ore sintering process. It was found that, considering productivity, fuel consumption and properties of the obtained sinter, the content of the tested biochar should not exceed 10 wt% in total fuel. When using the tested biochar, the content of FeO in the sinter decreased. The sinter was characterised by better ISO T strength than when using only coke breeze. At the same time, the grindability of the ISO A sinter decreased with the increase in the content of the biochar in the total fuel. The use of the tested biochar can have a very positive effect on both the sinter strength and its reducing properties.

Pretreatment of kraft lignin by deep eutectic solvent and its utilization in preparation of lignin-based phenolic formaldehyde adhesive

To improve the reactive sites of kraft technical lignin, a deep eutectic solvent (DES) composed of ZnCl2 / lactic acid was used to pretreat kraft lignin from coniferous wood. The modified and unmodified lignin were used to replace different proportions of phenol (50%, 60%, and 70%) to prepare the lignin-phenol-formaldehyde (LPF) adhesive. The phenolic hydroxyl content of DES-treated lignin increased from 3.12 wt% to 3.93 wt% and methoxy content decreased from 11.83 wt% to 6.64 wt% under optimized experimental conditions. The bond strength of LPF adhesive prepared by DES reagent activated lignin was higher than that of the control sample. When the substitution degree of modified lignin for phenol reached 70%, the bond strength of the plywood prepared by the DES-pretreated lignin was 0.79 MPa and the free formaldehyde content was 0.28%, which met the requirements of the Chinese national standard GB/T 9846 (2015). However, the viscosity was higher than the control sample, and results indicate that DES reagent modification cannot improve the viscosity of LPF resin.