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This study investigates the mycelial biomass production and chitosan extraction potential of various Basidiomycota strains, including Heterobasidion annosum, Phanerochaete chrysosporium, Pleurotus ostreatus, Trametes versicolor, and Lentinus lepideus. Both submerged fermentation (SF) and solid-state fermentation (SSF) methods were employed. The chitosan yield in basidiocarps of Pleurotus ostreatus, Agaricus bisporus, and Ganoderma applanatum was also evaluated as a reference material. The chitosan extracted from fungal cells was characterized using elemental analyses and FTIR spectroscopy. Among the cultivated strains, P. chrysosporium exhibited the highest mycelial biomass concentration in SF (1.03 g 100 mL–1) after 14 days, while T. versicolor achieved the highest biomass concentration in SSF (3.65 g 100 mL–1). The highest chitosan yield was obtained from the mycelium of P. chrysosporium (0.38%) and T. versicolor (0.37%) in shaken SF. Additionally, commercially cultivated A. bisporus demonstrated the highest chitosan yield in fungal fruiting bodies (1.7%). The extracted chitosan holds potential as a functional biopolymer additive for eco-friendly materials, serving as an alternative to synthetic wet and dry strength agents in packaging materials. [ABSTRACT FROM AUTHOR]

The objective of the present study was to investigate the interaction between Cu-containing preservatives and birch (Betula spp.) and pine (Pinus sylvestris L.) wood, modified at a relatively mild temperatures (150 - 180°C). The disposition of wood to absorb water was evaluated by capillary absorption (CA) tests through the specimens' tangential and radial surface. Changes in wood drying characteristics due to thermal modification (TM) were evaluated by monitoring wood moisture dynamics after impregnation. In order to assess the capacity of wood to absorb preservatives, a vacuum/pressure process was used to impregnate small specimens for which uniform saturation into the entire volume can easily be reached. Quantitative determination of copper Cu content in the specimens was performed by using atomic absorption spectroscopy (AAS). The fixation of the absorbed Cu was evaluated by subjecting the specimens to leaching procedures according to EN 84 and assessing the ratio of retained Cu in the specimens. The CA test showed deceleration of capillary absorption in TM birch wood through both surfaces, with similar absorption rates regardless of treatment temperatures. A significant increase in the absorption rate through the tangential surface was recorded for TM pine wood and the increase was greater for specimens treated at higher temperatures. The results of moisture content monitoring showed a similar reduction in the drying rate due to thermal modification regardless of species. Comparing wood of one species with similar densities, less preservative was absorbed by TM wood. However, the results of AAS showed that, in comparison with unmodified wood, 10% (birch) and 25% (pine) more Cu per one gram of wood was introduced during impregnation. Nevertheless, TM also resulted in higher Cu leaching rates for both species. [ABSTRACT FROM AUTHOR]

A wood residue - sawdust of the mechanical processing of aspen (Populus tremula) wood - was used to obtain a short fibre filler in the form of the modified microparticles < 250 μm for polymeric composite materials. To reduce energy input for wood size reduction and the activation of the lignocellulosic matrix for modification, low temperature acid hydrolysis of the residue under mild conditions was carried out. The effect of the pre-treatment parameters (acid concentration, hydrolysis duration, hydromodulus) on the fractional and chemical composition as well as on the zeta potential and contact angle of the obtained filler were studied. A comparison of the mechanical properties (tensile, bending) of the composites filled with initial sawdust and hydrolysed microparticles modified with a non-stoichiometric polyelectrolyte complex showed a pronounced improvement of the mechanical properties of the composites filled with modified wood microparticles. [ABSTRACT FROM AUTHOR]

A lignin-containing adhesion enhancer, a water-soluble polyelectrolyte complex (LPEC) composed of soda hardwood lignin (HASL) and polyethylenimine (PEI), and the effect of the treatment of hydrolyzed and ammoxidized aspen sawdust with the LPEC nanoparticles were studied relative to the properties of wood-plastic composites (WPCs) based on recycled polypropylene (rPP). The presence of the excess of free amine groups and salt bonds between PEI and soda lignin, forming hydrophobic sites in the LPEC structure, caused the enhanced surface activity of the LPEC. The treatment with the LPEC nanoparticles increased the content of the fixed nitrogen in the modified sawdust samples and was accompanied by decreasing their water sorption and increasing contact angles that favored the decrease in the polar part of their surface free energy. The decreasing wetting ability enhanced the mechanical and water sorption properties of the obtained WPC samples. The improvement of the interfacial adhesion between the nitrogen-containing groups of the treated sawdust and the oxygen-containing groups of rPP was explained by the formation of both covalent and physicochemical bonds. [ABSTRACT FROM AUTHOR]

We report the preparation of polyurethane (PU) rigid foams from bio-based and recycled components. Rapeseed oil (RO) and recycled polyethylene terephthalate (rPET) were used to synthesize PU polyols. Fifty-five percent of the content of the proposed PU polyols originates from renewable or recycled material. Glycerol (GL) and adipic acid (ADA) were added to improve the final properties of the foams. The GL/ADA content was varied from 1 to 6 wt.%. The hydroxyl value, acid value, water content, and viscosity of the synthesized polyols were measured. Using compression tests on PU rigid foams, we found that for some GL/ADA contents the rigidity increased almost 3-fold; whereas the strength increased almost 2-fold. The water absorption of the foams was below 3 wt.%. Optical microscopy of foam cross-sections revealed a mean cell sizes of 330 μm for PU with GL/ADA, and 420 μm for PU supplemented with GL/ADA and RO. FTIR measurements revealed enhanced hydrogen bond networking due to the incorporation of GL/ADA fragments and RO long aliphatic blocks in the PU chain backbone. [ABSTRACT FROM AUTHOR]

To decrease climate changes, more research focuses on decreasing waste wood biomass (WWB) burning and increasing its conversion into value-added products. The WWB was isolated from model wood processing wastewater with a new hybrid coagulant by the coagulation/flocculation method. This study is aimed to characterize the WWB and to investigate its effect in the composition of a hybrid lignocellulosic filler on the properties of recycled polypropylene (rPP)-based wood–plastic composites (WPCs). The waste biomass contained high-molecular lignin and hemicelluloses substances and represented a finely dispersed powder. It was hydrophobic and was characterized by enhanced thermal stability. To minimize the negative effect of polymer wastes on the environment, recycled polypropylene as a polymer matrix was used with the hybrid filler in fabricating WPC samples. The presence of the coagulated WWB in the hybrid filler composition positively affects the mechanical properties, water uptake and dimensional stability of the composite samples. Such a behavior of the waste biomass showed its function as a compatibilizer, which promoted the interfacial adhesion in the composite system. [ABSTRACT FROM AUTHOR]

In this study, the relationship between the properties of the wood and kraft pulp fibers as well as paper characteristics of 27-year-old trees, lodgepole pine (Pinus contorta) and Scots pine (Pinus sylvestris), was assessed. All trees had been grown in Latvia, within the same forest type, Myrtillosa. Wood density, year ring width, chemical composition and cross-sectional cell wall dimensions were measured. Fiber characteristics were determined, and handsheets were made for all samples from unbeaten kraft pulp. The results showed that the amount of latewood had a positive correlation with wood density for both species and with further positive impact on the paper burst index. Also, slight differences in cross-sectional dimensions were observed. Lodgepole pine provided paper with higher burst strength than Scots pine. Since the former is of higher density, less wood per volume is needed to produce a ton of pulp, and results showed a higher pulp yield in the case of lodgepole pine. [ABSTRACT FROM AUTHOR]

It has been shown that the found regularities of the interaction between lignosulfonate and polymeric cations in aqueous media can serve as a scientific basis for chemical modification of lignin by way of the formation of the interpolyelectrolyte complexes. This energy-saving and non-complicated method of modification was applied for obtaining new lignin-based soil improving agents. Water-soluble polymeric products of the interaction of lignosulfonate with three synthetic polymeric cations have been used in order to study the effect of their adsorption at the clay soil surface on the water stability of the artificially soil aggregates formed by the treatment of soil with lignin-based polyelectrolyte complexes (LPECs). The obtained results are explained from the viewpoint of the complex mechanism of soil structure formation, combining simultaneously the flocculation of soil particles and stabilization of the formed aggregates. The conducted field tests have shown that the application of the lignin-based polyelectrolyte complex as a soil conditioner at a deep loosening of heavy clay soil allows the improvement of the hydrophysical properties and the filtration ability of the soil sublayers and, thereby, to enhance the barley yield. [ABSTRACT FROM AUTHOR]