Birch Wood Research Articles

Laboratory- to Pilot-Scale Fractionation of Lignocellulosic Biomass Using an Acetone Organosolv Process

Acetone organosolv fractionation of beech and birch wood at the lab-scale results in high sugar yields from the (hemi)cellulose and the isolation of a high-purity lignin. In this study, the process is scaled up to validate the technology at the pilot scale using industrial-size beech and birch wood chips and low liquid-to-solid ratios as a next step toward commercialization. Translation of the fractionation process to the pilot-scale showed a similar performance as compared to the lab-scale processing with a good conversion of the wood polymeric pentoses to mostly monomeric sugars and a high delignification. Continuous lignin precipitation by solvent evaporation using the LigniSep process resulted in the formation of nonsticky lignin aggregates with a good filterability. The improved lignin yields and advanced process design as compared to the traditional dilutive lignin precipitation approaches are likely to translate to a better process economy. The pulp washing efficiency and the recovery of (nonprecipitable) lignin from the aqueous hemicellulose stream still need to be improved for an efficient process design. However, the fractionation performance and high product concentrations in the spent liquor provide an excellent start position for improved process design at the commercial scale.

Predictions of burnout times of biomass char using experimentally determined CO to CO2 ratio

The ratio of CO to CO2 produced during char combustion is an important parameter affecting the temperature of the char particle, the rate of mass transfer of gaseous species to and from the surface of the particle, and, consequently, the burnout time. In the present work, the ratio of CO to CO2 from combustion was measured for a biomass char using a thermogravimetric method. A sample of biomass char was combusted in conditions where the process was entirely limited by transfer of oxygen to the external surface of the fuel particles. The experimentally-obtained rate of combustion was compared with the expected rate of CO and CO2 transport, from which the ratio of CO to CO2 was calculated. The CO/CO2 ratio was determined for a char derived from birch wood and the results were compared with those from graphite and activated carbon at the same conditions. The experiments were conducted at various temperatures between 973 and 1173 K, with a range of partial pressures of oxygen in the oxidising gas from 0.0057 to 0.023 bar.The experimental CO/CO2 ratios were used to model the combustion of a single particle of char, predicting the total burnout time. Two models were developed: (1) an analytical solution for the burnout time assuming pseudo-steady state combustion, and (2) a numerical model of a char particle, accounting for gas transport and the combustion reaction inside the porous fuel particle. To validate the models, a separate set of experiments was performed where single particles of birch wood (6 mm dia.) were mounted on the tip of a thin thermocouple, then inserted into a hot reactor through which was flowing N2. The wood particle pyrolysed, leaving a single particle of char (∼4 mm dia.). The char was then burned in a laminar flow of oxidising gas. The burnout times obtained with both models agreed well with the experimental results. Commonly-used empirical expressions for CO/CO2 ratios from the literature were also employed in simulations but were found to under-predict the burnout time.

Insight into mycelium-lignocellulosic bio-composites: Essential factors and properties

Mycelium-bonded bio-composites are promising new materials for replacing non-sustainable products. In such composite systems, fungal mycelia work as an adhesive, bonding together lignocellulosic substrate particles. In this work, we focus on the two groups of mycelium-bonded bio-composites: as-grown foams and hot-pressed (densified) panels. We used Trametes versicolor mycelium and yellow birch wood particles as a substrate and incubated the mixture for up to 30 days. We investigated the relationship between mycelium growth and essential end-use properties. We revealed that in as-grown foams, mycelial colonization does not significantly alter physical and mechanical properties but can reduce sound absorption. In contrast, increased mycelial density in hot-pressed panel products resulted in an increasing modulus of rupture, modulus of elasticity, and internal bond strength. In hot pressed panels, mycelia appear to act as an adhesive to bond particles forced into contact during compaction.

Влияние предгидролитической обработки древесины березы на физико-механические характеристики композитного материала, получаемого на ее основе

The effects of the birch wood pretreatment with hydrogen peroxide and its subsequent treatment by explosive autohydrolysis on the density, strength in static bending, water absorption and swelling of a composite material obtained on the basis of hydrolyzed wood pulp by hot pressing without the addition of binders are presented. The dependences of the density of the samples, their strength and hydrophobic characteristics on the amount used in the processing of hydrogen peroxide and the conditions of explosive autohydrolysis have been established. The threshold limit of hydrogen peroxide for each of the modes of explosive hydrolysis has been determined.

Moisture influence on solid wood bonded with modified starch

Moisture influence on solid wood bonded with modified starch. A growing and developing population is contributing to the ever-increasing global warming, which is caused, among other things, by the heavy use of chemicals. Most of them are crude oil-based, which is a non-renewable source. That is why the population tries to find organic substitutes in every area, even in the wood industry. Here, the most common and popular binders - amine resins, are subjected in research to partial or full replacement by more natural binders, non-formaldehyde, made of renewable raw materials, preferably plant-based. In this project, the studies were carried out on the possibility of starch-based glue application in wood bonding and its effect on glued birch wood (Betula L.) under various environmental storage conditions of bonded samples. The results show, that the samples at room temperature and normal humidity, as well as another – additionally dried, have a very similar shear strength. In-wood damages, on the other hand, are much more varied. The research also included moistened samples, which gave poorer results. Based on the results, it can be concluded, that modified starch is a very good organic glue, that can potentially replace some chemical products in certain applications.

DETERMINATION OF KINETIC CHARACTERISTICS OF SOLID FUEL.

The combustion process begins with the ignition of the fuel - bringing it to the auto-ignition temperature, which is one of the important components of the kinetic characteristics of the fuel.
 Fuel ignition does not occur immediately - but after a certain period, during which activation energy is accumulated: heat or active centers, depending on the mechanism of the process - thermal-kinetic or chain-kinetic, sufficient to overcome the potential barrier. At the same time, the period of reaching the self-ignition temperature is the induction period of this reactive system: for self-ignition or the ignition time during ignition.
 The purpose of the work is to substantiate the kinetic characteristics of the fuel: self-ignition temperature and induction period, methods of their experimental determination for solid fossil fuels and biomass waste.
 According to the methodology, an installation was created for the experimental determination of the self-ignition temperature and the induction period of solid fuel in the layer.
 Studies of such fuels as anthracite, hard coal, buckwheat husk, millet, oats, flax husks, birch wood, peat, and paper showed the dependence of the self-ignition temperature on the degree of metamorphosis and volatiles. With an increase in the degree of metamorphism and a decrease in volatiles in solid fuel, the self-ignition temperature increases. However, the self-ignition temperature does not depend on the size of its particles, their number in the layer and the temperature of the oxidizer.
 The above allows us to conclude that the self-ignition temperature depends only on the conditions of heat exchange (accordingly, on aerodynamics), and the absolute value of the auto-ignition temperature for an infinite space, in the absence of a jet stream, is a constant value, and only then, in the presence of heat exchange (with velocity gradients) , takes one or another value.
 It was found that the induction period depends only on the initial temperature of the process, the induction period decreases with increasing temperature. This is due to the more intensive transfer of heat to the fuel particles due to the increase in the temperature gradient and the acceleration of the development of the oxidation reaction.
 The induction period, as shown by the conducted experiments, does not depend on the size of the particles. This can be explained only by the fact that the rate of thermal destruction of the fuel is close to the rate of its heating. The burning time of coal particles, on the contrary, depends on the size of its particles.
 Expressions for determining the autoignition temperature and the induction period were obtained based on the processing of the results of the conducted experiments.
 The results of the work can be used in combustion technologies, in which self-ignition of fuel is one of the main components of the process - it ensures combustion in the self-ignition mode of fuel when in contact with an oxidizer.

ПОВЫШЕНИЕ ВОДОСТОЙКОСТИ ДРЕВЕСИНЫ ПРОПИТОЧНЫМ СОСТАВОМ НА ОСНОВЕ РАСТИТЕЛЬНОГО МАСЛА С НАНОПОРОШКОМ ДИОКСИДА КРЕМНИЯ

The aim of the work was to develop and study new compositions for the treatment of natural wood based on used vegetable oil with the addition of nanosized silicon oxide to obtain a wood composite with improved properties. Specimens of birch wood were chosen as objects of the study. The basis of the developed impregnating compositions was used frying vegetable oil. The compositions were supplemented with additives of amorphous and crystalline silicon oxide nanopowders at a dosage of 0.01 to 0.5%. To modify wood, a stable suspension of synthesized silicon oxide nanopowders in used sunflower oil was prepared. The processing of wood specimens was carried out by the method of "hot-cold impregnation". The obtained wood composites with the addition of nanosized silicon oxide had improved hydrophobic properties of wood (an increase in the contact angle by 30%), increased moisture and water resistance (by 11 and 14 times, respectively), as well as reduced swelling in the tangential (by 4 times) and radial (5 times) directions in comparison with natural wood after 1 day of testing. The optimal dosage of silicon oxide nanopowders (0.01%) was chosen. A comparative evaluation of the use of amorphous and crystalline silicon oxides in impregnating compositions based on used vegetable oil was carried out using birch wood as an example. Impregnation compositions based on waste vegetable oil have low toxicity and their use makes it possible to dispose of production waste

Использование наноразмерного ZnO в составах для защитной обработки древесины

Wood natural structure can be considered as a suitable matrix for modifying with nanoparticles of various chemical nature. The research aims at obtaining a woodbased nanocomposite by modifying wood with compositions of waste vegetable oil and zinc oxide nanoparticles and studying the properties of this nanocomposite. Silver birch (Betula pendula) wood samples were chosen as study objects. Refined sunflower oil left after cooking was the oil base of the developed impregnating compositions; nanosized zinc oxide powder was the filler and modifier. The sol-gel method providing a narrow range of particle size distribution was used for synthesis of zinc oxide nanoparticles from Zn(NO3)2·6H2O as starting material. Aqueous ammonia solution was used as a precipitant. The synthesized zinc oxide nanoparticles contained no impurities, were mostly spherical and had the size less than 20 nm. The size of zinc oxide agglomerates was no more than 100 nm, allowing them to easily penetrate into the wood material cavities. A stable suspension of synthesized zinc oxide nanopowder in used sunflower oil was prepared and applied for wood modification by hot-and-cold bath treatment. It was found that the use of nanoscale zinc oxide accelerates the drying process of vegetable oil coating, increases the strength of such a coating and its resistance to external influences. The use of developed compositions improves the hydrophobic properties of wood, its moisture and water resistance, as well as reduces swelling in the tangential and radial directions. We have chosen the optimal dosage of nanosized zinc oxide (0.1 %) in compositions based on waste vegetable oil for protective treatment of birch wood. Impregnating compositions on the base of waste vegetable oil are environmentally safe and their use allows recycling food industry wastes.

Discrimination of levoglucosan and its structural isomer in biomass pyrolysis products by iodometry, liquid chromatography, mass spectrometry

This study aimed to selectively determine the main products of the pyrolysis of pre-treated lignocellulosic biomass, namely, two structural isomers of 1,6-anhydro-β-D-glucose (AG) – its pyranose (levoglucosan, LG) and furanose (AGF) forms. The influence of AGF on the iodometric titration of LG was evaluated. The presence of AGF had a clear impact on the titration results, but with sample oxidation at pH 9 it was possible to obtain accurate (relative error 1–5%) titration results for total AG, summing up both isomers. More importantly, several liquid chromatography methods were compared for LG and AGF quantification to develop a simultaneous selective determination of the AG isomers. Three columns showed promising results for the selective quantification of LG and AGF – ligand exchange columns with Ag+ or Pb2+ as counterion coupled to HPLC-RID, and a HILIC column coupled to UHPLC-ELSD under gradient conditions. All three methods showed acceptable precision, linearity, and recovery of AGF and LG. UHPLC-ELSD with an amide column could only be used to quantify the summed amount of AG isomers without chromatographic separation. AGF and LG had similar response factors in RID and ELSD methods. Moreover, it was shown that UHPLC-QTOF-MS could be used for qualitative investigations of the sugar derivatives found in biomass pyrolysis products. Samples of fast pyrolysis products were analysed with varying content of AGF (7–55%) and LG (25–64%). The samples were obtained from pre-treated birch wood, and anhydrosugar fractions were separated from the pyrolysis liquids.

Experimental and theoretical study on horizontal flame spread through arrays of wooden dowels

AbstractFlame spread along discrete fuel element is of great interest for both fundamental science and fire prevention, whose combustion properties may be different from those of homogenous materials. It has been a long time for researchers in fire science to find a simple and effective method to construct a discrete flame spread model. This work was motivated by the research of 2‐D horizontal discrete flame spread behaviors with different spacings and rows, establishing the prediction model of ignition time and global mass loss rate (MLR). In this work, burning characteristics of the 2‐D discrete flame spread were experimentally studied with six different row numbers (1–11 with an interval of 2) of cylindrical dowels (birch wood, 3 mm diameter × 50 mm height) under three selected spacings (6, 7, and 8 mm). Based on the heat transfer model developed, the theoretical models of ignition time and MLR were obtained and validated. Moreover, combined with previous studies, the numerical correlation between dimensionless flame height and dimensionless heat release rate for the 2‐D horizontal discrete flame spread scenario was established. This study provided an insight into the horizontal discrete flame spread mechanism in the aspect of heat and mass transfer, which may be applied in the prediction and assessment of discrete fuel fires in reality.

Gloss of Varnished MDF Panels Veneered with Sanded and Thermally Compressed Veneer

The objective of this study was to investigate the gloss of different types of commercially manufactured varnish systems, including water-based (WB), polyurethane (PUR) and UV-cured (UV), applied on veneered MDF panels with sanded and thermally densified alder and birch wood veneers. The varnishes were applied at various numbers of layers on veneered panels. The gloss was measured at three angles of incident light: 20°, 60° and 85°. Statistical analysis showed that the type of varnish, the number of layers, the pre-treatment process, the wood species and direction of wood fibers significantly affect gloss of the coatings of veneered MDF panels. The type of varnish had a dominant effect on gloss. The highest gloss values were measured for the UV-varnished surface, and the lowest for WB- and PUR-varnished surfaces. Gloss was enhanced with an increase in the number of layers. Birch veneer provided higher gloss values compared to alder veneer. The gloss values measured along the wood fibers were higher than those measured across the fibers. No significant differences were found between the coatings created on sanded and thermally densified veneers for the average gloss values measured along the fibers at angles 60° and 85°. This study could have practical applications for producing value-added furniture elements using low-value wood species pre-treated by thermal compression.

Moisture sorption isotherms and hysteresis of cellulose, hemicelluloses and lignin isolated from birch wood and their effects on wood hygroscopicity

Moisture sorption isotherms and hysteresis of cellulose, hemicelluloses and lignin isolated from birch wood and their effects on wood hygroscopicity

Het Voornse Berkenrijs: van keizerlijk hakhout tot caravanopslag

Berkenrijs on Voorne: from imperial coppice to caravan park Berkenrijs means ‘birch coppice’, which was formerly used for the periodic harvesting of branches and twigs. On Voorne, ‘Berkenrijs’ is a field name that appears in records and on maps from the Middle Ages onwards. Now there are still street names: Berkenrijs, Berkenrijspad and Berkenrijsweg, all near the old Limiet between the former lordships of Rockanje and Oostvoorne. There is no longer any birch wood to be found here, but there is a single row of alders. If the land had remained the property of large landowners, coppices along the inner dune fringe would have often turned into standing wood, such as on the Voorne estates of Mildenburg and Kranenhout. After the old imperial estate Berkenrijs was given an agricultural purpose, probably not until the 20th century, it even ended up as a caravan park. In the protected village landscape established by the state (Ontginningen Voornes Duin, 2017), Berkenrijs appears to be a blind spot.

Analysis of steady and oscillating flames fueled by biomass particles and syngases considering two-step pyrolysis and heterogeneous and homogeneous reactions

Under unprecedented environmental crisis associated with greenhouse gas emission, biomass has attracted a great deal of attention due to renewable and carbon neutral nature. In this study, the premixed combustion of various types of wood and its derived syngases are examined for steady and oscillating sates. For this purpose, the poplar, birch, beech and pin sawdust woods and syngases composing of H2, CH4 and CO are considered. To model dust cloud combustion, a novel and comprehensive flame structure consisting of drying, two-step pyrolysis and homogeneous and heterogeneous reactions is proposed. Afterward, the governing equations and their appropriate boundary conditions are derived and solved analytically-numerically. The oscillating combustion is also modeled by exerting an external perturbation on the velocity field. The results indicate that due to the occurrence of heterogeneous reactions in wood combustion, the flame propagation velocity of wood is higher than that of syngases which contributes to high oscillations amplitude of syngases. When the mixture initial temperature changes between 300 and 550 K, the flame velocities of woods and syngases vary in the ranges of 0.4–0.7 m/s and 0.1–0.27 m/s, respectively. The maximum amplitude of temperature oscillation of syngases is approximately 8 times more than that of woods.

Acetylated Xylan Degradation by Glycoside Hydrolase Family 10 and 11 Xylanases from the White-rot Fungus <i>Phanerochaete chrysosporium</i>

Endo-type xylanases are key enzymes in microbial xylanolytic systems, and xylanases belonging to glycoside hydrolase (GH) families 10 or 11 are the major enzymes degrading xylan in nature. These enzymes have typically been characterized using xylan prepared by alkaline extraction, which removes acetyl sidechains from the substrate, and thus the effect of acetyl groups on xylan degradation remains unclear. Here, we compare the ability of GH10 and 11 xylanases, PcXyn10A and PcXyn11B, from the white-rot basidiomycete Phanerochaete chrysosporium to degrade acetylated and deacetylated xylan from various plants. Product quantification revealed that PcXyn10A effectively degraded both acetylated xylan extracted from Arabidopsis thaliana and the deacetylated xylan obtained by alkaline treatment, generating xylooligosaccharides. In contrast, PcXyn11B showed limited activity towards acetyl xylan, but showed significantly increased activity after deacetylation of the xylan. Polysaccharide analysis using carbohydrate gel electrophoresis showed that PcXyn11B generated a broad range of products from native acetylated xylans extracted from birch wood and rice straw, including large residual xylooligosaccharides, while non-acetylated xylan from Japanese cedar was readily degraded into xylooligosaccharides. These results suggest that the degradability of native xylan by GH11 xylanases is highly dependent on the extent of acetyl group substitution. Analysis of 31 fungal genomes in the Carbohydrate-Active enZymes database indicated that the presence of GH11 xylanases is correlated to that of carbohydrate esterase (CE) family 1 acetyl xylan esterases (AXEs), while this is not the case for GH10 xylanases. These findings may imply co-evolution of GH11 xylanases and CE1 AXEs.

Indentation Hardness and Elastic Recovery of Some Hardwood Species

The purpose of the study was to measure the Brinell hardness (HB) of six wood species and evaluate the ability to recover the depth of the imprint (self-re-deformation). Straight-grain clear samples of ash, beech, alder, birch, iroko, and linden wood were prepared. Measurements were made in the three main reference timber cross-sections: radial (R), tangential (T), and axial/longitudinal (L) and with two measuring loads of 30 kG and 100 kG (294.2 N and 980.7 N). The tested wood species could be classified into hard (ash, beech), medium-hard (alder, birch, iroko), and soft (linden) wood species. The HBs of each tested wood species differed in the cross-sections, i.e., side hardness (R, T) and end hardness (L). Higher HB values were obtained at 100 kG load in all species and all three cross-sections. The lowest influence of the measurement force value on the HB value was revealed for the soft wood species (linden: 107–118%). This influence was visible for the other five medium-hard and hard wood species, ranging from 125% to 176%. The percentage of temporary imprint in total imprint depth (x/H) varied from 12 to 33% (linden 12–18%—the lowest self-re-deformation ability; beech 25–33%—the highest self-re-deformation ability). The results of this study underline that the higher the density of the wood, the higher the Brinell hardness, and, simultaneously, the greater the measurement force used, the higher the Brinell hardness measured. The ability of self-re-deformation in wood’s R and T cross-sections depends on the wood density and the measuring force used. In contrast, this ability only depends on the wood density in the L cross-section. Those observations imply that the compaction of the cell structure during side compression is mainly non-destructive, while the longitudinal deformation of the cell structure (the buckling of cell walls and fracture of ends of the cells) is to a great degree destructive and irreversible. These results can be used in the construction and furniture sectors, especially when designing products and planning the woodworking of highly loaded wood floors and furniture elements.

Технология модификации древесины березы для создания нейтронозащитных материалов

The article considers a method for producing neutron shielding materials based on modified birch wood. It is known that shielding materials based on polyethylene with boron addition are widely used in the nuclear industry, medicine and the military-industrial complex to create protection against neutron radiation. Due to the high hydrogen content, their use makes it possible to protect objects from the effects of fast neutrons, and thermal neutrons are effectively contained due to the presence of boron atoms in the protective screens. Wood is also a hydrogen-containing material, therefore, it is of scientific and practical interest to create and study the properties of neutron shielding materials based on wood. The most expedient is the creation of neutron shielding materials from hardwood, which have a high specific density and, accordingly, a high content of hydrogen per unit volume. It is possible to increase the hydrogen content per unit volume of wood and, accordingly, to reduce the thickness of the protective layer due to the compaction of wood by the method of flat (singleaxis) pressing. The main condition for obtaining high-strength and form-resistant pressed wood is the preservation of its microstructure (without damage) during pressing. It has been theoretically found that the optimal pressing stage, at which the lowest percentage of microfractures in wood is observed, should not exceed 50 %. In the experimental part of the work, birch lumber was used for the production of an experimental neutron shielding material, radial sawn with a length of 200 mm, a width of 100 mm, and a thickness of 80 mm to obtain ready-made neutron shielding materials with a thickness of 40 mm, which is equivalent to a polyethylene shielding thickness of 26.8 mm. It is known that during flat pressing bursting forces occur in wood, which can lead to cracks, destruction of edges, buckling, delamination, and a decrease in the uniformity of the density distribution. The bursting force acts in the direction perpendicular to the action of the applied load. Therefore, in the manufacture of a neutron shielding composite material, it is necessary to use press molds (with side stops) that stop the impact of the bursting force. The design parameters of the press molds and pressing modes are determined taking into account the resistance caused by the friction forces of the wood against the side walls of the press mold. The design of a press mold that provides the production of a neutron shielding material of specified properties from wood is presented.

High-purity cellulose production from birch wood by γ-valerolactone/water fractionation and IONCELL-P process

This study presents an environmentally friendly process to produce high-purity cellulose (dissolving pulp) from birch wood by combining γ-valerolactone (GVL)/water fractionation and ionic liquid treatment of pulp, IONCELL-P (IP). A paper grade pulp was produced from optimal GVL cook with a similar composition to birch kraft pulp and was bleached with ECF sequence before the hemicelluloses were removed using the IONCELL-P process. The purity of the GVL-IP pulp significantly exceeded that of commercial prehydrolysis kraft (PHK) and prehydrolysis soda-anthraquinone (PH-Soda-AQ) pulps. IONCELL-P extraction removed more than 90% of the hemicelluloses, resulting in a dissolving pulp with a purity of 96% and a high molecular mass fraction, 2.3 times higher than that of a conventional PHK pulp. GVL-IP pulps are suitable not only for regenerated cellulose fibers or films, but also for high-purity, high-viscosity cellulose acetate and ethers, which cannot be produced in an environmentally friendly way by conventional processes.

Influence of substrate wood species on the formation of antiviral properties of <I>Inonotus rheades</I> Pers. P. Karst. (1882) mycelium extracts regarding tick-borne encephalitis virus

Background. The tick-borne encephalitis virus (TBEV) is one of the most dangerous and epidemiologically significant vector-borne pathogens. There is a need for effective antiviral agents for the treatment and prevention of this infection. Previously we found that the mycelium of Inonotus rheades grown on birch wood contains water-soluble substances with strong virulicidal properties against TBEV. It is necessary to check whether the mycelium of I. rheades can synthesize virulicidal substances from wood of other species.The aim: to study the antiviral properties of extracts of I. rheades mycelium grown on coniferous wood, both in the presence and in the absence of blue light during cultivation.Materials and methods. The mycelium of I. rheades was grown on birch, pine, and fir wood. The direct virulicidal effect of the extract was evaluated by the decrease in the titer of the infectious virus incubated in the presence of the extract. The ability of the extract to inhibit the reproduction of the virus in infected cells was studied by the calculation of 50 % effective concentration (EC50). The toxicity of extracts for cells was evaluated based on the calculation of 50 % cytotoxic concentration.Results. Mycelium extracts grown on conifers under blue light do not cause a statistically significant decrease in the concentration of infectious TBEV (p = 0.2563). However, the BP10 extract (pine, blue light) inhibits TBEV reproduction in infected cells (EC50 = 0.28 ± 0.06 mg/mL). Toxicity for SPEV cell culture is low. In the extracts of conifers grown in the dark, no antiviral effect was found at all.Conclusions. The component composition and mechanism of the antiviral action of I. rheades extracts are determined by the species of the wood substrate. The most promising sources of new drugs in relation to TBEV appear to be extracts of I. rheades mycelium grown on birch and pine.

Preparation of Renewable Thiol‐Yne “Click” Networks Based on Fractionated Lignin for Anticorrosive Protective Film Applications

AbstractThe synthesis of novel, renewable lignin‐based protective films with anticorrosive properties is presented in this work. Thermosetting films are prepared by means of tandem UV‐initiated thiol‐yne “click” synthesis and Claisen rearrangement strategy. These films contain high lignin loading, 46–61%, originating from a nickel‐catalyzed birch wood reductive catalytic fractionation (RCF) process. Lignin fractions with varying monomer content are compared before resins preparation, namely a mixture of monomers and oligomers without fractionation, or after fractionation via extraction and membrane separation. This study aims to determine if the separation of lignin monomers and oligomers is necessary for the application as a thermosetting resin. The resulting films exhibit remarkable adhesion to a metal surface and excellent solvent resistance, even after exposure to a corrosive environment. Moreover, those films show superior barrier properties, studied with odd random phase electrochemical impedance spectroscopy (ORP EIS). After 21 days of exposure, the examined films still show impressive high corrosion protection with the low‐frequency impedance ≈1010 Ω cm2 and capacitive behavior. This work demonstrates an interesting proof‐of‐concept where laborious, costly, and energy‐intensive separation of the depolymerized lignin mixture of monomers and oligomers is not necessary for the successful resin synthesis with excellent properties using the applied synthetic strategy.