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Highlights Wood flour (WF) at 10 wt.% and 20 wt.% loadings was used as a reinforcing filler to enhance the applicability of polypropylene (PP) for 3D printing. After performing printability tests of PP wood plastic composites (WPCs), the mechanical properties of both injection‐molded and 3D‐printed PP WPC specimens were explored. Test specimens were prepared from 3D printed hexagons for analyzing the mechanical properties. Adding WF to neat PP increased the storage modulus and the glass transition temperature while decreasing the degree of crystallinity and the coefficient of thermal expansion, while enhancing the printability of neat PP. The tensile strength, tensile modulus of elasticity, flexural strength, and flexural modulus of elasticity of injection‐molded neat PP improved by up to 21%, 59%, 30%, and 56%, respectively, with 20 wt.% WF. However, the impact strength of injection‐molded neat PP decreased by 85%, with 20 wt.% WF. After 3D printing, the tensile strength and tensile modulus of elasticity of printed neat PP increased by up to 84% and 60%, respectively, with 20 wt.% WF. The flexural strength and flexural modulus of elasticity of neat printed PP remained unchanged compared to those of PP filled with 20 wt.% WF, while the impact strength decreased by 87%. WF was used as a reinforcement in polypropylene designed for 3D printing A pilot‐scale, pellet‐fed 3D printer was used to print hollow hexagons, and then test specimens were fabricated from these hexagons for mechanical properties The tensile and flexural properties of 3D printed neat polypropylene improved, while the impact strength decreased after adding 20 wt.% WF to the neat PP. [ABSTRACT FROM AUTHOR]

The objective of the present work was to explore the effects of accelerated weathering test on properties of poly(lactic acid) (PLA)/poly(butylene adipate- co -terephthalate) (PBAT) blend and PLA)/PBAT/wood flour (WF)/wollastonite (WT) composite. The 70/30 (wt%/wt%) PLA/PBAT blend and its composite with 25 phr WF and 5 phr WT were prepared on a twin screw extruder and injection molding machine. Resulted blend and hybrid composite were exposed to accelerated weathering conditions of UV-irradiation and moisture cycles at 63°C in a laboratory Xenon Weather-Ometer chamber for various periods (250, 500, 750, and 1000 h). The alterations in the surface quality (color change), chemical structure, surface morphology, tensile properties, thermal behaviors, and thermal stability of the specimens were evaluated by spectrocolorimetry, Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), universal testing machine, differential scanning calorimetry and thermogravimetric analysis, respectively. The photo- and hydrolytic degradations were found to occur during the weathering exposure time. Both blend and composite showed a continuous increase in the total color change with prolonged exposure time, which was mainly due to the degradation of PLA and wood components, especially lignin. The SEM images also confirmed their degradations by illustrating roughness, voids, and cavities on the specimen surfaces after accelerated weathering. Meanwhile, the tensile and thermal properties of both blend and composite were found to decrease. Thus, this study can be used for quality control and material certification. [ABSTRACT FROM AUTHOR]

The paper presents the results of testing the properties of wood–polymer composites (WPC) based on plasticised poly(vinyl chloride) (PVC-P). Materials with variable contents of wood filler (Arbocel C 320) or plasticiser (di-isononyl phthalate) were produced and then analysed. The share of wood flour in the material was up to 50 phr, and the plasticiser content was up to 40 phr. Functional properties, such as tensile properties, mechanical properties at variable temperature (DMTA), and water absorption, as well as processing properties such as rheological properties and analysis of the fusion process, were analysed. The influences of wood flour and plasticiser on the composites' properties in the solid and melted state were found. For example, with 40 phr of plasticiser, increasing the filler share from 0 phr to 50 phr resulted in an increased tensile modulus from 18 MPa to 274 MPa and viscosity at a share rate of 20 s−1, from 721 Pa·s to 1581 Pa·s. However, increasing the share of plasticiser from 20 phr to 40 phr with 30 phr of filler reduces the value of these properties from 1760 MPa to 112 MPa and from 2768 Pa·s to 1151 Pa·s, respectively. It was also found that increasing the share of wood flour in the composite noticeably reduces the effectiveness of the plasticiser. [ABSTRACT FROM AUTHOR]

The effect of plant-based fillers on thermal resistance in highly filled biocomposites based on ethylene–vinyl acetate copolymer (EVA) was studied. Wood flour and microcrystalline cellulose were used as fillers. It was shown that the introduction of microcrystalline cellulose into EVA did not affect the thermal stability of the polymer matrix. In contrast, the introduction of wood flour into EVA led to a significant increase in the thermal stability of the entire biocomposite. Oxidation induction time increased from 0 (pure EVA) to 73 min (EVA + wood flour biocomposites). The low-molecular weight phenolic compounds contained in wood flour are likely able to diffuse into the polymer matrix, exerting a stabilizing effect. The discovered stabilizing effect is a positive development for expanding the possibilities of technological processing of biocomposites, including multiple processing. [ABSTRACT FROM AUTHOR]

Intending to minimize the cost of production of pipes intended for construction and building activities and waste recycling, this research studies the physical and mechanical characteristics of high-performance polypropylene random (PPR), a new material extracted from a homopolymer polypropylene. The PPR was filled with untreated and treated wood flour (WF) particles at various content levels 10, 20, 30, and 40 wt.%. The density, melt flow rate, tensile strength, tensile strain, modulus of elasticity, and hardness are used to evaluate the quality of the material. The hydrophobic character of WF resulted from degradation in the physical and mechanical properties. The results showed that the density, the modulus of elasticity, and the hardness increased with the percentage of treated wood flour (TWF). As the percentage of WF increased, the melt flow rate decreased. The tensile strength and strain increased to 27.7 MPa and 543.25%, respectively at 20 wt.% of WF, with 14.8% and 6.65% reached gains compared to the untreated wood flour composites (UWFC) (24.04 MPa and 495.6%). The enhancement of the mechanical properties is thanks to the formed strong links between the particles of WF and the PPR after the thermal and alkaline treatment with sodium hydroxide (NaOH). The removal of hydroxyl groups in the TWF enhances the interfacial bonding between the filler and the PP matrix in the resulting composites. When WF is treated, it is well dispersed; and facilitates the transfer of stress from the matrix to the fillers. The optimum percentage of WF to add into the inner layer of PPR pipes is at a composition of the filler of 20 wt.%. [ABSTRACT FROM AUTHOR]

The effects of heat treatment on Cupressus funebris Endl. wood were examined under different combinations of temperature, time, and pressure. The chemical composition, crystallinity, and microstructure of heat-treated wood flour and specimens were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Vacuum heat treatment led to changes in the functional groups and microstructure of C. funebris wood, and the relative lignin content decreased with increasing treatment temperature, which was significant at lower negative pressures. Cellulose crystallinity showed a change rule of first increasing and then decreasing throughout the heat treatment range, and the relative crystallinity ranged from 102.46% to 116.39%. The cellulose treated at 120 °C for 5 h at 0.02 MPa had the highest crystallinity of 44.65%. These results indicate that although heat treatment can improve cellulose crystallinity, very high temperatures can lead to decreased crystallinity. The morphology and structure of the cell wall remained stable throughout the heat treatment range; however, at elevated temperatures, slight deformation occurred, along with rupture of the intercellular layer. [ABSTRACT FROM AUTHOR]

The conducted study was focused on the development of a new type of technical blend reinforced with natural fillers. The study was divided into two parts, where, in the first stage of the research, unmodified POM was reinforced with different types of natural fillers: cellulose, wood flour, and husk particles. In order to select the type of filler intended for further modification, the mechanical characteristics were assessed. The 20% wood flour (WF) filler system was selected as the reinforcement. The second stage of research involved the use of a combination of polyoxymethylene POM and poly(lactic acid) PLA. The POM/PLA blend (ratio 50/50%) was modified with an elastomeric compound (EBA) and chain extender as the compatibilized reactive (CE). The microscopic analysis revealed that for the POM/PLA system, the filler–matrix interface is characterized by better wettability, which might suggest higher adhesion. The mechanical performance revealed that for POM/PLA-based composites, the properties were very close to the results for POM-WF composites; however, there is still a significant difference in thermal resistance in favor of POM-based materials. The increase in thermomechanical properties for POM/PLA composites occurs after heat treatment. The increasing crystallinity of the PLA phase allows for a significant increase in the heat deflection temperature (HDT), even above 125 °C. [ABSTRACT FROM AUTHOR]

The aim of the present study is to use beech wood flour (WF) and expanded ethylene vinyl acetate (EVA) copolymer industrial waste to develop a sustainable composite and its production method for further engineering use. Polyamide (PA) powder waste obtained after multiple selective laser sintering (SLS) thermal cycles was used to increase the strength and adhesion between the waste composite components. The morphological, mechanical, and thermal properties of the EVA/WF composites were characterised along with their interfacial wetting and water absorption properties. Optical and electron microscopy investigations revealed that the composites prepared have homogeneous dispersion and good interfacial adhesion between EVA and wood. The addition of SLS waste PA powder increases the strength and stiffness of the composite developed. The composite with 40 wt% WF exhibited the best water absorption, mechanical properties, and processability among the various compositions. The sustainable composite proposed can replace commercially available materials, which helps to save resources and reduce waste. [ABSTRACT FROM AUTHOR]

Wood‐plastic composites are green composites made of plastic as the matrix and wood as the filler; however, the incompatibility between these two leads to the degradation of the composites. This paper reports the synthesis of a novel bio‐based compatibilizer, annotated as OA‐g‐H20, by grafting oleic acid (OA) on a hyperbranched polyester (Boltorn H20). The effect of modifying recycled polypropylene‐based wood–plastic composites with this compatibilizer was then assessed. The Fourier transform infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography techniques were employed to characterize the fabricated OA‐g‐H20, while its modification effect was assessed by differential scanning calorimetry, dynamic thermomechanical analysis, scanning electron microscopy, and mechanical property tests. The experimental results revealed that the optimal addition amount of OA‐g‐H20 was 2.0 wt.%. Highlights: A new bio‐based compatibilizer, OA‐g‐H20, for wood–plastic composites is reported.OA‐g‐H20 was obtained by grafting oleic acid on a hyperbranched polyester (H20).OA‐g‐H20 provided good mechanical reinforcement for the wood–plastic composites.OA‐g‐H20 improved the crystallinity of the composites.The reinforcement mechanism of OA‐g‐H20 in wood–plastic composites is elucidated. [ABSTRACT FROM AUTHOR]

The Northwestern Federal District is a region of Russia rich in a variety of wood species. The properties of wood in this region differ significantly from the properties of wood grown in other countries or in the eastern part of Russia, which leads to differences in energy costs of grinding wood. The aim of this research has been to estimate the specific energy costs of grinding wood to the state of wood flour, which will be used as the basis for wood polymer composite consumables in additive technologies. Wood flour has been obtained by grinding wood in a laboratory disk mill, repeatedly reducing the particle size. The granulometric composition has been analyzed for beech, oak, larch, alder and pine wood at 1, 3, 5 and 10 grinding cycles. Particle sizes have been determined by analyzing images obtained using an optical microscope and processed in the ImageJ graphic program. The specific energy costs of grinding have been estimated by recording the power with a wattmeter every second with repeated feeding of wood flour for the known mill productivity. When calculating the specific energy consumption, the moisture content of each wood species has been taken into account, as well as productivity losses associated with the adhesion of wood particles to the working surfaces of the dispersing set and the inner area of the disk mill body. The research has revealed a relationship between the specific energy costs and the particle size of wood flour obtained from various wood species. Regression analysis of curves corresponding to different wood species has made it possible to obtain exponential and power-law dependencies that do not contradict the fundamental theoretical laws of grinding solid particles. Based on these results, pine wood flour has been recognized as the most energy-efficient option. The established dependencies can be used to predict the specific energy consumption for grinding beech, oak, larch, alder and pine wood in disk mills.

The demand for composite materials is growing every year. In this regard, the competitiveness of a particular product is determined primarily by the price-quality ratio. The most rational option for the production of wood-filled composites is using the materials with the increased performance characteristics. To date, it is the performance characteristics of modern composite materials that are the most significant, not only for final consumers, but also for manufacturers. In this regard, to improve performance characteristics in the production of wood-filled composites, various methods of pre-treatment of wood are used – thermal modification, acetylation, furfulation, ultra-high-frequency processing, alkali treatment, the use of various additives, etc. A promising way to improve the physical and mechanical properties of wood-filled materials is acetylation, whose mechanism consists in the formation of acetyl groups in wood during processing. To reduce production costs and the cost of the final product, it is possible to use a cheaper precursor (for example, icy acetic acid instead of acetic anhydride) with the possibility of intensifying the impregnation process. This article presents the results of obtaining wood-filled composites based on acetylated birch wood flour with its various proportions in the composition. The effect of introducing acetylated wood filler into the composition on the performance properties of composites (abradability, frost-resistance, flexural strength) has been evaluated in comparison with control samples made from untreated birch wood flour. The effect of acetylation with glacial acetic acid on the structure of birch wood flour has been characterized using Fourier-transform infrared spectroscopy. The IR-spectra of the control and acetylated samples contain absorption bands belonging to the corresponding groups of cellulose and lignin of hardwoods. The abradability and frost-resistance coefficients for a wood-filled composite based on acetylated birch wood flour are on average 1.5–2 times lower for all compositions compared to control samples. The results of the research allow us to conclude that acetylation of wood flour as a method of pre-treatment of the filler in order to improve the performance characteristics of the final product is promising for implementation in the production of wood-filled materials.

Intending to minimize the cost of production of pipes intended for construction and building activities and waste recycling, this research studies the physical and mechanical characteristics of high-performance polypropylene random (PPR), a new material extracted from a homopolymer polypropylene. The PPR was filled with untreated and treated wood flour (WF) particles at various content levels 10, 20, 30, and 40 wt. %. The density, melt flow rate, tensile strength, tensile strain, modulus of elasticity, and hardness are used to evaluate the quality of the material. The hydrophobic character of WF resulted from degradation in the physical and mechanical properties. The results showed that the density, the modulus of elasticity, and the hardness increased with the percentage of treated wood flour (TWF). As the percentage of WF increased, the melt flow rate decreased. The tensile strength and strain increased to 27.7 MPa and 543.25%, respectively at 20 wt.% of WF, with 14.8% and 6.65% reached gains compared to the untreated wood flour composites (UWFC) (24.04 MPa and 495.6%). The enhancement of the mechanical properties is thanks to the formed strong links between the particles of WF and the PPR after the thermal and alkaline treatment with sodium hydroxide (NaOH). The removal of hydroxyl groups in the TWF enhances the interfacial bonding between the filler and the PP matrix in the resulting composites. When WF is treated, it is well dispersed; and facilitates the transfer of stress from the matrix to the fillers. The optimum percentage of WF to add into the inner layer of PPR pipes is at a composition of the filler of 20 wt. %.

Abstract Mechanical properties of wood–plastic composites are influenced by a particle size and surface morphology of wood flour. Generally various sizes of wood flour are produced from single solid wood even if the single process is used. If the different particle size of wood flour is produced from different wood tissue such as earlywood (EW) and latewood (LW), not only particle size but also density and chemical composition of wood flour might influence the mechanical property of final products. This study aims to investigate the relationship between particle size and their origin; EW and LW. EW and LW were separately milled to produce the EW and LW flour by dry and wet milling. Hyperspectral images ranging 400–1000 nm for each wood flour were used as training data. Discriminant model of EW and LW flour developed by PLS-DA showed over 0.77 of accuracy. Then the EW and LW were dry and wet milled together and screened by three different sieve openings to obtain different particle size wood flour. Discriminant model was applied for the hyperspectral images of each size of wood flour to estimate the EW and LW ratio. The result showed that increasing sieve opening resulted in the increasing ratio of LW for dry milled wood flours. The results suggest that the EW was easily pulverized than LW.

This study involved the optimization of the molded pieces manufacturing process from a poly-3-hydroxybutyrate-co-3-hydroxyvalerate biocomposite containing 30% wood flour by mass. The amount of wood flour and preliminary processing parameters were determined on the basis of preliminary tests. The aim of the optimization was to find the configuration of important parameters of the injection process to obtain molded pieces of good quality, in terms of aesthetics, dimensions, and mechanical properties. The products tested for quality were dog bone specimens. The biocomposite was produced using a single-screw extruder, whereas molded pieces were made using an injection molding process. The Taguchi method was applied to optimize the injection molding parameters, which determine the products quality. Control factors were selected at three levels. The L27 orthogonal plan was used. For each set of input parameters from this plan, four processing tests were performed. The sample weight, shrinkage, elongation at break, tensile strength, and Young's modulus were selected to assess the quality of the molded parts. As a result of the research, the processing parameters of the tested biocomposite were determined, enabling the production of good-quality molded pieces. No common parameter configuration was found for different optimization criteria. Further research should focus on finding a different range of technological parameters. At the same time, it was found that the range of processing parameters of the produced biocomposite, especially processing temperature, made it possible to use it in the Wood Polymer Composites segment. [ABSTRACT FROM AUTHOR]

The work presents the results of a comprehensive study on obtaining compositions based on polypropylene and natural fillers modified by enzymatic preparations under high-shear forces. The experiment protocol includes determining the modification time and the ratio of water volume to the mass of natural filler (hydro modulus) during modification, which turned out to be different for each type of filler. Physical and mechanical analyses were conducted to evaluate the operational characteristics of the obtained composites, with particular attention given to comparing the modified compositions with their unmodified counterparts. The time and hydro module of the enzymatic modification of the natural fillers under consideration were investigated, which turned out to be different for each type of filler. It was found that surface modification of natural fillers improves mechanical properties; namely, the tensile strength of composites with wood and sunflower fillers increases by 10%, and the impact viscosity of composites also increases by 12% with wood and sunflower fillers. Water absorption decreases in composites, after 2 h boiling, with wood flour by 30% and with rice husk by 10%. After a 14-day test at room temperature, water absorption decreases by more than 30% in composites with rice husk. When determining the free surface energy of composites, it was found that the modification of the filler reduces the polarity of the composites in all samples, which can be interpreted as an improvement in the interaction between the filler and the polymer matrix. The findings of this research have important implications for the development of advanced polymeric materials that can be used in a wide range of applications, including automotive, aerospace, and construction industries. The results underscore the importance of surface modifications to optimize the properties of polymeric composites and provide valuable insights into the role of natural fillers in enhancing the performance of these materials. [ABSTRACT FROM AUTHOR]

This article summarizes findings in the field of the history, composition, and mechanical properties of WPCs (wood–plastic composites) formed by combining two homogeneous substances, i.e., a polymer matrix with cellulose fibers in a certain ratio (with the addition of additives). In relation to a wide range of applied natural reinforcements in composites, it focuses on wood as a fundamental representative of lignocellulosic fibers. It elucidates the concept of wood flour, the criteria for its selection, methods of storage, morphological characteristics, and similar aspects. The presence of wood in the plastic matrix reduces the material cost while increasing the stiffness. Matrix selection is influenced by the processing temperature (Tmax = 200 °C) due to the susceptibility of cellulose fibers to thermal degradation. Thermoplastics and selected biodegradable polymers can be applied as matrices. The article also includes information on applied additives such as coupling agents, lubricants, biocides, UV stabilizers, pigments, etc., and the mechanical/utility properties of WPC materials. The most common application of WPCs is in automotive sector, construction, aerospace, and structural applications. The potential biodegradability and lower cost of applications featuring composite materials with natural reinforcements motivated us to delve into this type of work. [ABSTRACT FROM AUTHOR]

Pretreatment serves as an important step in maximizing the efficient utilization of woody biomass feedstock. This study focused on enhancing the component and structural properties of apple wood to optimize the utilization of apple wood resources effectively. This study presents the optimization of, the apple wood pretreatment system, combining bioenzyme and hydrothermal treatments. This study aimed to investigate the effect of different bioenzyme pretreatment conditions on the components and structural properties of apple wood extract and to analyze the feasibility of enzyme solution reuse. Fourier transform infrared spectroscopy analysis revealed an increase in cellulose content in the wood flour following enzyme treatment. Concurrently, changes in characteristic peaks indicated an increased hemicellulose content and a reduction in lignin content after the pretreatment, correlating with fraction analysis results. Scanning electron microscopy illustrated that the dense structure of the fiber surface was disrupted after treatment. Notably, the results indicated that the recovered biocomposite enzymes exhibited excellent activity, suggesting their potential for reuse. [ABSTRACT FROM AUTHOR]

Background and aim: As a result of population growth, paper and wood products consumption has increased, and restrictions on using forest wood raw materials initiated the utilization poplar trees as fast-growing spices. The aim of this study was to focus on identification and comparison of the phenolic chemical components in poplar woods (populous nigra and populous deltoides). Materials and methods: In this study, three trees from each poplar tree were randomly felled in plantation near Nowshar, Iran. Then three discs were cut from each log. At first, wood was grounded and then wood flour extractive were measured using TAPPI standard procedure. Wood flour was extracted by acetone and extractives residue was added to BSTFA reactor and samples were kept in constant temperature bath at 70oC for an hour. The extractive samples were then analyzed by GC/MS. The compounds were identified using GC diagram which shows abundance and retention time of each compound, and calculation of quartz index and Adams table. Results: The result of GC-MS showed that there exist 68 and 105 compounds in wood of Populus nigra and Populus detoides, respectively. di-Limonene (30.26%), bis (2-ethylhexyl) phthalate (10.07%), Gamma-Sitosterol (1.06%), Hexadecanoic acid (2.0%), gamma-Terpinene (4.02%) and 4-Hydroxy-Benzoic acid (3.62%) were the most important compounds in wood of Populus detoides. There were the Limonene (25.62%), Anymol (5.29%), gamma-Terpinene (3.38%), 1, 2-Benzandicarboxylic acid (2.00%) and bis (2-ethylhexyl) phthalate (0.68%) as the most important compounds in wood of Populus nigra. Conclusion: The gas chromatographs showed that Limonene, Benzene methanol, alpha-Terpineol, beta-Bisabolene, Hexadecanoic acid and bis (2-ethylhexyl) phthalate were the 7 common compounds in the wood of Populus nigra and Populus deltoides. These compounds can play an important role in the durability and consumption of these woods. [ABSTRACT FROM AUTHOR]

Mechanical properties of wood–plastic composites are influenced by a particle size and surface morphology of wood flour. Generally various sizes of wood flour are produced from single solid wood even if the single process is used. If the different particle size of wood flour is produced from different wood tissue such as earlywood (EW) and latewood (LW), not only particle size but also density and chemical composition of wood flour might influence the mechanical property of final products. This study aims to investigate the relationship between particle size and their origin; EW and LW. EW and LW were separately milled to produce the EW and LW flour by dry and wet milling. Hyperspectral images ranging 400–1000 nm for each wood flour were used as training data. Discriminant model of EW and LW flour developed by PLS-DA showed over 0.77 of accuracy. Then the EW and LW were dry and wet milled together and screened by three different sieve openings to obtain different particle size wood flour. Discriminant model was applied for the hyperspectral images of each size of wood flour to estimate the EW and LW ratio. The result showed that increasing sieve opening resulted in the increasing ratio of LW for dry milled wood flours. The results suggest that the EW was easily pulverized than LW. [ABSTRACT FROM AUTHOR]

The fabrication of lignocellulose-based hydrogels typically involves complex modification or dissolution processes using a single component of lignocellulose. However, these processes often have a significant environmental impact, posing challenges to achieving green production of these hydrogels. In this study, we present a non-dissolving strategy to convert whole components of corn stover directly into hydrogel. The central step in this strategy is to expose more functional groups in the corn stover through steam explosion. The exposure of functional groups allowed the steam-exploded corn stover to strengthen the mechanical properties of poly(vinyl alcohol) (PVA) hydrogel by forming more hydrogen bonds with PVA molecules. The tensile strength of the prepared lignocellulose-based hydrogel reached 329.75 kPa, which was 432.69% higher compared to the pure PVA hydrogel. Furthermore, this hydrogel exhibited the advantageous properties of lignin, such as antioxidant and UV resistance capabilities, and was shown to be useful as a sand-fixing agent for large-scale applications. Finally, we verified the universal applicability of the non-solubilizing strategy by preparing similarly shaped hydrogel products from wheat bran and poplar wood flour as well. In summary, our non-dissolving strategy provides a simpler and more cost-effective method than the intricate process of creating lignocellulose-based hydrogels. This simplification helps convert abundant lignocellulosic materials into valuable products. [ABSTRACT FROM AUTHOR]

It is easier and cheaper to prevent forest fires than to extinguish them, therefore, the development of long-lasting and environmentally friendly fire-retarding materials is highly desirable to prevent the spread of forest fires. In this study, soluble carboxymethyl starch replaced insoluble carboxymethyl cellulose to improve the compressive strength of inorganic gel and overcome the weakness of fragility. When the concentration of polymer carboxymethyl starch and crosslinking agent aluminum citrate were 0.5% and 0.3%, respectively, the inorganic/organic composite gel showed the best comprehensive performance (including gelation time, water retention, seepage velocity and strength). Additionally, the antioxidant tannin was introduced into the inorganic/organic gel, which effectively inhibited the oxidation of wood flour, making its inhibition rate reached 23.1%, about twice that of pure inorganic gel. This is mainly attributed to the ability of tannin to inhibit the oxidation process of active groups, including carbon-oxygen, hydroxyl, and methyl of the wood powder, thereby enhancing the flame resistance of the composite gel. Probable mechanism of forest fire suppression by the antioxidant composite gel is proposed, which involves oxygen isolation, evaporative cooling, and chain reaction inhibition. [ABSTRACT FROM AUTHOR]

Wood–plastic composites (WPCs), abbreviated as WPCs, are typically composite materials made by mixing wood flour and thermoplastic resins, and then shaped through processes such as extrusion or compression. They have emerged as a viable and advanced alternative to traditional wood and plastic materials, offering an amalgamation of the best properties of both. This study utilized discarded milk bottles as the polymer matrix (mainly composed of high-density polyethylene, HDPE) and added wood flour, recycled protective clothing (Tyvek®), and diatomite recycled from brewery waste as reinforcement. Additionally, pre-treated aluminum hydroxide powder from waste artificial marble was added. The results indicated that the optimal processing temperature for the WPCs was 175 °C. The mechanical properties of the material increased with the addition of recycled protective clothing and pre-treated aluminum hydroxide powder. The increase in tensile strength can reach up to 28%. The thermal conductivity of the WPCs also significantly increased with the addition of pre-treated aluminum hydroxide powder. Furthermore, sunlight analysis showed that the surface temperature of the WPCs decreased by approximately 8.5 °C, which corresponds to a reduction of 13% after adding pre-treated aluminum hydroxide powder. Therefore, they can be applied to outdoor cool WPCs to reduce the risk of foot burns or used as roof heat-insulating layers to reduce indoor air conditioning usage, achieving energy-saving and carbon reduction. This study demonstrates that high-performance and high-value green plastics made from various recycled materials can contribute to the goals of a circular economy and sustainable carbon reduction. [ABSTRACT FROM AUTHOR]

CQDs are a type of fluorescent nanocarbon material that possess excellent optical properties. They have a wide range of raw material sources, making them a versatile option for various applications. The use of fluorescent materials to enhance the solar energy capture capacity of chloroplasts has the potential to significantly improve natural photosynthesis. CQDs and N-CQDs were prepared from natural Salix wood powder using a simple, green, and environmentally friendly hydrothermal method. These materials can effectively capture ultraviolet (UV) light and were used for photosynthesis to enable chloroplasts to utilize UV light that cannot be absorbed by them. The chlorophyll content of leaves treated with CQDs and N-CQDs increased, with the N-CQDs 25 mg/L treated group showing a 35.6% increase compared to the untreated group. Additionally, the treatment of CQDs and N-CQDs positively affected the transfer of electrons from photosystem II, further enhancing photosynthetic activity. This study presents ideas for expanding the use of solar energy, optimizing the photosynthesis charge transfer pathway, and improving solar energy conversion efficiency. [ABSTRACT FROM AUTHOR]

The intensive development of the polyurethanes industry and limited resources (also due to the current geopolitical situation) of the raw materials used so far force the search for new solutions to maintain high economic development. Implementing the principles of a circular economy is an approach aimed at reducing the consumption of natural resources in PU production. This is understood as a method of recovery, including recycling, in which waste is processed into PU, and then re-used and placed on the market in the form of finished sustainable products. The effective use of waste is one of the attributes of the modern economy. Around the world, new ways to process or use recycled materials for polyurethane production are investigated. That is why innovative research is so important, in which development may change the existing thinking about the form of waste recovery. The paper presents the possibilities of recycling waste (such as biochar, bagasse, waste lignin, residual algal cellulose, residual pineapple cellulose, walnut shells, silanized walnut shells, basalt waste, eggshells, chicken feathers, turkey feathers, fiber, fly ash, wood flour, buffing dust, thermoplastic elastomers, thermoplastic polyurethane, ground corncake, Tetra Pak®, coffee grounds, pine seed shells, yerba mate, the bark of Western Red Cedar, coconut husk ash, cuttlebone, glass fibers and mussel shell) as additives or fillers in the formulation of polyurethanes, which can partially or completely replace petrochemical raw materials. Numerous examples of waste applications of one-component polyurethanes have been given. A new unexplored niche for the research on waste recycling for the production of two components has been identified. [ABSTRACT FROM AUTHOR]

Rigid polyurethane foams (RPUF) filled with lignocellulosic fillers have gained considerable interest due to their mechanical performance and eco-friendly characteristics. However, their flammability and photodegradation resistance properties still need further improvement, which may be achieved by incorporating various particles. This study investigated the effect of adding 2.5% of wood flour and 5%–15% of an organophilic nanoclay (relative to the wood flour weight) on the RPUF morphology, density, compressive strength, thermal stability, flammability, and photodegradation resistance. The addition of wood flour and nanoclay made the RPUF cells more rounded and disrupted but did not affect density. The compressive properties were adversely impacted. Nevertheless, the nanoclay significantly improved both flammability and photodegradation resistance compared to the neat RPUF. [ABSTRACT FROM AUTHOR]

The effect of expanded vermiculite (e-VMT) was evaluated relative to the physical, mechanical, and flame retardancy performance of flat-pressed wood plastic composites (WPCs). Various contents of e-VMT (2.5, 5, 7.5, 10, 15%) were added instead of wood flour (WF) to the matrix. Due to the hydrophilic nature of the WF, water absorption (WA) and thickness swelling (TS) of WPCs increased as compared to neat polymer-based panels. Meanwhile, e-VMT incorporation limited the WA and TS values. As expected, the lowest WA and TS values were obtained from the highest e-VMT-reinforced WPCs. The addition of e-VMT was also found to enhance the mechanical properties of WPCs. As the e-VMT content increased and the WF content decreased, there was an improvement in flexural strength, modulus of elasticity (MOE), and tensile strength. Compared to the neat polymer panels, the MOE of WPCs increased by up to 77%. Additionally, the flame retardancy performance of WPCs improved with e-VMT reinforcement, with limiting oxygen index (LOI) values increasing up to 24%. Scanning electron microscopy (SEM) images also demonstrated the favorable integration of e-VMT with matrix, thereby improving the mechanical properties. The inconsistency between WF and polymer was also well-observed, highlighting the tendency of WF to interact easily with water. [ABSTRACT FROM AUTHOR]

Developing green composite with high biomass content is one crucial way to realize the strategy of 'carbon reduction'. The type of polyurethane prepolymer and its soft segment's structure have an important influence on the structure and properties of composite materials. This work focused on preparing different kinds of wood powder-polyurethane prepolymer (WCLPU) composite with high biomass content to study the effects of the molecular weight of the soft segment of the polyurethane prepolymer (PCLPU) on the structure and properties of the composites. The results showed that the composite materials with 70 wt% wood content exhibited high strength and good bending performance. Specifically, with decreasing molecular weight of the PCLPU soft segment, the bending strength and bending modulus of the modified WCLPU composite also increased. This work has laid a foundation for studying the effects of the molecular weight of the PCLPU soft segment on the structure and properties of composite materials. [ABSTRACT FROM AUTHOR]

In the modern world, many products are disposable or have a very short lifespan, while at the same time, those products are made from materials that will remain in the environment in the form of waste for hundreds or even thousands of years. It is a serious problem; non-biodegradable polymer wastes are part of environmental pollution and generate microplastics, which accumulate in the organisms of living beings. One of the proposed solutions is biodegradable polymers and their composites. In our work, three types of polylactide-based composites with plant-derived fillers: microcellulose powder, short flax fibers, and wood flour at 2 wt.% were prepared. Poly(lactic acid) (PLA)-based biocomposite properties were characterized in terms of mechanical and surface properties together with microscopic analysis and Fourier-transform infrared spectroscopy (FTIR), before and after a UV (ultraviolet)-light-aging process to determine the effects of each cellulose-based additive on the UV-induced degradation process. This research shows that the addition of a cellulose additive can improve the properties of the material in terms of the UV-aging process, but the form of the chosen cellulose form plays a crucial role in this case. The testing of physicochemical properties demonstrated that not only can mechanical properties be improved, but also the time of degradation under UV light exposure can be controlled by the proper selection of the reinforcing phase and the parameters of the extrusion and injection molding process. The obtained results turned out to be very interesting, not only in terms of the cost reduction of the biocomposites themselves, as mainly the waste from the wood industry was used as a low-cost filler, but also that the additive delays the aging process occurring during UV light exposure. Even a small, 2 wt.% addition of some of the tested forms of cellulose delayed surface degradation, which is one of the most important factors affecting the biodegradation process. [ABSTRACT FROM AUTHOR]

In this study, activated PLA/olive wood flour (OWF) composite films were prepared by a solvent casting process with different wood flour contents (0, 1, 3, 5 and 10 wt%). 3% Cinnamon Essential Oil (CEO) is incorporated into the biocomposite film to impart antimicrobial activity. OWF and CEO properties were examined using FTIR and total phenol quantification. Biocomposite films with and without CEO were tested by FTIR and tensile strength. The antimicrobial activity of biocomposite films was tested against four types of fungi and five types of bacteria. CEO and OWF extracts physically interact with PLA, affecting its mechanical and antimicrobial properties. In addition, only 1% of OWF and CEO achieved better performance. The best antifungal inhibition against A. flavus and F. oxysporum was observed in the case of 10% of OWF, and the best antibacterial activity for P. aeruginosa and S. aureus was observed for OWC0 films. The combined use of OWF and CEO showed synergistic antifungal properties. Overall, low content of OWF and CEO could bring antibacterial and antifungal activities to biocomposite PLA/OWF biofilms with satisfactory mechanical properties. The primary use of these films is cereal packaging applications. [ABSTRACT FROM AUTHOR]

To optimize powder explosive consolidation technology, an improved explosive consolidation device capable of relieving pressure was designed. Bulk nano-aluminum materials achieving more than 98% of standard density were successfully fabricated by explosive consolidation. The effect of different detonation velocities on the properties of the consolidated aluminum was investigated by varying the ratio of the ammonium nitrate explosive (AN-TNT) and wood flour to adjust the detonation velocity. The results revealed that the production of "Mach holes" (defects produced by excess energy in a converging shock wave) can be reduced by decreasing the detonation velocity. At a detonation velocity of 2158 m/s, bulk aluminum with high density, high hardness, high strength, and uniform microstructure without any Mach holes and with a grain size of about 80 nm can be achieved. The hardness of explosively consolidated aluminum was four times that of aluminum prepared by general industrial technology, and its compressive strength double that of industrially prepared aluminum. [ABSTRACT FROM AUTHOR]

The effect of plant-based fillers on thermal resistance in highly filled biocomposites based on ethylene–vinyl acetate copolymer (EVA) was studied. Wood flour and microcrystalline cellulose were used as fillers. It was shown that the introduction of microcrystalline cellulose into EVA did not affect the thermal stability of the polymer matrix. In contrast, the introduction of wood flour into EVA led to a significant increase in the thermal stability of the entire biocomposite. Oxidation induction time increased from 0 (pure EVA) to 73 min (EVA + wood flour biocomposites). The low-molecular weight phenolic compounds contained in wood flour are likely able to diffuse into the polymer matrix, exerting a stabilizing effect. The discovered stabilizing effect is a positive development for expanding the possibilities of technological processing of biocomposites, including multiple processing.

In this work, the influence of maleic anhydride-treated nanolignin as a coupling agent on the various properties of wood fiber-polypropylene composites was investigated. For this purpose, extracted lignin from Bagasse Soda black liquor was modified with maleic anhydride and then different ratios of unmodified and modified nanolignin (1, 3 and 5 wt%) were added to the wood fiber-polypropylene mixture. The composites were then manufactured by injection molding after mixing mechanically to the wood flour either virgin or maleated nanolignin and polypropylene. Structural and thermal properties of nanolignin after modification by maleic anhydride along with physical and mechanical properties of the manufactured composites were determined according to standard methods. The FTIR analysis indicated nanolignin rearrangements showing that some bonds changed or formed after its modification with maleic anhydride. The glass transition temperature of the nanolignin decreased by esterification from 130°C to 100°C. The panel testing results indicated that all physical and mechanical properties of the composites were continuously improved by increasing the maleated nanolignin content from 1 to 5wt%. Thus, the composites with maleated nanolignin presented higher dimensional stability and mechanical strength compared to those prepared with unmodified nanolignin. Scanning electron microscopy (SEM) showed that treatment with maleic anhydride improves the uniform dispersion of nanolignin in the polymer matrix. The manufactured WPCs can be used as interior and exterior building materials such as decks, sidings and etc. [ABSTRACT FROM AUTHOR]

Biodegradable polymers have recently become attractive and have been increasingly used as matrix materials to replace fossil plastics due to concerns about the environmental issue. However, their application areas are limited due to their high costs and natural properties. In this study, we fabricated ecofriendly and economical polybutylene adipate terephthalate (PBAT) composites loaded with various concentrations of wood flour (WF) to investigate the effects on the PBAT and WF interfaces as well as the physical properties of the WF/PBAT biocomposites. Then, WF was acetylated with acetic anhydride, and the effect of WF acetylation on the mechanical and thermal properties of the biocomposites were investigated. The results showed that the tensile strength, tensile modulus, flexural strength and flexural modulus increased with WF loading in the composites, and acetylation could not only further increase these properties, but also increase the impact strength and elongation at break. The incorporation of WF would weaken the thermal stability of PBAT, but the thermal stability of the biocomposite could be improved after WF acetylation. The cold crystallization temperature and hydrophobicity of the WF/PBAT samples would be increased with the increasing load of the WF, while the melting enthalpy and the crystallinity of the samples reduced gradually. A morphological analysis of the modified composites revealed that the matrix exhibited greater interfacial interactions with the WF compared to the WF/PBAT. Considering the much lower cost of WF compared to PBAT, the improved properties of WF/PBAT biocomposites will make it economically competitive with other commercial polymers, and these biocomposites should have much wider application areas. [ABSTRACT FROM AUTHOR]

The present paper studies the effect of reprocessing, on both dry and wet reprocessing conditions, on the rheological and mechanical properties of a biocomposite made of a bio-based, biodegradable polymer with 40 wt% wood flour. The results show that the viscosity of the matrix decreases as the number of extrusions increases, with the greatest reduction for samples processed under wet conditions. The same behavior was observed for the biocomposite, but since the viscosity of the biocomposite is much higher than that of the matrix, this causes a greater reduction of molecular weight. Mechanical results show that properties such as tensile strength and elongation decrease as the number of extrusions increases for the matrix. In terms of maximum variations, the tensile strength experiences a decrease of approximately 18%, while the elongation at break shows a more significant reduction of about 40%. Conversely, the biocomposite shows an increase in tensile strength (about 30%) and elongation at break (about 90%) after the first extrusion and then a slight decrease, but with values of tensile strength and elongation higher than those of the virgin biocomposite. [ABSTRACT FROM AUTHOR]

In this work, the thermal stability of wood flour (WF) was modified using a boric acid treatment. To further understand the impacts of incorporating various proportions of titanium dioxide (TiO2) nanoparticles loaded on polycarbonate (PC)/wood flour. The rheological, mechanical, thermal, electrical, and interfacial properties were studied. Various properties of the resultant PC/WF/TiO2 nanocomposites were then characterized. The viscosity of the nanocomposite was shown to decrease with shear rate and temperature. XRD investigation indicated that, by introducing TiO2 nanoparticles into PC/WF, the amorphous phase decreased, and the degree of crystallinity increased, as compared to bare PC/WF, from 65.78 to 42.29. In addition, the TGA profile showed that the nanocomposites have a higher resistance to thermal degradation than PC/WF alone. It was observed that the char residue resulting from the TGA of PC/WF/10%wt TiO2 increased to 5.69% compared to pure PC/WF (1.32%). It was found that an appropriate amount of TiO2 in PC/WF caused a significant increase in tensile strength, elongation at break, and on impact strength. These were attributed to an increase in the interface of the dispersed phase. The incorporation of nanoparticles enhanced the thermal conductivity of the nanocomposites, which was found to be higher when a TiO2 content of ∼3 wt% was used. The electrical conductivity of the PC/WF/TiO2 nanocomposite (<3 wt%) hindered the movement of free-moving ions, therefore reducing the nanocomposite's electrical conductivity. However, at > 3 wt% of TiO2, due to the aggregation of nanoparticles, TiO2 nanoclusters formed in the PC/WF composite. Therefore, the additional space so created for the movement of conduction ions at the interface may have resulted in increased ion mobility. This could be the one of explanations for the increased electrical conductivity associated with higher wt% of TiO2. Results showed that treating the PC/WF/TiO2 nanocomposites with boric acid decreased both the rate of heat release and the total heat release. [ABSTRACT FROM AUTHOR]

The following research aims to investigate selected properties of three-layer plywood, manufactured using dust from the milling of three-layer particleboard as a filler in the bonding mass. Four types of fillers were considered in the study: commercial rye flour, wood dust naturally occurring in the composition of particles used industrially for particleboard production, wood dust from the first batch of shredded particleboard, and dust from the second round of milled particleboard. The highest modulus of elasticity (MOE) values were observed for the reference samples. Notably, in the samples containing filler sourced from the secondary milling of particleboard, the MOE exhibited an upward trend in conjunction with increasing filler content. The modulus of rupture (MOR) decreased with an elevated degree of filler milling from 73.1 N mm−2 for the native filler, through to 68.9 N mm−2 for the filler after 1st milling, and to 54.5 N mm−2 for the filler after 2nd milling (with 10 parts per weight (pbw) of filler used as an reference), though it increased slightly as the filler content increased. The most favorable outcomes in shear strength were achieved in samples containing filler material from the initial milling of particleboard. The thickness swelling peaked in variants utilizing filler material from both the initial and secondary milling of particleboards (20.1% and 16.6% after 24 h of soaking for samples with 10 pbw filler after the 1st and 2nd milling, respectively, compared to 13.0% for the reference samples). Water absorption testing exhibited a more pronounced response in the newly introduced variants, although the samples containing filler from the initial and secondary milling processes eventually yielded results akin to the reference sample, with naturally occurring dust displaying higher water absorption values. The highest density values (about 1224 kg m−3) were observed in the reference samples. A similar density profile was recorded for samples with five parts of wood flour as filler, although the density of the bonding line was slightly lower in these instances (1130 kg m−3). This research confirms the feasibility of applying the aforementioned dust as an alternative to conventional fillers in plywood technology. It also raises the question of how to effectively remove glue residues from wood-based composite dust, which would enhance their absorption properties. [ABSTRACT FROM AUTHOR]

This study investigates the effects of thermal treatment and silver nanoparticles on the mechanical and thermal properties of additively manufactured wood/polylactic acid (PLA) specimens. The 5 and 10 wt% additions of the wood flour into the PLA matrix are done in the twin screw extruder. The test specimens are produced from the filaments with a diameter of 1.75 mm using 3D printer. The mechanical properties of the 3D‐printed wood/PLA specimens are affected by the wood flour content, thermal treatment of wood, and silver nanoparticles. The 3D‐printed neat PLA specimens have better mechanical properties than the wood flour‐filled PLA specimens. The bending strength of the specimens enhances with increasing wood flour content while the tensile strength decreases. The increases in the mechanical properties reveal that the thermal treatment of the wood improves the compatibility between wood and PLA matrix, which hereby improves the interfacial adhesion. The addition of the silver nanoparticles positively affects the mechanical properties and it is more compatible with thermally modified wood particles as compared to the untreated wood particles. [ABSTRACT FROM AUTHOR]

This research was aimed at studying the preparation of polypropylene based wood plastic composite material by twin-screw extrusion. The effects of the addition of the maleic anhydride (MAH) and wood flour on WPC properties were evaluated. WPC with 4, 5, 6, 7, 8, 9, 10 wt% of MAH contents were prepared. The mechanical properties and water resistance of WPC were studied. The result showed that with the increasing of MAH, the tensile strength of WPC increases at first and then decrease, and water absorption reduced by 39%. After immersing in water for 24 h, the tensile strength of WPC decreases but the impact strength increases, and with the increasing of MAH, the reducing extent of tensile strength increases, but the improvement extent of impact strength gradually decreases. When the MAH content exceeds 8 wt%, the impact strength of dried WPC samples (dried for 24 h) can be recovered basically. WPC with 10, 20, 30, 40 wt% of wood flour contents were prepared. The result showed that with the increasing of wood flour, the tensile strength of WPC increases at first and then decreases, the impact strength decreases, and water absorption increased by 62%. When the wood flour content exceeds 10 wt%, the impact strength of dried WPC samples can only recover partially. WPC containing different wood meal sizes was prepared. The result showed that with the decreasing of wood flour particle size, the water absorption of WPC increases obviously. The impact strength of dried WPC samples is higher than that of unsoaked WPC, when the particle size of wood flour is 60 meshes. It can be seen from the SEM photos that the distance between the wood powder fibers becomes larger after 24 h of WPC soaking in water. The finer the wood flour, the easier it is to aggregate in WPC. [ABSTRACT FROM AUTHOR]

Rising environmental pressure, new ways of using naturally-based composite materials, as well as technical innovations, has lead manufacturers to application of those materials (with the goal of reducing the consumption of financially demanding, non-recyclable types of reinforcements - e.g., fiberglass). Wood Plastic Composites (WPCs) are a product developed in 1980s. They consist of wood flour (natural fillers), polymer blends and suitable additives (to improve mechanical properties, rheological properties and production process). Technologies of WPC composite materials production frequently include extrusion, injection moulding, pressing (thermoforming), calendaring and fused layer modeming/laser sintering. When choosing a suitable matrix, it is necessary to pay attention to the processing temperature - max. TRmaxR = 200 °C. At a higher temperature, natural reinforcements are decomposed. The submitted paper includes information about plastic matrices from previous studies and provides comprehensive view in the given area. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the properties of a new composite material made from poly(vinyl chloride) plastisol (PVC) and conifer-derived wood flour. The material can be used for thermal insulation, floor coverings with high resistance to mechanical trauma, and protective coatings. The plastisol was made from emulsion poly(vinyl chloride), the plasticiser was bis(2-ethylhexyl) adipate, and the stabiliser was octyltin mercapeptide. Two types of flour were used: fine-grained and coarse-grained. Its properties, such as bulk density, oil number, and plasticiser number, were determined. The polymer-wood composite contained 20 or 30 wt.% wood flour in PVC. Plastisol was obtained by repeated mixing, mashing, and venting under vacuum. The produced composite material was gelated at temperatures of 130, 150, and 170 °C. The gelation process of the composites was studied in a Brabender apparatus. Samples in the form of polymer films were used to study density, hardness, thermal stability, and mechanical and thermomechanical properties. The structure of the composites was observed by scanning electron microscopy (SEM). A summary of all test results showed that composite films made from PVC plastisol with 20 wt.% of fine wood flour gelled at 150 °C had the most favourable physical, mechanical, and thermal properties. [ABSTRACT FROM AUTHOR]

The formula, influencing factors and performance evaluation of composite putty for filling gaps in plywood based on wood fiber particle size/wood powder type difference were explored, and the technology development of filling gaps and flatness control on plywood surface was devoted. The effects of temperature, wood flour type and wood fiber mesh on the performance of putty were discussed by single factor condition. The results showed that the wear resistance, dry strength, wet strength, compatibility and stability of putty filling materials with wood fiber improved significantly compared with those without wood fiber, except that the surface drying time was slightly higher than that of the control group. Under the condition of the same number of wood fibers, different types of wood fibers will also affect the properties of putty. The order of wet strength and roughness was eucalyptus powder, poplar powder, miscellaneous wood powder, pine powder and bamboo powder. The order of dry strength was eucalyptus powder, miscellaneous wood powder, poplar powder, pine powder and bamboo powder. The order of wear resistance was poplar powder, pine powder, miscellaneous wood powder, eucalyptus powder and bamboo powder. The types of wood fibers have no significant effect on the surface drying time, compatibility and stability of putty. [ABSTRACT FROM AUTHOR]

Shredding of a vehicle or an electrical and electronic equipment at its end-of-life (EOL) is a common practice to extract valuable critical raw materials. Unfortunately, this has the unintended consequence of mixing different polymers together and the only EOL options for this industrial mixed plastic waste are landfilling and incineration. Here in this work, we show that low value and highly heterogenous industrial mixed plastic can be mechanically upcycled sustainably using a composite approach, i.e., reinforcing with carbon fibres (CFs), glass fibres (GFs) and wood flour (WF). It was found that industrial mixed plastic can be successfully reprocessed, albeit possessing significantly poorer mechanical properties compared to its virgin counterpart. Nevertheless, the mechanical properties of the reinforced industrial mixed plastics were observed to be governed by the fibre or filler reinforcement, instead of the more inferior brittle industrial mixed plastic matrix. A lifecycle analysis (LCA) model with a functional unit designed using finite element analysis was developed to determine the environmental impact of upcycling industrial mixed plastic from shredder residue using this composite approach. In a "business as usual" scenario, our LCA model estimated a global warming potential (GWP) of 23 kg CO2-eq. per f.u. and a net abiotic depletion potential of fossil (ADPf) of 431 MJ f.u.−1. Using our proposed feedstock agnostic and pragmatic solution, the GWP and net ADPf could be reduced to only 11 kg CO2-eq. per f.u. and 160 MJ f.u.−1, respectively, when 40 wt% WF reinforcing filler was used. Our work also reports the influence of reinforcement on the tensile, flexural and fracture toughness properties, as well as the LCA hot spots in such an upcycling approach. [ABSTRACT FROM AUTHOR]

The use of pine wood in wood-plastic composite WPC promotes sustainability by incorporating recycled or renewable materials, reducing the reliance on traditional wood sources, and minimizing environmental impact. This study focuses on treating pine wood flour (WF) with biological treatments (xylanase, pectinase, laccase, steam explosion) for use in WPC. The Scanning Electron Microscopy (SEM), Fourier Transform Infared spectroscopy (FTIR), biochemical analysis, and Thermo Gravimetric Analysis (TGA) were used to evaluate the effectiveness of the treatments in terms of the morphological, compositional, surface, and thermal stability of WF. The wear behavior of WPC was exanimate before and after hydrothermal aging. Morphological analysis of WF revealed that the enzymatic treatment produced a clean surface; it removed Xylan and led to a higher cellulose content (70%), and more porosity, and improved thermal stability and adhesion between WF and high density polyethylene (HDPE). Through analysis of wear and aging, we found the best wear resistance for laccase treatment among all WPC before and after aging, and it was lower than the HDPE. These findings highlight the positive impact of the enzymatic treatment on the adhesion between WF and HDPE, leading to reduced water absorption and increased wear resistance. [ABSTRACT FROM AUTHOR]

This study investigated the effects of Iroko wood flour (WF) and nanotitanium dioxide (TiO2) concentration on the properties of polypropylene (PP)-based composites, including accelerated weathering resistance, tribological behavior, thermal stability, physical characteristics, mechanical strength, morphological features, color changes, and surface roughness. The results showed that the presence of WF and TiO2 significantly influenced the density, hardness, thermal stability, crystallinity, coefficient of friction, and wear rate of the composites. Both fillers positively impacted the tensile strength, flexural strength, and flexural modulus of the composites, although the elongation at break values decreased. TiO2 addition enhanced thermal stability and protection against UV radiation, whereas using wood flour negatively affected color properties. Moreover, the surface roughness of the composites was affected by weathering time and wood flour content. These findings highlight the potential of WF and TiO2 as effective fillers for enhancing PPbased composites' properties and weathering resistance. [ABSTRACT FROM AUTHOR]

Sustainable composites based on blends from polypropylene (PP) and recycled polyethylene terephthalate (RPET) and wood flour (WF) were prepared under industry‐relevant conditions by melt extrusion, followed by continuous drawing through spinnerets. Maleic anhydride grafted polypropylene (PP‐g‐MA) was employed to improve the compatibility between matrix and WF. The effects of incorporation of WF and RPET microstructure on the morphological features, rheological measurements, and mechanical properties were investigated. The drawing process converted elliptical RPET phase into highly oriented microfibrillar structure, as characterized by means of scanning electron microscopy (SEM). The highly oriented blend (HOB) represented nonterminal behavior due to the presence of physical networks and enhanced surface area of microfibers for chemical interactions. The tensile strength of neat PP increased by the addition of WF and the existence of microfibrillar RPET phase, whereas the microstructure of RPET had more pronounce effect. The tensile strength and elastic modulus of PP reinforced by WF and oriented RPET improved by 65% and 92%, respectively, demonstrating the high potential of this environmental‐friendly reinforcement method to intensify the mechanical properties of PP. [ABSTRACT FROM AUTHOR]