Search Results (289)

Wood polymer composites (WPCs) represent a rapidly growing class of sustainable materials, formed by combining lignocellulosic fibers with thermoplastic or thermoset polymeric matrices. This review summarizes the state of the art in WPC development, emphasizing the use of recyclable (or recycled) and biodegradable polymers as matrix materials. The integration of waste wood particles into the production of WPCs addresses global environmental challenges, including plastic pollution and deforestation, by offering an alternative to conventional wood-based and petroleum-based products. Key topics covered in the review include raw material sources, fiber pre-treatments, compatibilizers, mechanical performance, water absorption behavior, thermal stability and end-use applications. Full article

Construction wood has a high economic value, and its construction waste also has multiple consumption values. Natural wood has many advantages, such as thermal, environmental, and esthetic properties; however, wood sourced from artificial fast-growing forests is found to be deficient in mechanical strength. This shortcoming makes it less competitive in certain applications, leading many markets to remain dominated by non-renewable materials. To address this issue, various modification methods have been explored, with a focus on enhancing the plasticity and strength of wood. Studies have shown that hydrogen bonds in the internal structure of wood have a significant impact on its operational performance. Whether it is organic modification, inorganic modification, or a combination thereof, these methods will lead to a change in the shape of the hydrogen bond network between the components of the wood or will affect the process of its breaking and recombination, while increasing the formation of hydrogen bonds and related molecular synergistic effects and improving the overall operational performance of the wood. These modification methods not only increase productivity and meet the needs of efficient use and sustainable environmental protection but also elevate the wood industry to a higher level of technological advancement. This paper reviews the role of hydrogen bonding in wood modification, summarizes the mechanisms by which organic, inorganic, and composite modification methods regulate hydrogen bond networks, discusses their impacts on wood mechanical properties, dimensional stability, and environmental sustainability, and provides an important resource for future research and development. Full article

Biodegradable polymer composites offer promising alternatives to petroleum-based plastics, supporting the principles of a zero waste and circular economy. This study investigates the reinforcing potential of alkali-treated wood flour derived from recycled pine (Pinus brutia Ten.) and poplar (Populus alba L.) waste wooden pallets in poly(lactic acid) (PLA) biocomposites. Wood flour was initially recovered through grinding and screening during recycling, followed by alkali treatment via a green chemistry approach to enhance interfacial bonding with the PLA matrix. The impact of alkali concentration and two fabrication methods—additive manufacturing (AM) and injection molding (IM)—on the properties of developed biocomposite materials was assessed through mechanical, physical, morphological, and thermal analyses. IM samples outperformed AM counterparts, with the IM PLA containing 30 wt% wood flour (alkali-treated with 10% solution) showing the highest mechanical gains: tensile (+71.35%), flexural (+64.74%), and hardness (+2.62%) compared to untreated samples. Moreover, the AM sample with 10 wt% wood flour and 10% alkali treatment showed a 49.37% decrease in water absorption compared to the untreated sample, indicating improved hydrophobicity. Scanning electron microscopy confirmed that alkali treatment reduced void content and enhanced morphological uniformity, while thermal properties remained consistent across fabrication methods. This work introduces a green composite using non-toxic materials and treatments, facilitating eco-friendly production aligned with zero waste and circular economy principles throughout the manufacturing lifecycle. Full article

This study investigated the effect of in situ polymerization on the compressive strength of demolition-derived Scots pine, European beech, and black alder wood. The treatment applied was based on previously confirmed in situ polymerization systems in wood, which are known to lead to polymer formation and composite-like structures. In this study, we assumed similar behavior and focused on a mechanical evaluation of the modified wood. Three different polymer systems were applied to evaluate differences in performance. After modification, the compressive strength levels increased by 60% in beech, 119% in alder, and 150% in pine, with corresponding increases in density and weight percent gain (WPG). The highest relative improvement was observed in the least dense species, pine. The findings suggest that polymer treatment can significantly enhance the mechanical properties, likely due to the incorporation of polymer into the wood matrix; however, this inference is based on indirect physical evidence. Full article

This research aimed to evaluate the biological resistance to xylophagous organisms and the dimensional stability related to water absorption in plastic wood panels manufactured by compression molding and produced with pine wood and recycled thermoplastics. The wood–plastic composites (WPCs) were prepared from 50% pine sawdust and 50% recycled plastics (polyethylene terephthalate-PET, high-density polyethylene-HDPE, and polypropylene-PP). The thickness swelling test was carried out by immersing of the WPC samples in water at room temperature (25–30 °C) and evaluating the total change in WPC thickness after 1500 h (≈9 weeks or two months). In addition, the coefficient of initial swelling was evaluated to verify the variability of the swelling. For the biological resistance evaluation of the WPCs, tests were carried out with soil or arboreal termites (Nasutitermes corniger) and drywood termites (Cryptotermes brevis). The WPC loss of mass and termite mortality were evaluated. The use of PP promoted the best response to thickness swelling. The simple mathematical model adopted offers real predictions to evaluate the thickness of the swelling of the compounds in a given time. For some variables there were no statistical differences. It was shown that treatment 3 (T3) presented visual damage values between 0.4 for drywood termites and 9.4 for soil termites, in addition to 26% termite mortality, represented by the lowest survival time of 12 days. The developed treatments have resistance to termite attacks; these properties can be an important starting point for its use on a larger scale by the panel industries. Full article

The environmental impact of petroleum-based plastics has driven a global shift toward sustainable alternatives like biodegradable polymers, including polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL). Yet, these bioplastics often face limitations in mechanical and thermal properties, hindering broader use. Reinforcement with cellulose nanofibrils (CNFs) has shown promise, yet most research focuses on conventional sources like wood pulp and cotton, neglecting agricultural residues. This review addresses the potential of maize husk, a lignocellulosic waste abundant in South Africa, as a source of CNFs. It evaluates the literature on the structure, extraction, characterisation, and integration of maize husk-derived CNFs into biodegradable polymers. The review examines the chemical composition, extraction methods, and key physicochemical properties that affect performance when blended with PLA, PBS, or PCL. However, high lignin content and heterogeneity pose extraction and dispersion challenges. Optimised maize husk CNFs can enhance the mechanical strength, barrier properties, and thermal resistance of biopolymer systems. This review highlights potential applications in packaging, biomedical, and agricultural sectors, aligning with South African bioeconomic goals. It concludes by identifying research priorities for improving compatibility and processing at an industrial scale, paving the way for maize husk CNFs as effective, locally sourced reinforcements in green material innovation. Full article

The dynamic thermomechanical properties of wood–plastic composites (WPCs) are influenced by various factors, such as the selection of raw materials and processing parameters. To investigate the effects of different wood fiber content ratios and temperature on the loss modulus of WPCs, seven different proportions of Masson pine (Pinus massoniana Lamb.) and Chinese fir [Cunninghamia lanceolata (Lamb.) Hook.] mixed-fiber-reinforced HDPE composites were prepared using the extrusion molding method. Their dynamic thermomechanical properties were tested and analyzed. The storage modulus of WPCs showed a decreasing trend with increasing temperature. A reduction in the mass ratio of Masson pine wood fibers to Chinese fir wood fibers resulted in an increase in the storage modulus of WPCs. The highest storage modulus was achieved when the mass ratio of Masson pine wood fibers to Chinese fir wood fibers was 1:5. In addition, the loss modulus of the composites increased as the content of Masson pine fiber decreased, with the lowest loss modulus observed in HDPE composites reinforced with Masson pine wood fibers. The loss tangent for all seven types of WPCs increased with rising temperatures, with the maximum loss tangent observed in WPCs reinforced with Masson pine wood fibers and HDPE. A prediction method based on the Extreme Learning Machine (ELM) model was introduced to predict the dynamic thermomechanical properties of WPCs. The prediction accuracy of the ELM model was compared comprehensively with that of other models, including Support Vector Machines (SVMs), Random Forest (RF), Back Propagation (BP) neural networks, and Particle Swarm Optimization-BP (PSO-BP) neural network models. Among these, the ELM model showed superior data fitting and prediction accuracy, with an R² value of 0.992, Mean Absolute Error (MAE) of 1.363, and Root Mean Square Error (RMSE) of 3.311. Compared to the other models, the ELM model demonstrated the best performance. This study provides a solid basis and reference for future research on the dynamic thermomechanical properties of WPCs. Full article

This study aims to improve the performance of wood–plastic composites (WPCs) composed of cotton stalk powder and residual film particles. Additionally, it aims to promote the efficient utilization of cotton stalk biochar. The composites were prepared using modified cotton stalk biochar and xylem powder as the matrix, maleic anhydride grafted high-density polyethylene (MA-HDPE) as the coupling agent, and polyethylene (PE) residual film particles as the filler. The WPCs were fabricated through melt blending using a twin-screw extruder. Mechanical properties were evaluated using a universal testing machine and texture analyzer, Shore D hardness was measured using a durometer, and microstructure was analyzed using a high-resolution digital optical microscope. A systematic investigation was conducted on the effect of biochar content on material properties. The results indicated that modified biochar significantly enhanced the mechanical and thermal properties of the WPCs. At a biochar content of 80%, the material achieved optimal performance, with a hardness of 57.625 HD, a bending strength of 463.159 MPa, and a tensile strength of 13.288 MPa. Additionally, thermal conductivity and thermal diffusivity decreased to 0.174 W/(m·K) and 0.220 mm²/s, respectively, indicating improved thermal insulation properties. This research provides a novel approach for the high-value utilization of cotton stalks and residual films, offering a potential solution to reduce agricultural waste pollution in Xinjiang and contributing to the development of low-cost and high-performance WPCs with wide-ranging applications. Full article

This study explores the lamination performance of wood-plastic composite boards designed for indoor decoration, aiming to enhance adhesion between a wood fiber/high-density polyethylene (HDPE) composite board and poplar wood veneer by incorporating fabrics (canvas or polyester fibers) as an intermediate layer. Traditional adhesives, such as polyvinyl acetate (PVAc) and isocyanate, were utilized to create decorative panels with a multi-interface sandwich structure. The impacts of factors such as the hot-pressing temperature, wood fiber content in the substrate, and fabric type on the performance of the panels were systematically investigated. The results indicated that the hot-pressing temperature of the substrate had minimal effect on the lamination performance. Panels that used canvas fabric as the intermediate layer and bonded with a mixed adhesive of PVAc and isocyanate exhibited superior surface bonding strength (2.76 MPa), bending properties (strength = 49.21 MPa; modulus = 3.92 MPa), and tensile properties (strength = 31.62 MPa; modulus = 1.51 GPa). The enhanced performance was attributed to the covalent bonding formed by isocyanate with canvas fabric, polyester fibers, and wood veneer, whereas PVAc primarily established physical bonds through penetration. Full article

The growing volume of plastic waste from end-of-life vehicles presents environmental concerns, driving efforts to integrate recycled plastics. This study investigates the possibility of using recycled plastic from automotive parts (painted and unpainted bumpers, fuel tanks) as a 10% filler in the core layer of three-layer particleboards (P) and evaluates its impact on physical properties (water absorption—WA and thickness swelling—TS), mechanical properties (internal bonding strength—IB, modulus of rupture—MOR, modulus of elasticity—MOE and screw driving torque—SDT) and volatile organic compounds—VOC emissions. The boards were produced using conventional hot-pressing technology and analyzed according to applicable standards. Based on the results, the density of the reference (P) was 0.72 g·cm⁻³, while wood–plastic composites ranged from 0.70 g·cm⁻³ to 0.72 g·cm⁻³. After 24 h, WA reached 40% for reference (P) and from 36.9% (for (P) containing unpainted bumpers) to 41.9% (for (P) containing fuel tanks). TS reached 18% for (P) and from 16.8% (for (P) containing unpainted bumpers and fuel tanks) to 18.1% (for (P) containing painted bumpers). Plastic is a hydrophobic material and it is assumed that by increasing the proportion of plastic filler in the particleboards, the WA and TS of prepared boards will decrease. From the point of view of mechanical properties, values for (P) containing plastic filler were slightly lower compared to reference (P). The lowest value of IB (0.39 MPa) were reached for (P) containing painted bumpers. Plastic surface treatment could interfere with adhesion between the plastic and adhesive, weakening the bond in the core layer. For this reason, is preferable to use unpainted fillers, which provide better adhesive properties and higher structural integrity. VOC emissions from wood components consisted primarily of monoterpenes such as α-pinene, 3-carene and limonene. Adding 10% plastic to the particleboard did not increase overall VOC emissions. On the other hand, combining wood and plastic particles resulted in a reduction in overall VOC emissions. The findings confirm that recycled automotive plastics can be effectively incorporated into particleboards, maintaining standard performance while reducing reliance on virgin wood materials, making them a viable and sustainable alternative for furniture and interior applications. Full article

This paper presents an experimental investigation of six different types of composite sandwich panels manufactured from waste-based materials, which are comprised of two different types of skins (made from hemp and recycled PET (Polyethylene terephthalate) fabrics with bio-epoxy resin) and three different cores (composite wood, recycled plastic, and styrofoam) materials. The skins of these sandwich panels were investigated under five different environmental conditions (normal air, water, hygrothermal, saline solution, and 80 °C elevated temperature) over seven months to evaluate their durability performance. In addition, the tensile and dynamic mechanical properties of those sandwich panels were studied. The bending behavior of cores and sandwich panels was also investigated and compared. The results indicated that elevated temperatures are 30% more detrimental to fiber composite laminates than normal water. Composite laminates made of hemp are more sensitive to environmental conditions than composite laminates made of recycled PET. A higher-density core makes panels more rigid and less susceptible to indentation failure. The flexible plastic cores are found to be up to 25% more effective at increasing the strength of sandwich panels than brittle wood cores. Full article

Wood–plastic composites (WPCs) are important materials used in interior architectural decorations and landscape construction products. Enhancing the cutting performance of WPCs is of great significance for improving both production efficiency and product quality in factories. This study aims to elucidate the impact of fluorine nano-coating technology on the cutting performance of cemented carbide tools during the milling of WPCs. The main results are given as follows. The cutting force and surface roughness showed similar trends with the varied parameters; both increased with increasing cutting depth and decreased with increasing cutting speed. The fluorine nano-coating technology exerts a positive influence on the cutting performance in terms of lower cutting forces and surface roughness. Meanwhile, based on the analysis of variance results, the experimental factors of cutting speed, depth, and surface treatment had a significant contribution to both cutting force and surface roughness, and cutting depth had the greatest impact on cutting force and surface roughness, followed by cutting speed and tool surface treatment. In general, the cutting performance of WPCs can be improved by higher cutting speed and lower depth, with the tool surface treated with fluorine nano-coating. Full article

The new wood–plastic composites (WPC) biocomposites, a promising blend of poly(lactic acid) (PLA) and lignocellulosic fillers, are the subject of our study. We used bark and sawdust at 40, 50, and 60% as PLA fillers. The innovative use of ion implantation to modify the surface properties of the produced composites could have significant implications. Argon ions were used in three dosages (1 × 10¹⁵, 1 × 10¹⁶, and 1 × 10¹⁷ cm⁻²) at an accelerating voltage of 60 kV. The modified composites were then analyzed for changes in surface wettability, surface energy, and color. Our findings demonstrate that the dosage of argon ion implantation and the filler used have a profound impact on the properties of the modified surfaces. In general, ion implantation enhances the surface wettability of composites and pure PLA, with the recorded relationships being more pronounced in composites containing higher proportions of lignocellulosic fillers. Furthermore, the implantation of ions on the surface of composites induces changes in their color, opening up new possibilities for the field of materials science. Full article

This study aimed to (i) characterize municipal solid waste (MSW) sourced from Utah and Michigan transfer stations and (ii) upcycle, produce, and evaluate composites derived from this MSW. Composition analysis showed that the MSW was composed of a variety of commodity plastics, paper/cardboard, and inorganic materials. Detailed chemical analysis for lignin, cellulose, hemicellulose, and lipids was performed. The plastics identified were mainly polyethylene, polypropylene, polystyrene, and poly (ethylene terephthalate). The compoundability of the MSW was assessed by torque rheometry. Composites were prepared by compounding the MSW in an extruder. A composite flexural strength of 29 MPa and a modulus of 1.0 GPa was achieved. The thermal properties of the composites were also determined. The melt flow behavior of the MSW composites at 190 °C was comparable to wood plastic composite formulations. Full article

This paper review deals with frequent technologies of the production of materials based on Wood Plastic Composite, their brief definition, and description of components. The choice of processing technology depends on the polymer applied and the shape required of the part or the component. In the case of thermoplastic matrices, the dominant are extrusion and injection molding. In the case of thermosets application, the following technologies can be used: Resin Transfer Molding and Sheet Molding Compound. Currently, the research is also widely focused on composites with a matrix made of biodegradable thermoplastics—polylactide, which also brings to the forefront 3D printing technology of Fused Deposition Modeling. Each of these technologies is—to a certain extent—limited and impacts on the final characteristics of the composite material and its use. Full article