Search

The objective of this work was to evaluate selected physical and mechanical properties of experimental particleboards manufactured from pine and spruce with charcoal particles in their core layer. For all the manufactured boards the average density was 750 kg m-3, while the mass share of charcoal in the core layer was changed (0%, 10% and 50%). The manufactured panels were tested with respect to their mechanical and physical properties, including formaldehyde emission. The results indicated that the share of charcoal significantly influenced mechanical properties, swelling, and water relations of the boards. In addition, a test on formaldehyde emission from panels were carried out, which revealed that the charcoal share has a considerable impact on the amount of formaldehyde released by the manufactured boards. The 50% content of charcoal caused about 80% reduction of formaldehyde emission.

This manuscript explores the development of sustainable biopolymer composites using suberin extraction waste, specifically suberinic acid residues (SAR), as a 10% ( w / w ) reinforcing additive in polylactide (PLA) and thermoplastic starch-polylactide blends (M30). The materials were subjected to a detailed analysis using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) to assess their thermal, mechanical, and structural properties. The study confirmed the amorphous nature of the biopolymers and highlighted how SAR significantly influences their degradation behavior and thermal stability. M30 exhibited a multi-step degradation process with an initial decomposition temperature (T5%) of 207.2 °C, while PLA showed a higher thermal resistance with decomposition starting at 263.1 °C. Mechanical performance was assessed through storage modulus (E') measurements, showing reductions with increasing temperature for both materials. The research provides insights into the potential application of SAR-enriched biopolymers in sustainable material development, aligning with circular economy principles. These findings not only suggest that SAR incorporation could enhance the mechanical and thermal properties of biopolymers, but also confirm the effectiveness of the research in reassurance of the audience.

The aim of the study was to identify limiting factors for reusing wood through the recycling of window frames by conducting research under fully controlled conditions. The research involved manufacturing new window frames, seasoning them, and then shredding them into wood particles to prepare a three-layer particleboard. The proportion of wood particles in recycling was 0, 5, 10, 25, 50, and 100 parts by weight of the manufactured particleboard. Mechanical property tests were conducted: modulus of elasticity (MOE) and modulus of rupture (MOR), internal bond (IB), screw withdrawal resistance (SWR), and physical properties: density profile (DP), thickness swelling (TS) after water immersion, water absorption (WA), as well as formaldehyde emission and total volatile organic compound (TVOCs) tests. The research indicates a significant potential for utilizing wood from this sector of the wood industry, particularly considering variants with a higher proportion of recycled wood. MOR and MOE results are most promising for variants above 50 parts by weight of recycled wood. Based on the results obtained, it is clear that the production process should be improved or the raw material modified to enhance the internal bonding of particleboard, as these results were the weakest. Thus, recycled wood from window joinery has the potential to be reincarnated as particleboard, which continues to be widely used in their production.

This study investigates the potential of utilizing hazelnut shells (HS) as an innovative filler in three-layer plywood technology, addressing the growing need for sustainable, high-performance materials. Traditional plywood production relies on adhesives enhanced with various fillers to improve physical, mechanical, and operational characteristics. This research explores using native, chemically modified, and activated carbon derived from hazelnut shells as fillers in urea-formaldehyde (UF) resin. The produced plywood's mechanical properties, water absorption, and formaldehyde emissions were thoroughly analyzed. Key findings demonstrate that incorporating 10 part by weight (pbw) native hazelnut shell flour significantly enhances the modulus of rupture (MOR) to 138.6 N mm -2 and modulus of elasticity (MOE) to 13,311 N mm -2 . Chemically modified hazelnut shell flour achieves optimal results at 5 pbw, while activated carbon from hazelnut shells, even at 1 pbw, markedly improves bonding strength (2.79 N mm -2 referred to 0.81 N mm -2 for reference sample without filler added). Notably, activated carbon effectively reduces formaldehyde emissions (2.72 mg 100 g -1 oven dry panel referred to 3.32 mg 100 g -1 oven dry panel for reference samples with 10 pbw filler) and improves water resistance, indicating better further dimensional stability and lower environmental impact. The study also shows that excessive filler content negatively affects strength parameters, confirming the importance of optimizing filler concentration. These results highlight the potential of hazelnut shells as an eco-friendly alternative filler in plywood production, contributing to waste valorization and environmental sustainability. This study supports the practical application of hazelnut shell fillers, promoting a circular economy and reducing reliance on traditional, less sustainable materials, thus providing a valuable solution for the wood composite industry.

Nonwoven upholstery fabric is a waste product which is mainly generated during upholstered furniture production. The polyester composition makes it problematic to recycle and reuse this product. This study examined the manufacturing process of nonwoven fabric-reinforced plywood composites and their selected mechanical and physical properties. Nonwoven fabric was integrated between veneers bound with urea-formaldehyde resin to improve standard layered composites' mechanical and physical properties. Several board variants were produced, differing in the position of the nonwoven layers in the composite structure. The composites were evaluated for modulus of rupture (MOR), modulus of elasticity (MOE), internal bond, and screw withdrawal resistance, among others. The results showed that the addition of nonwoven fabric significantly improved some properties, like internal bond and screw withdrawal resistance. Variants with strategically placed nonwoven layers showed the highest performance increases. The results underscore the potential of nonwoven fabric as an effective reinforcing material, offering a path to developing high-performance plywood composites suitable for demanding applications. Another environmental advantage is that the nonwoven fabric waste used in the tested plywood production has not been subjected to burning or landfilling but, through its incorporation into plywood structure, has positively contributed to the Carbon Capture and Storage (CCS) policy. The findings advocate for a circular economy approach, in which industrial waste is effectively repurposed, contributing to the development of green materials in the wood-based composite industry.

This research focuses on producing particleboards from the biomass of plantation willow ( Salix viminalis L.) and poplar ( Populus spp.), aiming to explore their feasibility as sustainable materials for various applications. Fast-growing willow and poplar are known for their rapid growth and suitability for energy production. They present an intriguing alternative as raw materials with added value for particleboard manufacturing. This study investigates the selected mechanical and physical properties of the produced particleboards, considering parameters such as density profile, bending strength, modulus of elasticity, internal bond, water absorption, thickness swelling, and screw withdrawal resistance. The research results were also compared between different mass shares of willow and poplar particles in the particleboards. The results show that the panels produced entirely from the tested alternative raw materials had a modulus of rupture of 21.7 N mm -2 compared to 14.6 N mm -2 for the reference panels, with an internal bond of about 2.02 N mm -2 compared to 0.65 N mm -2 for the reference panels. The thickness swelling after 24 h of soaking was about 24.2% compared to 42.2% for reference panels. The findings underscore the promising potential of willow and poplar-based particleboards as eco-friendly alternatives in the construction and furniture industries, contributing to resource efficiency and carbon emission reduction efforts.

No matter where we reside, the issue of greenhouse gas emissions impacts us all. Their influence has a disastrous effect on the earth's climate, producing global warming and many other irreversible environmental impacts, even though it is occasionally invisible to the independent eye. Phase change materials (PCMs) can store and release heat when it is abundant during the day (e.g., from solar radiation), for use at night, or on chilly days when buildings need to be heated. As a consequence, buildings use less energy to heat and cool, which lowers greenhouse gas emissions. Consequently, research on thermally active medium-density fiberboard (MDF) with PCMs is presented in this work. MDF is useful for interior design and furniture manufacturing. The boards were created using pine ( Pinus sylvestris L.) and spruce ( Picea abies L.) fibers, urea-formaldehyde resin, and PCM powder, with a phase transition temperature of 22 °C, a density of 785 kg m -3 , a latent heat capacity of 160 kJ kg -1 , a volumetric heat capacity of 126 MJ m -3 , a specific heat capacity of 2.2 kJ kgK -1 , a thermal conductivity of 0.18 W mK -1 , and a maximum operating temperature of 200 °C. Before resination, the wood fibers were divided into two outer layers (16%) and an interior layer (68% by weight). Throughout the resination process, the PCM particles were solely integrated into the inner layer fibers. The mats were created by hand. A hydraulic press (AKE, Mariannelund, Sweden) was used to press the boards, and its operating parameters were 180 °C, 20 s/mm of nominal thickness, and 2.5 MPa for the maximum unit pressing pressure. Five variants of MDF with a PCM additive were developed: 0%, 5%, 10%, 30%, and 50%. According to the study, scores at the MOR, MOE, IB, and screw withdrawal resistance (SWR) tests decreased when PCM content was added, for example, MOE from 3176 to 1057 N mm -2 , MOR from 41.2 to 11.5 N mm -2 , and IB from 0.78 to 0.27 N mm -2 . However, the results of the thickness swelling and water absorption tests indicate that the PCM particles do not exhibit a substantial capacity to absorb water, retaining the dimensional stability of the MDF boards. The thickness swelling positively decreased with the PCM content increase from 15.1 to 7.38% after 24 h of soaking. The panel's thermal characteristics improved with the increasing PCM concentration, according to the data. The density profiles of all the variations under consideration had a somewhat U-shaped appearance; however, the version with a 50% PCM content had a flatter form and no obvious layer compaction on the panel surface. Therefore, certain mechanical and physical characteristics of the manufactured panels can be enhanced by a well-chosen PCM addition.

Finishing coatings in the wood-based composites industry not only influence the final appearance of the product but also serve to protect against fungi and molds and reduce the release of harmful substances, particularly formaldehyde and volatile organic compounds (VOCs). Carbon-rich materials, such as those derived from birch bark extraction, specifically suberin acids, can fulfill this role. Previous research has demonstrated that adding suberin acid residues (SAR) at 20% and 50% by weight significantly enhances the gas barrier properties of surface-finishing materials based on poly(lactide) (PLA) and polycaprolactone (PCL), particularly in terms of total VOC (TVOC) and formaldehyde emissions. This study aims to explore whether these properties can be further improved through the incorporation of nano-zinc oxide (nano-ZnO). Previous research has shown that these nanoparticles possess strong resistance to biological factors and can positively affect the characteristics of nanofilms applied as surface protection. The study employed PLA and PCL finishing layers blended with SAR powder at 10% w / w and included 2% and 4% nano-zinc oxide nanoparticles. The resulting blends were milled to create a powder, which was subsequently pressed into 1 mm-thick films. These films were then applied to raw particleboard surfaces. TVOC and formaldehyde emission tests were conducted. Additionally, the fungal resistance of the coated surfaces was assessed. The results showed that PLA/SAR and PCL/SAR composites with the addition of nano-zinc oxide nanoparticles exhibited significantly improved barrier properties, offering a promising avenue for developing biodegradable, formaldehyde-free coatings with enhanced features in the furniture industry. Furthermore, by utilizing SAR as a post-extraction residue, this project aligns perfectly with the concept of upcycling.

Molded plywood is used for furniture components such as seats, backrests, or integral seat shells, and it must be durable and harmless to health. Molded plywood is made with urea-formaldehyde (UF) adhesives; therefore, the issue of the fillers used in them is important. The potential of using ground beech ( Fagus sylvatica L.) bark as an eco-friendly additive in UF adhesives for molded plywood manufacturing was investigated in this work. Wheat flour was used as a reference filler. The beech bark (BB) level as a filler was 10%, a value verified under laboratory conditions. Nine-layer flat and molded plywood were produced under industrial conditions from beech veneers bonded with a UF adhesive mixture. The mechanical (bending strength and bonding quality) and physical (swelling and absorbency values after 2 and 24 h) properties of the industrially fabricated molded plywood were evaluated and compared with the European standard requirements (EN 310 and EN 314-2). The mechanical properties of the molded plywood with the addition of BB in the adhesive mixture were acceptable and met these standards' requirements. The positive effect of BB in the UF adhesive mixture on a reduction in formaldehyde emissions from the molded plywood was also confirmed. BB, considered to be wood-processing industry waste or a by-product, has significant potential to be used as a filler in UF resins for molded plywood production, providing an environmentally friendly, inexpensive solution for the industrial valorization of bark as a bio-based formaldehyde scavenger.

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.

During the production of furniture, large amounts of waste materials are generated, which are most often stored in warehouses without a specific purpose for their subsequent use. In highly developed countries, as many as 25 million tons of textile waste are produced annually, of which approximately 40% is non-clothing waste such as carpets, furniture and car upholstery. The aim of this research was to produce and evaluate dry-formed high-density fiberboards (HDF) bonded with urea-formaldehyde resin, 12% resination, with various shares of recycled particles of natural leather used in upholstery furniture production at different contents (1, 5 and 10% by weight). The panels were hot-pressed (200 °C, 2.5 MPa, pressing factor 20 s mm -1 ). Mechanical properties (modulus of rupture, modulus of elasticity and screw withdrawal resistance) and physical properties (density profile, thickness swelling after water immersion, water absorption and surface absorption) were tested. The density profile and contact angle of natural leather have been also characterized. The results show that increasing the content of leather particles in HDF mostly has a positive effect on mechanical properties, especially screw withdrawal resistance and water absorption. It can be concluded that, depending on the further use of HDF, it is possible to use recovered upholstery leather particles as a reasonable addition to wood fibers in HDF technology.

One of the ways of potential improvement of the particleboard properties, especially surface quality, can be the incorporation of wood fibers to face layers. This study aimed to evaluate the selected mechanical and physical parameters of single and multi-layered particleboards with the structure modified by the incorporation of various types and amounts of wood fibers. Single, 3- and 5-layers particleboards were produced with two different types of wood fibers added to the face and core layers. The basic mechanical parameters (modulus of rupture, modulus of elasticity, internal bond, surface soundness), as well as density profile and surface roughness, have been investigated. The results have shown that the single-layer panels with fibers did not meet the standard requirements due to unsatisfactory unstable parameters, probably caused by uneven resination. The remaining panels, 3- and 5-layer, met the standard requirements, and, due to fiber incorporation, there is also potential to reduce the panel density, still meeting standard requirements. The addition of fibers from 0% to 75% in face layers leads to an increase in the modulus of rupture from 10.6 N mm -2 to 15.6 N mm -2 . Depending on the fibers' type, the surface soundness can vary between 0.7 N mm -2 and 1.2 N mm -2 . Five-layer panels were of similar or even higher parameters, but due to much-complicated technology, it seems unreasonable to develop this type of composite. The novelty of the conducted research is the attempt to modify the structure of particleboards by adding various amounts of two different types of fibers by mixing them with particles or adding them as separate layers and producing panels of different densities.

This is a bridge between circular economy issues and wood-based panels technology, especially particleboards. Because these composites contain a significant amount of non-wood raw material (10-12% thermoset resin, high hardness laminates, among others), their mechanical recycling leads to an uncontrollable reduction in produced particle size. This problem can be especially significant since the particleboards can be intended for multiple recycling due to the shortening of their service life. This research aimed to produce particles in the cycle of multiple re-milling particleboards and evaluate the selected properties of the produced particles and particleboards. Thus, the response to the following scientific problem can be given: what factors qualitatively and quantitatively influence the properties of the particleboards produced by multi-re-milled particles? The novelty of this research is the approach to recycling the raw materials from particleboards in fully controlled conditions, providing the characterization of produced particles and producing particleboards with close-to-industrial parameters, and, finally, evaluating the features of produced particleboards in the light of raw materials used. The results confirmed that subsequent mechanical recycling of particleboards, where the other panels are made entirely of second-milling particles, leads to an unprofitable and unacceptable reduction in the mechanical properties of the panels. The physical parameters, such as thickness swelling and water absorption, are improved, but this can be the result of increased content of chemical ingredients, which negatively influence the hygienic features of panels (emission of formaldehyde and total volatile organic compounds-TVOC). Further research should be directed towards estimating the optimal addition of mechanically recycled particles to particleboard production.

A growing world population means that demand for wood-based materials such as particleboard is constantly increasing. In recent years, wood prices have reached record highs, so a good alternative can be the utilization of branches, which can reduce the cost of raw materials for particleboard production. The goal of the study was to confirm the feasibility of using an alternative raw material in the form of Pinus sylvestris L. pine branches for the production of three-layer particleboard. Characterization of the alternative raw material was also carried out, and the bulk density was determined. As part of the research, six variants of particleboard, 0%, 5%, 10%, 25%, and 50%, w / w , and two variants where the first one had the face layer made of branch particles and the core layer made of industrial particles, and the reverse variant (all produced panels were three-layer) were produced and then their physical and mechanical properties were studied. The results show that even if the bulk density of branch particles is significantly higher than industrial material, the internal bond and water absorption rises as branch particle content increases. In the case of bending strength and modulus of elasticity, these were decreased with a branch particle content increase. The conducted tests confirmed the possibility of using the raw material, which was usually used as fuel or mulch, to produce particleboards even in 50% content. The present solution also contributes to the positive phenomenon of carbon storage, due to incorporating the branches' biomass into panels rather than burning it. Further research should be focused on the modification of particle production from branches to obtain lower bulk density and to reach fraction shares closer to industrial particles. Furthermore, the chemical characterization of the pine branch particles (cellulose and lignin content, extractives content, pH value) would provide valuable data about this potential alternative raw material.

In this study, layered composites were produced with different biopolymer adhesive layers, including biopolymer polylactic acid (PLA), polycaprolactone (PCL), and biopolymer blends of PLA + polyhydroxybutyrate (PHB) (75:25 w / w ratio) with the addition of 25, 50% microcrystalline cellulose (MCC) and 3% triethyl Citrate (TEC) for these blends, which acted as binders and co-created the five layers in the elaborated composites. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), density profile, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analysis were obtained. The results showed that among the composites in which two pure biopolymers were used, PLA obtained the best results, while among the produced blends, PLA + PHB, PLA + PHB + 25MCC, and PLA + PHB + 25MCC + 3TEC performed best. The mechanical properties of the composites decreased with increases in the MCC content in blends. Therefore, adding 3% TEC improved the properties of composites made of PLA + PHB + MCC blends.

This research aimed to confirm the ability to reduce carbon dioxide emissions by novel composite production using plantation waste on the example of lignocellulosic particles of black chokeberry ( Aronia melanocarpa (Michx.) Elliott) and raspberry ( Rubus idaeus L.). Furthermore, to characterize the particles produced by re-milled particleboards made of the above-mentioned alternative raw materials in the light of further recycling. As part of the research, particleboards from wooden black chokeberry and raspberry were produced in laboratory conditions, and select mechanical and physical properties were examined. In addition, the characterization of raw materials (particles) on the different processing stages was determined, and the fraction share and shape of particles after re-milling of the produced panels was provided. The tests confirmed the possibility of producing particleboards from the raw materials used; however, in the case of boards with raspberry lignocellulose particles, their share cannot exceed 50% so as to comply with the European standards regarding bending strength criterion. In addition, the further utilization of chips made of re-milled panels can be limited due to the significantly different shape and fraction share of achieved particles.

In this research, the assessment of the impact of natural biopolymer binders on selected mechanical and physical properties of lignocellulosic composites manufactured with different resination (12%, 15%, 20%). Different mechanical and physical properties were determined: modulus of rupture, modulus of elasticity, internal bonding strength, thickness swelling, water absorption, contact angle, and density profile. Moreover, thermal properties such as thermogravimetric analysis and differential scanning calorimetry were studied for the polymers. The results showed significant improvement of characterized features of the composites produced using biopolymers. However, the rise of the properties was visible when the binder content raised from 12% to 15%. Further increase of biopolymer binder did not imply a considerable change. The most promising biopolymer within the tested ones seems to be polycaprolactone (PCL).

The sizeable global production of wood-based products requires new sources of raw material, but also creates large quantities of wastes or composites that do not comply with requirements. In this study, the influence of different shares of recovered high-density fiberboards (HDF-r), reversed into the production, on industrial HDF properties, has been examined. HDF-r may be a suitable partial substitute for raw pinewood for industrial HDF production. Although most of the mechanical properties, as well as thickness swelling and water absorption, had a linear decrease with the increase in the share of HDF-r share, the elaborated boards met most of the commercial requirements (EN 622-5). The property that did not meet the requirements was the internal bond strength for panels with 10% of HDF-r. The presented results show that, after some adjustments, it should be possible to produce HDF boards with up to 10% of recycled HDF being able to meet all commercial requirements.