Filters
Modified Buckwheat Husk as a Filler for Urea–Formaldehyde Resin in Plywood Production
The aim of the presented research was to determine the suitability of both non-modified and modified buckwheat husk (BH) as a filler for urea–formaldehyde adhesive in plywood production. The effect of two modification methods, acetylation and silanization, was investigated. Infrared spectroscopy outcomes confirmed that both acetylation and silanization of the filler had occurred. Based on the results, it was found that the introduction of BH had a significant effect on both the adhesive properties and the characteristics of the manufactured plywood. The application of non-modified husks led to a reduction in viscosity and an extension of the gelation time, and the produced plywood boards were characterized by reduced bonding quality and increased delamination. Modification of the husk surface by acetylation and silanization with 3-aminopropyltriethoxysilane contributed to the noticeable improvement in the resin properties. On the other hand, the improvement in plywood properties, consisting of the increase in bonding quality and reduced delamination, was observed only in the case of the silanized husk. Furthermore, the use of non-modified and acetylated husk did not significantly influence the formaldehyde emission. The reduction in the investigated emission of formaldehyde was observed only in the case of variants containing 15 and 20% of silanized buckwheat husk.
The effect of urea-formaldehyde adhesive modification with diisocyanate-functionalized nanocellulose on the properties of particleboard
Wood Particles of Various Sizes from Primary Wood Processing as Filler in Rigid Polyurethane Foams
The effect of wood particles polyesterification with sorbitol and citric acid on the properties of particleboard produced with the use of PF/pMDI adhesive
AbstractThis study investigated the effect of pine particle polyesterification with the mixture of sorbitol and citric acid (SCA) on the properties of particleboard bonded with the PF/pMDI hybrid resin. The use of SCA with a concentration of 35% contributed to improvement in the internal bond of the particleboards, their water resistance and dimensional stability. However, lowering the concentration to 25% resulted in a deterioration of the properties of produced materials. The effect of different loadings of pMDI in the PF/pMDI resin (0%, 5%, 15%, 25%) was also investigated and the outcomes showed a positive effect of the share of 15% and 25%. Furthermore, boards made of treated particles were characterized by slightly better flammable properties (lower mass loss, flashing point temperature and delayed ignition), and the visibility of the effect increased with the increase in the concentration of the impregnate. The results also indicate that the introduction of pMDI may also influence the ignition of the board.
The effect of veneer-surface modification with fumed nanosilica on the selected properties of water-resistant plywood
Properties of sandwich boards with a core made of bio-composite particleboard containing wood particles and walnut shells
AbstractThe aim of the research was to investigate the possibility of producing bio-composite particleboard with a density reduced to 500–550 kg/m3, containing 25% and 50% of walnut shells. In addition, the study also concerned the possibility of using these materials in sandwich systems. Based on the results, it was found that partial replacement of wood particles with ground shells leads to a significant reduction in the strength of the boards bonded with urea-formaldehyde (UF) resin. However, the implementation of a hybrid gluing method consisting of gluing wood particles with UF resin and walnut shells with 4,4′-methylenediphenyl isocyanate (pMDI) caused a significant improvement in the strength of the boards, especially for the variant with the highest shells content. Despite that, the manufactured materials still do not meet the requirements for furniture boards. The next step of the research has shown that these boards can perform well as a core layer in the sandwich boards covered with high-strength HDF boards. Moreover, it was found that increasing the share of walnut shells positively affected the dimensional stability of the resultant boards (thickness swelling and water absorption). However, substitution of wood with shells accelerated the ignition and flameout times of the boards. It increased the heat release without significantly affecting the percentage loss of the boards’ mass during exposure to fire.
Activated Carbon from Coconut Shells as a Modifier of Urea–Formaldehyde Resin in Particleboard Production
Various methods for the effective modification of urea–formaldehyde (UF) adhesives, aimed at enhancing the performance of wood-based materials, have been continually explored worldwide. The aim of this work was to investigate and evaluate the effect of introducing small amounts (0.25–1.5%) of activated carbon from coconut shells (ACCS) in UF adhesive on the properties of particleboard. The performed investigations of the adhesive mixture’s properties showed an increase in both viscosity and reactivity. Moreover, the use of loadings of 0.75% and 1% had a positive effect on mechanical properties such as bending strength, modulus of elasticity, and internal bond. In these variants, a delay in the degradation of the adhesive bonds by water was also observed, as indicated by the lower thickness swelling values measured after 2 h. However, under long-term exposure to water, the modification had no considerable effect on the dimensional stability of the boards. Markedly, the addition of 1 and 1.5% of ACCS resulted in a reduction in formaldehyde content, which can be attributed to the excellent adsorption capacity of activated carbon. Overall, a loading of 1% was found to be optimal, resulting in improved strength, enhanced water resistance, and reduced formaldehyde content.
Properties of Particle Boards Containing Polymer Waste
Nowadays, a significant increase in interest in renewable energy sources can be observed. Wind farms have been one of the solutions representing this trend for many years. One of the important elements of windmills is the blades. The data indicate that what to do with the blades after their use is a global problem, and so it is important to find a way to recycle them. Hence, this work aimed to use these blades in the production of wood-based materials. Two fractions of a fragmented blade were used for the tests: a small one and large one. Boards characterized by densities of 650 kg/m3 and 700 kg/m3 were produced, in which the assumed substitution of the wood material with a polymer was 20% or 40%. Mechanical properties such as bending strength (MOR), modulus of elasticity (MOE), and internal bond strength (IB) were investigated. The 2S65 variant achieved the highest static bending strength and a modulus of elasticity of 2625 N/mm2. The second best result was noted for the 4S65 variant, which was significantly different from the 2S65 variant. In the case of the variants with a density of 700 kg/m3, no significant differences were found and their results were significantly lower. Moreover, research on thickness swelling (TS) after 24 h of immersion and water absorption (WA) were also conducted. The obtained results indicate that the manufactured boards are characterized by good physical and mechanical properties.
Utilization of Pine and Birch Juvenile Wood for Low-Density Particleboard Production
This study investigated the effect of using juvenile pine and birch wood for the production of particleboards with lowered density, glued with urea-formaldehyde (UF) resin. The wood used was characterized by a number of annual rings ranging from 5 to 13, which ensured that only juvenile wood was used in the study. In addition to the basic characteristics of the wood particles obtained from this type of raw material, the density profiles of the manufactured particleboards, the internal bond, bending strength, modulus of elasticity, swelling, and water absorption after short-term water exposure (2 h) were also investigated. The results were compared to particleboards made from industrial wood particles from mature wood. It was found that particleboards made from juvenile pine wood exhibited higher internal bond than those made from juvenile birch wood. The bending strength of boards made from both types of juvenile wood was comparable to that of industrial particleboards; however, the modulus of elasticity of the particleboards made from juvenile pine was lower, which indicates reduced stiffness. These particleboards also showed higher swelling and water absorption, which may limit their durability under humid conditions. In contrast, birch boards exhibited lower internal bond, but their bending strength and modulus of elasticity were similar to those of industrial particles-based particleboards. Birch boards also showed slightly better water resistance than pine particleboards made from juvenile wood. However, their swelling remained higher than that of industrial particleboards. Overall, particleboards made from juvenile wood, especially birch, show good potential for further research.
Propolis extract as a bio-based modifier of urea-formaldehyde adhesive in particleboard production
Modified pine needles as a formaldehyde scavenger for urea-formaldehyde resin in plywood production
AbstractThe aim of the present work was to investigate whether it is possible to use ground pine needles as formaldehyde-scavenging filler for urea-formaldehyde resin in the production of plywood. The scope of the research included determinations of both optimal amount of introduced filler and the effect of its modification (silanization, hydrothermal and alkaline treatments). Properties of adhesives such as viscosity, gel time and pH were investigated and their morphology was assessed using scanning electron microscopy. The manufactured plywood panels were tested in terms of their wet shear strength, tendency to delamination in varying conditions and formaldehyde emission. It was found that the addition of pine needles lowers the pH and reduces gel time of the adhesive. Moreover, it was shown that despite the significant reduction in formaldehyde emission, the addition of non-modified needles causes a decrease in bonding quality of plywood. Based on the results, 10 parts by weight of needles per 100 parts by weight of resin can be considered as an optimal loading. The use of ground needles modified hydrothermally and with silane allows to minimize the negative effect on the strength of glue lines and leads to further reduction of formaldehyde emission. Therefore, it can be concluded that pine needle powder has strong potential for the application as a formaldehyde-scavenging filler for urea-formaldehyde adhesive in plywood production.
Effect of lysine-functionalized nanocellulose on urea-formaldehyde adhesive performance in particleboard production
Optimization of Isocyanate Content in PF/pMDI Adhesive for the Production of High-Performing Particleboards
Due to the fact that impregnation with fire retardant usually reduces the strength of the produced particleboards, this research was carried out to investigate whether it is possible to use phenol–formaldehyde (PF) resin modified using various amounts (0%, 5%, 10%, 15%, and 20%) of polymeric 4,4′-methylene diphenyl diisocyanate (pMDI) for this purpose. The need to optimize the addition of pMDI is particularly important due to health and environmental aspects and high price. Furthermore, the curing process of hybrid resins is still not fully explained, especially in the case of small loadings. Manufactured particleboards differed in the share of impregnated particles (50% and 100%). The mixture of potassium carbonate and urea was used as the impregnating solution. Based on the outcomes of hybrid resins properties, it was found that the addition of pMDI leads to the increase in solid content, pH, and viscosity of the mixtures, to the improvement in resin reactivity determined using differential scanning calorimetry and to the decrease in thermal stability in the cured state evaluated using thermogravimetric analysis. Moreover, particleboard property results have shown that using impregnated particles (both 50% and 100%) decreased the strength of manufactured boards bonded using neat PF resin. However, the introduction of pMDI allowed us to compensate for the negative impact of fire-retardant-treated wood and it was found that the optimal loading of pMDI for the board containing 50% of impregnated particles is 5% and for board made entirely of treated wood it is 10%.
Current Trends in the Use of Biomass in the Manufacture of Rigid Polyurethane Foams: A Review
This paper discusses methods of using biomass from the agriculture, forestry, food and aquaculture industries as potential raw materials for bio-polyols and as fillers in the production of rigid polyurethane (RPUR) foams. Various aspects of obtaining bio-polyols are discussed, as well as the impact of replacing petrochemical polyols with bio-polyols on the properties of foams. Special attention is paid to the conversion of vegetable oils and lignin. Another important aspect of the research is the use of biomass as foam fillers. Chemical and physical modifications are discussed, and important factors, such as the type and origin of biomass, particle size and amount, affecting the foaming process, microstructure and properties of RPUR foams are identified. The advantages and disadvantages of using biomass in foam production are described. It is found that bio-polyols can replace (at least partially) petrochemical polyols while maintaining the high insulation and strength of foams. In the case of the use of biomass as fillers, it is found that the shaping of their properties is largely dependent on the specific characteristics of the filler particles. This requires further research into process optimization but allows for the fine-tuning of RPUR foam properties to meet specific requirements.
Nanocellulose functionalized with ethylenediamine as a modifier of urea-formaldehyde adhesive in particleboard production
Alternative Wood Raw Material Sources in Particleboard and OSB Production—Challenges and Perspectives
This review examines the potential use of alternative wood raw materials, including fast-growing plantation species, juvenile wood, non-plantation species, and recycled wood, in the production of particleboard (PB) and oriented strand board (OSB). In light of the ongoing challenges faced by the wood-based industry in securing a stable and sustainable supply of raw materials, these alternatives present several advantages, such as cost-effectiveness, greater availability, and reduced reliance on natural forest resources. Fast-growing plantation species and juvenile wood are particularly suited for lightweight applications, while non-plantation species and recycled wood contribute to sustainability goals by lowering environmental impact and promoting resource efficiency. Nonetheless, the successful integration of these materials requires overcoming certain challenges, including variability in their physical and mechanical properties, as well as the need for tailored adhesive systems and processing parameters. This review examines strategies to optimize production processes and enhance the utilization of waste materials while emphasizing the role of alternative raw materials in advancing circular economy principles. The findings highlight the importance of future research to improve material knowledge, technological solutions, and industry practices, thereby supporting the sustainable development of the wood-based materials sector.