The paper investigates the possibility of manufacturing rapeseed particleboards (RPB) which could be used as construction material in eco buildings. Therefore, single-layer particleboards were produced from rapeseed straw particles glued with mixture of 4.4′-methylenediphenyl isocyanate (pMDI) and phenol–formaldehyde (PF) resins in the weight ratio 70:30 (hybrid pMDI/PF resin). The boards were manufactured with density of 650, 600, 550, 500 and 450 kg/m3. Next, their physico-mechanical properties were determined, i.e. modulus of rupture, modulus of elasticity, internal bond and internal bond after the boil test (V-100) and thickness swelling after 24 h soaking in water. The thermal conduction coefficient (λ) and sorption properties in changeable relative humidity conditions were also determined. Based on the obtained results, it was found that rapeseed straw may be a valuable material used in the production of construction particleboards which meet high strength requirements. Boards with density of 650 kg/m3 meet the requirements of EN 312 standard for type P7 boards. It is also possible to decrease their density to 600 kg/m3 (type P5 boards) and even 550 kg/m3 (type P3 boards). However, rapeseed particleboards are characterized by relatively high values of thickness swelling after 24 h of soaking in water. The weaker resistance to humidity has also been confirmed by tests on sorption and desorption of vapour in changeable relative humidity conditions. Nonetheless, an important advantage of these boards is the fact that they are characterized by better thermal insulation than particleboards.
1 November 2020 in Journal of Building Engineering
In this study, the possibility of using sawdust, a by-product of primary wood processing, as a filler (WF) for rigid polyurethane (PUR) foams was investigated. The effects of the addition of 5, 10, 15 and 20% of WF particles to the polyurethane matrix on the foaming process, cell structure and selected physical-mechanical properties such as density, thermal conductivity, dimensional stability, water absorption, brittleness, compressive and bending strengths were evaluated. Based on the results, it was found that the addition of WF in the amount of up to 10% does not significantly affect the kinetics of the foam foaming process, allowing the reduction of their thermal conductivity, significantly reducing brittleness and maintaining high dimensional stability. On the other hand, such an amount of WF causes a slight decrease in the compressive strength of the foam, a decrease in its bending strength and an increase in water absorption. However, it is important that in spite of the observed decrease in the values of these parameters, the obtained results are satisfactory and consistent with the parameters of insulation materials based on rigid PUR foam, currently available on the market.
6 November 2019 in Particulate Science and Technology
The present paper provides characteristics of three species of grain straw particles applied in the production of lignocellulose particleboards. For the sake of the investigation, rapeseed, rye, and triticale straw were fragmented to the size of particles used in the wood-based materials industry. The aim of the research was to determine physical properties of particle of rapeseed, rye, and triticale straw and to evaluate their usefulness in the process of manufacturing lignocellulose particleboards purposed for building constructions. Another aspect of the work was to determine the influence of moisture content of straw particles (using rapeseed straw as an example) on properties of the manufactured particleboards made with its use. The conclusion is that each of the investigated materials is characterized by different geometry, poured and tapped bulk density, varied angle of repose, and slippery angle of repose. Differences in sizes and shapes of particles of various grain species and in their moisture content strongly affect properties of particleboards produced with their use. The investigations prove that the best properties are observed for rye straw particleboards. However, due to their physical parameters, difficulties in storage, transport, and particleboards production may happen to be more considerable than in case of other materials.
The properties of particleboards and the course of their manufacturing process depend on the characteristics of wood particles, their degree of fineness, geometry, and moisture content. This research work aims to investigate the physical properties of wood particles used in the particleboard production in dependence on their moisture content. Two types of particles currently used in the production of three-layer particleboards, i.e., microparticles (MP) for the outer layers of particleboards and particles for the core layers (PCL), were used in the study. The particles with a moisture content of 0.55%, 3.5%, 7%, 10%, 15%, and 20% were tested for their poured bulk density (), tapped bulk density (), compression ratio (k), angle of repose (), and slippery angle of repose (). It was found that irrespective of the fineness of the particles, an increase in their moisture content caused an increase in the angle of repose and slippery angle of repose and an increase in poured and tapped bulk density, while for PCL, the biggest changes in bulk density occurred in the range up to 15% of moisture content, and for MP in the range above 7% of moisture content, respectively. An increase in the moisture content of PCL in the range studied results in a significant increase in the compression ratio from 47.1% to 66.7%. The compression ratio of MP increases only up to 15% of their moisture content—a change of value from 47.1% to 58.7%.
28 July 2015 in European Journal of Wood and Wood Products
This work examines the effect of applying fumed silica with nanoscopic-size particles as a filling material for melamine-urea-phenol-formaldehyde (MUPF) resin in the process of manufacturing water-resistant plywood. Moreover, this paper investigates the possibility of reducing the amount of MUPF resin mixture used in the process of gluing veneer sheets. Based on the investigations into the reactivity, viscosity and durability of MUPF resin mixture containing various amounts of nanofiller, it was found that the optimum amount of silica that can make the resin suitable for gluing sheets of veneer amounts to 2 PBW per 100 PBW of MUPF resin. The gluing properties for thus mixed resin were determined by measuring the contact angle and determining the parameters of its derivatives, which are an additional criterion for evaluating the gluing properties. The thermal stability was tested with simultaneous use of TG–DSC analysis. The experimental plywood manufactured using optimal nano-SiO2 was tested in terms of bond quality and mechanical properties according to appropriate standards. The investigations prove that it is possible to apply fumed silica as a filling material for the resin in the process of manufacturing water-resistant plywood. Introducing the above-mentioned amount of fumed silica into the resin makes it possible to increase the activation energy of the cross-linking process of MUPF resin and to optimize the process of gluing the sheets of veneer. Moreover, it is also possible to produce plywood of the required water-resistance with the amount of adhesive mixture reduced by 30 %.