Search Results (3)

Adhesives represent an important part in the wood-based composite production, and taking into account their impact on the environment and human health, it is a challenge to find suitable natural adhesives. Starting from the current concerns of finding bio-adhesives, this paper aims to use magnesium lignosulfonate in three adhesive recipes for particleboard manufacturing. First, the adhesive recipes were established, using oxygenated water to oxidize magnesium lignosulfonate (Recipe 1) and adding 3% polymeric diphenylmethane diisocyanate (pMDI) crosslinker (Recipe 2) and a mixture of 2% polymeric diphenylmethane diisocyanate with 15% glucose (Recipe 3). The particleboard manufacturing technology included operations for sorting particles and adhesive recipes, pressing the mats, and testing the mechanical strengths and formaldehyde emissions. The standardized testing methodology for formaldehyde emissions used in the research was the method of gas analysis. Tests to determine the resistance to static bending and internal cohesion for all types of boards and recipes were also conducted. The average values of static bending strengths of 0.1 N/mm², 0.38 N/mm², and 0.41 N/mm² were obtained for the particleboard manufacturing with the three adhesive recipes and were compared with the minimal value of 0.35 N/mm² required by the European standard in the field. Measuring the formaldehyde emissions, it was found that the three manufacturing recipes fell into emission classes E1 and E0. Recipes 2 and 3 were associated with good mechanical performances of particleboards, situated in the required limits of the European standards. As a main conclusion of the paper, it can be stated that the particleboards made with magnesium-lignosulphonate-based adhesive, with or without crosslinkers, can provide low formaldehyde emissions and also good mechanical strengths when crosslinkers such as pMDI and glucose are added. In this way magnesium lignosulfonate is really proving to be a good bio-adhesive. Full article

Growing global environmental problems force us to think about their impact and search for ways to protect the environment. While the construction industry and the production of construction materials contribute to environmental pollution, they also offer great potential for addressing many environmental problems. Important opportunities exist in the use and processing of a whole host of industrial and construction waste and in the use of mineral resources. Among such mineral resources is magnesite, whose deposits in Slovakia are abundant. The current sustainability trends impose strict requirements on construction materials and products, favoring solutions with sufficient ecological and efficiency performance characteristics. With this focus on efficient and sustainable solutions in mind, the objective of this research was to analyze magnesium oxide construction boards, as they are the most commonly used construction product based on MgO. The specific MgO-based boards that were studied were applied in selected constructions built using the so-called dry method of construction and were compared with traditional material solutions. The research methodology is based on an analysis of computational models of the proposed variants to determine selected thermal-technical parameters. The analyses of external and interior structures presented in this work suggest that when boards based on MgO and traditional materials are used for coating constructions built using the dry method of construction, the former provide certain benefits in terms of energy accumulation, improving living comfort, and in terms of the fire resistance of constructions, improving overall safety. The conclusion of the presented article is devoted to discussions with works that addressed various perspectives on the application of MgO in the field of materials research. The findings from this analysis are beneficial especially in terms of expanding the knowledge in the area. Full article

Edgewise compression response of a composite structural insulated panel (CSIP) with magnesium oxide board facings was investigated. The discussed CSIP is a novel multifunctional sandwich panel introduced to the housing industry as a part of the wall, floor, and roof assemblies. The study aims to propose a computational tool for reliable prediction of failure modes of CSIPs subjected to concentric and eccentric axial loads. An advanced numerical model was proposed that includes geometrical and material nonlinearity as well as incorporates the material bimodularity effect to achieve accurate and versatile failure mode prediction capability. Laboratory tests on small-scale CSIP samples of three different slenderness ratios and full-scale panels loaded with three different eccentricity values were carried out, and the test data were compared with numerical results for validation. The finite element (FE) model successfully captured CSIP’s inelastic response in uniaxial compression and when flexural action was introduced by eccentric loads or buckling and predicted all failure modes correctly. The comprehensive validation showed that the proposed approach could be considered a robust and versatile aid in CSIP design. Full article