Functionality of Beech Bark in Adhesive Mixtures Used in Plywood and Its Effect on the Stability Associated with Material Systems

Abstract

The results of research into utilizing grinded beech bark in order to substitute commonly used fillers in urea formaldehyde (UF) adhesive mixtures to bond plywood are presented in the present study. Four test groups of plywood with various adhesive mixtures were manufactured under laboratory conditions and used for experimentation. Plywood made using the same technology, with the common filler (technical flour), was used as a reference material. Three different concentrations of grinded beech bark were used. The thermal conductivity of the fillers used, viscosity and its time dependence, homogeneity and the dispersion performance of fillers were evaluated in the analysis of adhesive mixture. The time necessary for heating up the material during the pressing process was a further tested parameter. The produced plywood was analyzed in terms of its modulus of elasticity, bending strength, perpendicular tensile strength and free formaldehyde emissions. Following the research results, beech bark can be characterized as an ecologically friendly alternative to technical flour, shortening the time of pressing by up to 27%. At the same time, in terms of the statistics, the mechanical properties and stability of the material changed insignificantly, and the formaldehyde emissions reduced significantly, by up to 74%. The utilization of bark was in compliance with long-term sustainability, resulting in a decrease in the environmental impact of waste generated during the wood processing.

Construction of Wood-Based Lamella for Increased Load on Seating Furniture

“…Laminated furniture panels-lamellae and plywood-are widely used in furniture manufacturing. Properties of lamellae and plywood used in furniture projects depend on many various factors, such as moisture content of veneers, temperature, pressure and pressing time [54][55][56][57][58]. Adhesive properties, its viscosity, thickness of adhesive layer, quality of adhesive application, mechanical properties of veneers, treatment quality or removal of small elements from the surface (saw dust) are other factors affecting the bending strength [59][60][61][62][63].…”

Further Exploration of Sucrose–Citric Acid Adhesive: Investigation of Optimal Hot-Pressing Conditions for Plywood and Curing Behavior

“…Based on the investigation of the bond performance above, the optimal manufacture conditions of SC adhesive were: hot-pressing temperature-190 • C; hot-pressing time-7 min; spread rate-140 g/m 2 . Although the properties of the plywood which were manufactured under the optimal hot-pressing conditions satisfied the requirements of the China National Standard GB/T 9846-2015, these fabrication conditions were harsher than the industrial conditions [7,14]. Therefore, the curing behavior and reaction mechanism should be clarified in this research, which is helpful in determining the method to use to reduce the manufacturing conditions in future research.…”

“…Most of these materials are fabricated using synthetic adhesives that use raw materials derived from fossil fuel-based resources [10,11], many of which also contain formaldehyde to ensure sufficient reactivity and adhesive performance [12,13]. Due to the rapidly increasing environmental awareness and the toxicity of formaldehyde, some methods have been applied to reduce formaldehyde emissions, such as lowering the molar ratio of formaldehyde in the Urea-formaldehyde (UF) resin, adding formaldehyde scavengers in the resin, post-treatment with barrier layers and the development of green and sustainable alternative wood adhesives based on renewable resources [14][15][16][17][18][19].…”

Synthesis and Characterization of Sucrose and Ammonium Dihydrogen Phosphate (SADP) Adhesive for Plywood

“…Compared to novel bio-based materials, the traditional wood-based materials are more heavily utilized by societies worldwide. Most of these materials (such as particleboard [5], plywood [6][7][8][9], medium density fiberboard [10], and oriented strand board [11]) are manufactured by bonding wooden elements with adhesives derived from petroleum. Examples of such adhesives include urea-formaldehyde, phenolic-formaldehyde, and melamine-formaldehyde resins [12][13][14].…”