False heartwood is a phenomenon where penetration of oxygen discolors the wood. It is an undesirable defect which influences the applications of the wood. The properties and formation of false heartwood have been investigated but false heartwood as a filler material in composites has not been previously used. The aim of this research was to investigate the false heartwood fraction size and chemical modification effect on the physical and mechanical properties of wood-plastic composites. The effect of chemical treatment with NaOH and 3-aminopropyltriethoxyslane (APTES) was investigated to see if the modification will provide better interfacial adhesion. Wood-plastic composite boards were produced from three different false heartwood fraction sizes of 0.4 mm, 1 mm and 2 mm. The composites were chemically modified and compounded using a twin-screw compounder and the test specimens were produced via hot pressing and CNC milling. The composites physical properties were investigated using Fourier transform infrared spectroscopy (FTIR) and density measurement by immersion. The mechanical properties were investigated using three-point bend test, tensile test and Charpy impact test. The effect of fraction size and chemical modification was compared. The different fraction size of false heartwood does shows substantial differences in results. The density of the material reduced with increasing fiber size and with chemical modification using NaOH and APTES.
Keywords: wood-plastic composite, birch, false heartwood, modification
Authors
Kallakas H.
Laboratory of Wood Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
Martin M.
Laboratory of Wood Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
Ayansola G.
Laboratory of Wood Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
Poltimäe T.
Laboratory of Wood Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
Krumme A.
Laboratory of Polymers and Textile Technology,Department of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
Kers J.
Laboratory of Wood Technology, Department of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
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