Water Resistance of Wood-Based Panels Made without Binders

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Water Resistance of Wood-Based Panels Made without Binders

Journal Title: Lesnoy Zhurnal (Russian Forestry Journal) - Year 2020, Vol 8, Issue 3

Abstract

Water resistance of medium density panels made of hydrodynamically treated sawdust without binders was studied. It is customary to use panel swelling through-thickness after soaking in water for 24 hours and residual strength under static bending as criteria for water resistance. The effect of the following operation conditions of hot pressing on water resistance of panels was studied: temperature of press boards, specific pressing time and molding compound humidity. It is found that an increase in the temperature of press boards and specific pressing time results in a decrease in panel swelling through-thickness. The smallest value of this parameter was recorded at the press pulp humidity of 210 %. In comparison, the effect of boiling in water within 1 hour on the properties of the panels made of mechanically activated, as well as particle boards, high density fiberboards (HDF) and medium density fiberboards (MDF) of dry process was studied. It was found that the particle boards and medium density fiberboards were completely broken. High density fiberboards retained their shape, but the static bending strength was 89.7 % of the initial one. The panels made of mechanically activated wood particles had the static bending strength loss of 18.2 % of the initial one (before boiling – 22.4 MPa, after boiling – 17.4 MPa). The cyclic tests conducted according to the state standard GOST R 56309–2014 and by the “soaking–freezing–drying” method allowed us to find that the moisture deformations of the panels made of mechanically activated wood particles are reversible. As a result of 3 test cycles, a decrease in the static bending strength of the boards was 29.2 %. At the same time, their dimensions had no considerable changes. The value of residual swelling through-thickness was 0.62 %. The obtained results show that the preliminary hydrodynamic treatment of wood wastes (sawdust) allows making eco-friendly boards that have permanent water resistance. They can become widely used, especially under severe temperature and moisture conditions of operation.

Authors and Affiliations

V. N. Ermolin, M. A. Bayandin, S. N. Kazitsin, A. V. Namyatov, V. A. Ostryakova

Keywords

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EP ID EP683379
DOI 10.37482/0536-1036-2020-3-151-158
Views 307
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