Water absorption and thickness swelling of reinforced plywood during prolonged water exposure

Abstract

Тhe aim of this research is to study the physical properties during prolonged water exposure of experimental plywood reinforced with cotton fabrics pre-impregnated with alcohol-soluble phenol-formaldehyde resin. Plywood composition was consisted of eleven layers of peeled beech veneers with thickness of 1,5 mm and 1,85 mm. The veneers were bonded with alcohol-soluble phenol-formaldehyde resin. The pre-impregnated fabrics were incorporated in each adhesive layer of the plywood panel. On the basis of the obtained data for the changes of the physical properties of reinforced plywood after exposure to prolonged water treatment, water resistance of experimental plywood was evaluated. Tests for the thickness swelling, volume swelling and water absorption were made after immersion in water for prolonged period of 192 days in controlled laboratory conditions. The results from the research showed that the plywood model is characterized by uniform density; it is dimensionally stable during and after prolonged water exposure, without any deformations of the shape of the test specimens