Influence of Aging Procedure on Bonding Strength and Thermal Conductivity of Plywood Panels

Abstract

Wood and wood composite materials have been used in house, school, and office construction throughout the world. Wood composite materials are superior to other building materials in terms of thermal conductivity due to its porous structure. Bonding strength and thermal conductivity are two of many other significant properties of composite panels used in construction. It was essential to determine the effect of ageing process on the properties of panels used in structural applications. This study evaluates thermal conductivity and bonding strength of Scots pine and black pine plywood panels manufactured from rotary cut veneers dried at three different temperatures: 110 degrees C, 140 degrees C, and 160 degrees C. Phenol formaldehyde (PF) and melamine urea formaldehyde (MUF) were used as adhesives for plywood manufacturing. Panels were exposed to ageing process according to ASTM C 481-99 standard. Plywood panels with five plies and 10 mm thickness were manufactured for each group. Thermal conductivity and bonding strength values of plywood panels were determined. Thermal conductivity of the panels decreased with increase of the drying temperature. It was also found that the thermal conductivity of test panels decreased after the ageing process. Shear strength mean values obtained from the samples of all plywood panels were above the limit value (1.0 N/mm(2)) indicated in TS EN 314-2 standard but those of the panels with MUF after ageing process.