Effect of various fire retardants on surface roughness of plywood

In this study the surface roughness of plywood treated with various fire retardants was investigated. Commercially manufactured veneer of Akaba wood (Tetraberlinia bifoliolata) was treated with borax, boric acid, monoammonium phosphate and diammonium phosphate, then experimental plywood panels were made from these veneer sheets. A stylus method was employed to evaluate the surface characteristics of the samples. Three main roughness parameters, mean arithmetic deviation of profile (Ra), mean peak-tovalley height (Rz), and maximum roughness (Rmax) obtained from the surface of plywood were used to evaluate the effect of chemical treatments on the surface characteristics of the specimens. Significant difference was determined (p ¼ 0:05) between surface roughness parameters (Ra, Rz, Rmax) for four treatments and two retentions of fire retardants. Samples treated with 3% concentration of borax had the smoothest surface with 11:09 mm Ra while the roughest surface was found for the samples treated with 6% boric acid having Ra value of 12:44 mm. Results revealed that the surface quality of the panels reduced with increasing chemical concentration