REDUCING THE MOISTURE EFFECT ON THE CREEP DEFORMATION OF WOOD BY AN IRRADIATION-INDUCED POLYMER IMPREGNATION METHOD.

Abstract

This paper reports an attempt to reduce the sensitivity of creep deformation to moisture adsorption by impregnating a tropical wood with methyl-methacrylate and subsequent polymerization by gamma -irradiation. Beam specimens both of untreated wood and polymer impregnated wood were subjected to a three-point bend creep test under a constant load of 300 N at 23 plus or minus 1 degree C, at three different humidity levels of 50 plus or minus 5, 65 plus or minus 5 and 85 plus or minus 5%. A Norton-Bailey (power law) mathematical model successfully described the creep behavior, with the creep components determined by a nonlinear regression analysis. A significant reduction in the sensitivity of creep deformation to the humidity level was attained for the polymer impregnated wood. This could be explained by the ability of the impregnated polymer to form a strongly adhesive interface with the wood cell material, thereby acting as a physical barrier to reduce the movement of water to and from the wood cell material.