Mechanical strength studies on degraded waterlogged wood treated with sugars

Abstract

This study aims to measure the mechanical strength of chemically degraded wood samples and compare the values obtained with fresh wood and degraded wood treated with sugars. The mechanical strength of chemically degraded waterlogged wood samples was determined using a three-point bending system to generate load-deflection curves and subsequently calculate the modulus of elasticity and load to failure longitudinally. The values obtained allow us to compare the mechanical properties of white birch wood samples that were air dried after treatment with 60% w/v solutions of sucrose, trehalose, or sucralose. In addition, the same parameters were measured for fresh white birch wood samples and chemically degraded samples that were allowed to air dry without treatment. Fresh white birch was found to have a longitudinal modulus of elasticity of 11.5 GPa whereas this value decreased by 70% when the wood was degraded. Treatment with sugars increased the measured values of modulus of elasticity up to 36.9 GPa, a substantially higher value than for fresh wood. These data indicate that non-reducing sugars could be useful alternatives to polyethylene glycol for the conservation of waterlogged archaeological wood.