Conservation of Archaeological Wood using Non-Reducing sugars
In the conservation field there are many different thoughts on the best way to conserve waterlogged archaeological wood. The current method uses polyethylene glycol(PEG), a hydrophilic organic compound, to replace water within the wood. PEG, which is highly effective in the short term, is hygroscopic at low molecular weights and can reabsorb water leading to problems later on, such as the formation of acid within the wood and break down of PEG itself. These problems have proved especially difficult to deal with in the Vasa, a Swedish Viking ship, which is conserved with PEG. As a result conservators have been studying alternative treatments to PEG. Sugars such as sucrose have proven to be effective in the short term but can still reabsorb water, in addition to leaving crystalline deposits on the woods surface. Sucralose and trehalose, both analogs of sucrose, are non-reducing and less likely to reabsorb moisture. Our study evaluates the effective of these non-reducing sugars as a conservation practice. Tongue depressors serve as simple models for archaeological waterlogged wood. Samples are chemically degraded and then treated with varying concentrations of sugar solutions. Data collected from dimensional analysis, before and after drying, indicates that this method is effective in conserving degraded samples. Additional mechanical analysis shows that chemically degraded wood has increased elasticity and much lower mechanical strength, as is expected. Chemically degraded wood samples treated with sugars show improved mechanical properties, measured using a three point mechanical testing method. These results will demonstrate that non-reducing sugars are an effective consolidant for samples such as these and may prove to be more effective than PEG for improving the long-term stability of wooden artifacts.