An Evaluation of Supercritical Drying and PEG/Freeze-drying of Waterlogged Archaeological Wood
نویسنده
چکیده
Supercritical carbon dioxide has replaced many liquid organic solvents in industry due to its tunable solvent properties, environmental friendliness, and easily achievable critical parameters. The unique properties of supercritical fluids in general, such as gas-like diffusivity and zero surface tension, make them particularly applicable to the field of conservation. This presentation reports on the results of a study undertaken to evaluate the physical effects of drying waterlogged archaeological wood using supercritical carbon dioxide as compared to air-drying and the popular polyethylene glycol (PEG)/ freeze-drying method. Samples on the order of a few cubic centimeters were prepared from two archaeological waterlogged wood sources and grouped into three treatment sets: one for air-drying, one for PEG/freeze-drying, and the other for supercritical drying. Treatment-induced dimensional changes were tracked using 3D laser scanning and pins inset in the samples. Instrumental analysis was carried out to determine the state of preservation of the wood and the microscopic effects of the imposed treatments. Results of this study were in favor of freeze drying for all samples, and supercritical drying for certain types of wood. MCI Topics in Museum Conservation
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