Abstract
Archaeological waterlogged woods (WLW) become considerably fragile over time because of chemical hydrolysis and the deterioration by microorganisms in the wet buried environment. The methods are sought for the dimensional stabilization of such woods. In the present article, the conservation of archaeological WLW of Chamaecyparis pisifera (Sieb. et Zucc.) Endl. by means of a commercially available feather keratin was in focus. The impregnation of an ancient wood from the 9th century A.D. was examined by the noninvasive synchrotron X-ray microtomography, which is well suited for imaging fragile samples. The thickness of the cell walls of keratin-treated wood was preserved and was comparable with that of recent wood. Notably, the middle lamella (ML) of keratin-treated wood appeared to be electron dense as indicated by transmission electron microscopy. Thus, it can be concluded that feather keratin is predominantly adsorbed on the ML and it prevents wood cell walls from collapsing and provides reinforcement.
The authors wish to thank the Kyoto City Archaeological Research Institute for providing the archaeological wood samples. The authors also thank the Kyoto University professor emeritus Takao Ito for his assistance with wood identification. The synchrotron radiation experiments were performed at the BL20XU of Super Photon ring-8 with the approval of the Japan Synchrotron Radiation Research Institute (Proposal No. 2008B1563).
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