Evaluation of the Polyethylene Glycol Impregnation and Vacuum Freeze-Drying Method for Waterlogged Archaeological Wood: Conservation of the Yenikapı 1 Shipwreck

ABSTRACT

The YK 1 shipwreck, found at Yenikapı, Istanbul, is one of 37 shipwrecks dating to the medieval era. This paper describes the studies and the processes which were conducted to conserve the YK 1. Firstly, the level of physical and chemical degradation of the wood from the YK 1 was examined, which revealed that the wood was highly degraded. Therefore, PEG 2000 was chosen for the impregnation process before vacuum freeze-drying. In addition, the ASE values confirmed that the PEG 2000 impregnation and vacuum freeze-drying method together were successful in conserving the YK 1, with values higher than PEG 2000 impregnation and vacuum freeze-drying methods alone. The concentration of the PEG solution in the tank was monitored throughout the impregnation process. Following this, samples taken from the wood cores were analysed using FTIR to evaluate the effectiveness of the impregnation process. Finally, SEM was used to examine the effectiveness of the PEG 2000 impregnation and vacuum freeze-drying method. The SEM images showed that the PEG 2000 was uniformly distributed, and the wood had no deformation after freeze-drying.

KEYWORDS:

• Yenikapı shipwrecks
• Conservation
• Waterlogged archaeological wood
• Polyethylene glycol (PEG)
• Vacuum freeze-drying

Acknowledgements

The authors acknowledge Prof. Dr. Ufuk Kocabaş, İstanbul Archaeology Museums, TÜBA (Turkish Academy of Sciences), Yenikapı Shipwrecks Project Team, Dr. Quoc Khoi Tran, Kristiane Strætkvern, Prof. Dr. Ünal Akkemik, and Prof. Dr. Cemal Pulak for their help and support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

In addition, the authors thank İstanbul University Scientific Research Projects Unit for the financial support for the doctoral dissertation study of Namık Kılıç (Project no: SDK-2016-3777).