Degradation of PEG in the Warship Vasa

Authors

  • Jens Glastrup,

    Corresponding author
    1. The National Museum of Denmark, Dept. of Conservation, Brede, Post box 260, I.C. Modewegsvej, DK-2800 Kgs. Lyngby, Denmark
    • The National Museum of Denmark, Dept. of Conservation, Brede, Post box 260, I.C. Modewegsvej, DK-2800 Kgs. Lyngby, Denmark. Fax: (+45) 33 47 35 34
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  • Yvonne Shashoua,

    1. The National Museum of Denmark, Dept. of Conservation, Brede, Post box 260, I.C. Modewegsvej, DK-2800 Kgs. Lyngby, Denmark
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  • Helge Egsgaard,

    1. Biosystems Department, Risø National Laboratory, P.O. Box 49, DK-4000 Roskilde, Denmark
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  • Martin Nordvig Mortensen

    1. The National Museum of Denmark, Dept. of Conservation, Brede, Post box 260, I.C. Modewegsvej, DK-2800 Kgs. Lyngby, Denmark
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Abstract

The distribution and ageing of polyethylene glycol (PEG) in the Vasa warship has been examined and compared with other archaeological shipwrecks which have also been impregnated with PEG. The distribution of the PEG has been characterised using a variety of mass spectrometric and FT-IR techniques. Our results show that the PEG after 30 years is still in a reasonably good condition, with a molecular weight distribution that resembles fresh PEG. Only minor levels of degradation products were found. It seems that the PEG preserved wood contains an increased amount of formic acid and the results suggest that it originates from the PEG. Acetic acid is also present; this probably originates from the wood.

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