The Effects of the Ammonia Neutralizing Treatment on Marine ArchaeologicalVasaWood

The Formation of Chemical Degraders during the Conservation of a Wooden Tudor Shipwreck

“…Therefore, it may be assumed that this lignin component was less susceptible to degradation. This is in good agreement with previous observations of the Vasa hull which revealed that the lignin in waterlogged wood are less prone to degradation than (hemi)cellulose components . We can therefore use this lignin band as a baseline for (hemi)cellulose degradation by calculating the band intensity ratios (1733 cm −1 for hemicellulose and 1161 cm −1 for both hemicellulose and cellulose).…”

“…The intensity of each vibrational band depends on a number of factors, including wood slice thickness, absorbance coefficient, and concentration of the absorber. We can avoid this slice thickness dependency and potentially assess the extent of wood degradation by analysing the vibrational band intensity ratios . The band intensity for lignin observed at 1506 cm −1 was found to be constant along the core sample depth, irrespective of spray treatment or drying.…”

Sulfur and iron analyses of marine archaeological wood in shipwrecks from the Baltic Sea and Scandinavian waters

“…However, it seems feasible to substantially slow down the oxidation processes, especially of organic-bound sulfur, by carefully controlling humidity and temperature in the museum indoor climate to reduce diffusion and transport of water and oxygen into the wood (Crumlin-Pedersen, 2002;Hocker, 2010). Catalytically active iron(II) ions may also be deactivated by a deacidifying ammonia gas treatment, as has been shown for the Batavia and in laboratory experiments on Vasa wood (Fors et al, 2007;Fors and Richards, 2010).…”

Analytical Aspects of Waterlogged Wood in Historical Shipwrecks

“…The change in the molecular weight distribution (MWD) indicates the degree of depolymerization of the cellulose chains. 35,36 SEC has also been used for determining the molecular mass of PEG. 37,38 3·5 Gas chromatography (GC-MS) and MALDI-TOF mass spectrometry Gas chromatography with mass spectrometric detection (GC-MS) has been used to quantify the content of acetic acid in archaeological wood, 39 to chemically characterize organic wood extractives and also to chemically characterize compounds derived from lignin degradation.…”

“…42 CP/MAS 13 C-NMR spectroscopy can also be useful for evaluating possible effects on the cellulose crystallinity in wood samples from shipwrecks exposed to ammonia. 25,36,40 The carbohydrate content in waterlogged wood, which is an indicator of the degree of degradation, can be measured by high resolution solid-state 13 C NMR, 43 while the spin-spin relaxation time, T2, of water, measured by proton NMR, was found to correspond to three types of environments correlated to wood cavities of different diameters. 37 …”