Nanotechnologies for the restoration of alum-treated archaeological wood

The project Saving Oseberg is funded by the Norwegian State with the aim to preserve the Viking Age wooden objects from the Oseberg burial mound. They were excavated in 1904 near Tønsberg, Norway, and many have been treated in the past with alum salts (KAl(SO4)212H2O). Alum was widely used during the early 1900s as a treatment for archaeological wood to prevent shrinkage and impart strength. In the 1990s, conservators observed an alarming condition of the objects. Initial investigations showed that the alum treatment has initiated a slow but ongoing deterioration process, attacking the wood for over 100 years. Today, the artefacts are highly acidic and have significantly reduced mechanical strength. In the last decade, the use of nonaqueous alkaline nanoparticle dispersions has provided successful results for the protection of cellulose-based materials. Alum-treated archaeological wood samples from Oseberg, with a pH B 2, have been treated with alkaline nanoparticle dispersions, and the effects of the treatment have been evaluated by thermal analysis (TGDTG), infrared spectroscopy (ATR-FTIR) and X-ray microtomography (micro-CT) analyses. In this contribution, the preliminary results will be presented.