Please cite this article in press as: M. Broda, B. Mazela, Application of methyltrimethoxysilane to increase dimensional stability of waterlogged wood, Journal of Cultural Heritage (2017), http://dx.doi.org/10.1016/j.culher.2017.01.007 ARTICLE IN PRESS G Model CULHER-3184; No. of Pages 8 Journal of Cultural Heritage xxx (2017) xxx–xxx Available online at ScienceDirect www.sciencedirect.com Original article Application of methyltrimethoxysilane to increase dimensional stability of waterlogged wood Magdalena Broda ∗ , Bartłomiej Mazela Institute of Wood Chemical Technology, Faculty of Wood Technology, Pozna´ n University of Life Sciences, ul. Wojska Polskiego 38/42, 60-637 Pozna´ n, Poland a r t i c l e i n f o Article history: Received 7 October 2016 Accepted 13 January 2017 Available online xxx Keywords: Archaeological waterlogged wood Silanes Dimensional stability Wood stabilisation Methyltrimethoxysilane a b s t r a c t Conservation of historic wooden monuments, especially regarding waterlogged archaeological wood, is a complex, long-term, multi-stage and also a quite difficult process. The main problem is poor dimensional stability of such artefacts due to a high degree of wood tissue degradation and its significant saturation with water. Exposing wood to a natural drying process causes its shrinkage, cracking and irreversible deformation due to collapse. Therefore, the first stage of maintenance of waterlogged wooden objects is to replace the water filling cell lumina and cell walls with an appropriate consolidation agent that will pro- tect wood against shrinkage, collapse and loss of shape. Silanes have so far been used mainly as additives for wood preservatives and coatings, increasing wood hydrophobicity or decreasing its hygroscopicity. Some silanes show resistance to biotic degradation. As confirmed in scientific reports, their ability to improve dimensional stability of contemporary wood makes them a potential agent for stabilisation of archaeological wood. The aim of the research was to determine the influence of methyltrimethoxysilane (MTMOS) treatment on the dimensional stability of waterlogged elm wood excavated from the Lednica Lake in the Wielkopolska Region. Freshly taken from the lake and still completely saturated with water, elm wood samples were treated with ethanol solution of 50% MTMOS by the vacuum-pressure impreg- nation method. Pre- and post-treatment dimensions of wood samples were measured and anti-shrink efficiency (ASE) was calculated. ASE values of elm wood treated with MTMOS varied from 69.4% to 94.5%, depending on the state of wood degradation. In case of reference wood samples treated with polyethylene glycol, ASE ranged between 96.1% and 100%. Taking into account the improvement of wood dimensional stability obtained, the aesthetic end result of the treatment and its properties of hydrophobicity and anti- fungal activity, the silane MTMOS can be considered as a potential agent for conservation of waterlogged wood and seems to be worth further study. © 2017 Elsevier Masson SAS. All rights reserved. 1. Introduction Serious degradation of wood excavated from lakes, rivers, marine sites, wet soil or peat bogs, results from long exposure to various biotic and abiotic factors. This process starts with leach- ing water-soluble substances, such as carbohydrates, mineral salts or tannins. Then, cell wall decomposition begins through cel- lulose hydrolysis caused by bacteria or fungi. Even the middle lamella containing lignin, that has remained after the first step of wood degradation and supports wood structure, decomposes over time. Consequently, bonds between wood components loosen up and intercellular spaces extend. Wood becomes more porous and extremely permeable for water [1,2]. Its structure resembles ∗ Corresponding author. Tel.: +48 61 848 7459; mob. +48 510 110 310; fax: +48 61 848 7452. E-mail address: mbroda@up.poznan.pl (M. Broda). a sponge, and thus absorbs huge amounts of water. Although the main components of wood are degraded and its cell walls are weak- ened, the lignin remains of the middle lamella together with the absorbed water enable wooden objects to keep their shape and dimensions of as long as they remain wet. However, the absorbed water evaporates after exposure to air. The emerging capillary tension and the increase of surface tension forces of the evapo- rating water cause collapse of the weakened cell walls [3]. Wood shrinks, cracks and loses its shape and dimensions [1]. If the wooden object is a valuable historic monument, it requires particularly effective preservation. In the first step of waterlogged wood conser- vation, the water filling the wood structure must be replaced with an appropriate chemical compound that will protect the wooden object against shrinkage and deformation. At present, the most popular conservation agent is polyeth- ylene glycol (PEG) which is freely soluble in alcohols (ethanol, methanol, isopropanol) as well as in water. PEG is commercially available in a range of molecular weights from 300–600 (liquids), http://dx.doi.org/10.1016/j.culher.2017.01.007 1296-2074/© 2017 Elsevier Masson SAS. All rights reserved.