RICERCA ITALIANA     

The sustainable consolidation of waterlogged wood: new approaches of impregnation and polymerization with a low environmental impact

Università di Pisa

Abstract

The proposed project deals with the sustainable conservation of waterlogged wood which present profoundly different problems from those of dry wood. The studies will be focused on the wet wood, constituting objects of historic, artistic, architectural and archaeological interest. From an initial evaluation of the degradation state, the studies will be aimed to describe the behavior of environmental friendly consolidant/impregnant materials, the interactions between wood and metals, and the evaluation of the environmental impact of consolidation methodologies. The diagnosis helps to understand the past or ongoing degradation processes and gives us the possibility to choose materials and techniques to be adopted in the conservation. All the units involved in the project, having the possibility to use several innovative instrumental non invasive (NIR technique, color measure spectrophotometry, contact angle) and microinvasive (SEM, TEM, NMR, HPLC, GC/MS, PY/GC/MS, FTIR, Raman, DSC, TGA) methods, will contribute in the definition of the degradation state highlighting the chemical-physical parameters. The efficacy and durability of the consolidation/impregnation methods implemented in this project will be also evaluated. To carry out the project, the research units will work on wooden materials provided by the Sovrintendenza ai Beni Archeologici della Toscana and by the Recanati Institute for Maritime Studies at the University of Haifa (Israel). These specimens will be >>>

Principal Investigator

Maria Perla COLOMBINI Università di PISA

Research Objectives

The proposed project deals with the sustainable conservation of waterlogged wood, constituting objects of historic, artistic, architectural and archaeological interest.
Chemical science contributes to the achievement of the following targets:

1. CHARACTERISATION OF DEGRADED WOOD AND ASSESSMENT OF ITS CONSERVATION STATE AND OF ONGOING AND PASTE DEGRADATRIVE PROCESSES. Specific instrumental techniques and chemical and physical chemical procedures, suitable to the morphological study and to the determination of decay markers, need to be selected and optimized for this purpose. In addiction to optical microscopy, SEM, TEM, physical properties determination, thermogravimetric techniques, gas chromatographic and pyrolysis techniques coupled with mass spectrometry , NMR , also innovative non destructive near infrared time-resolved spectroscopy techniques (NIR) will be used. The possibility to measure simultaneously the absorption and scattering spectrum in a highly diffusive medium will allow to obtain information on both chemical composition and structure of the wooden object. In particular, the study will be focused on the correlation between the measured optical parameters (absorption and diffusion coefficient) and the chemical/physical properties (density, porosity, humidity, water content) and conservation state.

2. DEVELOPMENT OF MATERIALS AND METHODS FOR CONSERVATION AND CONSOLIDATION OF WATERLOGGED DEGRADED WOOD. The research units >>>

Timescale

24 months

National and international background

Not only is wood fundamental in terms of the ecological value of forests, but it is also an indispensable resource in many fields of activity and industry, including the production of energy and its use as a possible source of chemical products. The production of wood is still higher today than that of other materials such as polymers, steel, cement, etc. Conserving wooden objects is fundamental to avoid waste and to protect and preserve artistic, historical and archaeological objects. Wood is subject to chemical and biological degradation due to biological agents and environmental factors such as moisture, temperature and pH. Degraded wood is characterised by modifications in its chemical composition and by changes in its physical and mechanical properties.
The degradation of wood has been a well known problem since ancient times, involving issues that are very different from other materials [1 ] and requiring different approaches for dry and for waterlogged objects. It is particularly difficult to conserve waterlogged wooden objects such as those recovered underwater, with a very high water content (100-2000 % w/w), for example historical or archaeological objects or architectural structures present in high moisture environments [2 ]. In favourable conditions of low temperatures and low amounts of oxygen, wooden artefacts can survive surprisingly well underwater, as in the case of the Vasa ship conserved in the Vasa Museum in Stockholm [3 ,4 ], or for the Roman >>>