Constantin Luca

Thermogravimetric study on the ageing of lime wood supports of old paintings

Abstract This paper presents thermogravimetric data of some samples of soft lime tree ( Tillia cordata Mill ) wood from the structure of the supports of old paintings (mobile icons and iconostasis) 100–200 years old. In order to determine the ageing processes, the physical, structural and chemical changes that have occurred in time under the influence of environment have been correlated with thermogravimetric data. It has been established that the thermal characteristics for the elimination of physically adsorbed water depend on the samples age and on the conservation treatments. The variation of the thermal characteristics with the wood age is important for the main decomposition step. The temperatures for the onset and the maximum rate of degradation as well as the global activation energy increase with the woods age while the weight loss decreases. These characteristics could be used to assess the age and conservation status of the paintings. The variation of the characteristics could be due both to the loss in time of the volatile compounds that lead to lower thermal characteristics and to the structural changes occurring in the wood that, for the highly deteriorated and/or degraded wood leads to a totally different thermal behaviour.

SURVEY ON BEHAVIOUR OF INTERVENTIONS FOR PROBOTA MONASTERY INDOOR FRESCOES CONSERVATION UNDER ENVIRONMENTAL FACTORS INFLUENCE. III. CORRELATIONS BETWEEN THERMAL, HYGROSCOPIC AND SONIC PARAMETERS

The paper deals with the correlations between thermal, hygroscopic and sonic parameters modifications of the components from the preparation layers of the indoor frescoes, after two years from the restoration of the Church of Probota Monastery (Romania), more precisely the old layers of arriccio and intonaco, that were subject to the interventions of consolidation, stabilization and structural reintegration.