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

Domenii publicaţii > Chimie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Irina Crina Anca Sandu, Mihai Brebu, Constantin Luca, Ion Sandu, Cornelia Vasile

Editorial: Elsevier Science Ltd., Polymer Degradation and Stability, 80, p.83-91, 2003.

Rezumat:

Lucrarea prezinta date termogravimetrice ale unor probe de lemn de tei, cu o vechime cuprinsa intre 100 si 200 de ani, in vederea determinarii corelatiilor intre procesele de imbatranire si caracteristcile fizico-structurale si chimice. S-au stabilit caracteristicile proceselor de degradare termica pentru trei trepte de descompunere si anume energia de activare, ordinul de reactie si variatia acestora cu gradul de transformare. In baza acestor date s-au stabilit curbe de corelatie a caracteristicilor termice cu vechimea lemnului. Studiile permit elaborarea unor metode de datare a lemnului vechi de tei. This paper presents thermogravimetric data of some samples of soft lime tree owwd from the structure of the supports of old paintings 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 the the thermal characteristics for the elimination of physically adsorbed water depend on the main decomposition step. The temperatures for the onset and the maximum rate of degradation as well as the global activation energy increase withe the wood’s 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.

Cuvinte cheie: degradare termica, imbatranirea lemnului, starea de conservare, stare de colaps, picturi vechi // Thermal degradation, soft wood, wood ageing, conservation status, collapsed wood, old paintings