Supervisor: Dr. Ribechini Erika

Title: The role of tannin-based dyes in the degradation of historical textiles.

Abstract: The large number of historic textiles still preserved today represents an important field of our cultural heritage. The state of conservation of these examples of our historic handicraft may differ in dependence of numerous factors. Different kind of degradation effects can be observed, like fading or loss of material, occurring in the fibres unevenly. Particularly, it is possible to notice that tannin dyed textiles usually show more extended degradation phenomena than tissues dyed with other colouring materials, even in the same condition of preservation. In order to face the problems related to the occurrence of tannins in dyed textiles, the project The Short Life of Tannins has been founded by the Regione Toscana (FAS grants 2008-2013). The PhD project aims at creating a model describing the ageing processes taking place in textile fibres dyed with iron-tannin complexes. The final goal of the research is to appoint a conservation protocol to arrest or to slow degradation processes, on the basis of the developed predictive model. The project entails the study of textile reference specimens, also subjected to artificial ageing. Different analytical techniques will be used: spectrophotometry, SEM-EDX, chromatography and mass spectrometry. Particularly, HPLC-MS/MS and GC/MS will be used not only for the characterisation of lipids, proteins, dies, phenol, but also for the identification and quantification of degradation products. Results obtained by the characterisation of raw materials and textile reference specimens by optical and scanning electron microscope will be presented, discussed and compared to the data obtained by HPLC-DAD, DE-MS, GC/MS analysis.