Publié le 18 mars 2021–Mis à jour le 12 juillet 2022
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Guest Lecture de Antonella Salvini & Mara Camaiti
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Synthesis and applicative study of innovative materials obtained from natural and renewable sources for the conservation of cellulosic artefacts (Antonella Salvini) & Design and testing of innovative partially fluorinated materials for stone conservation (Mara Camaiti)
Prof. Antonella Salvini et le Dr. Mara Camaiti de l'Université de Florence sont invitées du LCB
Antonella Salvini
In recent times, the use of biopolymers for the production of green formulations has considerably increased in many different fields, because they easily degrade to products that are not harmful for the environment and because they are obtained from natural renewable sources.
On this basis, several new biopolymers and nanocomposites were synthesized from “green monomers”, obtained using saccharides as renewable feedstocks (α,α’-trehalose and D-glucose). Properly designed synthetic procedures were used to obtain copolymers with high purity and without protection/deprotection steps in agreement with the principles of green chemistry and industrial sustainability. The choice of renewable starting materials was made in accordance to the growing interest for the exploitation of lignocellulosic biomasses and the valorization of wastes recovered from food processing and agro-industries. Moreover, saccharides were chosen as starting materials for the synthesis of bio-based monomers, in order to introduce units with a structure similar to that of the cellulosic materials in the final products. This allowed to obtain new biopolymers that showed high affinity and compatibility for the cellulosic substrates, like paper or wood, and which are suitable for applications like adhesion or consolidation in the field of cultural heritage.
Stone artworks conservation is still a challenge for conservators and scientists. The use of fluorinated compounds as protective agents for stone surfaces against water uptake started in the '80s of the last century. Due to the high chemical and photo-oxidative stability of the C-F bond, perfluopolyethers and their derivatives were firstly used to give hydrophobic properties to calcareous and siliceous stone artifacts. Later on, modifications to the original compounds have been studied and made in order to have solubility in non toxic and environmental friendly solvents, without changing the high chemical and photo-oxidative stability. Recently, partially fluorinated oligoamides have been designed, synthesized and tested on highly and low porous stones arriving to obtain super-hydrophobic surfaces with very low amount of applied product. Moreover, the stone coated with these compounds maintains its natural permeability to water vapour and chromatic features. Finally, the solubility of the products after ageing assures the reversibility of the treatment.
