Rheoreversible hydrogels in paper restoration processes: a versatile tool.

摘要

Background: Paper based artworks are probably ones of the most difficult materials to restore, because of theirudcomplexity and fragile structure. Cleaning of paper artifacts, one of the process commonly carried out duringudrestoration, usually involves the use of solvents (organic or not), that may cause several troubles, like swelling anduddissolution of some components, and may also be harmful to the users.udResults: Innovative procedure for cleaning paper artworks is reported in this paper. It is based on the use ofudrheoreversible, biocompatible hydrogels containing poly(ethylene oxide) or poly(ethylene oxide)-poly(propyleneudoxide)-poly(ethylene oxide) and α-cyclodextrin. We have studied two types of polymer with different hydrophobicudproperties in order to obtain two different hydrogels with slightly different cleaning capabilities. Our overall strategyudhas been to develop innovative systems based on these hydrogels so as to better confront the problems that audrestorer faces during the cleaning of paper samples. Rheoreversible hydrogels are intriguing materials because theirudapplication and removal is not invasive and does not require a liquid treatment that could induce damage to the paper.udConclusions: These hydrogels have been applied in the cleaning of both new and aged paper samples and theirudcleaning efficiency has been established. Moreover, by comparison with traditional methods, the greater efficacy of theudproposed procedure has been demonstrated.udTo assess the cleaning efficacy of these hydrogels, a multidisciplinary approach, combining non-invasive spectroscopicudinfrared techniques together with scanning electron microscopy, chromatographic (HPLC) analysis and pHudinvestigations has been used. Near infrared spectroscopy spectra were coupled with a chemometric analysis toudachieve a better interpretation of data.udThis work constitutes a preliminary step towards focused study in the development of α-cyclodextrin/polymer hydrogeludfamily which will allow cleaning of paper artifacts with peculiar characteristics.udKeywords: Rheoreversible hydrogel, Cleaning treatment, Paper artworks, FTIR, HPLC, PCA analysis