Polyvinyl butyral organogels for cleaning of artworks

Novel polyvinyl butyral (PVB)-based organogels have been tailored for the safe cleaning of artworks. The gels were synthesized by cross-linking PVB polymer chains with a polyisocyanate in non-protic organic solvents under mild conditions. High gel fraction values were obtained, and the resulting gels are transparent and elastic, with high cohesion and porosity. Physicochemical and rheological characterizations, including FT-IR, SEM, and oscillatory shear tests, confirmed the formation of stable polyurethane networks and porous structures, suitable for solvent absorption. Solvent loading and release experiments demonstrated high affinity and controlled release for green solvents such as MEK, 2-propanol, and DMC. Cleaning trials on mock-ups coated with a terpenic varnish and a hydrophobic and protective fluorinated oligomer layer showed effective removal with minimal surface alteration, highlighting their potential for treating sensitive Cultural Heritage surfaces. These PVB-based organogels offer an environmentally friendly alternative to traditional cleaning methods in conservation science.