Reversible polymeric resin cured by ionizing radiation for consolidation of wooden artifacts of cultural heritage

Abstract

This study investigated the application of Paraloid B72 resin, modified with methyl methacrylate (MMA) and butyl methacrylate (MaBu) monomers, to develop new materials for the consolidation and restoration of wooden objects. The curing process was conducted using ionizing radiation from a gamma source (cobalt-60), eliminating the need for organic solvents. After characterization by gel fraction analysis, the Paraloid 30 % formulation with MMA 40 % and MaBu 30 % was selected for further characterizations, including Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and impregnation tests. The formulation was impregnated into wooden artifacts, cured using ionizing radiation, and subsequently characterized by FTIR, Scanning Electron Microscopy (SEM), and Computed Tomography (CT). The results showed that ionizing radiation replaces the need for catalysts, increasing the thermal stability of the resin and allowing cure control through dose (in kGy) and dose rate (kGy/h). This enabled the resin impregnation without compromising the integrity or the information contained in the consolidated artifact. The development of the methodology and resin formulation presented scientific challenges, particularly in ensuring that the desirable characteristics and reversibility were maintained.