1H-NMR-relaxation and colorimetry for evaluating nanopolymeric dispersions as stone protective coatings

Non-destructive and non-invasive assessment of new nanopolymeric dispersions for protecting stone materials was accomplished; the effectiveness of five formulations was tested regarding commercial products widely used in conservation on Lecce, Montescaglioso and Matera stones. We observed the specimens’ wettability during capillary water absorption up to saturation by nuclear magnetic transverse relaxation time measurements, using a surface and portable probe. The comparison between treated and the untreated ones, concerning their specific hydration behavior, allowed establishing the effects of the polymer films. Finally, color evaluations were performed to inspect differences induced by treatments. The data analysis enabled to select the most satisfactory protective coating for each lithotype.