Partially fluorinated acrylic copolymers as coatings for stone protection: characterization and surface properties

摘要

On Candoglia marble, TFEM/MA is the best performing copolymer as the distribution of fluorinated groups in the macromolecule is more uniform and the surface energy of the coated sample is appropriate. The new coatings, tetra- and ter-polymers, show poor protection efficacy most probably due to an uneven distribution of the trifluoromethyl-groups on the coating surface. This situation is characteristic of the marble surface, as well as of similar very compact stones, where the polymers aren't penetrating into the porous structure; in such cases the distribution of the coating on the surface is a critical parameter both for the task of protection and for the long-term resistance. On the Noto calcarenite all the polymers perform well except the unfluorinated one. The fluorinated polymers display higher protective effectiveness. Further DCA and vibrational analysis of the contact angles for the stone coated samples are necessary to determine the characteristics of the polymer surface when effectively deposited on stone materials. Moreover, DCA analysis of the aged polymers is necessary to confirm the importance of the surface dynamic, already suggested by the static angle results.