Conventional stone consolidation in the field of cultural heritage conservation is frequently based on treatment of the deteriorated substrate with silane derivatives of various composition. On the other hand, both acrylic and siloxane polymers are usually employed as water-repellent protective coatings. While the former often suffer from poor long-term efficacy and inadequate protective properties, the latter do not usually display any significant consolidation effect, due to either poor cohesive and adhesive properties, or to insufficient penetration of the viscous polymeric solution into the porous structure of the substrate. New water-borne organic-inorganic hybrids based on reactive poly(acrylate) particles with an alkylalkoxysilane network as the outer shell have been prepared by means of sequential radical initiated emulsion polymerisation and sol-gel process. Control of particle size and particle surface composition is expected to be the key factor for a successful application of these materials. On the other hand, the chemical composition of the hydrophobic acrylic copolymer and of the network-forming silane derivatives, and the ensuing adhesive and cohesive properties, govern the mechanical behaviour of the film-forming material before and after application. The optimisation of the resulting latex composition and particle size and morphology, and the study of its behaviour as protective coating and stone consolidation material, is presently carried out on different stone materials. The first results will be presented and related to such critical issues as the penetration depth and the chemical evolution of these reactive system.
Water-borne silane-acrylic hybrid polymer particles for the consolidation and protection of porous stone surfaces
CASTELVETRO, VALTER;CIARDELLI, FRANCESCO;
2003-01-01
Abstract
Conventional stone consolidation in the field of cultural heritage conservation is frequently based on treatment of the deteriorated substrate with silane derivatives of various composition. On the other hand, both acrylic and siloxane polymers are usually employed as water-repellent protective coatings. While the former often suffer from poor long-term efficacy and inadequate protective properties, the latter do not usually display any significant consolidation effect, due to either poor cohesive and adhesive properties, or to insufficient penetration of the viscous polymeric solution into the porous structure of the substrate. New water-borne organic-inorganic hybrids based on reactive poly(acrylate) particles with an alkylalkoxysilane network as the outer shell have been prepared by means of sequential radical initiated emulsion polymerisation and sol-gel process. Control of particle size and particle surface composition is expected to be the key factor for a successful application of these materials. On the other hand, the chemical composition of the hydrophobic acrylic copolymer and of the network-forming silane derivatives, and the ensuing adhesive and cohesive properties, govern the mechanical behaviour of the film-forming material before and after application. The optimisation of the resulting latex composition and particle size and morphology, and the study of its behaviour as protective coating and stone consolidation material, is presently carried out on different stone materials. The first results will be presented and related to such critical issues as the penetration depth and the chemical evolution of these reactive system.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
