Two kinds of product to be used in restoration and conservation treatments of stone objects and buildings have been prepared and tested: one specifically useful for the protection of stones with low and medium porosity (partially fluorinated polyamides), and the second for the consolidation of substrates having high porosity (fluoroelastomers based formulations). Partially fluorinated polyamides have been synthesized in two steps from ethyl ester of a perfluoropolyetheric monocarboxylic acid and not fluorinated polyamides containing two terminal amine groups for molecule. The not fluorinated polyamides (1st step) have been prepared from ethylene- or hexamethylenediamine and ethyl ester of succinic acid. The ethyl ester of the perfluoropolyetheric acid at molecular weight of 893 amu has been used for grafting the perfluorinated chain to the not fluorinated polyamides (2nd step). The final products have low molecular weight (oligomers), high water-repellence, insolubility in water and chlorofluorocarbons (CFC), and solubility at 60°C in iso-propanol/water (80/20) mixture. Fluoroelastomers based formulations have been obtained by mixing fluoroelastomers, dissolved in acetone, and nano silica, dissolved in water. The composite material obtained after solvents evaporation shows a suitable flexibility and gives high water-repellence, associated to good cohesive properties, to highly porous stones (i.e. tuff). Moreover, these formulations allow an excellent penetration depth of the consolidation agents and do not change the colour of the treated stone surface.
Formulati a base di poliammidi parzialmente fluorurate e fluoroelastomeri per la protezione e il consolidamento di manufatti lapidei
Camaiti Mara;Benvenuti Emilia;
2011
Abstract
Two kinds of product to be used in restoration and conservation treatments of stone objects and buildings have been prepared and tested: one specifically useful for the protection of stones with low and medium porosity (partially fluorinated polyamides), and the second for the consolidation of substrates having high porosity (fluoroelastomers based formulations). Partially fluorinated polyamides have been synthesized in two steps from ethyl ester of a perfluoropolyetheric monocarboxylic acid and not fluorinated polyamides containing two terminal amine groups for molecule. The not fluorinated polyamides (1st step) have been prepared from ethylene- or hexamethylenediamine and ethyl ester of succinic acid. The ethyl ester of the perfluoropolyetheric acid at molecular weight of 893 amu has been used for grafting the perfluorinated chain to the not fluorinated polyamides (2nd step). The final products have low molecular weight (oligomers), high water-repellence, insolubility in water and chlorofluorocarbons (CFC), and solubility at 60°C in iso-propanol/water (80/20) mixture. Fluoroelastomers based formulations have been obtained by mixing fluoroelastomers, dissolved in acetone, and nano silica, dissolved in water. The composite material obtained after solvents evaporation shows a suitable flexibility and gives high water-repellence, associated to good cohesive properties, to highly porous stones (i.e. tuff). Moreover, these formulations allow an excellent penetration depth of the consolidation agents and do not change the colour of the treated stone surface.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
