Evaluation of polymers for conservation treatments of outdoor exposed stone monuments. Part II: Photo-oxidative and salt-induced weathering of acrylic–silicone mixtures

Innovative consolidating products for stone materials: field exposure tests as a valid approach for assessing durability

“…A wide range of synthetic polymers has been extensively used in stone conservation treatments, but their long lasting efficacy and performance in preventing further deterioration has been recently drastically reconsidered as they frequently undergo chemical modifications induced both by environmental conditions and irreversibility of the treatment [8][9][10]. Traditional inorganic treatments, though usually more compatible with the carbonate matrices, suffer from low solubility and therefore a resulting low amount of applied product as well as from a scarcely cohesive effect.…”

Evaluation of five fluorinated compounds as calcarenite protectives

“…Table 3 reports the static contact angles obtained after 10 days of ageing at 60 C; the conditions used in this work are less severe than those previously used [9,10]. In this respect, recently published works [15,16] report photo-oxidation studies of polymeric film, used in the restoration of marble, induced by UV radiation at ageing temperatures as low as 40 C. In addition it has also been shown that an increase in temperature of a few degree induces modifications at the protective surface that can be related to the amount of heat released [17] and then to the temperature used in the test. The concentration of the solutions was 4% v/v, the immersion time 1 min, the surfaces were the ''smooth'' ones, and the reported values are averaged over six measurements.…”

“…This loss ranges from about 10%, found in the FSA and FSP compounds, to about 30% found in the 9027. The oxygen increase should be related to the photo-oxidation processes that occur at the surface of the polymeric film [15,16]. While in the FSA and FSP compounds the fluorine loss is accompanied by a lowering of the carbon content of the same extent, on the contrary, in the 9027 and 9361 compounds the fluorine loss is accompanied by a relative increase of the carbon and of the oxygen content.…”

“…Work is in progress to ensure this aspect. In addition it must be pointed out that these compounds were used in dilute solutions of low polluting solvents, which is at variance with many other commercial products that are soluble in aromatic and/or chlorine-containing solvents only [15,16].…”

Unilateral NMR investigation of multifunctional treatments on stones based on colloidal inorganic and organic nanoparticles

“…Hydrophobic alkyl functional groups of alkyl alkoxy silanes are able to confer a good protective effect to treated substrata; however, in some papers, a decreased durability of treatments performed by modified silanes has been reported. [13,14] Although the innovative properties of nanomaterials may have advantageous application in stone conservation, apart from the use of colloidal silica nanoparticles, a few papers have been focused on the application of metal or inorganic nanoparticles to enhance the properties of materials applied for stone treatments. [15][16][17][18] In this paper, we report an investigation of new treatments for stone conservation based on the combined use of TEOS and colloidal inorganic (silica) and organic (polytetrafluoroethylene, PTFE) nanoparticles.…”