Silane/Siloxane Surface Treatment for Cohesion Ability and Strengthening Agent of Historical Stone

Abstract

Ir Cons Sci J 2017; 1(1): [23][24][25][26][27][28][29][30][31] Silane/siloxane surface treatment are proposed as potential polymeric materials for protective and consolidation coatings of limestone substrates. The silane and silioxane coatings are widely used to strengthen and waterproof of historical monuments. Historical stones are very fragile because of bearing many years in sever weathering conditions. Strengthening historical stones requires paying attention to surface treatment by the aim of decreasing humidity and improvement of mechanical properties. Toward this end, the consolidation coatings using silane and siloxane resins can improve the mechanical properties of historical stones against weathering condition. In this study, two types of coatings based on mixed of silane/siloxane as potential coatings to consolidate historical stones were proposed and the mechanical results were compared with uncoated stones. The mechanical tests approved the silane and siloxane resins can be considered as a proper choice to protect and strengthen historical stones. The results indicated that the contact angle of the coated samples rises up with treating by silane/siloxane resins. This could be due to the presence of organic groups of poly siloxanes act as hydrophobic agents which increase the hydrophobic nature of the surface contact angle. In addition, Si-OH bond of silane as well as consolidation effect can be created the covalent bonding by mineral surface and filling of the small fissures in the stone surfaces.

Durability of Biodegradable Polymers for the Conservation of Cultural Heritage

“…Therefore, further efforts were focused on copolymers or blends from both acrylic and fluorinated polymers (Mazzola et al, 2003;Malshe and Sangaj, 2009). Furthermore, silanes and siloxanes (Tsakalof et al, 2007;Vacchiano et al, 2008;Ershad-Langroudi et al, 2017) also showed interesting properties in terms of impermeability and protection against color loss, although these were strongly dependent on the specific substrate. Polymers from cellulose have been extensively used and studied for application on cultural heritage, finding that both cellulose ethers (Feller and Wilt, 1990) and nitrate (Selwitz, 1988) have some stability issues.…”

A Two-Step Surface Modification Methodology for the Advanced Protection of a Stone Surface

“…The impregnation of the limestone surface with 3-MPTMS showed a film coating similar to the impregnated travertine surface ( Figure 8 c), with gel formation and attached to both stone surfaces, as noticed for the different impregnation of treated stone [ 29 , 52 , 53 , 54 ]. Comparing SEM images obtained for the two types of stones showed that depending on the structure of the stones, the coupling agent should be chosen [ 14 , 28 ]. Both coupling agents showed that they modify the surface, and this can be correlated with the FTIR microscopy, too.…”

“…The adsorption of the coupling agent depends on the stone structure, and coupling agents thus facilitate the formation of a film as a crust or can penetrate easily the porous surface of certain stones [ 24 ]. Based on these observations, it can be concluded that silanization leads to a rough surface, which theoretically can enhance the bacterial colonization, but hopefully, the combination of the coupling agent and silver nanoparticles will lead to a resistant surface against biofilm formation [ 28 ].…”

“…The combination of covalent and ionic bonding mechanisms contributes to the effectiveness and longevity of the treatment, making it a promising method for enhancing the properties of natural stone surfaces. One important aspect of the stone treatment is the right selection of coupling agent, which ensures the anchoring of most nanoparticles on the mineral substrate [ 28 , 33 ].…”

“…The protection against developing microbial growth on different substrates is performed with a wide range of surface coatings with advantages and disadvantages; thus, a polymeric film confers cohesion between the grains of the stone structure but appears dark and as spots rising from the stone surface [ 27 ]. Usually, coating products contain resins that act like adhesive or gluing agents and do not really impregnate or strengthen the stone surface [ 28 ]. The application of a coating using various resin materials serves as a protective measure against environmental factors for the stone surface.…”