Preparation And Application In Baodingshan Sand Rock Of Modified Silicone Protectants

Stone relics not only have reference value to explore their culture and history for archaeologists, but also have the great significance to develop tourist industry and further promote regional economy. However, the cultural relics have suffered from comprehensive diseases from outdoor environment and damages posed by modern industries. Their life has been shorted year by year and protection situation is quite serious. Therefore, it is imminent to develop high-performance protection material for the conservation of stone relics. Two types of stone protectants including modified silicone protectants and modified titanium-silicone protectants have been fabricated by sol-gel method in the present article.The protection effects of protectants on the Baodingshan sandstone of Dazu sculputrues are also studied.Modified silicone protectants are prepared through the sol-gel reaction of TEOS precursor, using surfactant(F127, CTAB or n-octyamine) as additives and hydroxyl-terminated silicone oil(PDMS-OH) as modifying agent. The results show that modified silicone protectants with 3.0 vol% PDMS-OH and a certain amout of F127 or CTAB surfactant have excellent hydrophobic performance, air permeability, and resistance to staining, acid-attack, ultraviolet aging, cold-hot alternation and salt-errosion.Modified titanium-silicon protectants are prepared through adding tetrabutyl titanate(TBOT) or nano TiO2 to the above modified silicon protectants. The results show that modified titanium-silicon protectants also have excellent hydrophobic performance, air permeability, and resistance to staining, acid-attack, ultraviolet aging, cold-hot alternation and salt-errosion. The protectants of 2.0 vol% nano TiO2 alcohol liquid with F127 additive,1.9 vol % TBOT with F127 additive, 2.7 vol % TBOT with CTAB additive and 1.0 vol %TBOT with n-octyamine additive have excellent comprehensive performance.The above modified titanium-silicone protectants are applied to conserve the bottom of No.31 grottoes statues of Baodingshan in Dazu. The protectants of 1.0 vol% and 1.9vol% TBOT with F127 additive, 2.2 vol% and 2.7 vol% TBOT with CTAB additive, 1.0vol% TBOT with n-octyamine additive have good in situ protective effectivenees.