Study of TiO2-Modified Sol Coating Material in the Protection of Stone-Built Cultural Heritage

Abstract

Coating materials can effectively protect stone-built cultural heritage and, as such, research into coating materials has gained comprehensive attention from researchers. The aim of this work is to prepare a TiO 2 -modified sol coating material (TSCM) and study its protective effects on stone-built cultural heritage. TSCM and pure TiO 2 sol (p-sol, unmodified; for comparison) were applied evenly over the entire surface of stone samples. The prepared stone samples included untreated stone, stone treated with pure sol, and stone treated with TSCM. The protective effects of TSCM were evaluated by water absorption, water vapor permeability, acid resistance, and weather resistance experiments. The results show that stone treated with TSCM has excellent water absorption and water vapor permeability, strong acid resistance, and good weather resistance, compared with untreated stone or stone treated with p-sol. The acid resistance of stone treated by TSCM was 1.75 times higher than that treated with traditional coating materials. The weather resistance cycle number of stone treated by TSCM was four times higher than that treated with organic protective materials. These findings are expected to provide useful suggestions for the protection of stone-built cultural heritage.Coatings 2020, 10, 179 2 of 11 or added to acrylic polymers [22][23][24], but they could be easily removed from the coating surface owing to weak bonding [25][26][27]. In order to avoid the loss of TiO 2 nanoparticles, some researchers have proposed to composite TiO 2 nanoparticles into a SiO 2 -sol [28], which can enhance its photocatalytic activity when applied to a building. To the best of our knowledge, there have been no scientific studies about compositing TiO 2 nanoparticles into a TiO 2 -sol for the protection of stone-built cultural heritage. More importantly, the method presented in the work of [28] provides us with valuable suggestions about the protection of stone-built cultural heritage. Hence, it is necessary to investigate a modified TiO 2 -sol with significant protective effect on stone-built cultural heritage.The aim of this paper is to prepare a TiO 2 -modified sol coating material (TSCM) that is capable of protecting stone-built cultural heritage. Analyses of the composition and microscopic morphology of TSCM were conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Some experiments were conducted to evaluate the protective effects of TSCM, in terms of wettability, weather resistance, and acid resistance. The results suggest that TSCM has excellent water absorption, water vapor permeability, acid resistance, and weather resistance. The study, therefore, provides a new method for the protection of stone-built cultural heritage.

The study of rod-shaped TiO2 composite material in the protection of stone cultural relics

“…In comparison, the acid resistance of sample C was more significant, indicating that TCM has a strong corrosion resistance, that is because rod-shaped TiO 2 nanoparticles compounded in TiO 2 -sol can improve acid resistance of TCM. Moreover, the acid resistance of TCM is stronger than that of normal shaped TiO 2 nanoparticles composite material previously studied [24]. The acid resistance of TCM meets protective requirements of stone cultural relics.…”

“…It is necessary to emphasize that the weight of the stone samples treated with TCM changed with increase in cycle time, indicating that the stone samples treated with TCM were slight damaged, which is difficult to be observed in Figure 5c and f. In short, the weight change rate of sample C was least, indicating that TCM can protect the stone samples from the damage caused by environmental factors. And the weather resistance of TCM is more excellent than that of normal shaped TiO 2 nanoparticle composite material previously studied [24].…”

“…Normal shaped TiO 2 nanoparticles with an average particle size of 1 µm were purchased from Ze Chang Titanium Industry (Yunnan Province), and rod-shaped TiO 2 nanoparticles were prepared by the hydrothermal method. The TCM was synthesized as follows: the rodshaped TiO 2 nanoparticles were added to the TSS at the optimal ratio of 0.05 g/100 mL (the value of optimal ratio was obtained through multiple experiments [24]), followed by stirring with a magnetic stirrer for 2 h and high-power ultrasonic agitation for 1 h. Last, TCM was prepared after allowed to stand for 1 h.…”

“…The layer numbers are determined by two parameters: the total color difference (ΔE*) of the stone samples and the amount of TiO 2 nanoparticles added. The total color difference (ΔE*) should be less than 5, and the optimal layer number is 4 [24]. The classification and name of the stone samples are shown in Table 1.…”

Spin Coating Immobilisation of C-N-TiO2 Co-Doped Nano Catalyst on Glass and Application for Photocatalysis or as Electron Transporting Layer for Perovskite Solar Cells

“…Modified TiO 2 nano composites were used as coating layers on various supports and exceptional results have been achieved. For instance, Hui Shu et al [25] studied the protection of stone-built cultural heritage by brushing TiO 2 -modified sol coating material (TSCM) and pure TiO 2 sol (p-sol). The protective properties of TSCM were assessed by various analyses including water absorption, water vapor permeability, acid resistance, and weather resistance.…”