Water can trigger freeze–thaw cycles, acid rain corrosion, and microbial colonisation, all of which destroy stone. Water is one of the most influential factors in the destruction of outdoor stone heritage. Therefore, materials with excellent hydrophobic properties and durability are urgently required to effectively retard long-term stone weathering. In this study, two nanoparticles, TiO₂ and SiO₂, were used to modify dodecyltrimethoxysilane (DTMS), a waterproof coating commonly used for stone heritage protection, to fabricate nanocomposite superhydrophobic coatings. The micromorphology, water repellence (water contact angle and capillary water absorption), suitability to protect stone heritage (color change and water vapor permeability), and durability (thermal, light, and chemical stability) of DTMS and nanocomposite coatings were evaluated. The scanning electron microscope (SEM) images revealed that adding 0.5% (w/w) SiO₂ produced nanoscale roughness on the sandstone surface, leading to superhydrophobicity. The results of ultraviolet -visible (UV–Vis) spectrophotometer showed that adding 0.01% TiO₂ shielded more than 90% of UV light but accelerated the decrease in the contact angle under UVA irradiation. The addition of SiO₂ was able to avoid the detrimental effect of TiO₂ under UV light. The thermogravimetric analysis (TGA) results showed that both SiO₂ and TiO₂ nanoparticles improved the thermal stability of the coatings. In particular, the fabricated nanocomposite coating, SiO₂ and TiO₂ co-modified DTMS, had excellent water repellence, low color change and outstanding durability, and retained about 85% of the water vapor permeability of the stone, showing promise for stone protection.

The “Tian Di Chang Chun” horizontal plaque was inscribed by General Feng Yü-hsiang in R.O.C. 25 (1936). Due to the aging of the materials and some factors in the preservation environment, the red painted layer on the surface of the plaque has shed. In this study, in order to analyse the materials and techniques used for the production of the inscribed plaques, the digital microscope system, scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and micro-Fourier transform infrared spectroscopy (μ-FTIR) were used to analyse the materials and techniques used on this plaque. It has been shown that the decorative layer of the plaque consists of a red Chinese lacquer film layer on the surface and a ground layer. The red lacquer film layer comprises Chinese lacquer, tung oil, and cinnabar. The materials used for the ground layer are blood putty made of a blood product, youman (flour–oil–lime mixture), and brick powder. The technique used is the SDH (San Dao Hui) layer technique in ancient buildings. This study provides physical evidence regarding the materials and techniques used in inscribed plaque relics, and also provides technical support to further protect and restore the plaque.

Moisture-curable polyurethane (MCPU) is a specifically designed material for the consolidation of fragile cultural objects in high-humidity environments. In order to solve the problem of its susceptibility to yellowing due to heat ageing, polyhedral oligomeric silsesquioxane (POSS) was added to the MCPU to prepare POSS/MCPU. The appearance, stability and mechanical properties of the POSS/MCPU films were characterized using a UV–Vis spectrophotometer, a gloss meter, a colorimeter, a thermal analyzer and a universal material testing machine. The results showed that the films are colorless and transparent and have a light transmission of over 80%. The addition of POSS has almost no effect on the chromaticity of the MCPU, while the thermal stability of the POSS/MCPU is improved compared to the pristine MCPU. The modified film is 2.50 times more resistant to yellowing by heat. The addition of POSS also simultaneously enhances the strength and toughness of the film. Using POSS/MCPU to reinforce the fragile object, the material was found to be significantly effective, indicating it has the potential to be used during the extraction of fragile cultural objects from archaeological sites.