The Cultural Heritage deterioration is a spontaneous decay process due to water percolation and air pollutant deposition. In this context, novel acrylic (Twinswet, TW) and siloxane-based (Alpha^®SI30) resins were exploited starting from commercial products and then modified by adding either a commercial polysiloxane-based additive (TegoPhobe 1500 N) or a precursor of SiO₂ nanoparticles (Tetraethyl ortosilicate, TEOS) to improve the Vicenza stone surface hydrophobicity. Properties of the coated materials were studied using different techniques such as water contact angle (WCA), capillary absorption, colorimetric and water vapor permeability measurements. Accelerated UV aging and eight-month outdoor exposure tests (at Milan University campus) were also performed to determine the coatings durability. Notably, the addition of both additives slightly enhanced the surface hydrophobicity resulting in WCAs of about 140°, and decreased the water absorption especially for Alpha-based resins. Conversely, a reduction of water vapor permeability was observed, even if within the threshold value of 50%. Concerning the color variation, Alpha^®SI30 preserved the stone external aspect; instead, TW smoothly modified the surface color. All of the studied coatings were stable to both UV aging and outdoor exposure. Hence, the present modified commercial coatings revealed to be very promising for the protection of historical monuments.

中文翻译：

---

新型有机/无机添加剂改性树脂增强的历史石灰石保护

由于水的渗入和空气污染物的沉积，文化遗产的恶化是自发的衰变过程。在这方面，新颖的丙烯酸（Twinswet，TW）和硅氧烷类（阿尔法^® SI30）树脂被利用从市售品开始，然后修饰通过加入任一商业聚硅氧烷系添加剂（TegoPhobe 1500 N）或SiO的前体₂纳米颗粒（原硅酸四乙酯，TEOS）可改善维琴察石材的表面疏水性。使用不同的技术，例如水接触角（WCA），毛细管吸收，比色法和水蒸气透过率测量，研究了涂层材料的性能。还进行了加速的紫外线老化和八个月的户外暴露测试（在米兰大学校园），以确定涂料的耐久性。值得注意的是，两种添加剂的添加都会略微提高表面疏水性，导致WCA约为140°，并且降低吸水率，尤其是对于基于Alpha的树脂。相反，即使在阈值50％以内，也观察到水蒸气透过率降低。关于颜色的变化，阿尔法^®SI30保留了石材的外观；相反，TW平滑地修改了表面颜色。所有研究的涂料对紫外线老化和户外暴露均稳定。因此，本发明的改性商业涂料显示出对保护历史古迹非常有前途。