The application of coating polymers to building materials is a simple and cheap way to preserve and protect surfaces from weathering phenomena. Due to its environmentally friendly character, waterborne coating is the most popular type of coating, and improving its performance is an important key of research. The study presents the results regarding the mechanical and photo-oxidation resistance of some water-based acrylic coatings containing SiO₂ nanoparticles obtained by batch miniemulsion polymerization. Coating materials have been characterized in terms of hydrophobic/hydrophilic behavior, mechanical resistance and surface morphology by means of water-contact angle, and scrub resistance and atomic force microscopy (AFM) measurements depending on silica-nanoparticle content. Moreover, accelerated weathering tests were performed to estimate the photo-oxidation resistance of the coatings. The chemical and color changes were assessed by Fourier-transform infrared spectroscopy (FTIR) and colorimetric measurements. Furthermore, the nanofilled coatings were applied on two different calcareous lithotypes (Lecce stone and Carrara Marble). Its properties, such as capillary water absorption and color modification, before and after accelerated aging tests, were assessed. The properties acquired by the addition of silica nanoparticles in the acrylic matrix can ensure good protection against weathering of stone-based materials.

The composites based on basalt fibres and poly(lactic acid) (PLA) show promising applications in biomedical and automotive fields, but their mechanical performance is still largely hindered by poor interfacial properties. Zinc oxide nanorods have been successfully used to tune the PLA/basalt fibre interface by growing them on commercially available basalt fabrics. The hierarchical fibres significantly enhanced the mechanical properties of PLA-based composites, especially their flexural strength and stiffness. These values are 26% and 22% higher than those of unmodified basalt/PLA composites, and 24% and 34% higher than those of glass/PLA composites used as a baseline. The increase in tensile and flexural properties hinges on the mechanical interlocking action promoted by ZnO nanorods and on the creation of a compact transcrystallinity structure. A degradation of PLA matrix was detected but it was positively counteracted by the better interfacial stress transfer. This study offers a novel approach for modifying the fibre–matrix interface of biocomposites intended for high-performance applications.