Processes of Fatigue Destruction in Nanopolymer-Hydrophobised Ceramic Bricks

Abstract

Abstract:The article presents a proposal of a model of fatigue destruction of hydrophobised ceramic brick, i.e., a basic masonry material. The brick surface was hydrophobised with two inorganic polymers: a nanopolymer preparation based on dialkyl siloxanes (series 1-5) and an aqueous silicon solution (series 6-10). Nanosilica was added to the polymers to enhance the stability of the film formed on the brick surface. To achieve an appropriate blend of the polymer liquid phase and the nano silica solid phase, the mixture was disintegrated by sonication. The effect of the addition of nano silica and sonication on changes in the rheological parameters, i.e., viscosity and surface tension, was determined. Material fatigue was induced by cyclic immersion of the samples in water and drying at a temperature of 100 • C, which caused rapid and relatively dynamic movement of water. The moisture and temperature effect was determined by measurement of changes in surface hardness performed with the Vickers method and assessment of sample absorbability. The results provided an approximate picture of fatigue destruction of brick and hydrophobic coatings in relation to changes in their temporal stability. Additionally, SEM images of hydrophobic coatings in are shown.

Novel Attribute of Organic–Inorganic Hybrid Coatings for Protection and Preservation of Materials (Stone and Wood) Belonging to Cultural Heritage

“…The addition of silica nano-particles to the polymer does not significantly reduce the water vapor permeability [51], in particular for porous stone materials [40,64]. Reduction in breathability is measured at high nanosilica concentration, being this reduction associated with the density of the aggregates formed on the surface of the treated stone [52].…”

“…After the nano-particles' addition, the mixture with polymer(s) can be subjected to sonication [42,48,50,51] or vigorous stirring in order to prepare an optimal and homogeneous dispersion [37,47,52]. However, sometime the stirring procedure did not ensure nano-particles homogeneously dispersed in the polymer film; SEM (scanning electron microscopy) observations highlighted aggregates with average diameters dependent on the nano-particles concentration [38,52].…”

“…However, sometime the stirring procedure did not ensure nano-particles homogeneously dispersed in the polymer film; SEM (scanning electron microscopy) observations highlighted aggregates with average diameters dependent on the nano-particles concentration [38,52]. Sonication has been found useful to change the basic rheological properties of polymers by partial disintegration of the primary polymer chain structure and cavitation exerts, thus impacting on the ability of polymers to well penetrate and fill the pores of the stone substrate [51].…”

“…The mechanical characterization has demonstrated a positive influence of the addition of silica nano-particles on impact resistance [47], scratch resistance [61], as well as on surface hardness, because of capacity of coating reorganization and reconstruction during the mechanical tests [51]. Where the products penetrate the stone less deeply, the surface resistance, rather than the compression strength, has been found more appropriate for evaluating the effectiveness of the consolidation for this stone [53].…”

Impact of epoxy resin modification on their strength parameters

“…[12][13] The amount of filler usually depends on the weight of the resin (volumetric dosing is less accurate due to the change of resin density with temperature changes). In order to ensure regular and effective distribution of the filler in the volume of resin, in the technology of polymers the ultrasound are used [14][15] [16] [17]. Dynamic phenomena caused by ultrasound (high frequency vibrations, cavitation, pressure and temperature changes) cause the formation of temporary atomic bonds between the filler particles and the polymer chains.…”