Search Results (4)

This article deals with the simple preparation of environmentally friendly acrylic latex binders, which are functionalized with nanoparticles of metal oxides, namely MgO, ZnO, La₂O₃ and combinations of MgO and ZnO, serving as functional components to achieve antimicrobial properties, but also to improve physical–mechanical properties and chemical resilience. The incorporation of uncoated powder nanoparticles was performed during the synthesis, using the two-stage semi-continuous emulsion radical polymerization technique, to obtain latexes containing 0.5%–1.3% nanoparticles relative to the polymer content. Changes in latex performance due to nanoparticles were compared from the point of view of the type and concentration of metal oxide nanoparticles in latex. The results of the tests showed that all types of nanoparticles showed very promising properties, while with increasing concentration of nanoparticles there was an improvement in properties. The nanoparticles in latex provided interfacially crosslinked transparent smooth coating films with high gloss and good physical–mechanical properties. Latexes containing the highest concentration of nanoparticles provided coatings with significant antimicrobial activity against all tested bacterial and fungal strains, but also in-can preservative stability of liquid latex. Furthermore, the coatings were resistant to solvents, and in addition, latexes with MgO nanoparticles showed a significant decrease in the minimum film-forming temperature, and latex with a concentration of about 1.3% MgO did not show any flash corrosion under the coating film cast on a steel substrate. The latexes containing MgO and La₂O₃ nanoparticles provided coatings that were very resistant to water bleaching. Full article

We present a facile approach to fabricate superamphiphobic surfaces by spray coating silica-fluoropolymer core-shell particles without substrate pretreatment with an additional binder resin. A series of SiO₂@poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (SiO₂@PFMA) core-shell particles with core particles of different sizes were prepared via thiol-lactam initiated radical polymerization (TLIRP). The surface of each SiO₂ particle with an average particle size of 12, 80, 150, and 350 nm was modified with (3-mercaptopropyl) trimethoxysilane and used as a seed for TLIRP. The SiO₂@PFMA particles with various SiO₂ sizes and contents were coated on aluminum substrates by a spray gun and then thermally treated to form a stable, rough composite layer. During the spray coating, the core-shell particles were aggregated by rapid evaporation of the solvent and then irregularly adhered to the substrate resulting in hierarchical structures. In the case of SiO₂@PFMAs with low SiO₂ contents, the roughness created mainly by the polymer shell disappeared during heat treatment. However, the substrates coated with SiO₂@PFMAs with high SiO₂ contents maintained the roughness even after heat treatment. The core-shell particles prepared with 12 nm SiO₂ formed a stable superamphiphobic surface. The water/hexadecane contact and sliding angles on an aluminum plate coated with SiO₂@PFMA, prepared using 12 nm silica at 46 wt% silica content (12 nm-SiO₂(46)@PFMA), were 178.5°/159.2° and 1°/7°, respectively. The cross-cut tape test showed that adhesion between the 12nm-SiO₂(46)@PFMA and the aluminum substrate was classified as 5B. A glass surface spray-coated with the core-shell composite particles exhibited transparent superhydrophobicity and translucent superamphiphobicity by controlling the concentration of the coating solution. Full article

This paper is focused on a simple preparation of functional acrylic latex coating binders comprising embedded nanoparticles originating from ZnO and MgO, respectively, in the role of interfacial ionic self-crosslinking agents. The incorporation of surface-untreated powdered nano-oxides into the coating binder was achieved in the course of the latex synthesis performed by a technique of the two-step emulsion polymerization. By means of this technological approach, latexes comprising dispersed nanoparticles in the content of ca 0.5–1.1 wt % (based on solids) were successfully prepared. For the interfacial covalent self-crosslinking, diacetone acrylamide repeat units were introduced into the latex polymer to ensure functionalities for the subsequent reaction with adipic acid dihydrazide. The latex storage stability and coating performance were compared with respect to the type and concentration of the incorporated nanoparticles. It was determined that all latex coating binders comprising nanoparticles exhibited long-term storage stability and provided interfacially crosslinked transparent smooth coating films of high gloss, excellent solvent resistance, and favorable physico-mechanical properties. Moreover, latexes with embedded nanoparticles, which originated from MgO, manifested a pronounced drop in minimum film forming temperature and provided highly water whitening resistant coating films. Full article

According to the latest estimates, 40% of urban areas are covered by pavements. One of the most remarkable effects on the urban environment is the increase in impermeable surfaces which leads to problems related to water infiltration into the ground and the increase in wash-off volumes. The use of permeable and porous layers in urban applications for cycle lanes, footpaths and parking areas is growing in interest, increasing the potential for control and management of urban runoff. In this paper, a physical and mechanical characterization is proposed of an innovative mixture, prepared with a polymeric transparent binder for semi-porous layers with reduced contribution to the urban heat island effect. Two versions of this mixture are compared, one with just virgin and the one with artificial synthetic aggregates, produced through the alkali-activation of waste basalt powder. Results show suitable properties for both materials if compared to porous asphalt concretes in traditional pavements. Furthermore, the application of synthetic aggregates seems to be a viable solution for the production of innovative and eco-friendly mixtures, allowing the recycling of waste materials. Full article