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Transparent and intumescent polymer-silicate hydrogels were synthesized by free-radical polymerization, in the presence of the redox initiators system (potassium persulphate/sodium thiosulphate) and cross-linking monomer (N,N'-methylenebisacrylamide). Hydrogels obtained in such a manner were theologically tested and it was found that the same sample with a different sodium acrylate concentration polymerized faster when its content was lower. The spectroscopic and thermal analysis proved that the polymer combines with sodium silicate by hydrogen bonds and during thermal degradation only small polymer fragments and water molecules were released. NMR studies have shown that the content of water glass causes shorter relaxation times. Conducted fire tests showed that glass panes systems filled with the tested hydrogels meet the relevant construction standards and what is their big advantage, a thin 1 mm layer of polymer-silicate gel is sufficient for this purpose. We believe that these results will contribute to the development of intumescent hydrogels with enhanced fire-retardant properties., INTRODUCTION Aqueous solutions of soluble silicates, such as salts of a weak silicic acid and a strong base, for example, sodium, are alkaline. Therefore, as a result of the reaction [...]

The development of the mining industry has resulted in the accumulation of large amounts of waste, which effectively degrades the environment. The aim of this study is to check whether the addition of post-flotation sludge from copper production to the typical ceramic mass of the "gress porcelanato" will allow to obtain qualified sintered or faience tiles. By adding successive amounts of post-flotation sludge to the high-quality lamellar mass, typical parameters such as firing shrinkage, water absorbability and bending strength after firing were assessed. The structure of the obtained ceramic materials, using scanning electron microscopy (SEM with EDS), was also determined. Obtaining positive results would allow not only to significantly reduce the production costs of ceramic tiles, because the sludge is finely divided and no grinding is necessary, but, above all, will allow to eliminate the environmental risk. The present study has shown that it is possible to introduce up to 20% post-flotation sludge for gres porcellanato tile production and up to 50% post-flotation slugde for faience tile production. Both types of ceramic materials with an appropriate proportion of sludge, meet the requirements of tile standards in terms of mechanical strength and water absorption. [ABSTRACT FROM AUTHOR]

The article presents results of the research on the influence of graphite/kaolin and graphite/titanium oxide systems on thermal properties, intumescence degree and the integrity of the structure of intumescent protective films based on epoxy resins for steel. The TG/DTG/DSC analysis showed that graphite/kaolin system shifted the decomposition reaction of epoxy resin towards higher temperatures, even by about 30°C. Fire endurance tests and the SEM analysis confirmed these results because more thermally resistant (T500°C reached after 37.5 min for 1.1 coating thickness), swollen (about 20 times) and homogeneous coatings were obtained. The presented results suggest that ceramic fire retardants can successfully cooperate with organic components in intumescent protective coatings for steel elements. [ABSTRACT FROM AUTHOR]

Copyright of Inzynieria Mineralna is the property of Polskie Towarzystwo Przerobki Kopalin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Safety & Fire Technology / Bezpieczeństwo i Technika Pożarnicza is the property of Centrum Naukowo-Badawcze Ochrony Przeciwpozarowej and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Studies on the sorption and desorption of selected Na+, Ca2+, Mg2+, Mn2+, Cu2+ and Cr3+ cations by materials based on modified brown coal were carried out. The chemical modification of the sorbent material consisted of grinding involving different inorganic substances and organic polymers. Samples were subjected to chemical modification at elevated temperatures for several hours. For comparative purposes, as apart from brown coal, pure humic acids are known for the highest cations exchange capacity, samples of brown coal before and after purification were also analyzed. The ion capacity was determined under static conditions, measuring the difference in the concentration of cations in the sorbent before and after sorption and then after rinsing the sorbent with distilled water (A), and after the desorption process with hydrochloric acid (B). Studies have shown that sorbents based on modified brown coal have rather significant exchange capacities in the range of 270-450 meq/100 g for the first stage and 90-200 meq/100 g for the second stage. It was also found that purified humic acid (450-200 meq/100 g) has the highest exchange capacity and modified brown coal obtained at 250°C has the lowest. The measurement of desorption showed that approximately 10% of the cations are already leached by distilled water and the residue is desorbed under the influence of 10% hydrochloric acid, but the total amount of cations is compatible with the measurement process of the second stage. The sorption affinity to various cations is different. In the case of the sorption measurements, modified sorbents show the highest sorption affinity with respect to calcium, while the unmodified raw brown coal with respect to chromium. The next stage of the measurement showed that the valence of the cation has the highest impact on the sorption affinity. [ABSTRACT FROM AUTHOR]