A study on mechanical properties and structure of anhydrite binder modified by ultra-dispersed siltstone

This research is devoted to modification of physical and mechanical properties and structure of a binder based on natural anhydrite. A sedimentary rock siltstone was added into the composition as a mineral ultrafine additive. The presence of aluminosilicate minerals proves that finely ground siltstone can be used as a mineral additive in the composition of the anhydrite binder, accelerating crystallization of gypsum new formations and densifying the structure of gypsum stone. For the first time, the effectiveness of using sodium and ammonium phosphates as hardening activators of an anhydrite binder was shown. Siltstone, added to the composition in the amount from 0 to 5%, lead to up to 40% increase in strength, which is due to the action of siltstone particles as “crystallization centers” and formation of crystalline hydrates of calcium sulfate dihydrate on their surface. Combined action of calcined siltstone and lime leads to a 45% increase in strength due to the additional compaction by new hydration products formed in the course of metakaolin and lime interaction. Microstructural analysis showed that samples with calcined siltstone and lime have a more dense and uniform structure with a lower porosity, compared to those with only natural siltstone. First published online 03 February 202

Use of technogenic alumo-chrome catalyst in anhydrite compositions

In this work the influence of alumo-chrome catalyst on the properties and structure of anhydrite binder by means of mechanical tests, X-ray phase analysis and raster electron microscopy was investigated. Taking into account the high dispersity in the presence of alumina in the amorphous state, the catalyst intensifies the solidification of anhydrite composition increasing the mechanical strength by 80–100%. The catalyst also influences on the morphology and size of gypsum crystals. The addition of the catalyst in the range of 2–5% leads to the formation compact fine-grained structure, it allows increasing the mechanical properties of anhydrite binder

Modification of the carrier mobility of conducting PF-EP polymer by formation of their composites with thiophene derivatives

In the paper we present synthesis and characterization of new donor-acceptor thiophene derivatives (TDs) containing vinylbenzo[d]thiazole, vinylpyridine and 1H-imidazo[4,5-f][1,10]phenanthroline residues. Using CELIV method, electron and hole mobility have been studied in the polymer layers based on poly [9,9-bis(6diethoxyl-phosphorylhexyl)fluorine] (PF-EP) doped with the TDs. Polymer light-emitting diodes (PLEDs) containing newly synthesized polyfluorene (PF) as emitting layers and PF-EP/TD composites as electron transporting layers show higher brightness at 15V as compared with TD free PF-EP