Environmental footprint as a criterion in the ZTA composites forming process via centrifugal slip casting

The main goal of this study was to optimize the technological process of forming and sintering Zirconia Toughened Alumina (ZTA) composites in terms of reducing energy demand. Based on the results of Life Cycle Assessment carried out according to ISO 14044 and EN 15805 standards, the elimination of preliminary homogenization of ceramic suspension in the planetary mill, allowed to reduce energy consumption by over 25%. The method of forming ZTA materials by CSC method, allowed to obtain finished tube-shaped products, which did not require any mechanical treatment after sintering. Such an approach may be an alternative solution for production of ZTA pipes that can be used in transport of aggressive substances, even in extreme corrosive or temperatures conditions.     

The synthesis of novel,visible-wavelength,oxidizable polymerization sensitizers based on the 8-halogeno-5,12-dihydroquinoxalino[2,3-b]quinoxaline skeleton

Novel dyes, based on the 8-halogeno-5,12-dihydroquinoxalino[2,3-b]quinoxaline skeleton, were synthesized and characterized using ¹H NMR spectroscopy and chemical ionization mass spectroscopy. Their electrochemical and spectral properties, such as absorption and emission spectra, quantum yield of fluorescence and quantum yield of singlet oxygen generation, were also measured. These dyes were used as oxidizable sensitizers for diphenyliodonium and N-alkoxypyridinium salts. Photoredox pairs, consisting of dyes and pyridinium or iodonium salts, were found to be effective visible-wavelength initiators of free radical or cationic polymerization, respectively. The ability of each dye to act as a photoinitiator strongly depended upon its chemical structure. The heavy atoms present in the chemical structure could lead to excited triplet states within the dye, thereby facilitating electron transfer from these states.