“Green” thermally stable hardener was synthesized from a PET waste. The rigid molecular linear structure of the new hardener suggests that it will provide the polymer matrix with the necessary physical and mechanical characteristics. It also allows the expectation that cured matrix based on this hardener can provide increased toughness. New hardener was used as a curing agent for three epoxy resins—tetraglycidyl methylenedianiline (TGDMA, 111–117 EEW), diglycidylether of bisphenol A (DGEBA, 170-192 EEW) and solid epoxy resin (SER)—with a medium molecular weight (860–930 EEW) based on DGEBA. The mixtures were found to have the highest T_g for the DGEBA resin, and high of that for TGDMA and SER. According to the DMA analysis for two cured matrices, the hardener proved to be no worse than the standard ones, and made it possible to obtain cured matrices with excellent mechanical properties, which allows us to hope for further application of new hardener cured epoxy matrices in appropriate composite materials at high temperatures.

The synthesis of imidazo[1,2-a]pyridines was carried out via 5-exo-dig cyclization of the corresponding N-(pyridin-2-yl)methanimines and terminal acetylenes, catalyzed by the cationic complex [Cu(CH₃CN)₄]BF₄. For the first time, the catalytic activity of the cationic Cu(I) complex in the synthesis of imidazo[1,2-a]pyridine derivatives was investigated. A series of 15 derivatives of imidazo[1,2-a]pyridine with various substituents (Cl, Br, CO₂Et, and OMe) was obtained with yields of 52–69%.