Reactor polymer compositions (RPC) of ultrahigh molecular weight polyethylene (UHMWPE) with Mw = 1,000 kg/mol and low molecular weight high density polyethylene (LMWPE) with Mw = 160 kg/mol were synthesized in a two‐stage ethylene polymerization with a rac‐Me2Si(Ind)2ZrCl2/methylaluminoxane catalyst. The conditions of the stages that ensure the formation of UHMWPE and LMWPE fractions with the desired molecular weight and properties were selected based on the study of one‐stage ethylene polymerization over this catalyst in a wide temperature range. The order of fraction synthesis in RPC preparation was changed. Two series of compositions UHMWPE/LMWPE and LMWPE/UHMWPE with UHMWPE content from 20 to 90 wt% were obtained. The SEM method was used to study the morphology of the nascent polymer particles. It was shown that RPC physical and mechanical properties depend not only on the UHMWPE content, but also on the morphology of the particles of reactor powders, which is determined by the order of polymer fraction synthesis. Materials of LMWPE/UHMWPE series have higher tensile properties compared to UHMWPE/LMWPE of the same composition. The LMWPE/UHMWPE compositions containing ≤50 wt% of UHMWPE flow even at a load of 10.5 kg.
The article considers the prerequisites for the creation of regular police in the Russian Empire, as well as the features of the acquisition of professional training of the regular police of the Russian Empire in 1718-1800.the thesis that the lack of a constantly functioning police body was the reason for the backlog of the Russian state in the field of law enforcement and public security is Substantiated.
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