SynopsisNucleophilic additives and potassium and sodium chlorides, complexing with alkyl aluminum chlorides, are shown to result in an increase in the 1,2 structure of polybutadiene and a sharp decrease in molecular weight and polymerization rate. Trialkyl aluminum behaves in a similar way. There exists a correlation between these effects and the reducing power of the system. A mechanism of the influence of various compounds on the polymerization process is proposed. A mechanism of the formation of 1,4 and 1,2 polymer units is discussed with respect to the role of ... -allylic systems in diene polymerization and the nonequivalence of carbon atoms bonded to metal atoms in ... -erotylic systems.This communication deals with the mechanism of action of the so-called "positive" and "negative" additives in butadiene polymerization initiated by the cobalt catalyst system and the mechanism of the formation of polymer units in stereospecific diene polymerization initiated by 'lI"-allylic systems.The cobalt catalyst used to produce cis-polybutadiene is known to consist mainly of two components, dialkyl aluminum chloride and cobalt salt, the molar ratio of 150: 1. A characteristic feature of this system is the specific influence of nucleophilic agents on polymer structure. The addition of ethers, amines, and dialkyl sulfides in amounts commensurable with the dialkylaluminum chloride content produces an increase in the 1,2 structure and a simultaneous sharp decrease in polymerization rate and molecular weight of the polymer.'::" These dependences are illustrated by the data for dibutyl sulfide shown in Figure 1. Similar results are observed with potassium chloride and to a somewhat lesser extent with sodium chloride, which are known to form complexes with alkyl aluminum halides (Figs. 2 and 3).The addition of small amounts of trialkyl aluminum also results in a strong decrease in polymerization rate and molecular weight of polymer and also in an increase in 1,2 structure. Figure 4 presents the data on the 3685

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The comparative study of the antioxidant activity of whey protein concentrate, native colostrum, their ultrafiltered hydrolysates, as well as complexes of ultrafiltered hydrolysates with Y-cyclodextrin was carried out. The dependences of the fluorescence intensity of fluorescein on the logarithm of the concentration of all samples were obtained, from which the IC50 values were graphically determined, which were in the range of 7,2-103,4 gg/ml. Complexes of ultrafiltrate hydrolysates with Y-cyclodextrin restored fluorescein fluorescence to 88-96 % at a sample concentration of 0,68-0,75 mg/ml.

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