It was found that incorporation of the microencapsulated fireproofing compound (MIC FC) T-2 in siliconcontaining shells in polyethylene does not alter the effective viscosity of the polymer melt at 200~ During thermolysis of PE containing MIC FC in a polyvinylethoxysiloxane (PVES) The results of studies to obtain polyethylene (PE) with reduced combustibility by incorporating phosphorus-and nitrogen-containing fire retardants (FC) in the polymer melt [1, 2], particularly T-2 fireproof'rag compound microencapsulated in polymer shells, suggests the possibility of eliminating the basic drawback of this FC -the hydrophilicity. MIC FC in shells based on PE, polyvinylethoxysiloxane (PVES), and polyamin~ (PAPES) have been recommended for modification of PE since they make the surface of T-2 FC hydrophobic to a greater degree by increasing the affinity of the MIC FC for PE.During processing, PE is exposed to high temperatures and shear forces so that homolytic breaking of carbon-carbon bonds and the formation of macroalkyl free radicals which initiate radical chain reactions take place [3].In the stage of processing of PE, due to the presence of oxygen, thermal oxidation reactions can also take place with the formation of hydroperoxides which initiate subsequent reactions of oxidative degradation of the polymer. As a result of these processes, the polymer chain breaks, which causes a decrease in the molecular weight and loss of the most important qualities of the polymer. Incorporation of FC in the melt to decrease the combustibility of polyolefins can affect the occurrence of these reactions.We investigated the effect of the processing parameters on the technological properties of PE containing MIC FC. In this respect, we investigated the effect of MIC FC added to a PE melt in spinning on the rheological (viscosity) properties characterizing a change in the molecular weight of the polymer. The melt flow index (MFI), a simple standardized method of determining the viscosity, was used as the basic characteristic of the effective viscosity of the PE melt [3].The change in the MFI of PE containing MIC FC of different compositions was investigated and the effective viscosity of the melt was calculated. The effective viscosity of a PE melt as a function of the temperature in the presence of different FC -finely disperse T-2 and T-2 encapsulated in shells based on PVES, PAPES, and PE -is shown in Fig. I.We know that incorporation of solid fillers in polymer melts increases the effective viscosity of the melt [4], which is confirmed by our data. Incorporation of T-2 in PE increases the viscosity at 190-200~ in comparison to the starting poly-*Deceased.Moscow State Textile Academy, Institute of Synthetic Polymer Materials, Russian Academy of Sciences.

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