The role of compatibilizing agent in the formation of structure, fire-retardant and mechanical properties of high-density polyethylene

The present work is devoted to the study of the influence of a compatibilizing agent based on functionalized polyethylene grade PF-1, developed and produced at the MPRI of NAS of Belarus, on the formation of the structure, fireretardant properties and mechanical characteristics of high-density polyethylene (HDPE) containing a nitrogen-phosphorus flame retardant (NPFR). Using IR spectroscopy, the formation of interfacial interactions between PF-1 and NPFR was established, which causes an increase in the compatibility of components in the HDPE matrix. Analysis of micrographs obtained by scanning electron microscopy (SEM) showed that the introduction of PF-1 into the HDPE/NPFR composite leads to a significant modification of the morphology, characterized by a decrease in the average particle size of the dispersed NPFR and an improvement in the adhesion between the NPFR particles and the polymer matrix. Differential scanning calorimetry revealed a decrease in the enthalpies of melting and crystallization of the HDPE/PF-1/NPFR composite, indicating an increase in the interfacial interaction of the components. It was shown that the flame-retardant HDPE composition containing NPFR together with PF-1 has a reduced combustion rate, which is due to a more uniform distribution of the flame retardant in the polymer matrix. The results of the mechanical tests indicate an increase in the tensile modulus and yield strength for the HDPE/NPFR composite with the addition of the PF-1 compatibilizer.