Effect of Fe₃O₄ Iron Oxide Nanoparticles on the Structure and Thermal Properties of High-Density Polyethylene-Based Nanocomposites

High-density polyethylene (HDPE)/Fe₃O₄ composites with Fe₃O₄ nanofiller contents of ω = 1, 3, and 5 vol % have been obtained by hot pressing of a homogeneous mixture of HDPE and a synthesized Fe₃O₄ nanopowder. The structure and thermal properties of the HDPE/Fe₃O₄ nanocomposites have been studied; it has been found that, with an increase in the Fe₃O₄ nanoparticle concentration in the polymer matrix, the morphology of the supramolecular structure of the HDPE matrix drastically changes. It has been established that, with an increase in the nanofiller concentration, the mobility of macromolecular chains in the matrix and the crystalline lamellae thickness decrease. Nanoparticles disrupt the regularity of lamellae in the crystalline phase of the polymer matrix and prevent the formation and growth of new crystalline domains in the amorphous region.