Abstract <p>The effect of nickel oxide nanoparticles stabilized by a matrix of high-pressure polyethylene obtained on the structure and properties of nanocomposites based on isotactic polypropylene containing multilayer carbon nanotubes has been studied. The physical-mechanical, thermophysical and thermal properties of the obtained composites were studied. The methods of differential thermal analysis and scanning electron microscopy were used. The study of the morphology of polypropylene and a nanocomposite based on it confirms the results of the physical, mechanical and thermal properties and shows that nickel oxide nanoparticles with multilayer carbon nanotubes have a noticeable effect on the structuring of polypropylene macromolecules.</p>