Structures and properties of low-crystallinity polyolefins modified with nanodiamonds

To search for new methods of governing the structures and properties of low-crystallinity ethylene-octene copolymers with densities of 0.861 and 0.885 g/cm(3), the effect of small additives of diamond-like nanoparticles on the mechanical properties and structuring processes in these elastomers is studied. It is shown that nanodiamonds are distributed sufficiently well in the matrixes of the copolymers and improve the stress-strain characteristics even at a low content of nanoparticles. The influence of the functional composition of the modifier surface, the preparation method and thermal prehistory of the composites, and the degree of crystallinity of the elastomer matrix on the structure and properties of the nanocomposites is investigated. The copolymers contain a hexagonal mesophase and orthorhombic crystallites, with their amount in the composites being higher. The efficiency of nanomodifiers in the matrix with a higher crystallinity is noticeably lower. Aerosils rank much below nanodiamonds in terms of efficiency, especially in the low-concentration range. The pattern of deformation dependences of thermodynamic parameters is similar to that of typical thermoplastic elastomers. The effect of nanoparticles on the thermomechanical behavior of the copolymers depends on both the modifier amount and the degree of crystallinity of the matrix.