Investigation of the improvement of the physical and mechanical properties of polymer composite materials with nano-sized powders

Polymer composites are widely applied in modern aviation. However, their shortcomings force scientists to look for material enhancing methods. Therefore experimental research of the influence of nanoparticles on the polymer strength and the electromagnetic properties was conducted. The polymer modification was realized by two kinds of nano-sized powders: iron and diamond. The addition of 0.67 % nanodiamonds mass content in polymer increases its strength (about 2 times). This can be explained by electrical interaction of nanoparticles with high specific surface energy and monomer molecules having dipole moments. The samples for dielectric permittivity measuring were made from pure resin and from resin reinforced with 0.67 % nanodiamonds and 1 % nano-iron mass content. The results show that the addition of nanodiamonds decreases the resin dielectric permittivity but nano-iron addition increases it. The electrical conductivity σ and the magnetic permeability μ were measured on samples with 1 %, 3 %, 10 % and 25 % weight content of nanoscale iron. The electrical conductivity did not uniformly increase according to the percolation theory. This percolation transition (by 5 orders of magnitude) corresponds to nano-iron mass content 3 %.