IMPACT TOUGHNESS OF NANOCOMPOSITE MATERIALS FILLED WITH FULLERENE60 PARTICLES

The dynamics of fracture of epoxy composites on various loadings of fullerene C-60 particles was investigated. Epoxy diane oligomer ED-20 was employed as the basic bonding agent in composite formation. It is characterized by its ability of providing high adhesion and cohesive strengths, easy processibility, as well as low coating shrinkage on deposition onto long-length surfaces of complex profile parts. Polyethylene polyamine (PEPA) was used for cross-linking of the epoxy composites, which made it possible to carry out the curing process at room temperature. With the use of IR spectral analysis, the nucleation of new links at the polymer-filler interface was determined, which was implied to result from the improved chemical activity of the dispersed particle surface. It is confirmed by the shift of the absorption bands as well as by the increase in the transmission rate intensity, half-width, and in the relative area of absorption bands. The loading of nanoparticles into the epoxy binder at the optimal content of q = 0.025 parts by weight (pts. wt.) allows one to improve the impact toughness by 2.5 times in contrast with the neat epoxy matrix. With the use of an RKP-300 impact pendulum machine for high-rate bending, the characteristic fracture stages of epoxy nanocomposites were revealed in regard to: i) crack initiation, ii) crack growth, and iii) the fracture point. The use of the VUHI-CHARPY data processing software made it possible to determine the components of fracture energy of the corresponding failure stages. The fracture surface of the nanocomposite materials was investigated with the use of optical and scanning electron microscopy (SEM). By the analysis of SEM micrographs of the fracture surface the homogeneous topology at the nanoscale formed through the action of the particles as a stopper system was revealed. The latter provides the retardation of microcrack propagation processes in the material bulk.