Impact and wear resistance of polymer nanocomposites at low filler content

It is well known that inorganic filler particles enhance the mechanical and tribological properties of polymers. The stiffness, toughness, and wear performance of the composites are extensively determined by the size, shape, volume content, and especially the dispersion homogeneity of the particles. In the present study, various amounts of micro- and nano-scale particles (titanium dioxide TiO2, 200-400 nm, calcium silicate CaSiO3, 4-15 mum) were introduced into an epoxy polymer matrix for its reinforcement. The influence of these particles on the impact strength, dynamic mechanical thermal properties, and block-on-ring wear behavior was investigated. Using only the nano-particles, the results demonstrate the best improvement in stiffness, impact strength, and wear resistance of the epoxy at a nano-particle content of 4 vol% TiO2. Therefore, this nanocomposite was used to act as a matrix for the CaSiO3 micro-particles, in the hope of finding synergistic effects between the micro- and the nano-particles. Results show, in fact, a further improvement of wear resistance and stiffness, whereas the impact strength suffers. Geometrical properties of the particles, the homogeneous dispersion state, energy dissipating fracture mechanisms, and a transition of wear mechanisms mostly contribute to the increase in performance.