Abstract
Viscoelastic properties of 3D fabric reinforced Vinyl Ester composites were studied in different
directions using Dynamic Mechanical Thermal Analysis (DMTA). Such materials filled by
nanoparticles (silicon carbide) with different concentrations were also investigated. The increases of
storage and loss moduli with addition of nanoparticles and with increase of their concentrations
were observed. The maximal tangent of the angle of mechanical losses was especially compared at
below and over glass transition temperature. Below glass transition temperature the presence of
nanoparticles increases storage and loss moduli and loss tangent. These effects achieved maximum
at glass transition temperature. Over glass transition, the loss modulus and loss tangent are
decreased with increase of the concentration of nanoparticles.