Influence of particle properties on the viscosity of polymer–alumina composites

The influence of different micro- and nanosized alumina fillers, dispersed in an unsaturated polyester resin as polymer matrix, on the resulting composite flow behaviour was investigated systematically. It was found that the composite viscosity depends strongly on the properties of the applied particles like particle size, particle size distribution, solid load and especially on the specific surface area. The change of the relative viscosity with load can be described by using the different established semiempirical approaches for the estimation of the critical filler load. The value of the latter one decreases with increasing fillers surface area value significantly. The impact of the solid load as well as the fillers specific surface area on composite's flow behaviour will be discussed in the following.