Influence of the Nanoparticle Surface Polarity on the Flow Behavior of Polymer Matrix Composites

The influence of different nanosized titanias with opposite surface polarity, dispersed in an unsaturated polyester matrix, on the resulting composite flow behaviour like shear rate and load dependent viscosity as well as on the temperature influence was investigated systematically. It is known from composites containing microsized particles that a surface polarity conversion from the original hydrophilic to the polymer-like hydrophobic character allows higher solid loads due to a pronounced viscosity reduction. In this work it was derived from viscosity measurements that a large hydrophobic surface causes a pronounced attractive interaction between the filler and the polymer matrix reducing the maximum accessible filler load in comparison to a similar hydrophilic titania.