Rheological Properties of Suspensions of Brilliant Carmine 6B in Polybutadiene

Time dependent viscoelastic properties and stress overshoot of suspensions of brilliant carmine 6B in polybutadiene were investigated. Brilliant carmine 6B used in this study is a common magenta pigment and its particles have scaly shape. The disperse medium, fluid polybutadienes have relatively defined chemical structure and can be adjusted in their viscosity. We have dispersed 20wt% of the pigment to the medium by flushing method. The effects of viscosity of the disperse medium on the rheological properties of the disperse system are discussed in comparison with suspensions of carbon black. In a low viscosity medium, the suspension of brilliant carmine 6B forms a denser network structure than in a high viscosity medium. Furthermore, in the case of low viscosity, network formation is faster and the strain sensitive viscoelastic properties are more pronounced. From a comparison with the suspensions of carbon black, on stress overshoot measurements, it was deduced that the unit structures broken down of brilliant carmine 6B were finer and the recovered structures were more fragile than those of carbon black.