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Summary:
Non-linear viscoelastic properties of suspensions of Carmine 6B in polybutadiene were investigated. The pigment particles of brilliant carmine 6B have a scaly shape and form denser network structure in disperse medium and show complicated rheological properties depending on flow history. In this study suspensions of carmine 6B in polybutadiene having different molecular weight were used as sample suspensions. Dynamic viscoelastic properties under various flow histories were mainly investigated and we discussed about the relations between the rheological properties and network structure formed by carmine 6B pigments. The followings are concluded. The anisotropic shape carmine 6B pigments in lower viscosity disperse medium tends to stack together which results in rupturing the network structure and this phenomenon is accelerated with applying moderate amplitude of oscillatory shear. The peculiar non-linear viscoelastic behavior in suspension of carmine 6B can be explained by the competition between formation and breaking down of the network structure of flocculated particles. The anisotropic shape carmine 6B pigments in lower viscosity disperse medium tends to stack together which results in rupturing the network structure and this phenomenon is accelerated with applying moderate amplitude of oscillatory shear. The peculiar non-linear viscoelastic behavior in suspension of carmine 6B can be explained by the competition between formation and breaking down of the network structure of flocculated particles.