Synthesis and Electrorheological Property of Chitosan Phosphate and Its Rare Earth Complex

The chitosan (CTS) phosphate and its rare earth (yttrium) complex were synthesized by a very simple sedimentation and grinding method. The nontoxic and facile CTS as a substrate of the materials, as well as phosphoric acid and Y(NO3)3 were chosen as starting materials. The electrorheological (ER) properties of the suspensions of CTS, CTS phosphate and its rare earth complex materials in silicon oil were investigated under DC electric field. The formation of CTS phosphate and the complex helped to decrease the shear stress and viscosity of the suspension at zero electric field, and to enhance the ER effect of CTS material. The ER performance of the complex material was the best among the studied materials, the shear stress (τ0) of the suspension of this material was very low at no electric field, and its relative shear stress (τr, τE/τ0, E = 4.2 kV·mm−1) reached 100.4, which was 13.6 times higher than that of the suspension of pure CTS. In addition, the complex material had better thermal stability. These properties of the complex material were very advantageous in the material's application.