Multifunctional polymer composite with excellent shear stiffening performance and magnetorheological effect
A novel multi-functional polymer composite (MPC) with both excellent shear stiffening (ST) performance and magnetorheological (MR) effect is prepared by dispersing magnetic particles into shear stiffening polymer matrix. Besides having the magnetically dependent mechanical properties (MR effects), this multi-functional MPC automatically changes its rheological behavior in response to external shear stimuli. The mechanical properties of this smart composite can be alternatively achieved by varying the particle's types and contents. Upon applying a shear stress with excitation frequency from 1 Hz to 100 Hz, the storage modulus (G′) of the MPC increases from 102 to 106 Pa, demonstrating an excellent ST effect. Interestingly, the ST effects of the MPC are also tunable by varying the external magnetic field, and the area of G′ could be greatly increased and precisely controlled. Based on the experimental results, a possible mechanism is proposed and discussed. It is believed that the “cross bonds” and the particle chains induced by the magnetic field are due to the excellent multi-functional stimulus-response properties.