Effects of Flocks Doping on the Dynamic Mechanical Properties of Shear Thickening Gel

Polymethyl methacrylate (PMMA) was used as the dispersed phase and mold silicone was used as the continuous phase to prepare the shear thickening gel (STG) doped with a certain amount of flocks by rotary stirring. STG doped with flocks by a rotary rheometer was tested and observed through a scanning electron microscope. Results revealed that both the rotary stirring sample preparation and the rheological test method of the rotary rheometer could lead to the regular arrangement of flocks and could not reflect shear thickening performance accurately. The flocks showed a random arrangement in STG after the mixing process, and the dynamic mechanical properties were able to be measured with a dynamic mechanical analyzer (DMA). Flocks with a fineness of 3 Denier, 1 mm in length, and a mass ratio of 5% had significant effects on the dynamic mechanical properties of STG. Due to long continuous shearing time, flocks were arranged regularly when the sweeping frequency was higher than 125 Hz, then the shear thickening performance of the doped STG was declined.