Authors: H. Mahfuz, F.E. Clements and J. Stewart
Affilation: Florida Atlantic University, United States
Pages: 358 - 361
Keywords: shear thickening fluid
Traditionally, the development of shear thickening fluid (STF) begins with micron size silica suspended in water. This material is transformed into STF through centrifugation and exchange processes. In other approaches polyethylene glycol (PEG) is added in incremental quantity directly to the silica suspension and water is removed through evaporation, repeatedly, until the admixture reaches the desired ratio of silica to PEG by weight. STF developed in this manner is usually dissolved in ethanol and impregnated into Kevlar fabric and then dried to remove ethanol. Once ethanol is removed, the resulting composite is Kevlar impregnated with a mixture of PEG and silica. At this stage, the Kevlar composite does not show any STF characteristics, the intention was to directly disperse silica particles into a mixture of PEG and ethanol bypassing the repeated evaporation routes. We have used an ultrasonic cavitation technique to disperse silica particles, which is chosen over mechanical mixing because of its accelerated and intensified properties for diffusion, dissolution and dispersion. In addition, we have used nanometer size fumed silica particles in place of micron size silica, to enhance the interaction between the particle and the polymer. The results show that although the STF fabrication route was bypassed, the sonicated mixture of nanophased silica particles and PEG can attribute remarkable stab resistance properties.