Study on the mechanical properties of shear thickening fluid-filled polyurethane foam composites

Abstract

The previous work on nanocomposites containing silica nanoparticles has indicated that when a relatively high silica nanoparticles content is used, reinforcing effect of that weakens due to the formation of agglomerates of nanoparticles within the polyurethane matrix. Therefore, in this paper, shear thickening fluid-enhanced polyurethane foams were synthesized to resolve such problems. Because hydroxyl groups can form hydrogen bonds with some polar molecules, several layers of molecules in PEG-400 can be adsorbed on the surface of silica nanoparticles. The silica nanoparticles could be dispersed in that polymer matrix very well and surface energy of silica nanoparticles decreases. The comparative study of polyurethane foam (PUF) composites based on shear thickening fluid (STF) had been reported. A wt%-dependent SEM analysis was carried out to understand the effects of STF on the cell morphologies of STF PUF. The linear viscoelastic properties of polymer matrix with STF was characterized by parallel plate rheometer. Finally, the mechanical properties were investigated. The results indicated that when the content of shear thickening fluid is more than 7.5%, the synergistic effect of SiO2 with PEG-400 on enhanced PUF was a major cause of improvement of its mechanical properties.