Energy dissipation and rate-dependent deformation behavior of shear thickening fluid integrated polyurethane foam nanocomposites

Designing energy dissipative polymeric foams is essential for many applications to withstand various loading scenarios. This study is aimed to improve the compressive and energy absorption properties of polyurethane foams with shear thickening fluid (STF) integration while discussing microstructure-mechanical property relationship. Initially, STFs were fabricated with between 19 and 28 wt% fumed silica content and investigated by a rheometer. 26 wt% silica was found to be optimum for integration into polyurethane foams, yielding an excellent thickening ratio of 67. Therefore, 26 wt% STFs were integrated into rigid PU foams at 0.5, 1, and 3 wt%, and morphological analyses, cyclic compression tests at various strains and strain rates were performed to develop microstructure-mechanical property relationship. The results revealed that 1 wt% STF-integrated polyurethane foams presented the highest specific compressive strength with 33 % and 10.4 % enhancements, respectively. Furthermore, 1 wt% STF integration generated up to 50 % greater energy dissipation over 10 cycles.