Preparation and properties of shear thickening fluid (STF) capsule filled graded buffer composites

Abstract

In this study, we prepared a graded buffer composite by using shear thickening fluid (STF) capsules, polyurethane (PU) foam, and low-melting point PET fabric or spacer fabric with improved energy absorption performance. Various graded buffer composites are fabricated including STF capsule/PU foam covered with PET fabric (SC/PU/PET-CM) and STF capsule/PU foam covered with warp-knitted spacer fabric (SC/PU/WKSF-CM). The thermal stability and the mechanical properties of the graded buffer composite were tested. After adding STF capsules, PU foam still has good thermal stability whose weight- loss temperature reaches 200 ℃; and the compression energy and buffer performance both increases. The compression energy of S4-STF/PU is 2.26 times than that of S4-PU and 5.65 times than that of pure PU foam. Among SC/PU/PET-CM samples, HP-STF/PU graded foam composite showed the lowest impact force (3833 N). Comparatively, among SC/PU/WKSF-CM samples, the buffer performance of S4-STF/PU shows the best, and the impact value is reduced to 3921 N, which is 848 N lower (17.7%) than that of PU foam. The composites can be used as an alternative material in the field of protection.