This paper mainly studies the effect of shear thickening gel on the impact resistance of polyurethane foam. First, flexible polyurethane foams with strain rate sensitivity, shape memory, and impact resistance were prepared by a convenient one-step foaming method. Then, the surface morphology and impact resistance of the composites were characterized by SEM, AFM, and low-velocity impact tests. The results demonstrated that the addition of the shear thickening gel makes the cell size of the composites more uniform and the molecular chain arrangement more regular. When the amount of the shear thickening gel was 20 parts, the surface roughness of polyurethane foams was increased from 14.7 to 74.7 nm. More importantly, the addition of the shear thickening gel significantly enhanced the impact resistance of polyurethane foam. When the impact velocity was 5.5 m s −1 , the ratio of absorbed energy to impact energy of the FPUF-15pbw reached 91.35%, which was 20.12% higher than the FPUF-0pbw.

Cushioning energy absorbing materials are developing towards lightweight and high specific strength. Therefore, how to ensure the lightweight and high strength of materials is an important issue of common concern to researchers. In this paper, a stretchable shear thickening gel/ polyurethane foam composite material, with excellent shear hardening and energy absorption characteristics, was prepared by one-step foaming method. The strain rate sensitivity of the composite was 1.5-1.9 times than that of the pure polyurethane foam. Importantly, the addition of shear thickening gel increased the specific strength and specific energy absorption of the composite material by 82% and 96% respectively compared with pure polyurethane foam.