Auxetic composites made of 3D textile structure and polyurethane foam

KGaA, Weinheim Auxetic composites have attracted considerable attention in recent years and have demonstrated a high potential of applications in different areas due to their wonderful properties as compared to non-auxetic composites. In this study, a three-dimensional (3D) auxetic textile structure previously developed was used as reinforcement to fabricate auxetic composites with conventional polyurethane (PU) foam. Both the deformation behavior and mechanical properties of the auxetic composites under compression were analyzed and compared with those of the pure PU foam and non-auxetic composites made with the same materials and structural parameters but with different yarn arrangement. The results show that the negative Poisson's ratio of composites can be obtained when suitable yarn arrangement in a 3D textile structure is adopted. The results also show that the auxetic composites and non-auxetic composites have different mechanical behaviors due to different yarn arrangements in 3D textile structure. While the auxetic composites behave more like damping material with lower compression stress, the non-auxetic composite behaves more like stiffer material with higher compression stress. It is expected that this study could pave a way to the development of innovative 3D auxetic textile composites for different potential applications such as impact protection.