A polymer “bridge” was designed to connect graphene oxide and poly(ether ether ketone), making stronger and tougher composites.

Auxetic structures have garnered considerable interest for being lightweight and exhibiting superior properties such as an excellent energy absorption capability. In this paper, re-entrant and missing rib square grid auxetic structures were additively manufactured via the fused deposition modeling technique using two types of polyether imide materials: ULTEM 9085 and ULTEM 1010. In-plane quasi-static compressive tests were carried out on the proposed structures at different relative densities to investigate the Poisson’s ratio, equivalent modulus, deformation behavior, and energy absorption performance. Finite element simulations of the compression process were conducted, which confirmed the deformation behavior observed in the experiments. It was found that the Poisson’s ratio and normalized equivalent Young’s modulus of ULTEM 9085 and ULTEM 1010 with the same geometries were very close, while the energy absorption of the ductile ULTEM 9085 was significantly higher than that of the brittle ULTEM 1010 structures. Furthermore, a linear correlation exists between the relative density and specific energy absorption of missing rib square grid structures within the investigated relative density range, whereas the relationship for re-entrant structures follows a power law. This study provides a better understanding of how material properties influence the deformation behavior and energy absorption characteristics of auxetic structures.