Enhancement effect of polyurea coating on the impact resistance of aluminum foam

Abstract

A polyurea coating was prepared to enhance the impact protection performance of aluminum foam, and its mechanical properties were analyzed. Polyurea‐coated aluminum foam composite specimens were prepared by coating the polyurea on the surface of aluminum foam. The mechanical properties of composite specimens under quasi‐static and dynamic loading were tested, and the stress–strain relationship at different strain rates was analyzed. The deformation process and failure mode of typical specimens under different loading conditions were discussed. The influence of polyurea coating on the energy absorption characteristics of aluminum foam was explained. The results show that when the polyurea is coated on the end surface of aluminum foam specimen, the sawtooth oscillation in the yield plateau stage of the stress–strain curve is weakened. The existence of polyurea coating makes the stress transfer of cell wall of aluminum foam uniform, and can effectively prevent the damage caused by the splash of aluminum foam fragments under high‐speed impact load. Coating polyurea on the opposite to load‐receiving surface of aluminum foam specimen can effectively improve the yield stress of composite specimen under dynamic load, and make the specimen still maintain good integrity after failure. When the polyurea is coated on the end surface of aluminum foam specimen, the final energy absorption per unit volume and the ideal energy absorption efficiency peak of the specimen are improved.

A Shear-Stiffening Mouthguard with Excellent Shock Absorption Capability and Remoldability via a Dynamic Dual Network

“…Moreover, polyurea is a widely used polymer, which exhibits excellent impact resistance performance via abundant and strong hydrogen bonds. − Such urea-based polymers have attracted considerable attention from an industrial perspective in the field of protection and bullet proof and antiexplosion materials. − For example, He et al fabricated a bioinspired cellular ceramic structure/polyurea dual-phase architecture, whose energy-absorbing ability is 50.34 times that of a cellular ceramic structure without polyurea; Dragonshield BC (Specialty Polymers Inc., USA) is an ultrahigh-strength polyurea elastomer product, which is used as a coating material on armored vehicles to mitigate blast and protect soldiers from fragment injury; XS-350 (LINE-X, USA) is an aromatic spray polyurea elastomer product, which has been applied as a protective layer in boats, farm equipment, construction equipment, etc. , Therefore, polyurea provides a dynamic supramolecular network for mouthguards to possess shock absorption ability thereby suiting the current processing method.…”