Aniline-terminated polyether polyurea with ultra strength, toughness and impact-resistant for enhanced ballistic protection

Impacts on structural materials can cause greater safety hazards, and it will be difficult to reinforce the original structure. Therefore, it is important to investigate a coating that can improve the impact resistance of materials. Polyurea coatings with excellent mechanical properties have become a widely used protective coating military and residential applications. However, it is still a significant challenge to prepare polyurea elastomers with high strength, toughness, tear and impact resistance. In this work, two polyurea elastomers (BPU1000 and BPU650) with different soft segment molecular weights of high mechanical strength and toughness are fabricated by introducing the rigid benzene ring structure between the soft and hard segment. Moreover, the hard segment units are cross-linked by reversible hydrogen bonding, which promotes a significant increase in stiffness, strength, toughness and tearing. Compared to the unmodified coating, BPU1000 and BPU650 showed significantly improved tensile strength and toughness. Specifically, the tensile strengths of BPU1000 and BPU650 are 36.93 MPa and 37.78 MPa and the toughness is 230.78 MJ/m³ and 156.29 MJ/m³, respectively. The drop hammer and penetration experiments show that BPU1000 and BPU650 possess excellent impact resistance, much higher than the previously reported elastomers, which provides a new choice for the application of polyurea coatings for structural protection.