Impact Resistance of Polyurethane Elastomers Enhanced by MMT/CNTs Composites

Polyurethane elastomer (PUE) is extensively used for impact protection owing to commendable strength and toughness. However, PUE suffers from insufficient energy absorption and easy cracking under high-speed impact. Herein, hybrid nanomaterials (MMT/CNTs), formed by combining functionalized carbon nanotubes (CNTs) and organically modified montmorillonite (MMT) through ionic bonding, were incorporated into PUE, which enhances the impact resistance significantly under high-speed conditions. The enhancement of the impact resistance of the PUE composites was ascribed to the hybridization of CNTs and MMT, which facilitated the dispersion of each other in the matrix. Meanwhile, the CNTs anchored in the MMT interlayer can effectively support the interlayer space and promote internal stress and heat transfer. The results revealed that incorporating CNTs expanded MMT's interlayer spacing to 3.84 nm. Compared to pure PUE, the composites containing 2 wt% MMT/CNTs showed an increase in compressive strength, modulus of elasticity, dynamic compressive strength, and energy absorption by 61.0%, 111.6%, 73.8%, and 49.0%, respectively. This work shows that the PUE-MMT/CNTs is expected to be used as a high-performance impact-resistant material in aerospace, military defense, and other high-speed impact fields.