Dynamic strengthening of UHMWPE yarns by incorporating ZrO2/PU coatings

Wrapping is an effective technique for reducing defects in fabric weaving and promoting even wetting in composite manufacturing, which is potential to enhance the impact resistance of armor materials. In this study, we impregnated UHMWPE yarns with a polyurethane (PU) compound and cured them to create composite yarns, and ZrO2 was introduced to improve the toughness. The microstructures were analyzed using three-dimensional X-ray computed tomography, optical microscopy, and scanning electron microscopy (SEM). Quasi-static and dynamic tensile experiments were conducted using a universal testing machine and Kolsky tension bar, respectively. High-speed imaging was used to capture the real-time failure process, and post-fracture analysis was performed to examine the fracture morphology. The effects of strain rate, gauge length, and the presence of PU and ZrO2 on the mechanical behavior of the yarns were investigated. The results showed that the peak force of the composite yarns with PU coatings exhibited strain-rate dependency at low strain rates (below 4.4 × 10−2 s−1) but became insensitive to strain rate in the higher range of 4.4 × 10−2 s−1 to 1500 s−1. Furthermore, the introduction of ZrO2 effectively increased the peak force, potentially by strengthening the bonding between individual fibers within the yarn.