Ballistic performance of boron carbide nanoparticles reinforced ultra-high molecular weight polyethylene (UHMWPE)

Abstract

Ultra-high molecular weight polyethylene (UHMWPE) is well known for its remarkable mechanical properties including excellent ballistic performance. These properties might be further improved by reinforcement fillers, especially nanoparticles (NPs). In the present work, UHMWPE is incorporated with 0.01, 0.05 and 0.1 wt% of boron carbide (B4C) NPs by twin-screw extrusion at 200 °C. These nanocomposites are characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) and then, for the first time, ballistic tested with 0.22 caliber ammunition. HRTEM images reveal B4C NPs with sizes in the range of 10–55 nm. SEM disclosed uniform incorporation of 0.01 and 0.05 wt% B4C NPs. The nanocomposites crystallinity index, obtained by XRD, remained practically constant (44–49%) but significantly lower than the neat UHMWPE (66%). A slight decrease in the nanocomposite's thermal stability was shown by TGA, while no significant changes were found by DSC as compared to the neat UHMWPE. The DMA properties of all nanocomposites were improved. In particular, the storage modulus of the 0.05 wt% B4C nanocomposite increased by 89% compared to neat UHMWPE. The ballistic result of the 0.05 wt% B4C nanocomposite showed the lowest bullet penetration depth and confirmed its advantage for personal armor application.

Keywords

• Ultra-high molecular weight polyethylene (UHMWPE)
• Boron carbide (B4C)
• Nanocomposites
• Twin-screw extruder
• Ballistic armor