New strategy for the development of lightweight ballistic armors with limited backface signature

In this study, a new strategy is adopted for the development of advanced, and lightweight ballistic armor. This new generation of ballistic protections is referred to as “hybrid”, in which certain layers of Kevlar have been impregnated with a high-performance green and bisphenol-A free thermosetting resin, namely the vanillin-based benzoxazine (Va-BZ). The role of thermosetting polymer is to slow down and stop the projectile. In addition, the backface signature (BFS) with a minimum number of Kevlar layers is reduced. Indeed, this kind of matrix not only possesses one of the highest crosslinking densities in the field, but also offers excellent mechanical and thermal properties. The adopted experimental approach consists in gradually changing, in increments of 5, the number of impregnated Kevlar layers. The ultimate goal is to reduce the number of Kevlar layers from 26 (currently in use) to 20 while ensuring a BFS of less than 44 mm (as per the requirement of the National Institute of Justice standard NIJ-0101.06). Indeed, the adopted strategy allowed significant reduction in the BFS. For instance, armors made of 20 layers of Kevlar layers in which 10 layers were impregnated by the Va-BZ displayed the minimal BFS value of 36.54 mm. Hence, by introducing the Va-BZ resin, the non-perforated Kevlar fabrics gained enough rigidity to sustain the impact with minimal deformation. Overall, these newly developed armors offer the best BFS possible to protect vital human body parts.