Sustainable innovation in ballistic vest design: Exploration of polyurethane-coated hemp fabrics and reinforced sandwich epoxy composites against 9 mm and .40 S&W bullets

This research aimed to evaluate the bulletproof capabilities of hemp fabrics and optimize the design factors for effective ballistic vests. Three main aspects were investigated: enhancing toughness with polyurethane-coated hemp fabrics, determining optimal placement of fabric-reinforced hemp epoxy composites in various configurations, and identifying the optimal number of fabric layers for performance against 9 mm and .40 S&W bullets. Penetration depth was measured in ballistic gelatin to analyze the results. The study showed strong statistical correlations between factor variables and penetration depth shifts. The most effective strategies included polyurethane-coated hemp on all layers and increased layering. The ammunition of 9 mm bullets exhibited the least penetration depth when tested against the sandwich-reinforced configuration. In contrast, the larger .40 S&W bullets demonstrated that the frontal arrangement yielded the minimum penetration depth. Notably, 9 mm bullets penetrated 1.25 times deeper than .40 S&W bullets. These findings emphasize hemp fabric's potential for reliable ballistic vests. Utilizing polyurethane-coated hemp fabric in epoxy composites within a sandwich reinforcement of at least 212 layers is recommended to stop 9 mm bullets effectively. The research contributes valuable insights to sustainable ballistic vest development, utilizing natural materials with exceptional bullet protection capabilities.