Ballistic properties of curaua-aramid laminated hybrid composites for military helmet

The present research aimed to develop laminated hybrid-composite with aramid woven fabric and curaua non-woven mat, to evaluate the possibility of using as military ballistic helmets. It explores the potential of hybrid solutions, which are more socio-environmentally sustainable and cheaper. All hybrid composites were produced in non -alternate layers model. In addition to hybrid configurations, epoxy laminated composites reinforced with only aramid woven fabric or only curaua non-woven mat were also investigated, with 73 and 58 vol.% of reinforcement, respectively. The cold compression molding process was used for all composites. The ballistic characterization was performed through protection level determination and residual velocity tests to estimate the ballistic limit and absorbed energy, with their corresponding reduction maps. As results, com-posites with 15 layers of aramid (52 vol.%) and one layer of curaua (15 vol.%) obtained the maximum level of ballistic protection. For composites with two layers of curaua the bal-listic limit estimate was 292 m/s, which is similar to 15% lower than the limit of the 9 mm projectile velocity corresponding to the maximum level (level II), compared to the composite commonly used in ballistic helmets. Curaua non-woven mat structure and its positioning behind the aramid woven fabric, as well as the lower total number of layers, reduced the ballistic resistance capacity of the hybrid composites. Although the proposed configura-tions with curaua non-woven mat did not meet the ballistic level requirement of the Brazilian COBRA helmet, these mentioned results are a strong indication of the enormous potential of hybrid composite for military helmet applications.