Graphene-based nanocomposites for body armour: tensile, impact and bulletproof properties

Resumen

Graphene-based nanocomposites constitutes one of the most active research fields because it sensitively improves several properties of diverse polymers [1, 2]. In the field of the application of these nanocomposites to improve the dynamical strength to supersonic impacts, there is published only one paper related to the graphene behaviour against the penetration of spherical silica microprojectiles [3]. Looking for improvements in this field we have fabricated, following a similar procedure to that described in one of our patents [4], several laminated plates of graphene-based nanocomposites composed of a polyester resin matrix doped with pristine few-layer graphene (FLG) and reinforced with glass fiber woven fabric (FGRP), using doping percentages ranging between 0.25% and 1% w/w. The ballistic limit (V0) of such plates against the 7.62x51 mm NATO Ball ammunition, fired with an Accuracy International AW sniper rifle has been investigated in accordance with (acc.) NATO STANAG 2920 standard [5], as is shown in Fig. 1. The tensile mechanical properties (tensile strength, Young´s modulus and elongation at break) and impact properties (Charpy impact strength) of the laminates were also characterised acc. UNE-EN ISO 527-4 [6] and UNE-EN ISO 179-1 [7] standards, respectively. V0 rises with the increment of graphene doping percentage, reaching a maximum value of 266.4 m/s at 1% w/w, which means an improvement of a 72.2% in relation to the undoped FRGP laminate (Fig. 2). The graphene doped samples also showed a better tensile and impact properties. Existing bullet proof vests are ineffective against high-speed military ammunitions, as those used in our study, if they are not complemented with steel or ceramic tiles. Therefore, our results show that graphene-based nanocomposites could open a promising research area in the design of a new generation of body armour systems with better protection levels against assault and sniper rifles ammunitions, which should provide a substantial improvement in terms of ballistic performance and comfort for defence and security forces personnel.