BR-102024018275-A2 - Nanocomposite based on epoxy resin reinforced with natural fibers and functionalized with graphene nanoplates (NPG), production process and its use in multilayer ballistic armor.

Abstract

The present invention applies to the field of ballistics and armor materials and describes a nanocomposite material formed by a resin matrix functionalized with graphene nanoplatelets (NPG) and reinforced with continuous and aligned natural fibers. The material is applied to the field of ballistic armor.

Inventors

• SERGIO NEVES MONTEIRO
• ARTUR CAMPOSO PEREIRA
• LUCIO FABIO CASSIANO NASCIMENTO
• ULISSES OLIVEIRA COSTA
• MATHEUS PEREIRA RIBEIRO
• FABIO DA COSTA GARCIA FILHO
• MICHELLE SOUZA OLIVEIRA

Assignees

• INSTITUTO MILITAR DE ENGENHARIA

Dates

Publication Date

20260317

Application Date

20240905

Claims (10)

1. 1. Nanocomposite CHARACTERIZED by comprising epoxy resin with graphene nanoplatelets (NPG), together with a hardener and natural fibers.
2. 2. Nanocomposite, according to claim 1, CHARACTERIZED by comprising up to 30% of natural fiber functionalized with up to 2% of NPG in an epoxy matrix.
3. 3. Nanocomposite, according to claim 1 or 2, CHARACTERIZED in that the graphene nanoplatelet (NPG) comprises nanometer thickness less than 100 nm.
4. 4. Nanocomposite, according to claim 1, CHARACTERIZED in that the hardener comprises triethylene tetramine TETA.
5. 5. Nanocomposite, according to claim 1 or 2, CHARACTERIZED in that natural fibers are structured in such a way that they are continuous and aligned and are selected from at least one of the group comprising: piaçava, jute, fique, carnauba and hemp.
6. 6. Process for obtaining a nanocomposite comprising an epoxy resin functionalized with graphene nanoplatelets (NPG) and reinforced with natural fibers CHARACTERIZED by comprising the steps of: (a) Functionalizing the natural fibers with NPG; (b) Aligning the functionalized natural fibers together with liquid epoxy in a mold with ballistic shield dimensions; (c) Curing.
7. 7. Process according to claim 6, CHARACTERIZED in that in step (a), the natural fibers are functionalized with up to 2 wt% of NPG, wherein liquid phase exfoliation occurs; and wherein the NPG concentrations are selected from 0.1%; 0.3%; 0.5% and 0.7 wt% and are dispersed in acetone by a homogenizer at a frequency of 20 kHz for 10 min.
8. 8. Process according to claim 6, CHARACTERIZED in that in step (b), the mixture is added to the epoxy resin, sonicated for a further 10 min and mixed with a mechanical stirrer for 30 min.
9. 9. Process according to claim 6, CHARACTERIZED in that step (c), the mixture is heated to 70 °C in a vacuum oven for 24 hours to remove acetone from the epoxy mixture and after the removal of the acetone, the curing agent is added to the mixture according to the recommendations of the epoxy resin manufacturer, and the mixture is mechanically stirred for 5 min.
10. 10. Use of a nanocomposite CHARACTERIZED as being in multilayer ballistic shielding, arranged between a front layer of Al2O3/Nb2O5 and a layer of aluminum plate.

Description

FIELD OF APPLICATION [0001] The present invention applies to the field of ballistics and armor materials. The present invention describes a nanocomposite material formed by a resin matrix functionalized with graphene nanoplatelets (NPG) and reinforced with continuous and aligned natural fibers. FUNDAMENTALS OF THE INVENTION [0002] Multilayer ballistic armor consists of multiple layers of materials with specific properties. The layers play a crucial role in absorbing and dissipating the energy from a projectile impact. These layers can include materials such as aramid fibers, ceramics, metal alloys, and special polymers. For example, armed forces worldwide use aramid fiber fabrics commercially known as Kevlar®. The combination of these materials allows multilayer ballistic armor to offer efficient protection against high-powered gunfire, distributing and dissipating the impact energy across the different layers, thus reducing the risk of penetration of the human body. [0003] Currently, body armor is made with expensive synthetic fabrics and materials, especially aramid fibers. Such armor is used in personal vests and vehicles. However, the development and implementation of multi-layered ballistic armor also presents significant challenges. One of the main problems is finding a balance between the strength of the layers and the final weight. Adding multiple layers of materials can significantly increase the weight of the armor, making it less practical and limiting the user's mobility. Furthermore, obtaining materials that are efficient, durable, and low-cost is another obstacle to overcome. [0004] In order to solve the problems described above, the present invention describes a nanocomposite material formed by an epoxy resin matrix functionalized with graphene nanoplatelets (NPG) and reinforced with continuous and aligned natural fibers. The characteristics of this material, technically known as a nanocomposite, are such that they make it so resistant for use in multilayer ballistic armor aimed at protection against rifle fire with high-impact ammunition. Thus, it allows the replacement of much more expensive synthetic materials currently used in armed forces worldwide, such as aramid fiber fabrics commercially known as Kevlar®. STATE OF THE ART [0005] The scientific article “Dynamic and Ballistic Performance of Graphene Oxide Functionalized Curaua Fiber-Reinforced Epoxy Nanocomposites”, DOI: https://doi.org/10.3390/polym14091859, reveals the use of a composite material with an epoxy matrix with natural curaua fibers, functionalized with graphene oxide in a multilayer shielding system (SBMs), highlighting a composite material formed by an epoxy resin using natural fibers and graphene oxide. [0006] However, to carry out the present invention, a high level of knowledge of each type of natural fiber, its origins and processing is necessary. Before manufacturing the composite, both the fibers and/or fabrics must be studied and differentiated. The use of different natural fibers is justified because each fiber is physically and chemically different from the others. Their lignin and cellulose constituents and their microfibrillar angle are examples that each fiber has different values, and this results in different properties. Therefore, when seeking to present an innovation with the respective fiber, it is ensured that the final product is different from others. [0007] The scientific article “Piassava Fiber as an Epoxy Matrix Composite Reinforcement for Ballistic Armor Applications”, DOI: https://doi.org/10.1007/s11837-018-3148-x, describes the ballistic performance of epoxy matrix composites reinforced with piassava fiber being evaluated as an intermediate layer in SBMs. The composites were produced by varying the volumetric fractions of piassava fibers, in the range of 10-50% vol., embedded in DGEBA/TETA as an epoxy matrix. These composites were used as a second layer in an SBM composed of a front Al2O3 ceramic plate and an aluminum alloy plate as a third layer. Ballistic tests were performed with 7.62 mm high-velocity ammunition. The evaluation of the system's ballistic performance was measured by the depth of penetration caused in a clay sample, which simulates the consistency of the human body. The fractured materials were analyzed after ballistic testing by scanning electron microscopy. The ballistic results showed that the SBMs using piassava fiber composites as a second layer are within the standard penetration depth limit to be considered efficient protection. This indicates that piassava fiber, an environmentally friendly material, is promising for use in composites for ballistic armor applications. [0008] The manufacture of composites, whether reinforced with natural or synthetic fibers, seeks maximum performance with the most suitable reinforcement/matrix interfacial adhesion possible. A negative example would be the pullout effect, which is the tearing of the fiber from the matrix. To overcome this p