EP-4380913-B1 - ENERGETIC FORMULATIONS CONTAINING EPOXY-MODIFIED GRAPHENE OXIDE

Inventors

• WEINREB, ABRAHAM
• KENIG, SHMUEL
• NAVEH, Naum
• KIDRON, Menahem
• ASSCHER, MICHA

Dates

Publication Date

20260506

Application Date

20220801

Claims (13)

1. An energetic formulation, comprising graphene oxide functionalized with a molecule containing at least one epoxy group, wherein the functionalized graphene oxide is coated onto ammonium perchlorate.
2. The energetic formulation of claim 1, wherein the graphene oxide is further functionalized through oxidation with a nitro-group, an amino-group, or an oxoacid at a different location than a location of functionalization with the epoxy group.
3. The energetic formulation of claim 1, wherein the graphene oxide comprises at least one functional group containing nitrogen between a graphene sheet and the at least one epoxy group.
4. The energetic formulation of claim 1, wherein the epoxide is sourced from an epoxy silane, and the graphene oxide comprises at least one functional group containing nitrogen between a graphene sheet and the at least one epoxy group.
5. The energetic formulation of claim 1, wherein the epoxide is sourced from a hydrocarbon compound containing a plurality of epoxy groups.
6. The energetic formulation of claim 1, wherein the functionalized graphene oxide is used as a stand-alone energetic material in powder form, mixed as powder in a liquid fuel, or mixed as a powder in a solid fuel.
7. The energetic formulation of claim 6, wherein the functionalized graphene oxide is mixed in a liquid fuel or solid fuel that is metal-free.
8. A method of preparing an energetic formulation, comprising functionalizing graphene oxide with a molecule containing at least one epoxy group, and further comprising coating ammonium perchlorate with the functionalized graphene oxide.
9. The method of claim 8, comprising further functionalizing the graphene oxide through oxidation of the graphene oxide with a nitro group, an amino group, or an oxoacid, at a different location than a location of functionalization with the epoxy group.
10. The method of claim 8, wherein the functionalizing step comprises modifying an epoxy-containing molecule with at least one functional group containing nitrogen, and functionalizing a graphene sheet with the modified epoxy-containing molecule, such that the at least one functional group containing nitrogen is between the graphene sheet and the at least one epoxy group.
11. The method of claim 8, wherein the epoxide is sourced from an epoxy silane, and functionalizing step comprises functionalizing at least one functional group containing silicon between a graphene sheet and the at least one epoxy group.
12. The method of claim 8, wherein the epoxy group is sourced from a hydrocarbon compound containing a plurality of epoxy groups.
13. The method of claim 8, further comprising using the functionalized graphene oxide as a stand-alone energetic material in powder form, mixing the functionalized graphene oxide within a liquid fuel, or mixing the functionalized graphene oxide as a powder in a solid fuel.

Description

Field of the Invention The present disclosure, in some embodiments, concerns an energetic formulation containing graphene oxide that is functionalized with epoxy groups. Background of the Invention Graphene oxide is a single-layered material made of carbon, hydrogen, and oxygen molecules, produced through oxidation of graphite. The carbon sheets of graphene oxide are functionalized by oxygen-containing groups. Carboxyl groups are arranged on the edges of the sheets, and hydrophilic oxygen groups, such as hydroxyl, epoxy, and carbonyl groups, are arranged on the surface of the sheets. An exemplary molecular structure of graphene oxide is depicted in FIG. 1. Various derivatives and complexes of graphene oxide have been explored as energetic materials. Energetic materials are a class of materials with a large amount of stored chemical energy, which can be rapidly released. Graphene oxide is considered to have unique energetic properties for at least the following reasons. First graphene oxide itself is a kind of energetic material with self-sustained combustion ability, because the oxygen groups on the graphene oxide sheet can decompose and generate a large amount of heat by absorbing a small amount of heat at a relatively low temperature (approximately 200°C), which can form a positive thermal feedback effect. Second, graphene oxide can promote mass transfer (mainly oxygen transfer) in an energetic composite system, resulting in rapid and thorough thermal reactions because the decomposition of the oxygen groups of graphene oxide is a process of oxygen release, whereas the thermal reaction of most energetic materials requires or includes oxygen transfer. In addition, reduced graphene oxide, produced by the decomposition of oxygen groups, possesses high thermal conductivity, leading to high combustion propagation by promoting heat transfer. Much recent experimentation regarding energetic materials derived from graphene oxide has focused on formation of metallic or polymeric complexes between sheets of the GO. The most commonly used metal ions for coordination with functionalized graphene ligands include copper, nickel, and aluminum. However, metallic complexes are disfavored in many energetic applications. This is for two reasons. First, combustion of metals produces environmentally unfriendly emissions. Second, combustion of metals leaves a detectable signature. Functionalized graphene oxide has previously been introduced into solid or liquid fuels, for the purpose of improving the combustion characteristics of those fuels. For example, it has been observed that the presence of GO functionalized with organic molecules having nitro- and amino-groups serves as a burning rate catalyst. Similarly, it has also been observed that the presence of GO functionalized with long-chain, nitrogen-containing alkyl groups improves the burning characteristics of liquid fuel, in parameters such as energy density, thrust, and flame speed. In addition to serving as a precursor for energetic materials, graphene oxide has many other uses. GO has been used as a precursor for conductive films, surfactants, fluorescence and photoluminescence means, filtration apparatuses, and biosensors. Some such applications of GO have functionalized GO with an epoxy group, as an intermediate step. During preparation of the final product, the epoxy group is removed and replaced, or further reacted to form a covalent bond between the oxygen and a new functional group. Zhang et al., Materials Research Bulletin 50 (2014) 73-78 discloses the synthesis of nitrated graphene oxide (NGO) by nitrifying GO with nitro-sulfuric acid and investigates the catalytic effect of the NGO for the thermal decomposition of ammonium perchlorate. Summary of the Invention The present disclosure relates to a novel energetic material derived from graphene oxide. The novel energetic material does not rely on metallic complexes formed between graphene sheets, but instead is formed through functionalizing oxygen groups on each individual graphene sheet. Specifically, a molecule containing at least one epoxide group is functionalized onto graphene oxide. The epoxy-modified graphene oxide (EMGO) exhibits highly efficient energetic characteristics, as measured by exothermic enthalpy per unit mass, as well as high energy release rates, as measured by power (watts) per unit mass. The energetic material is easy to manufacture, requiring only a single condensation step, for a short time, at a relatively low temperature, and with non-toxic, non-explosive, solvents. According to a first aspect, an energetic formulation includes graphene oxide functionalized with a molecule containing at least one epoxy group, wherein the functionalized graphene oxide is coated onto ammonium perchlorate. In another implementation according to the first aspect, the graphene oxide is further functionalized through oxidation with a nitro-group, an amino-group, or an oxoacid at a different location than a loc