Graphene-based composite flame retardants

1. A method of improving fire retardant properties of a substrate, the method comprising coating the substrate with a graphene-based composite comprising graphene-based material intercalated with inorganic metal hydrate, wherein the inorganic metal hydrate comprises hydrated sodium metaborate.

2. The method according to claim 1 , wherein the coating includes surface impregnation with a liquid composition of the graphene-based composite.

3. The method according to claim 1 , wherein the substrate is provided with the graphene-based composite by (i) coating the substrate with a liquid composition comprising the graphene-based material and the inorganic metal hydrate, and (ii) removing liquid from the coated composition so as to retain the graphene-based material and the inorganic metal hydrate in the coated composition and form the graphene-based composite.

4. The method according to claim 1 , wherein the substrate is a thermoplastic polymer and the method further includes incorporating therein the graphene-based composite by melt processing the polymer with the graphene-based composite.

5. The method according to claim 1 , wherein the substrate is a thermoset polymer and the method further includes blending the graphene-based composite with precursor materials used to make the thermoset polymer.

6. The method according to claim 1 , wherein the graphene-based composite comprises one or both of reduced graphene oxide and graphene.

7. The method according to claim 1 , wherein the inorganic metal hydrate further comprises hydrated: metal oxides, metal hydroxides, metal oxide hydroxides, metal borates, or and combinations thereof.

8. The method according to claim 1 , further including impregnating the substrate with inorganic metal hydrate that does not form part of the graphene-based composite.

9. The method according to claim 1 , wherein the substrate comprises cellulosic material, polymeric material or combinations thereof.

10. A substrate with improved fire retardant properties, the substrate having a surface coated with a graphene-based composite comprising graphene-based material intercalated with inorganic metal hydrate, wherein the inorganic metal hydrate comprises hydrated sodium metaborate.

11. The substrate according to claim 10 , further including the graphene-based composite distributed by impregnation throughout the substrate matrix material of the substrate.

12. The substrate according to claim 10 , wherein the graphene-based composite comprises one or both of reduced graphene oxide and graphene.

13. The substrate according to claim 10 , wherein the inorganic metal hydrate further comprises hydrated: metal oxides, metal hydroxides, metal oxide hydroxides, metal borates, or combinations thereof.

14. The substrate according to claim 10 , wherein the substrate is impregnated with inorganic metal hydrate that does not form part of the graphene-based composite.

15. The substrate according to claim 10 , wherein the substrate comprises cellulosic material, polymeric material or combinations thereof.

16. A graphene-based composite to improve fire retardant properties of a substrate, wherein the graphene-based composite comprises graphene-based material intercalated with inorganic metal hydrate between layers of the graphene-based material, wherein the inorganic metal hydrate comprises hydrated sodium metaborate.

17. The graphene-based composite of claim 16 , provided as a liquid coating or impregnate.

18. The graphene-based composite of claim 16 , the graphene-based composite comprising reduced graphene oxide and hydrated sodium metaborate.

19. The graphene-based composite of claim 16 , including a further amount of said metal hydrate not intercalated with the graphene-based material.

20. The method of claim 1 , wherein the substrate is coated by soaking the substrate in the graphene-based composite.

21. The substrate of claim 10 , wherein the coating is a soak or dip coating.