Synthetic barrier material and method of manufacture thereof
A synthetic barrier material includes a light-cured polymer and graphene nanoplatelets in parallel alignment in the polymer. Disclosed further is a method for manufacturing the synthetic barrier material. The graphene nanoplatelets are dispersed in a photocurable resin and polarically aligned by an electric field. Furthermore, disclosed is a synthetic barrier film manufactured from the aforementioned synthetic barrier material or the aforementioned method.
1 . A method of manufacturing a synthetic barrier material, the synthetic barrier material comprising graphene nanoplatelets, wherein the method comprises:
a) dispersing the graphene nanoplatelets in a photocurable resin, wherein the photocurable resin comprises styrenic, acrylic or vinylic monomers or oligomers thereof and a photo-initiator, and wherein the photocurable resin comprises epoxy diacrylate and glycol diacrylate; and
b) applying an electric field to polarically align the graphene nanoplatelets in the photocurable resin, wherein the graphene nanoplatelets are in parallel alignment in the photocurable resin at a predefined spacing to prevent end-to-end contact between adjacent nanoplatelets; and
c) applying a light source to cure the photocurable resin to obtain a light-cured photopolymer in which the graphene nanoplatelets have been dispersed and polarically aligned;
wherein the graphene nanoplatelet has a thickness in a range of 5-10 nanometers and a diameter in a range of 15-50 micrometers, and the synthetic barrier material has a graphene nanoplatelets content in the range of 1 to 5% by weight relative to the weight of the synthetic barrier material, wherein the graphene nanoplatelets comprise a grafted functionalized alkyl silyl group, wherein the graphene nanoplatelets are aligned within the light-cured photopolymer at a predefined spacing, such that the graphene nanoplatelets form parallel, closely packed layers structurally separated by the light-cured photopolymer, thereby forming a brick-and-mortar architecture in which the graphene nanoplatelets act as the bricks and the light-cured photopolymer acts as the mortar.
2 . The method of manufacturing a synthetic barrier material of claim 1 , wherein successive layers of synthetic barrier material are built up by repetition of steps a) to c).
3 . The method of manufacturing a synthetic barrier material of claim 2 , wherein the method further comprises pre-treating the virgin graphene nanoplatelets using a chemical treatment process, and wherein the graphene nanoplatelets comprise the grafted functionalized alkyl silyl group, and wherein the chemical treatment process comprises:
treating virgin graphene nanoplatelets with a mineral acid, in the presence of an oxidizing agent for pre-determined time period at pre-determined temperature;
filtering the treated virgin graphene nanoplatelets;
dispersing the filtered graphene nanoplatelets in water to obtain a nanoplatelet suspension;
dissolving a functionalized alkyl silane ester in water-soluble non-aqueous solvent to obtain a silane solution; and
combining the nanoplatelet suspension with the silane solution to obtain graphene nanoplatelets comprising the grafted functionalized alkyl silyl group.
4 . The method of manufacturing a synthetic barrier material of claim 3 , wherein the mineral acid is nitric acid.
5 . The method of manufacturing a synthetic barrier material of claim 3 , including an oxidizing agent wherein the oxidizing agent is potassium dichromate.
6 . The method of manufacturing a synthetic barrier material of claim 3 , wherein the mineral acid is sulphuric acid.
7 . The method of manufacturing a synthetic barrier material of claim 3 , wherein the functionalized alkyl silane ester is functionalized with a group selected from —OH or NH2.
8 . The method of manufacturing a synthetic barrier material of claim 3 , wherein the alkyl group of the functionalized alkyl silane ester comprises a C2 to C5 linear alkyl group.
9 . The method of manufacturing a synthetic barrier material of claim 3 , wherein the functionalized alkyl silane ester is 3-amino-n-propyltriethoxysilane.
10 . The method of manufacturing a synthetic barrier material of claim 1 , wherein the photo-initiator is selected from group consisting of organic peroxides, azo-dyes, cationic onium salts.
11 . The method of manufacturing a synthetic barrier material of claim 1 , wherein the method comprises generating the electric field by using a direct-current voltage, and wherein the electric field generated is in the range 100 to 1000 Volts/centimeter.
12 . The method of claim 1 , wherein the graphene nanoplatelet has a diameter in a range of 15-20 micrometers.