Thermally conductive boron nitride films and multilayered composites containing them
Composite multilayered material compositions are provided which contain one or more hexagonal boron nitride (hBN)-containing layers, together with layers comprising optional polymeric binders, glass fibers, magneto-ceramic materials, and a super-hydrophobic outer coating. Methods are provided for making the composite materials and products containing them. The composite materials are useful for making radomes and other coverings for electronic components and equipment.
1 . A layered composite material comprising:
i) a hexagonal boron nitride thermally conducting layer disposed at a first surface of the composite material;
ii) an optional core layer;
ii) a fiber reinforced layer; and
iv) a superhydrophobic surface layer disposed at a second surface of the composite material, opposite the first surface;
wherein the superhydrophobic layer is formed from a fiber fabric comprising a woven fiber layer and a layer of z-aligned milled fibers extending across the woven fiber layer,
the layer of z-aligned milled fibers comprising a densely-packed, continuous array of z-aligned, milled carbon fibers that are situated substantially parallel to each other and substantially perpendicular to the woven fiber layer;
wherein the fiber fabric is impregnated with an adhesive such that the z-aligned milled fibers are partially embedded in the adhesive;
and wherein the z-aligned milled fibers are coated with polytetrafluoroethylene and exposed at the second surface.
2 . The layered composite material of claim 1 , comprising said core layer, wherein the core layer comprises air, a foam, a honeycomb, a ferrite material, a magneto-ceramic material, a metal, a polymeric material, a fibrous material, or a combination thereof.
3 . The layered composite material of claim 2 , wherein the core layer comprises polystyrene, polyethylene, PVC foam, polyurethane foam, polycarbonate honeycomb, honeycomb paper, synthetic fiber, wood, carbon fiber, or a combination thereof.
4 . The layered composite material of claim 1 , wherein the fiber reinforced layer comprises a synthetic fiber, glass fiber, quartz fiber, carbon fiber, or a combination thereof.
5 . The layered composite material of claim 1 , wherein the boron nitride layer comprises or consists of one or more layers of hexagonal boron nitride platelets.
6 . The layered composite material of claim 1 , wherein the fiber reinforced layer comprises one or more woven glass fiber fabrics embedded in a binder.
7 . The layered composite material of claim 6 , wherein the binder is an epoxy.
8 . The layered composite material of claim 1 , comprising a hexaferrite core and fiberglass layers bound to opposite surfaces of the hexaferrite core, wherein the hexagonal boron nitride layer is bound to one of said fiberglass layers.
9 . The layered composite material of claim 1 , wherein the material is configured as a radome, a radio frequency filter, a covering for an electronic component or device, or a portion thereof.
10 . A product comprising the layered composite material of claim 1 .
11 . The product of claim 10 , wherein the product is selected from the group consisting of a radome, a nosecone, a circuit board shield, a heat shield for an electronic device, a battery package, an aerodynamic heat shield, a satellite heat shield, a cellular network antenna heat shield, an engine heat shield, an exhaust heat shield, a band-pass filter, a CPU or GPU heatsink, a building material, and a thermal soak heat shield.
12 . The layered composite material of claim 1 , wherein the adhesive comprises an epoxy resin, a cyanate resin, a polyester resin, a polyimide resin, an organic silicone resin, a polytetrafluoroethylene resin, a cyanoacrylate, a bimaleimide resin, a polyether ether ketone resin, a phenolic resin, a polyethylene resin, or any combination thereof.