Double diaphragm shaping of composite materials, assemblies for such shaping, and resulting composite materials
Disclosed herein are methods for isolating a composite material from the environment, as well as the isolated composite material. Also disclosed herein are methods for shaping a composite material that include the use of isolated composite materials. For example, disclosed is a method for mechanical thermoforming of a composite material to form a shaped composite material.
1. A method for shaping a composite material, the method comprising:
(a) surrounding a substantially planar composite material with a gas-impermeable, flexible, frameless diaphragm structure;
(b) creating a sealed pocket in the diaphragm structure, which houses the composite material alone, by removing air from between the composite material and the diaphragm structure and sealing all open edges of the diaphragm structure, thereby forming a layered structure, such that:
air and contaminants are impeded from entering the sealed pocket without use of a frame, and the composite material is held stationary within the sealed pocket until heat, force, or a combination thereof, is applied thereto;
(c) optionally disposing the diaphragm structure within a structural frame; and
(d) shaping the composite material within the sealed pocket of the diaphragm structure.
2. The method of claim 1 , wherein creating a sealed pocket comprises sealing the open edges of a diaphragm bag or folded diaphragm sheet disposed about the composite material.
3. The method of claim 1 , wherein creating a sealed pocket comprises sealing two diaphragm sheets around the entire periphery of the composite material.
4. The method of claim 1 , wherein sealing all open edges of the diaphragm structure comprises mechanical sealing, application of adhesive, heat sealing, welding or any combination thereof.
5. The method of claim 1 , wherein removing air comprises applying vacuum pressure between the composite material and the flexible diaphragm structure.
6. The method of claim 1 , wherein the diaphragm structure comprises a film comprising one or more layers, each independently selected from a plastic layer or an elastic layer.
7. The method of claim 6 , wherein the film is disposable.
8. The method of claim 6 , wherein the film is reusable.
9. The method of claim 1 , wherein sealing the diaphragm structure provides a seal strength sufficient to inhibit intake of contaminants for a period of time from 1 month to 6 months under ambient conditions.
10. The method of claim 1 , wherein sealing the diaphragm structure provides a seal strength sufficient to inhibit intake of contaminants during the shaping in step (c).
11. The method of claim 1 , wherein sealing the diaphragm structure provides a seal strength sufficient to inhibit intake of contaminants during shipping and handling of the composite material.
12. The method of claim 1 , wherein sealing the diaphragm structure provides a seal strength sufficient to inhibit intake of contaminants during storage of the composite material, wherein storage occurs for up to about 6 months.
13. The method of claim 1 , wherein the sealed pocket maintains vacuum integrity for a period of at least about 1 month under ambient conditions.
14. The method of claim 1 , further comprising machining the composite material according to a pattern prior to step (a).
15. The method of claim 1 , wherein the layered structure is manipulated by automated means.
16. The method of claim 1 , wherein the composite material comprises structural fibers of a material selected from aramid, high-modulus polyethylene (PE), polyester, poly-p-phenylene-benzobisoxazole (PBO), carbon, glass, quartz, alumina, zirconia, silicon carbide, basalt, natural fibers and combinations thereof.
17. The method of claim 1 , wherein the composite material comprises a binder or matrix material selected from thermoplastic polymers, thermoset resins, and combinations thereof.