Abstract The efficient production of pervious low density carbon fiber reinforced composite articles is made possible through the use of the present invention. A fibrous open weave tape (as described) which is capable of undergoing conversion to a carbonaceous fibrous material is continuously passed in the direction of its length through a series of heating zones to form a fibrous carbon tape (preferably of graphitic carbon) wherein an open weave construction is maintained. At least one layer of the resulting fibrous open weave carbon tape may be impregnated with a thermosetting resinous material, and subsequently cured to form a pervious composite article. The composite articles of the present invention exhibit a high specific modulus and strength, and are extremely lightweight. The lightweight composite articles may be utilized as structural elements, and are particularly suited for use as a facing sheet of an acoustic sandwich liner which serves as a noise suppression function in jet engines.
A process in accordance with claim 1 wherein said warp ends of said tape prior to passage through said series of heating zones are an acrylic fibrous material containing at least about 85 mol per cent of acrylonitrile units and up to about 15 mol per cent of one or more monovinyl units copolymerized therewith.
Claim 2
Dependent Claim
26 words
A process according to claim 1 wherein said warp ends of said tape prior to passage through said series of heating zones are an acrylonitrile homopolymer.
Claim 3
Dependent Claim
34 words
A process according to claim 1 wherein the composition of said warp ends of said tape prior to passage through said series of heating zones is substantially identical to that of said weft pick.
Claim 4
Dependent Claim
29 words
A process according to claim 1 wherein said weft pick of said tape prior to passage through said series of heating zones is a previously stabilized acrylic fibrous material.
Claim 5
Dependent Claim
18 words
A process according to claim 1 wherein said heating zones comprise a stabilization zone, and a carbonization zone.
Claim 6
Dependent Claim
33 words
A process according to claim 1 wherein said tape following passage through said heating zones contains at least about 95 per cent carbon by weight and exhibits a predominant graphitic X-ray diffraction pattern.
Claim 7
Dependent Claim
17 words
A process according to claim 1 wherein said thermosetting resinous material upon curing is an aromatic polyimide.
Claim 8
Dependent Claim
42 words
A process according to claim 1 wherein the formation of lateral interstices between said adjacent warp ends within a given layer of said tape is enhanced by the passage of a current of gas therethrough following impregnation with said thermosetting resinous material.