Fiber-based ablative and high temperature pre-preg material

Abstract

A fabric-matrix composite structure [ 10] for making parts [ 13] suitable for use in hostile, high-temperature environments, such as rocket exhaust nozzles. The structure [ 10] includes a fabric [ 11] formed of polyacrylonitrile fiber, especially a polyacrylonitrile fiber that has been oxidized, and especially a combination of polyacrylonitrile fibers that have been oxidized to different degrees. The structure [ 10] also includes a binder [ 12] that impregnates the fabric [ 11]. The binder [ 12] might be a phenolic resin. The structure is formed [ 30], partially cured [ 40], formed into a product [ 50], and finish cured [ 60].

What I claim as my invention is: 
     
         1 . A structure involving a pre-preg formulation that is thermosetting in nature and is cured/molded into rocket/missile components, high temperature components and carbon/carbon preform components at temperatures between 250 F and 425 F. 
     
     
         2 . A structure as recited in  claim 1 , wherein the pre-preg formulation includes a fibrous material that is woven, non-woven or aligned unidirectional fibers, pre-impregnated with a thermosetting phenolic matrix resin. 
     
     
         3 . A structure as recited in  claim 1 , wherein the pre-preg formulation includes discontinuous fibers. 
     
     
         4 . A structure as recited in  claim 3 , wherein the fibrous material or discontinuous fibers consist of fibers of two different fiber materials. 
     
     
         5 . A structure as recited in  claim 4 , wherein the two fiber materials consist of carbon fiber based on polyacrylonitrile (PAN) at a carbon content of 95+/−3% and polyacrylonitrile (PAN) based pre-ox carbon fiber at a carbon content of 60+/−5%. 
     
     
         6 . A structure as recited in  claim 5 , wherein the fibrous materials or fibers are blended into a yarn at a ratio such that the carbon content of the yarn is 82+/−10%. 
     
     
         7 . A structure as recited in  claim 6 , wherein the yarn is manufactured into a substrate that is impregnated with a phenolic resin. 
     
     
         8 . A structure as recited in  claim 7 , wherein the substrate can be woven, non-woven or aligned unidirectional fibers. 
     
     
         9 . A structure as recited in  claim 7 , wherein the phenolic resin contains particulate fillers, short fibers, plate shaped fillers and/or nanometer-sized fillers. 
     
     
         10 . A structure as recited in  claim 1 , wherein the pre-preg can be used as broad goods, molding compound, straight tapes or biased tapes. 
     
     
         11 . A structure as recited in  claim 1 , wherein the pre-preg can be processed into parts via the use of compression molding, vacuum bag molding in oven, vacuum bag molding in autoclave or vacuum bag molding in hydroclave. 
     
     
         12 . A structure as recited in  claim 1 , wherein the pre-preg, after processing into parts via the use of compression molding, vacuum bag molding in oven, vacuum bag molding in autoclave or vacuum bag molding in hydroclave, can be converted from a phenolic impregnated fabric molded structure to a carbon impregnated fabric molded structure (also known as carbon/carbon), via exposure to a minimum of 1200 F in a nitrogen atmosphere. 
     
     
         13 . A structure as recited in  claim 7 , wherein the phenolic resin system is capable of being formulated with appropriate solvents for impregnation into fibrous woven fabrics, fibrous nonwoven fabrics or aligned unidirectional fibers. 
     
     
         14 . A structure as recited in  claim 1 , wherein the pre-preg can be molded to the required thickness for the application as described in  claim 1  and then processed into parts via the use of compression molding, vacuum bag molding in oven, vacuum bag molding in autoclave or vacuum bag molding in hydroclave. 
     
     
         15 . A structure as recited in  claim 14 , wherein multiple layers of the pre-preg can be used to achieve the required thickness. 
     
     
         16 . A method of forming a product for use in ablative conditions, comprising the steps of:
 a.) forming a composite structure comprised of a polyacrylonitrile or polyacrylonitrile-derivative fabric impregnated with a phenolic polymer,   b.) partially polymerizing the polymer,   c.) forming the structure into the form of the product, and   d.) fully polymerizing the polymer.   
     
     
         17 . A method of using a product in ablative conditions, comprising the steps of:
 a.) forming a composite structure comprised of a polyacrylonitrile or polyacrylonitrile-derivative fabric impregnated with a phenolic polymer,   b.) partially polymerizing the polymer,   c.) forming the structure into the form of the product,   d.) fully polymerizing the polymer, and   e.) exposing the product to ablative conditions.