Continuous composite coextrusion methods, apparatuses, and compositions

Abstract

A process for continuous composite coextrusion comprising: (a) forming first a material-laden composition comprising a thermoplastic polymer and at least about 40 volume % of a ceramic or metallic particulate in a manner such that the composition has a substantially cylindrical geometry and thus can be used as a substantially cylindrical feed rod; (b) forming a hole down the symmetrical axis of the feed rod; (c) inserting the start of a continuous spool of ceramic fiber, metal fiber or carbon fiber through the hole in the feed rod; (d) extruding the feed rod and spool simultaneously to form a continuous filament consisting of a green matrix material completely surrounding a dense fiber reinforcement and said filament having an average diameter that is less than the average diameter of the feed rod; and (e) arranging the continuous filament into a desired architecture to provide a green fiber reinforced composite.

We claim:  
     
         1 . A green reinforced fiber reinforced composite comprising a reinforcement material selected from the group consisting of carbon fiber, carbon fiber tow, ceramic fiber or metal fiber, the reinforcement completely surrounded by a proximal matrix of material selected from the group consisting of graphite or boron, the proximal matrix surrounded by a distal matrix of material selected from the group consisting of hafnium carbide, hafnium diboride, zirconium carbide, silicon carbide, or silicon nitride.  
     
     
         2 . A green fiber reinforced composite comprising an outer layer matrix having a longitudinal axis and comprising a first material-laden polymer composition comprising a thermoplastic polymer and at least about 40 volume % of a ceramic or metallic particulate material, an intermediate layer having a longitudinal axis and comprising a second material-laden polymer composition that is different from the first material-laden polymer composition, and a core having a longitudinal axis comprising fiber reinforcement, the fiber reinforcement completely surrounded by the intermediate layer and the intermediate layer completely surrounded by the outer layer matrix.  
     
     
         3 . The green fiber reinforced composite of  claim 2  wherein the first material-laden polymer composition includes a material selected from the group consisting of hafnium carbide, hafnium diboride, zirconium carbide, silicon carbide, or silicon nitride.  
     
     
         4 . The green fiber reinforced composite of  claim 2  wherein the second material-laden polymer composition includes a material selected from the group consisting of graphite or boron nitride.  
     
     
         5 . A product formed from the method comprising the steps of: 
 (a) forming a feed rod having a longitudinal axis and comprising a material-laden polymer composition comprising a thermoplastic polymer and at least about 40 volume % of a ceramic or metallic particulate material;    (b) forming a hole down the longitudinal axis of the feed rod;    (c) inserting the start of a continuous spool of ceramic fiber, metal fiber, or carbon fiber through the hole in the feed rod;    (d) extruding the feed rod and the spool simultaneously to form a continuous filament consisting of the material-laden polymer composition completely surrounding the fiber and said filament having an average diameter that is less than the average diameter of the feed rod; and    (e) firing the filament to remove the thermoplastic polymer from the filament.    
     
     
         6 . A fiber reinforced composite comprising an outer layer matrix having a longitudinal axis and comprising a ceramic or metallic particulate material, an intermediate layer having a longitudinal axis and comprising a second material-laden polymer composition that is different from the ceramic or metallic particulate material of the outer layer matrix, and a core having a longitudinal axis comprising fiber reinforcement, the fiber reinforcement completely surrounded by the intermediate layer and the intermediate layer completely surrounded by the outer layer matrix.  
     
     
         7 . The fiber reinforced composite of  claim 6  wherein the ceramic or metallic particulate material includes a material selected from the group consisting of hafnium carbide, hafnium diboride, zirconium carbide, silicon carbide, or silicon nitride.  
     
     
         8 . The reinforced composite of  claim 6  wherein the intermediate layer includes a material selected from the group consisting of graphite or boron nitride.  
     
     
         9 . A method for continuous composite coextrusion comprising: 
 (a) forming a feed rod having a longitudinal axis and comprising a material-laden polymer composition comprising a thermoplastic polymer and at least about 40 volume % of a ceramic or metallic particulate material;    (b) forming a hole down the longitudinal axis of the feed rod;    (c) inserting the start of a continuous spool of ceramic fiber, metal fiber, or carbon fiber through the hole in the feed rod; and    (d) extruding the feed rod and the spool simultaneously to form a continuous filament consisting of the material-laden polymer composition completely surrounding the fiber and said filament having an average diameter that is less than the average diameter of the feed rod, the filament comprising a fiber reinforced matrix composite;    (e) firing the filament to remove the thermoplastic polymer from the filament; and    (f) consolidating the fiber reinforced matrix composite.    
     
     
         10 . A product formed from the method of  claim 9 .  
     
     
         11 . A method for continuous composite coextrusion comprising: 
 (a) forming a matrix feed rod having a longitudinal axis and comprising a first material-laden polymer composition comprising a thermoplastic polymer and at least about 40 volume % of a ceramic or metallic particulate material;    (b) forming a hole down the longitudinal axis of the matrix feed rod;    (c) inserting an interface feed rod having a longitudinal axis through the hole in the matrix feed rod, the interface feed rod comprising a second material-laden polymer composition that is different from the first material-laden polymer composition;    (d) forming a hole down the longitudinal axis of the interface feed rod;    (e) inserting the start of a continuous spool of ceramic fiber, metal fiber or carbon fiber through the hole in the interface feed rod;    (f) extruding the matrix feed rod, interface feed rod and the spool simultaneously to form a continuous filament consisting of the first material-laden polymer composition completely surrounding the second material-laden polymer composition, and the second material-laden composition completely surrounding the fiber, said filament having an average diameter that is less than the average diameter of the matrix feed rod, the filament comprising a fiber reinforced matrix composite;    g. firing the filament to remove the thermoplastic polymer from the filament, the filament comprising a fiber reinforced matrix composite; and    h. consolidating the fiber reinforced matrix composite.    
     
     
         12 . A product formed from the method of claim  11 .