Reinforcing nanofiber additives

Abstract

Provided herein are high performance reinforcing nanostructure additives, high throughput processes for using such additives, and composites comprising such additives. Such nanostructure additives include nanofibers, including nanofiber fragments, of various matrix materials, including metal(s) (e.g., elemental metal(s), metal alloy(s), etc.), metal oxide(s), ceramic(s), metal carbide(s), carbon (e.g., carbon nanocomposites comprising carbon matrix with metal component embedded therein), and/or combinations thereof.

What is claimed is: 
     
         1 . A composite comprising a reinforcing additive and a matrix material, the reinforcing additive comprising a plurality of nanostructures, each of the plurality of nanostructures comprising a continuous matrix of silicon carbide, the silicon carbide constituting at least 90 wt. % of the plurality of nanostructures, on average;
 the plurality of nanostructures having an average aspect ratio of more than 20;   the plurality of nanostructures having a Young's modulus of at least 500 GPa, on average; and   the plurality of nanostructures having an ultimate strength of at least 4000 MPa, on average.   
     
     
         2 . The composite of  claim 1 , wherein the nanostructures have a diameter of less than 2000 nm, on average. 
     
     
         3 . The composite of  claim 2 , wherein the nanostructures have a diameter of 100 nm to 1000 nm, on average. 
     
     
         4 . The composite of  claim 2 , wherein the nanostructures have a diameter of less than 50 nm, on average. 
     
     
         5 . The composite of  claim 1 , wherein the nanostructures have a Young's modulus of at least 1000 GPa, on average. 
     
     
         6 . The composite of  claim 1 , wherein the nanostructures have an average Young's modulus-to-diameter ratio of at least 0.15 GPa/nm. 
     
     
         7 . The composite of  claim 5 , wherein the nanostructures have an average Young's modulus-to-diameter ratio of at least 0.2 GPa/nm. 
     
     
         8 . The composite of  claim 6 , wherein the nanostructures have an average Young's modulus-to-diameter ratio of at least 0.5 GPa/nm. 
     
     
         9 . The composite of  claim 1 , wherein the nanostructures have a fracture toughness of at least 3 MPa·m 1 /z, on average. 
     
     
         10 . The composite of  claim 1 , wherein the nanostructures have a fracture toughness-to-diameter ratio of at least 0.002 MPa·m 1/2 /nm. 
     
     
         11 . The composite of  claim 10 , wherein the nanostructures have a fracture toughness-to-diameter ratio of at least 0.005 MPa·m 1/2 /nm. 
     
     
         12 . The composite of  claim 1 , wherein the plurality of nanostructures are low-defect nanostructures, the low-defect nanostructures comprising at most 50 defects per linear mm of the nanostructure. 
     
     
         13 . The composite of  claim 12 , wherein the defects include anomalous morphologies, voids, and/or narrowing of the nanostructure to less than 10% of the average nanostructure diameter. 
     
     
         14 . The composite of  claim 1 , wherein the nanostructures have a ultimate strength of at least 8000 MPa. 
     
     
         15 . The composite of  claim 1 , wherein the continuous matrix material is crystalline. 
     
     
         16 . The composite of  claim 1 , wherein the matrix material is a polymer, a metal, or a ceramic. 
     
     
         17 . The composite of  claim 16 , wherein the matrix material is a polymer and the polymer is a thermoplastic or a thermoset. 
     
     
         18 . A silicon carbide reinforcing nanostructure, the nanostructure comprising a continuous matrix of silicon carbide, the silicon carbide constituting at least 95 wt. % of the nanostructure;
 the nanostructure having a diameter of less than 2000 nm;   the nanostructure having an aspect ratio of more than 20;   the nanostructure having a Young's modulus of at least 1,000 GPa;   the nanostructure having an ultimate strength of at least 8000 MPa;   the nanostructure having a fracture toughness of at least 3 MPa·m 1/2 ; and   the nanostructure having a length of at least 500 μm.   
     
     
         19 . The reinforcing additive of  claim 18 , wherein the nanostructure has an electrical conductivity of at least 1 log(S/m). 
     
     
         20 . The reinforcing additive of  claim 18 , wherein the nanostructure has a length of at least 10,000 μm.