Functionally graded polymer articles and methods of making same

Abstract

Disclosed herein are methods for manufacturing a functionally graded polymer material. A method comprises preparing a melted polymer mixture comprising a thermoplastic polymer and a magnetic filler; molding the melted polymer mixture; and applying a magnetic field to a portion of the melted polymer mixture to form the functionally graded article, wherein as the melted polymer mixture flows into the mold, the melted polymer mixture comes into contact with the magnet field. Another method comprises molding the melted polymer mixture; and applying a magnetic field from a first magnet to a first portion of the melted polymer mixture and applying a magnetic field from a second magnet to a second portion of the melted polymer mixture to form the functionally graded article, wherein the first magnet and the second magnet are positioned in a manner such that the magnetic field produced by each are nonoverlapping.

I/We claim: 
     
         1 . A method of manufacturing a functionally graded article, comprising:
 preparing a melted polymer mixture comprising a thermoplastic polymer and a magnetic filler, wherein the magnetic filler is dispersed in the thermoplastic polymer;   molding the melted polymer mixture; and   applying a magnetic field to a portion of the melted polymer mixture to form the functionally graded article, wherein as the melted polymer mixture flows into the mold, the melted polymer mixture comes into contact with the magnet field.   
     
     
         2 . The method of  claim 1 , wherein the magnet is an electromagnet. 
     
     
         3 . The method of  claim 1 , wherein the functionally graded article has a magnetic filler gradient and wherein the filler gradient is formed through a portion of a thickness of the functionally graded article, wherein the portion of the thickness is less than the entire thickness of the functionally graded article. 
     
     
         4 . The method of  claim 1 , wherein the magnetic filler is modified by coating, chemical modification, or a combination comprising at least one of the foregoing. 
     
     
         5 . The method of  claim 1 , wherein the magnetic field is applied from a magnet incorporated into the mold. 
     
     
         6 . The method of  claim 1 , wherein the magnetic filler comprises magnetic particles, magnetic fibers, iron, nickel, cobalt, ferrites, rare earth magnets, or a combination comprising at least one of the foregoing. 
     
     
         7 . The method of  claim 6 , wherein the magnetic fibers are metal fibers, metal-coated fibers or a combination of metal fibers and metal-coated fibers. 
     
     
         8 . The method of  claim 1 , further comprising maintaining the melted polymer in a melted state until the functionally graded article has attained a desired functional gradation. 
     
     
         9 . A method of manufacturing a functionally graded article, comprising:
 preparing a melted polymer mixture comprising a thermoplastic polymer and a magnetic filler, wherein the magnetic filler is dispersed in the thermoplastic polymer;   molding the melted polymer mixture; and   applying a magnetic field from a first magnet to a first portion of the melted polymer mixture and applying a magnetic field from a second magnet to a second portion of the melted polymer mixture to form the functionally graded article;   wherein the first magnet and the second magnet are positioned in a manner such that the magnetic field produced by each are nonoverlapping.   
     
     
         10 . The method of  claim 9 , wherein the first and second magnets are electromagnets. 
     
     
         11 . The method of  claim 9 , wherein the functionally graded article has a magnetic filler gradient and wherein the filler gradient is formed through a portion of a thickness of the functionally graded article, wherein the portion of the thickness is less than the entire thickness of the functionally graded article. 
     
     
         12 . The method of  claim 9 , wherein the first and/or second magnet is placed within the mold. 
     
     
         13 . The method of  claim 9 , wherein the magnetic filler is further modified by coating, chemical modification, or a combination comprising at least one of the foregoing. 
     
     
         14 . The method of  claim 9 , wherein the magnetic field from at least one of the first magnet and the second magnet is applied as the melted polymer mixture flows into the mold. 
     
     
         15 . The method of  claim 9 , wherein the magnetic filler comprises magnetic particles, magnetic fibers, iron, nickel, cobalt, ferrites, rare earth magnets, or a combination comprising at least one of the foregoing. 
     
     
         16 . The method of  claim 15 , wherein the magnetic fibers are metal fibers, metal-coated fibers or a combination of metal fibers and metal-coated fibers. 
     
     
         17 . The method of  claim 9 , further comprising maintaining the melted polymer in a melted state until the functionally graded article has attained a desired functional gradation.