Conductive polyolefins with good mechanical properties

Abstract

This invention discloses a polymeric material reinforced with single-wall nanotubes (SWNT) or multiple-wall nanotubes (MWNT) with good electrical and mechanical properties. It also discloses a process for preparing said reinforced polymeric material and their use in electrically dissipative material.

1 - 11 . (canceled)  
     
     
         12 . An elongated polymer product comprising a polymeric matrix material reinforced with a plurality of carbon nanotubes which are substantially free of an impurity component selected from the group consisting of catalyst particles, support particles and mixtures thereof, said reinforced polymeric material having an electrical conductivity and elastic modulus greater than the electrical conductivity and elastic modulus of a corresponding elongated polymer product formed of said polymeric matrix material reinforced with carbon black in a concentration in said polymeric matrix equal to or greater than the concentration of said carbon nanotubes in said polymeric matrix.  
     
     
         13 . The polymer product of  claim 12  wherein the polymeric matrix material is a polyolefin.  
     
     
         14 . The polymer product of  claim 13  wherein the polyolefin is a homopolymer or copolymer of ethylene.  
     
     
         15 . The polymer product of  claim 13  wherein the polyolefin is an atactic, isotactic or syndiotactic homopolymer or copolymer of propylene.  
     
     
         16 . The polymer product of  claim 12  wherein said carbon nanotubes have an aspect ratio of at least 100.  
     
     
         17 . The polymer product of  claim 12  wherein said carbon nanotubes have an aspect ratio of at least 500.  
     
     
         18 . The polymer product of  claim 12  wherein said carbon nanotubes are present in a concentration within the range of 0.1-20 wt. % of said polymeric matrix material.  
     
     
         19 . A process for preparing a polymeric material reinforced with carbon nanotubes comprising: 
 (a) providing a plurality of carbon nanotubes containing an impurity component selected from the group consisting of support particles, catalyst particles, and mixtures thereof;    (b) treating said nanotube component to at least partially remove said impurity component therefrom to provide an assembly of carbon nanotubes which have been at least partially purified;    (c) providing a polymeric matrix material;    (d) dispersing said at least partially purified carbon nanotubes in said matrix material to provide a mixture of said partially purified carbon nanotubes and said polymeric matrix material; and    (e) recovering a product comprising said polymeric matrix material which has been reinforced with said carbon nanotubes.    
     
     
         20 . The process of  claim 19  wherein the dispersion of said carbon nanotubes in said polymeric matrix material is carried out by dissolving said nanotubes and said polymeric matrix in a solvent, mixing said dispersion of said carbon nanotubes and said polymeric matrix material and thereafter evaporating said solvent to provide a product of said reinforced matrix material.  
     
     
         21 . The process of  claim 19  wherein said carbon nanotubes are mixed with said polymeric matrix material in a concentration of less than 50 wt. % of said polymeric matrix material.  
     
     
         22 . The process of  claim 21  wherein said carbon nanotubes are mixed with said polymeric matrix material in a concentration of no more than 30 wt. % of said polymeric matrix material.  
     
     
         23 . The process of  claim 21  wherein said carbon nanotubes are mixed with said polymeric matrix material in a concentration of no more than 20 wt. % of said polymeric matrix material.  
     
     
         24 . The process of  claim 21  wherein said carbon nanotubes are mixed with said polymeric matrix material in a concentration of no more than 5 wt. % of said polymeric matrix material.  
     
     
         25 . The process of  claim 19  wherein said carbon nanotubes have an aspect ratio of at least 100.  
     
     
         26 . The process of  claim 19  wherein said carbon nanotubes have an aspect ratio of at least 500.  
     
     
         27 . The process of  claim 19  wherein said carbon nanotubes have an aspect ratio of at least 1,000.  
     
     
         28 . The process of  claim 19  wherein said carbon nanotubes are single wall carbon nanotubes having a hollow core diameter of 5 nanometers or less and a length within the range of 1-50 microns.  
     
     
         29 . The process of  claim 19  wherein said carbon nanotubes are multi-wall carbon nanotubes having a hollow core diameter of no more than 200 nanometers.  
     
     
         30 . The process of  claim 29  wherein said carbon nanotubes are multi-wall carbon nanotubes having a hollow core diameter of no more than 100 nanometers.  
     
     
         31 . The process of  claim 30  wherein said carbon nanotubes are multi-wall carbon nanotubes having a hollow core diameter of no more than 50 nanometers.  
     
     
         32 . A process for preparing a polymeric material reinforced with carbon nanotubes comprising: 
 (a) providing a plurality of carbon nanotubes containing an impurity component selected from the group consisting of support particles, catalyst particles, and mixtures thereof;    (b) treating said nanotube component to at least partially remove said impurity component therefrom to provide an assembly of carbon nanotubes which have been at least partially purified;    (c) providing a polymeric matrix material which has been heated to a temperature material sufficient to place the polymeric matrix material in the molten state;    (d) dispersing said partially purified carbon nanotubes in said polymeric matrix material to provide a blend of said nanotubes and said polymeric material; and    (e) reducing the temperature of said blend of at least partially purified carbon nanotubes in said polymeric matrix material to provide a composite product comprising a mixture of said at least partially purified carbon nanotubes in said polymeric matrix material.    
     
     
         33 . The process of  claim 32  wherein said blend of said nanotubes and said polymeric material is elongated to form an elongated composite product in which said carbon nanotubes are oriented along the major dimension thereof.  
     
     
         34 . The process of  claim 33  wherein said elongated polymer product is oriented in the longitudinal direction by stretching said composite product after reducing the temperature of said blend.