Polymer and Elastomer Compositions Having Carbon Nanostructure Additives and Articles Formed Therefrom for Use in EMI and RFI Shielding and in Pressure Sensing Seals Having Quantum Tunneling Composite Effects

Abstract

Compositions of at least one matrix polymer that may be a thermoplastic and/or curable polymer having at least one functional group for crosslinking for use in forming articles are disclosed as well as methods for making such articles, wherein the compositions and methods include a carbon nanostructure additive that is three-dimensional, branched and crosslinked. The resulting articles can in one embodiment provide a volume resistivity level of about 0.5 ohm-cm or less which are useful in applications requiring conductivity sufficient to provide electromagnetic interference shielding and/or radio frequency interference shielding. Other articles formed using compositions disclosed herein in other embodiments can demonstrate dissipative and/or quantum tunneling effects and so are useful as self-sensing pressure sensitive articles, such as self-sensing seals.

1 . A composition for forming an article, comprising
 at least one matrix polymer selected from the group consisting of at least one thermoplastic polymer and at least one curable polymer having at least one functional group for crosslinking; and   a three-dimensional, branched and/or crosslinked carbon nanostructure additive provided in an amount such that after forming an article the composition, the article is conductive and has a volume resistivity level of about 0.5 ohm-cm or less.   
     
     
         2 . The composition according to  claim 1 , wherein when formed into an article, the article is an electromagnetic interference shielding article and/or a radiofrequency interference shielding article. 
     
     
         3 . The composition according to  claim 1 , wherein the at least one matrix polymer is at least one curable polymer selected from the group consisting of a curable polymer comprising at least one silicon-containing monomer, a curable polymer comprising at least one monomer containing silicon and fluorine, a curable copolymer comprising at least one acrylonitrile monomer and at least one butadiene monomer, a curable polymer comprising at least one olefinic monomer, a curable polymer comprising at least one fluorinated monomer, a curable polymer comprising at least one perfluorinated monomer, and blends and copolymers thereof. 
     
     
         4 . The composition according to  claim 3 , wherein upon cure, the cured polymer composition comprises one or more elastomers selected from the group consisting of a silicone, a fluorosilicone, a fluoroelastomer, a perfluoropolyether, a perfluoroelastomer, and cured elastomers formed from blends and copolymers thereof. 
     
     
         5 . The composition according to  claim 3 , wherein the at least one curable polymer is selected from the group consisting of a curable fluorinated polymer, and a curable perfluorinated polymer. 
     
     
         6 . The composition according to  claim 5 , wherein the at least one curable polymer is at least one curable perfluorinated polymer. 
     
     
         7 . The composition according to  claim 5 , wherein the at least one curable polymer is a blend of or a copolymer of at least one curable fluoropolymer and at least one curable perfluoropolymer. 
     
     
         8 . The composition according to  claim 1 , wherein the matrix polymer is at least one curable polymer having at least one functional group for crosslinking and the composition further comprises at least one crosslinking additive for reacting with the at least one functional group for crosslinking. 
     
     
         9 . The composition according to  claim 8 , wherein upon curing the curable polymer composition, the resulting cured material is used in an electromagnetic interference shielding application or a radio frequency interference shielding application. 
     
     
         10 . The composition according to  claim 1 , wherein the carbon nanostructure additive has a carbon content of greater than or equal to about 97% and a bulk density of about 0.135 g/cm 3 . 
     
     
         11 . The composition according to  claim 1 , further comprising at least one filler different from the at least one nanostructure additive. 
     
     
         12 . The composition according to  claim 1 , comprising about 0.1 part by weight to about 300 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         13 . The composition according to  claim 12 , comprising about 0.25 to about 250 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         14 . The composition according to  claim 13 , comprising about 0.5 to about 250 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         15 . The composition according to  claim 14 , comprising about 0.5 to about 80 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         16 . The composition according to  claim 1 , wherein the at least one matrix polymer is selected from the group consisting of at least one curable fluoropolymer, at least one curable perfluoropolyether, and at least one curable perfluoropolymer, and the composition comprises about 10 to about 80 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         17 . The composition according to  claim 16 , wherein the composition comprises about 10 parts to about 50 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         18 . The composition according to  claim 17 , wherein the composition comprises about 20 parts to about 40 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         19 . The composition according to  claim 1 , wherein the matrix polymer is a thermoplastic polymer selected from the group consisting of polyarylene-based polymers, thermoplastic melt-processible fluoropolymers, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, chlorinated fluoropolymers, silicon-based polymers, and non-curable fluoropolymers and perfluoropolymers, polyolefins, polyethylene terephthalates, polysiloxanes, polyurethanes, polyaramid, polyamides, polyimides, polyetherimides, polyphenylene sulfides, polyphenylene sulfones, polyether sulfones, polyamideimides, polybenizmidizoles, polycarbonates, polyacrylonitrile-butadiene-styrenes, polybutadiene-styrenes, polyepoxides, and similar materials, as well as blends, copolymers, alloys, and other combinations thereof. 
     
     
         20 . The composition according to  claim 1 , further comprising one or more conductive filler different from the carbon nanostructure additive that are powders, flakes or fiber fillers comprising one or more of carbon; metal-plated glass; metal-plated particles wherein the particles comprise a metal or a polymer; nickel-coated graphite; graphene; graphite; carbon black; graphene derivatives; single-wall carbon nanotubes; multi-wall carbon nanotubes; gold; silver; nickel; copper; and combinations or mixtures thereof. 
     
     
         21 . The composition according to  claim 20 , wherein the composition comprises about 0.25 parts by weight to about 100 parts by weight of the one more conductive filler different from the carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer. 
     
     
         22 . An elastomeric article and/or a thermoplastic article formed from the composition according to  claim 1 . 
     
     
         23 . The article according to  claim 22 , wherein the article is selected from a gasket, a seal, a cover, and a component part, for use in an electromagnetic interference shielding device or in a radio frequency interference device. 
     
     
         24 . An electromagnetic interference shielding and/or a radio frequency interference shielding composition, comprising:
 at least one matrix polymer selected from a thermoplastic and/or a curable polymer having at least one functional group for crosslinking that is selected from at least one curable fluoropolymer, at least one curable perfluoropolyether, at least one perfluoropolymer, at least one curable polymer comprising silicon and fluorine, and copolymers and blends thereof; and   about 5 parts by weight to about 300 parts by weight of a carbon nanostructure additive per 100 parts by weight of the at least one matrix polymer,   wherein when the composition is cured and formed into an article, it has a volume resistivity level of about 0.5 ohm-cm or less, and   wherein the carbon nanostructure additive is three-dimensional, branched and crosslinked.   
     
     
         25 . The electromagnetic interference shielding and/or a radio frequency interference shielding composition according to  claim 24 , wherein the at least one matrix polymer is at least one curable perfluoropolymer, and wherein the composition comprises about 10 parts by weight to about 80 parts by weight of the carbon nanostructure additive per 100 parts by weight of the at least one curable polymer. 
     
     
         26 . The composition according to  claim 24 , wherein the at least one carbon nanostructure additive has a carbon content of greater than or equal to about 97% and a bulk density of about 0.135 g/cm 3 . 
     
     
         27 .- 41 . (canceled) 
     
     
         42 . A method of making an article, comprising
 providing a composition comprising at least one matrix polymer selected from a thermoplastic and/or a curable polymer having at least one functional group for crosslinking and at least one carbon nanostructure additive that is three-dimensional, branched and/or crosslinked, wherein the at least one carbon nanostructure additive is present in an amount of about 0.1 part by weight to about 300 parts by weight per 100 parts by weight of the at least one matrix polymer; and   forming an article from the composition by either heat-forming the composition or by curing and heat-forming the composition, wherein the article may be used in at least one of an electromagnetic shielding device and a radio frequency shielding device.   
     
     
         43 . The method according to  claim 42 , wherein the article has a volume resistivity of about 0.5 ohm-cm or less. 
     
     
         44 . The method according to  claim 42 , wherein the at least one matrix polymer is a curable polymer and the composition further comprises at least one crosslinking additive for reacting with the at least one functional group for crosslinking. 
     
     
         45 . The method according to  claim 42 , wherein the article is selected from a seal, a gasket, a cover or a component part of an electromagnetic interference shielding device and/or a radio frequency interference shielding device. 
     
     
         46 .- 54 . (canceled)