Multifunctional graphene-silicone elastomer nanocomposite, method of making the same, and uses thereof

Abstract

A nanocomposite composition having a silicone elastomer matrix having therein a filler loading of greater than 0.05 wt %, based on total nanocomposite weight, wherein the filler is functional graphene sheets (FGS) having a surface area of from 300 m 2 /g to 2630 m 2 /g; and a method for producing the nanocomposite and uses thereof.

1 . (canceled) 
     
     
         2 . A method for production of a nanocomposite composition comprising a silicone elastomer matrix and functionalized graphene sheets having a surface area of from 300 m 2 /g to 2,630 m 2 /g, comprising:
 dispersing functional graphene sheets (FGS) in a polar solvent to form an FGS suspension;   combining the FGS suspension with a vinyl terminated polysiloxane comprising a diorganosiloxane unit and at least two silicon-bonded alkenyl groups, the diorganosiloxane unit comprising a phenyl group;   removing the polar solvent;   combining the resulting mixture with a crosslinker and a hydrosilylation catalyst;   curing the resulting mixture to provide the nanocomposite;   wherein the functional graphene sheets have a loading of greater than 0.05 wt % based on total nanocomposite weight;   wherein the hydrosilylation catalyst is present at a concentration of about 367 ppm to about 5600 ppm;   wherein the nanocomposite comprises a silicon hydride to vinyl molar ratio of about 1.5 to about 2.1; and   wherein the functional graphene sheets are present within the nanocomposite in a continuous three-dimensional connected network in a manner wherein individual functional graphene sheets have nanometer scale separation at contact point between individual functional graphene sheets.   
     
     
         3 . The method of  claim 2 , wherein the curing is performed at elevated temperature for a period of time from 1 to 48 hours. 
     
     
         4 . The method of  claim 3 , wherein the curing temperature is about 100° C. 
     
     
         5 . The method of  claim 3 , wherein the curing is performed for a period of time from 5 to 30 hours, 20 to 25 hours, or approximately 24 hours. 
     
     
         6 . The method of  claim 5 , further comprising molding the nanocomposite in a manner to yield fewer functional graphene sheet contacts point in a transverse direction of the nanocomposite compared to a longitudinal direction of the nanocomposite. 
     
     
         7 . The method of  claim 2 , wherein the functional graphene sheets have a loading of from 0.5 to 3 wt %, based on total nanocomposite weight. 
     
     
         8 . The method of  claim 2 , wherein the silane cross-linker is a member selected from the group consisting of tetrakis(dialkylsiloxy)silanes and poly(hydromethyl siloxane) crosslinkers. 
     
     
         9 . The method of  claim 2 , wherein the silane cross-linker is a tetrakis(dimethylsiloxy)silane. 
     
     
         10 . The method of  claim 2 , wherein the vinyl-terminated polysiloxane has a viscosity of from 100 to 300,000 mPas. 
     
     
         11 . An article formed from a nanocomposite produced by the method of  claim 2 . 
     
     
         12 . The article of  claim 11 , wherein the article is formed by casting. 
     
     
         13 . The article of  claim 11 , wherein the article is formed by molding. 
     
     
         14 . The article of  claim 11 , wherein the molding process results in the article comprising a longitudinal direction and a transverse direction, the transverse direction comprising fewer functional graphene sheet contact points compared to functional graphene sheet contact points of the longitudinal direction. 
     
     
         15 . The article of  claim 11 , wherein the article is a member selected from the group consisting of coatings, adhesives, sealants, flexible electrodes, actuators, pressure sensors, printed circuits, and electromagnetic interference shielding materials. 
     
     
         16 . A method for production of a nanocomposite composition comprising a silicone elastomer matrix and functionalized graphene sheets having a surface area of from 300 m 2 /g to 2,630 m 2 /g, comprising:
 dispersing functional graphene sheets (FGS) in a polar solvent to form an FGS suspension;   combining the FGS suspension with a vinyl terminated polysiloxane having a viscosity of from 100 to 300,000 mPas, the vinyl terminated polysiloxane comprising a diorganosiloxane unit and at least two silicon-bonded alkenyl groups, the diorganosiloxane unit comprising a phenyl group;   removing the polar solvent;   combining the resulting mixture with a crosslinker and a hydrosilylation catalysts, wherein the silane cross-linker is a member selected from the group consisting of tetrakis(dialkylsiloxy)silanes and poly(hydromethyl siloxane) crosslinkers, and wherein the hydrosilylation catalyst is a member selected from the group consisting of chloroplantinic acid, elementary platinum, solid platinum supported on a carrier; platinum-vinylsiloxane complexes; platinum-phosphine complexes; platinum-phosphite complexes; Pt (acac) 2 , wherein (acac) represents acetylacetonate group; platinum-hydrocarbon conjugates; platinum alcoholates; RhCl(PPh 3 ) 3 ; RhCl 3 ; Rh/Al 2 O 3 ; RuCl 3 ; IrCl 3 ; FeCl 3 ; AlCl 3 ; PdCl 2 .2H 2 O; NiCl 2 ; and TiCl 4 ; and   curing the resulting mixture to provide the nanocomposite, wherein the curing is performed at elevated temperature for a period of time from 1 to 48 hours;   wherein the functional graphene sheets have a loading of greater than 0.05 wt % based on total nanocomposite weight;   wherein the hydrosilylation catalyst is present at a concentration of about 367 ppm to about 5600 ppm;   wherein the nanocomposite comprises a silicon hydride to vinyl molar ratio of about 1.5 to about 2.1; and   wherein the functional graphene sheets are present within the nanocomposite in a continuous three-dimensional connected network in a manner wherein individual functional graphene sheets have nanometer scale separation at contact points between individual functional graphene sheets.   
     
     
         17 . The method of  claim 16 , further comprising molding the nanocomposite in a manner to yield fewer functional graphene sheet contacts point in a transverse direction of the nanocomposite compared to a longitudinal direction of the nanocomposite. 
     
     
         18 . The method of  claim 16 , wherein the vinyl terminated polysiloxane comprises a siloxane unit selected from selected from the group consisting of R 3 SiO 1/2 , RSiO 3/2 , and SiO 4/2 , where R represents a substituted monovalent hydrocarbon group or a unsubstituted monovalent hydrocarbon group. 
     
     
         19 . The method of  claim 2 , wherein the vinyl terminated polysiloxane comprises a siloxane unit selected from selected from the group consisting of R 3 SiO 1/2 , RSiO 3/2 , and SiO 4/2 , where R represents a substituted monovalent hydrocarbon group or an unsubstituted monovalent hydrocarbon group.