Initiator nanoconstituents for elastomer crosslinking and related methods and articles

Abstract

An initiator nanoconstituent comprises a nanoparticle covalently bonded to a group having a free radical. The nanoparticle may be bonded to the group via an ether group or an amide group. The initiator nanoconstituent may be formed in situ, in a mixture comprising an elastomer material to be crosslinked. The initiator nanoconstituent is formed from an organic nanoconstituent compound that includes the nanoparticle and an organic group that does not include a free radical at the time the mixture is formed. At least one chemical bond of the organic nanoconstituent compound may be ruptured, in situ, to form the initiator nanoconstituent, which may then bond with polymer molecules of the elastomer material and form a crosslinked elastomer material. Downhole tools or components thereof may include such crosslinked elastomer material.

1 . An initiator nanoconstituent for crosslinking an elastomer, the initiator nanoconstituent comprising a nanoparticle covalently bonded to a subgroup comprising at least one free radical, wherein the at least one free radical is a sulfur atom. 
     
     
         2 . A downhole tool comprising a crosslinked elastomer material, the crosslinked elastomer material comprising a polymer molecule bonded to a subgroup covalently bonded to a nanoparticle. 
     
     
         3 . The downhole tool of  claim 2 , wherein the polymer molecule is covalently bonded to the subgroup. 
     
     
         4 . The downhole tool of  claim 2 , wherein the nanoparticle is covalently bonded to the subgroup via one of an —O— and an —N—. 
     
     
         5 . The downhole tool of  claim 2 , wherein the downhole tool comprises a packer tool including a packer element comprising the crosslinked elastomer material. 
     
     
         6 . The downhole tool of  claim 2 , wherein the downhole tool comprises a downhole drilling motor including a drive section having a stator former comprising a coating comprising the crosslinked elastomer material. 
     
     
         7 . A method of forming a crosslinked elastomer material, comprising:
 dispersing, in a precursor elastomer material, at least one compound to form a precursor mixture, the at least one compound comprising a nanoparticle bonded to a subgroup via an —O— or an —N—;   heating the precursor mixture to rupture at least one bond of the at least one compound, forming an initiator nanoconstituent comprising the nanoparticle and a terminal free radical; and   bonding the initiator nanoconstituent to a polymer molecule of the precursor elastomer material.   
     
     
         8 . The method of  claim 7 , further comprising, before the dispersing act, reacting a functionalized nanoparticle with an organic derivative compound, the functionalized nanoparticle comprising the nanoparticle, the organic derivative compound selected from the group consisting of a carboxylic acid derivative of a peroxide compound, a carboxylic acid derivative of a diaza compound, a carboxylic acid derivative of a disulfide compound, an amide derivative of a peroxide compound, an amide derivative of a diaza compound, and an amide derivative of a disulfide compound. 
     
     
         9 . The method of  claim 8 , further comprising, before the dispersing act, reacting a functionalized nanoparticle with an organic derivative compound, the functionalized nanoparticle comprising the nanoparticle, the organic derivative compound having the following formula:
   Y 1 —R—Y 2 —R—Y 1  
   
       wherein
 Y 1  represents one of a carboxyl group and an amide group; 
 R represents an organic group; and 
 Y 2  represents one of C(═O)—O—O—(O═)C, N═N, and S—S. 
 
     
     
         10 . The method of  claim 7 , wherein heating the precursor mixture also forms another free radical compound in addition to the initiator nanoconstituent. 
     
     
         11 . The method of  claim 10 , further comprising bonding the another free radical compound with another polymer molecule of the precursor elastomer material. 
     
     
         12 . The method of  claim 7 , wherein dispersing, in a precursor elastomer material, at least one compound comprises cooling the precursor elastomer material while dispersing the at least one compound. 
     
     
         13 . The method of  claim 7 , further comprising, before the dispersing, reacting a hydroxy-functionalized carbon nanotube with at least one of succinic acid peroxide and glutaric peroxide acid to form the at least one compound, the nanoparticle comprising the carbon nanotube, the subgroup comprising an oxygen-oxygen (O—O) group, and the carbon nanotube being bonded to the subgroup via the —O—. 
     
     
         14 . The method of  claim 13 , further comprising selecting the precursor elastomer material to comprise a precursor nitrile butadiene rubber (NBR) material. 
     
     
         15 . The method of  claim 13 , wherein heating the precursor mixture comprises heating the precursor mixture to rupture a bond of the oxygen-oxygen (O—O) group in the subgroup. 
     
     
         16 . The method of  claim 13 , wherein heating the precursor mixture comprises forming another free radical compound comprising another terminal free radical, the another free radical compound comprising a carboxyl group bonded to an organic group. 
     
     
         17 . The initiator nanoconstituent of  claim 1 , wherein the nanoparticle is a silica-based nanoparticle. 
     
     
         18 . The initiator nanoconstituent of  claim 1 , wherein the nanoparticle is covalently bonded via an —O— or an —N— to the subgroup comprising the at least one free radical. 
     
     
         19 . The initiator nanoconstituent of  claim 1 , wherein the sulfur atom of the at least one free radical is a terminal sulfur atom. 
     
     
         20 . The downhole tool of  claim 2 , wherein the subgroup comprises a sulfur atom covalently bonded to the polymer molecule.