Clays pre-activated with intercalated polymerization initiation sites

Abstract

A modified clay may be made by contacting a clay with an unsaturated cationic compound and an alkoxyamine, or an adduct thereof. The resulting pre-activated clay, which contains a cationic alkoxyamine bound to the clay, may be further treated with a monomer to provide a polymer that is bound to the clay, thereby forming a nanocomposite material. The nanocomposite material may in turn be blended with another polymer prepared from the same or a different monomer.

1 . A composition comprising a clay having layers and exchangeable sites and, disposed between the layers, a cationic alkoxyamine according to formula I:  
       Y—W-Z-C(R 1 )(CH 2 R 2 )—V n —O—NR 3 R 4   I  
     wherein Y is a heterocyclic quaternary ammonium moiety,  + NX 1 X 2 X 3 , or  + PX 1 X 2 X 3  wherein X 1 , X 2 , and X 3  are each individually H or a C1-C20 group selected from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, and any of these substituted with one or more of oxygen, nitrogen, sulfur, and phosphorus; W is a direct bond or a C1-C20 alkyl, aryl, arylalkyl, or alkylaryl spacer group; Z is selected from O, NH, O—CO, NH—CO, and phenylene; V is a vinylic monomer repeat unit; n is an integer from 0 to 100,000; R 1  and R 2  are as defined for X 1 , X 2 , and X 3 ; and R 3  and R 4  are each individually selected from C1-C10 alkyl or together form part of an unsubstituted or alkyl-substituted piperidine or pyrrolidine ring, provided that at least one of R 3  and R 4  is substituted alpha to N with PO(OR 7 ) 2 , wherein each R 7  is individually selected from the group consisting of H, lower alkyl, aryl, arylalkyl, and alkylaryl.  
   
   
       2 . The composition of  claim 1 , wherein the composition is substantially free of vinylic monomer.  
   
   
       3 . The composition of  claim 1 , wherein at least 25% of exchangeable sites are associated with the cationic alkoxyamine of formula I.  
   
   
       4 . The composition of  claim 1 , wherein the clay is selected from the group consisting of naturally-occurring and synthetic smectite clays.  
   
   
       5 . The composition of  claim 1 , wherein n is zero.  
   
   
       6 . The composition of  claim 1 , wherein n is between 1 and 10,000.  
   
   
       7 . The composition of  claim 1 , wherein Y is  + PX 1 X 2 X 3 .  
   
   
       8 . The composition of  claim 1 , wherein X 1 , X 2 , and X 3  are each individually C5-C10 aryl, C5-C10 heteroaryl, or lower alkyl substituted with C5-C10 aryl or C5-C10 heteroaryl.  
   
   
       9 . The composition of  claim 1 , wherein each of X 1 , X 2 , and X 3  is phenyl.  
   
   
       10 . The composition of  claim 1 , wherein W is C 6 H 4 —CH 2  and Z is O—CO.  
   
   
       11 . The composition of  claim 1 , wherein R 1  is H or methyl.  
   
   
       12 . The composition of  claim 1 , wherein R 2  is C(R 8 ) 2 —COOH, C(R 8 ) 2 —COO-(lower alkyl, aryl, arylalkyl, or alkylaryl), or C(R 8 ) 2 —CON-(lower alkyl, aryl, arylalkyl, or alkylaryl) 2  wherein R 8  is H or a lower alkyl group.  
   
   
       13 . The composition of  claim 1 , wherein R 3  is tert-butyl.  
   
   
       14 . The composition of  claim 1 , wherein R 4  is CH(tert-butyl)PO(OEt) 2 .  
   
   
       15 . The composition of  claim 1 , having further disposed between the layers a cationic diluent Y—R 1 , wherein Y and R 1  are as defined in  claim 1 .  
   
   
       16 . The composition of  claim 1 , further comprising a polymer not according to formula I.  
   
   
       17 . A method for making a modified clay, the method comprising performing in any sequence the steps of: 
 a) contacting a clay with a compound according to formula III:      Y—W-Z-C(R 1 )═CH 2   III; and    b) contacting the clay with an alkoxyamine according to formula IV:      R 2 —O—NR 3 R 4   IV;    wherein Y is a heterocyclic quaternary ammonium moiety,  + NX 1 X 2 X 3 , or  + PX 1 X 2 X 3  wherein X 1 , X 2 , and X 3  are each individually H or a C1-C20 group selected from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, and any of these substituted with one or more of oxygen, nitrogen, sulfur, and phosphorus; W is a direct bond or a C1-C20 alkyl, aryl, arylalkyl, or alkylaryl spacer group; Z is selected from O, NH, O—CO, NH—CO, and phenylene; V is a vinylic monomer repeating unit; n is an integer from 0 to 100,000; R 1  and R 2  are as defined for X 1 , X 2 , and X 3 ; and R 3  and R 4  are each individually selected from C1-C10 alkyl or together form part of an unsubstituted or alkyl-substituted piperidine or pyrrolidine ring, provided that at least one of R 3  and R 4  is substituted alpha to N with PO(OR 7 ) 2 , wherein each R 7  is individually selected from the group consisting of H, lower alkyl, aryl, arylalkyl, and alkylaryl.    
   
   
       18 . The method of  claim 17  wherein steps a) and b) are both performed in the absence of vinylic monomer.  
   
   
       19 . The method of  claim 17 , wherein step a) is performed before step b).  
   
   
       20 . The method of  claim 17 , wherein Y is  + PX 1 X 2 X 3 .  
   
   
       21 . The method of  claim 17 , wherein X 1 , X 2 , and X 3  are each individually C5-C10 aryl, C5-C10 heteroaryl, or lower alkyl substituted with C5-C10 aryl or C5-C10 heteroaryl.  
   
   
       22 . The method of  claim 17 , wherein each of X 1 , X 2 , and X 3  is phenyl.  
   
   
       23 . The method of  claim 17 , wherein W is C 6 H 4 —CH 2  and Z is O—CO.  
   
   
       24 . The method of  claim 17 , wherein R 1  is methyl.  
   
   
       25 . The method of  claim 17 , wherein R 2  is C(R 8 ) 2 —COOH or C(R 8 ) 2 —COO-(lower alkyl) wherein R 8  is H or a lower alkyl group.  
   
   
       26 . The method of  claim 17 , wherein R 3  is tert-butyl and R 4  is CH(tert-butyl)PO(OEt) 2 .  
   
   
       27 . The method of  claim 17 , further comprising contacting the clay with a compound Y—R 1 , wherein Y and R 1  are as defined in  claim 17 .  
   
   
       28 . The method of  claim 17 , further comprising contacting the clay with a vinylic monomer.  
   
   
       29 . The method of  claim 28 , wherein the vinylic monomer is styrene.  
   
   
       30 . The method of  claim 28 , wherein the vinylic monomer is selected from the group consisting of acrylic acid, methacrylic acid, and esters and amides of these.  
   
   
       31 . A modified clay made by the method of  claim 17 .  
   
   
       32 . A modified clay made by the method of  claim 28.