Clays pre-activated with intercalated polymerization initiation sites
View Patent ↗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 method for making a modified clay, the method comprising:
a) contacting a clay with an aqueous solution comprising a compound according to formula III:
Y—W—Z—C(R 1 )═CH 2 III; and thereafter
b) contacting the clay with an organic solvent solution comprising 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.
2. The method of claim 1 wherein steps a) and b) are both performed in the absence of vinylic monomer.
3. The method of claim 1 , wherein Y is + PX 1 X 2 X 3 .
4. The method 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.
5. The method of claim 1 , wherein each of X 1 , X 2 , and X 3 is phenyl.
6. The method of claim 1 , wherein W is C 6 H 4 —CH 2 and Z is O—CO.
7. The method of claim 1 , wherein R 1 is methyl.
8. The method of claim 1 , 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.
9. The method of claim 1 , wherein R 3 is tert-butyl and R 4 is CH(tert-butyl)PO(OEt) 2 .
10. The method of claim 1 , further comprising contacting the clay with a compound Y—R 1 , wherein Y and R 1 are as defined in claim 1 .
11. The method of claim 1 , further comprising contacting the clay with a vinylic monomer.
12. The method of claim 11 , wherein the vinylic monomer is styrene.
13. The method of claim 11 , wherein the vinylic monomer is selected from the group consisting of acrylic acid, methacrylic acid, and esters and amides of these.