Nano-particle preparation and applications
View Patent ↗A nano-particle composition including a poly (alkenylbenzene) core and a poly (conjugated diene) or a poly(alkylene) surface layer is provided. The nano-particles have a mean average diameter less than about 100 nm. The nano-particles can be modified via, for example, hydrogenation or functionalization. The nano-particles can advantageously be incorporated into rubbers, elastomers, and thermoplastics.
1. A process for forming polymer nano-particles comprising:
a. polymerizing alkenylbenzene and conjugated diene monomer in a hydrocarbon solvent solvent in the presence of a functionalized initiator to form a diblock polymer;
b. forming a mixture including micelles of said diblock polymer; and
c. adding at least one cross-linking agent to the polymerization mixture to form cross-linked nano-particles from said micelles, said nano-particles comprising a poly (alkenylbenzene) core and a poly (conjugated diene) surface.
2. The process of claim 1 wherein said functionalized initiator comprises lithium.
3. The process of claim 1 further including a hydrogenation step converting said poly (conjugated diene) surface to a poly (alkylene) surface.
4. The process of claim 1 further including polymerization of alkenylbenzene to form a mono-block polymer.
5. The process of claim 4 wherein the ratio of said mono-block polymer to said diblock polymer is controlled by selective addition of initiator and optionally a further monomer addition.
6. The process of claim 1 wherein said diblock polymer includes a poly(alkenylbenzene) block and a copolymer block.
7. A process for forming polymer nano-particles comprising:
a. polymerizing alkenylbenzene monomer and conjugated diene monomer in a hydrocarbon solvent in the presence of a functionalized initiator to form a diblock polymer;
b. forming a polymerization mixture including micelles of said diblock polymer;
c. adding at least one crosslinking agent to the polymerization mixture to form crosslinked nano-particles from said micelles; and
d. hydrogenating a poly(conjugated diene) layer of said nano-particles to form nano-particles containing a poly(alkenylbenzene) inner layer and a polycrystalline outer layer.
8. The process of claim 7 wherein step a is performed in the presence of a functionalized lithium initiator.
9. The process of claim 7 wherein subsequent to step a, further hydrocarbon solvent is added to the polymerization mixture.
10. The process of claim 7 including a further step wherein mono-block polymer comprising poly(alkenylbenzene) is formed prior to step b.
11. A process for forming a functionalized polymer nano-particle composition comprising:
a. polymerizing alkenylbenzene monomer and conjugated diene monomer in a hydrocarbon solvent, in the presence of a functionalized initiator, to form a diblock polymer;
b. forming a polymerization mixture including micelles of said diblock polymer; and
c. adding at least one crosslinking agent to the polymerization mixture to form crosslinked nano-particles from said micelles, said nano-particles having a mean average diameter less than about 100 nm.
12. The process of claim 11 wherein said functionalized initiator is a functionalized lithium initiator.
13. The process of claim 12 wherein said functionalized lithium initiator includes a functional group selected from the group consisting of carboxylic acids, alcohols, amines, formyl, tin, silicon, silyl ether, and mixtures thereof.
14. The process of claim 13 wherein said functionalized anionic polymerization initiator is hexamethylene imine propyllithium.
15. The process of claim 12 further including a hydrogenation step.
16. The process of claim 1 wherein said nano-particles have diameters less than about 100 nm.
17. The process of claim 7 wherein said nano-particles have diameters less than about 100 nm.
18. The process of claim 1 wherein said nano-particles have a dispersity less than about 1.3.
19. The process of claim 7 wherein said nano-particles have a dispersity less than about 1.3.
20. The process of claim 11 wherein said nano-particles have a dispersity less than about 1.3.
21. The process of claim 1 wherein said hydrocarbon solvent is selected from pentane, hexane, heptane, octane, nonane, decane, cyclohexane, methyl cyclopentane, cyclooctane, cyclopentane, cycloheptane, cyclononane, cyclodecane and mixtures thereof.
22. The process of claim 7 wherein said hydrocarbon solvent is selected from pentane, hexane, heptane, octane, nonane, decane, cyclohexane, methyl cyclopentane, cyclooctane, cyclopentane, cycloheptane, cyclononane, cyclodecane and mixtures thereof.
23. The process of claim 11 wherein said hydrocarbon solvent is selected from pentane, hexane, heptane, octane, nonane, decane, cyclohexane, methyl cyclopentane, cyclooctane, cyclopentane, cycloheptane, cyclononane, cyclodecane and mixtures thereof.
24. The process of claim 1 wherein step c is performed at a temperature between about 40 and 100° C.
25. The process of claim 7 wherein step c is performed at a temperature between about 40 and 100° C.
26. The process of claim 11 wherein step c is performed at a temperature between about 40 and 100° C.
27. The process of claim 1 wherein said cross-linking agent is selected from di-or-tri-vinyl substituted aromatic compounds.
28. The process of claim 7 wherein said cross-linking agent is selected from di-or-tri-vinyl substituted aromatic compounds.
29. The process of claim 11 wherein said cross-linking agent is selected from di-or-tri-vinyl substituted aromatic compounds.
30. The process of claim 1 wherein said diblock polymer has a Mw between about 5,000 and 200,000.
31. The process of claim 7 wherein said diblock polymer has a Mw between about 5,000 and 200,000.
32. The process of claim 11 wherein said diblock polymer has a Mw between about 5,000 and 200,000.
33. The process of claim 1 wherein a polymerization of conjugated diene monomer is performed before step a, such that said diblock polymer includes a mono-block portion.
34. The process of claim 7 wherein step d is performed in the presence of a catalyst and hydrogen gas.
35. The process of claim 34 wherein said catalyst comprises one of Pt, Pd, Rh, Ru, Ni and mixtures thereof.
36. The process of claim 1 wherein said initiator is selected from ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, phenyllithium, tolyllithium, vinyllithium, propenyllithium, tetramethylene lithium, pentamethylene lithium, p-tolyllithium, 4-phenylbutyl lithium, 4-butylcyclohexyl lithium, 4-cyclohexylbutyl lithium, lithium dialkyl amines, lithium dialkyl phosphines, lithium alkyl aryl phosphine, lithium diaryl phosphine and mixtures thereof.
37. The process of claim 7 wherein said initiator is selected from ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, phenyllithium, tolyllithium, vinyllithium, propenyllithium, tetramethylene lithium, pentamethylene lithium, p-tolyllithium, 4-phenylbutyl lithium, 4-butylcyclohexyl lithium, 4-cyclohexylbutyl lithium, lithium dialkyl amines, lithium dialkyl phosphines, lithium alkyl aryl phosphine, lithium diaryl phosphine and mixtures thereof.
38. The process of claim 11 wherein said initiator is selected from ethyllithium, propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, phenyllithium, tolyllithium, vinyllithium, propenyllithium, tetramethylene lithium, pentamethylene lithium, p-tolyllithium, 4-phenylbutyl lithium, 4-butylcyclohexyl lithium, 4-cyclohexylbutyl lithium, lithium dialkyl amines, lithium dialkyl phosphines, lithium alkyl aryl phosphine, lithium diaryl phosphines and mixtures thereof.
39. The process of claim 1 , wherein said initiator includes a functional group selected from amino, formyl, carboxylic acid, alcohol, tin, silicon, silyl ether, and mixtures thereof.
40. The process of claim 7 , wherein said initiator includes a functional group selected from amino, formyl, carboxylic acid, alcohol, tin, silicon, silyl ether, and mixtures thereof.