Preparation of Amphiphilic Block Polymers by Controlled Radical Micellar Polymerisation

• US 20140378617A1
• Filed: 10/24/2012
• Published: 12/25/2014
• Est. Priority Date: 10/24/2011
• Status: Active Grant

• Current Assignee: Specialty Operations France
• Original Assignee: Rhodia Operations (Solvac SA)
• Inventors: Wilson, James, Destarac, Mathias, Cadix, Arnaud
• Granted Patent: US 9,580,535 B2
• Time in Patent Office: Days
• US Class Current: 525/291
• CPC Class Codes: C08F 2/38 Polymerisation using regulators, e.g. chain terminating agents , e.g. telomerisation
• CPC Class Codes: C08F 2438/03 Use of a di- or tri-thiocarbonylthio compound, e.g. di- or tri-thioester, di- or tri-thiocarbamate, or a xanthate as chain transfer agent, e.g . Reversible Addition Fragmentation chain Transfer [RAFT] or Macromolecular Design via Interchange of Xanthates [MADIX]
• CPC Class Codes: C08F 293/005 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• CPC Class Codes: C08F 297/026 polymerising acrylic acid, methacrylic acid or derivatives thereof
• CPC Class Codes: C09K 8/04 Aqueous well-drilling compositions
• CPC Class Codes: C09K 8/588 characterised by the use of specific polymers polymeric surfactants C09K8/584
• CPC Class Codes: C09K 8/882 obtained by reactions only involving carbon-to-carbon unsaturated bonds

Abstract

The present invention relates to the preparation of block copolymers, which can be used in particular as rheology agents, suitable, inter alia, for oil extraction, comprising a step of radical micellar polymerisation wherein the following are brought into contact in an aqueous medium: —hydrophilic monomers, dissolved or dispersed in the aqueous medium; —hydrophobic monomers in the form of a micellar solution, i.e. containing, in a dispersed state, micelles comprising these hydrophobic monomers; —at least one radical polymerisation initiator; and —at least one radical polymerisation control agent. The polymers obtained according to the invention can be used in particular for enhanced oil recovery (EOR).

Claims

1. A process for preparing a block copolymer, which comprises a step (E) of micellar radical polymerization in which the following are placed in contact, in an aqueous medium (M):

hydrophilic monomers, dissolved or dispersed in said aqueous medium (M);

hydrophobic monomers in the form of a micellar solution, i.e. containing, in dispersed form in the medium (M), micelles comprising these hydrophobic monomers;

at least one radical polymerization initiator, and

at least one radical polymerization control agent.

2. The process as claimed in claim 1, in which the radical polymerization control agent is a compound which comprises a thiocarbonylthio group —

S(C═

S)—

.

3. The process as claimed in claim 1, in which the radical polymerization control agent is an oligomer of water-soluble or water-dispersible nature bearing a thiocarbonylthio group —

S(C═

S)—

.

is soluble or dispersible in the aqueous medium (M) used in step (E); and

/or

is not capable of penetrating into the micelles of the micellar solution.

4. The process as claimed in claim 3, in which the radical polymerization control agent is a prepolymer bearing a thiocarbonylthio group —

S(C═

S)—

, obtained after a step (E⁰), prior to said step (E), said step (E⁰) placing the following in contact;

said hydrophilic monomers;

said radical polymerization initiator; and

said control agent bearing a thiocarbonylthio group —

S(C═

S)—

.

5. The process as claimed in claim 1, in which the hydrophilic monomers of said step (E) comprise (meth)acrylic acid and/or acrylamido or methacrylamido monomers.

6. The process as claimed in claim 5, in which the monomers of said step (E) are (meth)acrylamides.

7. The process as claimed in claim 1, in which the radical polymerization initiator used in said step (E) is a redox initiator.

8. The process as claimed in claim 7, in which the redox initiator comprises a combination of ammonium persulfate and sodium formaldehyde sulfoxylate.

9. The process as claimed in claim 1, in which the reaction medium of said step (E) is free of copper or comprises copper in combination with a copper-complexing agent, in an amount capable of masking its presence.

10. The process as claimed in claim 1, in which the process of the invention comprises, after said step (E), a step (E1) of hydrolysis, ozonolysis or reaction with amines, which is capable of deactivating and/or destroying all or some of the transfer groups present on the polymer prepared in said step (E).

11. A block polymer that may be obtained according to the process of claim 1.

12. The use of a polymer as claimed in claim 11, for regulating the rheology of a liquid medium, especially an aqueous medium.

13. The use as claimed in claim 12, in which the polymer is used as a rheology regulator for extracting oil or natural gas, especially for making drilling fluids, for fracturing, for stimulation or for enhanced oil recovery.

14. The use as claimed in claim 12, in which the polymer is used for an enhanced oil recovery EOR.