Preparation of hydrophilic polymers of high mass by controlled radical polymerization

Patent metadata

Field	Value
Publication number	US-9975980-B2
Application number	US-201113876887-A
Country	US
Kind code	B2
Filing date	Sep 27, 2011
Priority date	Sep 30, 2010
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

The present invention concerns a process for preparing a polymer comprising at least one gel polymerization step (E) in which the following are contacted:
ethylenically unsaturated water-soluble monomers, the same or different; a source of free radicals adapted to the polymerization of the said monomers, typically a redox system; and a radical polymerization control agent, preferably comprising a thiocarbonylthio —S(C═S)— group;

with a concentration of monomers in the reaction medium of step (E) sufficiently high to cause gelling of the medium if polymerization was conducted without the control agent.

First claim

The invention claimed is:

1. A process for preparing a polymer comprising at least one polymerization in a reaction medium wherein the polymerization comprises contacting:
ethylenically unsaturated water-soluble monomers, the same or different;
a source of free radicals adapted to the polymerization of said monomers; and
a radical polymerization control agent, wherein said control agent is a reversible transfer agent;
wherein the polymerization is performed without any cross-linking agent and the concentration of monomers in the reaction medium of the polymerization is sufficiently high to cause gelling of the medium and lead to a non-covalent gel if polymerization was conducted without the control agent,
wherein in the polymerization, the initial concentration of control agent in the medium is chosen so that the number-average molecular weight M n of the synthesized polymer is higher than 100,000 g/mol;
wherein the control agent is a compound carrying an —S(C═S)O— xanthate function; and
wherein number-average molecular weight M n of the synthesized polymer is of 500 000 g/mol or higher.

2. The process according to claim 1 wherein the monomers, the source of free radicals and the control agent are contacted in an aqueous medium.

3. The process according to claim 1 wherein the monomers comprise acrylamido monomers.

4. The process according to claim 1 wherein the initial concentration of monomers in the reaction medium is between 10 and 40% by weight relative to the total weight of the reaction medium.

5. The process according to claim 1 wherein the source of free radicals used is a redox initiator.

6. The process according to claim 5 wherein the source of free radicals is a redox system which is an association of ammonium persulfate and sodium formaldehyde sulfoxylate.

7. The process according to claim 1 wherein the reaction medium is free of copper.

8. The process according to claim 1 , wherein the control agent is a compound carrying an O-ethyl xanthate function of formula —S(C═S)OCH 2 CH 3 .

Assignees

• Destarac Mathias
• Guinaudeau Aymeric
• Mazieres Stephane
• Wilson James
• Rhodia Operations
• Centre Nat Rech Scient

Inventors

• Destarac Mathias
• Guinaudeau Aymeric
• MAZIERES Stéphane
• Wilson James

Classifications

• C08F293/005 Primary

  using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent · CPC title

• C08F2/38 Primary

  Polymerisation using regulators, e.g. chain terminating agents {, e.g. telomerisation} · CPC title

• C08F2400/02

  Control or adjustment of polymerization parameters · CPC title

• C08F271/00 Primary

  Macromolecular compounds obtained by polymerising monomers on to polymers of nitrogen-containing monomers as defined in group C08F26/00 · CPC title

• C08F265/10

  on to polymers of amides or imides · CPC title