Control Over Controlled Radical Polymerization Processes

• US 20140155512A1
• Filed: 02/07/2014
• Published: 06/05/2014
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Pilot Polymer Technologies Incorporated
• Original Assignee: ATRP Solutions, Inc. (Pilot Chemical Corp.)
• Inventors: Jakubowski, Wojciech, Spanswick, James
• Granted Patent: US 9,012,528 B2
• Time in Patent Office: Days
• US Class Current: 522/66
• CPC Class Codes: C08F 112/08 Styrene
• CPC Class Codes: C08F 120/10 Esters
• CPC Class Codes: C08F 2/38 Polymerisation using regulators, e.g. chain terminating agents , e.g. telomerisation
• CPC Class Codes: C08F 2/40 using retarding agents
• CPC Class Codes: C08F 2/50 with sensitising agents
• CPC Class Codes: C08F 220/14 Methyl esters , e.g. methyl (meth)acrylate
• CPC Class Codes: C08F 220/1804 C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
• CPC Class Codes: C08F 4/00 Polymerisation catalysts
• CPC Class Codes: C08F 4/40 Redox systems

Abstract

A procedure for improved temperature control in controlled radical polymerization processes is disclosed. The procedure is directed at controlling the concentration of the persistent radical in ATRP and NMP polymerizations procedures and the concentration of radicals in a RAFT polymerization process by feeding a reducing agent or radical precursor continuously or intermittently to the reaction medium through one of more ports.

Claims

1. A polymerization process, comprising:

polymerizing free radically (co)polymerizable monomers in the presence of a reducing agent and a polymerization medium initially comprising;

at least one transition metal catalyst; and

an atom transfer radical polymerization initiator; and

wherein the molar ratio of the transition metal catalyst to the atom transfer radical polymerization initiator is less than 0.10, preferably less than 0.05; and

wherein the reducing agent is continuously added to the reaction medium at a rate commensurate with the rate of radical-radical termination reactions.

2. The process of claim 1 wherein the reducing agent is a free radical initiator.

3. The process of claim 1 wherein the reducing agent reacts with the higher oxidation state transition metal complex in a non-radical forming, and a non-ATRP initiator, forming reaction.

4. The process of claim 3 wherein the reducing agent comprises a stable organic molecule including sulfites, bisulfites, thiosulfites, mercaptans, hydroxylamines, amines, hydrazine (N₂H₄), phenylhydrazine (PhNHNH₂), hydrazones, hydroquinone, food preservatives, flavonoids, beta carotene, vitamin A, α

-tocopherols, vitamin E, propyl gallate, octyl gallate, BHA, BHT, propionic acids, ascorbic acid, sorbates, reducing sugars, sugars comprising an aldehyde group, glucose, lactose, fructose, dextrose, potassium tartrate, nitrites, nitrites, dextrin, aldehydes, glycine, and many antioxidants.

5. The process of claim 1 wherein the reducing agent or radical initiator reduces the concentration of the higher oxidation state transition metal formed by radical-radical termination reactions to a concentration close to the concentration present in the system after the addition of the previous addition of the reducing agent or radical initiator.

6. The polymerization process of claim 1, comprising:

polymerizing free radically (co)polymerizable monomers in the presence of a photoresponsive radical initiator and a polymerization medium initially comprising;

at least one transition metal catalyst; and

an atom transfer radical polymerization initiator; and

wherein the molar ratio of the transition metal catalyst to the atom transfer radical polymerization initiator is less than 0.10, preferably less than 0.05; and

wherein a fraction of the added photoresponsive radical initiator is periodically decomposed by a pulse of light wherein the intensity and duration of the photostimulation is commensurate with the moles of radical-radical termination reactions that occurred since the previous pulse of light.

7. The polymerization process of claim 1 wherein the polymerization is conducted in a bulk polymerization processes, performed in the presence of a solvent, conducted from solid surfaces, conducted in a biphasic polymerization process including emulsion polymerization processes, mini-emulsion polymerization processes, microemulsion polymerization processes, reverse emulsion polymerization processes, and suspension polymerization processes.

10. The disclosed controlled radical polymerization processes of claim 1 where the rate of addition of a reducing agent/radical initiator is continuously adjusted to maintain the targeted temperature of the reaction by controlling the rate of polymerization.

11. The disclosed controlled radical polymerization processes of claim 1 where the rate of addition of a reducing agent/radical initiator is continuously adjusted to maintain the targeted rate of polymerization.

12. The disclosed controlled radical polymerization processes of claim 1 where the rate of addition of a reducing agent/radical initiator is continuously adjusted to allow the conversion of monomer to polymer to exceed 80%, preferably exceed 90% and optimally exceed 95%.

13. The disclosed controlled radical polymerization processes of claim 1 where the reducing agent/radical initiator is added to the reactor through multiple addition ports.

14. The disclosed controlled radical polymerization processes of claim 1 wherein the process is conducted in a bulk polymerization process, a processes performed in a solvent, a processes conducted from solid surfaces, or a biphasic polymerization process including emulsion polymerization processes, mini-emulsion polymerization processes, microemulsion processes, reverse emulsion polymerization processes, and suspension polymerization processes.

8. A polymerization process, comprising:

polymerizing free radically (co)polymerizable monomers in the presence of an alkoxyamine wherein the concentration of the formed nitroxide, the persistent radical in a NMP, is controlled by the rate of decomposition of the added initiator whereby the rate of decomposition of the added initiator is selected to match the rate of radical/radical termination reactions that would otherwise build up the concentration of the stable free radical and reduce the rate of propagation.

9. A polymerization process, comprising:

polymerizing free radically (co)polymerizable monomers in the presence of a degenerative transfer agent wherein the rate of polymerization is controlled by the rate of decomposition of the added initiator whereby the rate of decomposition of the added initiator is selected to maintain the selected reaction temperature.