Purification of functionalized triblock copolymers via methanol trituration

Patent metadata

Field	Value
Publication number	US-8952126-B2
Application number	US-201313938874-A
Country	US
Kind code	B2
Filing date	Jul 10, 2013
Priority date	Jul 10, 2013
Publication date	Feb 10, 2015
Grant date	Feb 10, 2015

Abstract

A method of making a pure block copolymer includes forming a crude block copolymer; heating a solution of the crude block copolymer and alcohol; and cooling the solution to promote precipitation of a purified block copolymer, wherein an amount of impurities remaining in the purified block copolymer is from about 0 to about 5 wt % based on a total weight of the purified block copolymer; a ratio of a polydispersity index of the crude block copolymer to a polydispersity index of the purified block copolymer is from about 1.02 to about 1.25; a ratio of a molecular weight of the crude block copolymer to a molecular weight of the purified block copolymer is from about 0.75 to about 1.0; and a ratio of a number average molecular weight of the crude block copolymer to a number average molecular weight of the purified block copolymer is from about 0.65 to about 1.

First claim

What is claimed is:

1. A method of purifying a block copolymer comprising:
heating a solution containing a crude block copolymer and an alcohol;
cooling the solution to promote precipitation of a purified block copolymer; and
isolating the purified block copolymer, wherein isolating the purified block copolymer comprises filtering the solution to separate the purified block copolymer from a filtrate and recovering unreacted monomer and catalyst from the filtrate,
and further wherein:
an amount of impurities remaining in the purified block copolymer is from about 0 to about 5 wt % based on a total weight of the purified block copolymer;
a ratio of a polydispersity index of the crude block copolymer to a polydispersity index of the purified block copolymer is from about 1.02 to about 1.25;
a ratio of a molecular weight of the crude block copolymer to a molecular weight of the purified block copolymer is from about 0.75 to about 1.0; and
a ratio of a number average molecular weight of the crude block copolymer to a number average molecular weight of the purified block copolymer is from about 0.65 to about 1.

2. The method of claim 1 , wherein the block copolymer is a functionalized block copolymer of a polyester/polycarbonate hybrid.

3. The method of claim 2 , wherein the block copolymer is a polycaprolactone-b-polycarbonate-b-polylactide block copolymer.

4. The method of claim 1 , wherein the alcohol is methanol.

5. The method of claim 1 , wherein the solution is heated to a temperature of from about 50° C. to about 120° C.

6. The method of claim 1 , wherein the solution is cooled to a temperature of from about −30° C. to about 10° C.

7. A method of making a block copolymer comprising:
forming a crude block copolymer;
heating a solution containing the crude block copolymer and alcohol;
cooling the solution to promote precipitation of a purified block copolymer; and
isolating the purified block copolymer, wherein isolating the purified block copolymer comprises filtering the solution to separate the purified block copolymer from a filtrate and recovering unreacted monomer and catalyst from the filtrate,
and further wherein:
an amount of impurities remaining in the purified block copolymer is from about 0 to about 5 wt % based on a total weight of the purified block copolymer;
a ratio of a polydispersity index of the crude block copolymer to a polydispersity index of the purified block copolymer is from about 1.02 to about 1.25,
a ratio of a molecular weight of the crude block copolymer to a molecular weight of the purified block copolymer is from about 0.75 to about 1.0; and
a ratio of a number average molecular weight of the crude block copolymer to a number average molecular weight of the purified block copolymer is from about 0.65 to about 1.0.

8. The method of claim 7 , wherein forming the crude block copolymer comprises a one-pot, organocatalytic, neat ring-opening polymerization.

9. The method of claim 8 further comprising polymerizing the mixture to form a block copolymer, wherein the polymerization comprises:
sequentially adding monomers to a reactor to form a mixture;
capping the mixture with succinic anhydride; and
cooling the mixture to room temperature to form the crude block copolymer.

10. The method of claim 9 , wherein sequentially adding monomers comprises:
adding ε-caprolactone, and a catalyst to the reactor to form a first reaction mixture;
heating the first reaction mixture;
polymerizing a first block;
adding a functionalized carbonate monomer to the reactor to form a second reaction mixture;
polymerizing a second block;
adding D,L-lactide to the reactor to form a third reaction mixture; and
polymerizing a third block.

11. The method of claim 7 , wherein the block copolymer is a functionalized block copolymer of a polyester/polycarbonate hybrid.

12. The method of claim 11 , wherein the block copolymer is a polycaprolactone-b-polycarbonate-b-polylactide block copolymer.

13. The method of claim 7 , wherein the alcohol is methanol.

14. The method of claim 7 , wherein the solution is heated to a temperature of from about 50° C. to about 120° C.

15. A one-pot method of making an ABC tri-block copolymer, the method comprising:
adding ε-caprolactone, hexanol, and a catalyst to a reactor vessel to form a first reaction mixture;
heating the first reaction mixture at a temperature within a range of from about 125° C. to about 145° C. for about 36 to about 72 hours to ring-open and polymerize the ε-caprolactone, forming a reaction mixture comprising an A block polymer;
adding a functionalized carbonate monomer to the reaction mixture comprising the A block polymer to form a second reaction mixture;
maintaining the second reaction mixture at a temperature within a range of from about 125° C. to about 145° C. for about 20 to about 40 minutes to ring-open and polymerize the functionalized carbonate monomer with the A block, forming a reaction mixture comprising an AB block copolymer;
adding D,L-lactide to the reaction mixture comprising the AB block copolymer to form a third reaction mixture;
maintaining the third reaction mixture at a temperature within a range of from about 125° C. to about 145° C. for about 20 to about 40 minutes to ring-open and polymerize the D,L-lactide with the AB block copolymer, forming a reaction mixture comprising an ABC tri-block copolymer;
adding succinic anhydride to the reaction mixture comprising the ABC tri-block copolymer to form a fourth reaction mixture;
maintaining the fourth reaction mixture at a temperature within a range of from about 125° C. to about 145° C. for about 2 to about 12 minutes to cap the ABC tri-block copolymer with the succinic anhydride to form a clear melt comprising a capped ABC tri-block copolymer;
cooling the clear melt to room temperature to form a crude solid;
adding methanol to the crude solid to form a solution;
heating the solution containing the crude solid and methanol to a temperature of from about 130° C. to about 140° C. and refluxing for about 0.1 to about 1 hours;
cooling the refluxed solution to a temperature of from about −30° C. to about 10° C. for about 8 to about 20 hours; and
isolating a solid from the cooled reflux solution to obtain a purified capped ABC tri-block copolymer;
wherein:
the purified copolymer is a polycaprolactone-b-polycarbonate-b-polylactide block copolymer;
a ratio of a polydispersity index of the crude solid to a polydispersity index of the purified copolymer is from about 1.02 to about 1.25;
a ratio of a molecular weight of the crude solid to a molecular weight of the purified block copolymer is from about 0.75 to about 1.0;
a ratio of a number average molecular weight of the crude solid to a number average molecular weight of the purified copolymer is from about 0.65 to about 1.0; and
an amount of impurities remaining in the purified copolymers is from about 0 to about 5 wt % based on a total weight of the purified copolymer.

Assignees

• Xerox Corp
• Nat Res Council Canada

Inventors

• Myles Andrew J
• Moffat Karen A
• Wosnick Jordan H
• Farrugia Valerie M

Classifications

• C08G63/912 Primary

  derived from hydroxycarboxylic acids · CPC title

• C08G63/64

  Polyesters containing both carboxylic ester groups and carbonate groups · CPC title

• C08G63/90 Primary

  Purification; Drying · CPC title