Method of purifying a polymer
View Patent ↗A method for purifying a polymer comprising providing a first mixture comprising at least one solvent and at least one polymeric material, diluting the first mixture with veratrole to produce a second mixture in which the polymeric material is substantially dissolved at a temperature less than 100° C., performing at least one step selected from (i) contacting the second mixture with an aqueous wash solution, and (ii) filtering the second mixture.
1. A method of purifying a polymer, said method comprising:
(a) providing a first mixture comprising at least one solvent and at least one polyetherimide wherein the at least one solvent comprises a halogenated aromatic solvent;
(b) diluting said first mixture with veratrole to produce a second mixture in which the polyetherimide is substantially dissolved, as indicated by a single organic phase at a temperature in a range from about 25° C. to about 100° C., and then;
(c) performing at least one step selected from:
(i) contacting the second mixture with an aqueous wash solution, and
(ii) filtering said second mixture.
2. The method according to claim 1 , wherein said polyetherimide has a glass transition temperature in a range from about 230° C. to about 280° C.
3. The method according to claim 2 , wherein said polyetherimide has a glass transition temperature in a range from about 250° C. to about 270° C.
4. The method according to claim 1 , wherein the polyetherimide comprises structural units having Formula (I):
wherein X comprises a bond, a —C(CH 3 ) 2 group, —O—, or —S—.
5. The method according to claim 1 , wherein the polyetherimide is a polyetherimidesulfone comprising structural units having Formula (II):
6. The method according to claim 1 , wherein said polyetherimide is a polyetherimide-polyetherimide sulfone copolymer.
7. The method according to claim 1 , wherein said at least one solvent comprises orthodichorobenzene.
8. The method according to claim 1 , wherein said at least one solvent consists essentially of orthodichorobenzene.
9. The method according to claim 1 , wherein diluting is carried out at a temperature in a range from about 80° C. to about 250° C.
10. The method according to claim 1 , wherein diluting is carried out at a temperature in a range from about 80° C. to about 180° C.
11. The method according to claim 1 , wherein said aqueous wash solution comprises an acid.
12. The method according to claim 11 , wherein said acid is an inorganic acid.
13. The method according to claim 1 , wherein said first mixture comprises at least 20 percent by weight polyetherimide based on a total weight of polyetherimide and solvent.
14. The method according to claim 1 , wherein said second mixture comprises from about 5 weight percent to about 15 weight percent of polyetherimide based on a total weight of polyetherimide, solvent, and veratrole.
15. A method of preparing a polymer, said method comprising:
(a) polymerizing a dianhydride and a diamine to provide a first mixture comprising at least one solvent and at least one polymeric material wherein the at least one solvent comprises a halogenated aromatic solvent;
(b) diluting said first mixture with veratrole to produce a second mixture in which the polymeric material is substantially dissolved at a temperature less than 100° C.;
(c) performing at least one step selected from:
(i) contacting the second mixture with an aqueous wash solution, and
(ii) filtering said second mixture.