Polycarbonate block copolymers
The disclosure pertains to amphiphilic block copolymers comprising an aliphatic polycarbonate chain coupled to a hydrophilic polymer. Such amphiphilic polymers may have the formula A-L-B, where A- is a polycarbonate or polyethercarbonate chain having from about 3 to about 500 repeating units, L is a linker moiety and —B is a hydrophilic oligomer having from about 4 to about 200 repeating units. Provided copolymers are useful as surfactants capable of emulsifying aqueous solutions and supercritical carbon dioxide. Provided copolymers also have utility as additives for use in enhanced oil recovery methods.
1. A polymer composition comprising a block copolymer having a formula:
where X is selected from the group consisting of: halogen; —OH; azide, nitrile, and —OR z ;
each R a , R b , R c , and R d is independently selected from the group consisting of: hydrogen, halogen, —CH 2 OR z , optionally substituted C 1-10 aliphatic, optionally substituted 6- to 14-membered aromatic, optionally substituted 3- to 14-membered heterocyclic, and optionally substituted 5- to 14-membered heteroaryl, and where any two or more of R a , R b , R c , and R d may be taken together to form an optionally substituted 3- to 12-membered ring, optionally containing one or more heteroatoms;
L is a bond or a polyfunctional moiety;
B is a hydrophilic oligomer having from about 4 to about 100 repeating units;
n is an integer between 4 and 100;
R z is selected from the group consisting of R 10 , —C(O)R 10 ,—SO 2 R 10 , —Si(R 10 ) 3 , —C(O)N(R 10 ) 2 ; and
R 10 is an optionally substituted moiety selected from the group consisting of: C 1-20 aliphatic; C 1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.
2. The polymer composition of claim 1 , wherein the block copolymer has the formula:
wherein, R 100 is optionally present, and if present is selected from the group consisting of —CH 3 , —CF 3 , —CH 2 CH 3 , —CH 2 OR z , and —CH 2 Cl.
3. The polymer composition of claim 2 , wherein the block copolymer has the formula:
4. The polymer composition of claim 2 , wherein the block copolymer has the formula:
wherein X′ is selected from the group consisting of —OH and —OR z .
5. The polymer composition of claim 2 , wherein R 100 is a methyl group.
6. The polymer composition of claim 2 , wherein R 100 is an ethyl group.
7. The polymer composition of claim 2 , wherein R 100 is a random mixture of methyl groups and one or more moieties selected from group consisting of ethyl, trifluoromethyl, chloromethyl, —CH 2 OR z and a C 6-30 alkyl group.
8. The polymer composition of claim 1 , wherein X is —OH.
9. The polymer composition of claim 1 , wherein X is —OR z .
10. The polymer composition of claim 1 , wherein —B is selected from the group consisting of: polyethers, polyolefin bearing hydrophilic functional groups, polypeptides, polysaccharides and polyamines.
11. The polymer composition of claim 10 , wherein —B is a polyether.
12. The polymer composition of claim 11 , wherein the block copolymer has the formula:
wherein, m is an integer between 5 and 200;
R 100 is optionally present, and if present is selected from the group consisting of —CH 3 ,
—CF 3 , —CH 2 CH 3 , —CH 2 OR z , and —CH 2 Cl;
—Z— is an optionally substituted C 1-6 aliphatic group; and
—Y is selected from the group consisting of —H and R z .
13. The polymer composition of claim 12 , wherein —Z— is —CH 2 CH 2 —.
14. The polymer composition of claim 12 , wherein —Z— is —CH(CH 3 )CH 2 —.
15. The polymer composition of claim 12 , wherein the copolymer has the formula:
wherein X′, is —OH or —OR z , and
Y′ is selected from the group consisting of optionally substituted C 1-8 aliphatic, a silyl protecting group, and —C(O)R 10 .
16. The polymer composition of claim 13 , wherein the block copolymer comprises polypropylene carbonate) and poly(ethylene glycol).
17. The polymer composition of claim 16 , wherein the block copolymer is selected from the group consisting of:
18. A polymer composition comprising a block copolymer having a formula:
wherein
X′ is selected from the group consisting of —OH and —OR z ;
R 100 is optionally present, and if present is selected from the group consisting of —CH 3 , —CF 3 , —CH 2 CH 3 , —CH 2 OR z , and —CH 2 Cl;
each n is independently an integer between 4 and 100;
—Z— is an optionally substituted C 1-6 aliphatic group;
m is an integer between 5 and 200;
R z is selected from the group consisting of R 10 , —C(O)R 10 , 13 SO 2 R 10 , —Si(R 10 ) 3 ,)—C(O)N(R 10 ) 2 ; and
R 10 is at each occurrence an optionally substituted moiety independently selected from the group consisting of: C 1-12 aliphatic; C 1-12 heteroaliphatic; 6- to 14-membered aryl;
and 5- to 14-membered heteroaryl.
19. The polymer composition of claim 12 , wherein the copolymer is selected from the group consisting of:
20. The polymer composition of claim 18 , wherein the copolymer is selected from the group consisting of:
21. The polymer composition of claim 1 , wherein the polycarbonate chain contains greater than about 90% carbonate linkages.
22. The polymer composition of claim 1 , wherein the polycarbonate chain contains greater than about 95% carbonate linkages.
23. The polymer composition of claim 1 , wherein the polycarbonate chain contains essentially no detectable ether linkages.
24. The polymer composition of claim 1 , wherein, on average in the composition, the head-to-tail ratio of adjacent
groups is greater than 80%.
25. A method of forming an emulsion of supercritical CO 2 and an aqueous phase, the method comprising a step of agitating supercritical CO 2 and the aqueous phase in the presence of a block copolymer of claim 1 .
26. A method of modifying the viscosity of a fluid comprising a mixture of supercritical CO 2 and water, the method comprising a step of agitating the mixture in the presence of a block copolymer of claim 1 .
27. A method of forming an emulsion of supercritical CO 2 and an aqueous phase, the method comprising a step of agitating supercritical CO 2 and the aqueous phase in the presence of a block copolymer of claim 18 .
28. A method of modifying the viscosity of a fluid comprising a mixture of supercritical CO 2 and water, the method comprising a step of agitating the mixture in the presence of a block copolymer of claim 18 .