Polycarbonate polyol compositions and methods
In one aspect, the present disclosure encompasses polymerization systems for the copolymerization of CO 2 and epoxides comprising 1) a catalyst including a metal coordination compound having a permanent ligand set and at least one ligand that is a polymerization initiator, and 2) a chain transfer agent having two or more sites that can initiate polymerization. In a second aspect, the present disclosure encompasses methods for the synthesis of polycarbonate polyols using the inventive polymerization systems. In a third aspect, the present disclosure encompasses polycarbonate polyol compositions characterized in that the polymer chains have a high percentage of —OH end groups and a high percentage of carbonate linkages. The compositions are further characterized in that they contain polymer chains having an embedded polyfunctional moiety linked to a plurality of individual polycarbonate chains.
1. A polycarbonate polyol composition comprising an epoxide CO 2 copolymer, characterized in that the copolymer has:
an Mn between about 1,000 and about 3,000 g/mol; and
greater than 99% carbonate linkages;
wherein the composition comprises epoxide CO 2 copolymer chains denoted P 1 that:
(i) have the formula:
wherein
each E comprises predominantly —CH 2 CH(CH 3 )— units derived from propylene oxide;
p ranges from 5 to 10,000; and
-A- is a polyether; or
(ii) are derived from a diol chain transfer agent selected from a polyether; and
wherein the composition is characterized in that more than 99% of the epoxide CO 2 copolymer chains are of type P 1 .
2. The polycarbonate polyol composition of claim 1 , further comprising epoxide CO 2 copolymer chains denoted P 2 having a formula selected from the group consisting of:
wherein
X is a bound form of an anion capable of initiating only one polymer chain;
wherein the ratio of P 1 polymer chains to P 2 polymer chains is greater than 100:1.
3. The polycarbonate polyol composition of claim 2 , characterized in that the copolymer has an Mn of about 1,000 g/mol, about 2,000 g/mol, or about 3,000 g/mol.
4. The polycarbonate polyol composition of claim 3 , wherein the composition comprises epoxide CO 2 copolymer chains denoted P 1 that have the formula:
wherein
each E comprises predominantly —CH 2 CH(CH 3 )— units derived from propylene oxide;
p ranges from 5 to 10,000; and
-A- is a polyether.
5. The polycarbonate polyol composition of claim 4 , wherein the chains of type P 1 are derived from a diol chain transfer agent selected from a poly(propylene glycol) having a Mn from 234 to 2,000 g/mol.
6. The polycarbonate polyol composition of claim 4 , characterized in that:
the polydispersity index is less than about 1.1; and
more than 99% of linkages between adjacent epoxide monomer units are head-to-tail linkages.
7. The polycarbonate polyol composition of claim 5 , characterized in that:
the polydispersity index is less than about 1.1; and
more than 99% of linkages between adjacent epoxide monomer units are head-to-tail linkages.
8. A method for the synthesis of a polycarbonate polyol composition of claim 1 , the method comprising the step of:
a) providing a reaction mixture comprising:
(i) propylene oxide;
(ii) carbon dioxide;
(iii) a metallosalenate metal complex; and
(iv) a chain transfer agent selected from a poly(propylene glycol) having a Mn from 234 to 2,000 g/mol;
b) allowing the polymerization reaction to proceed; and
c) terminating the polymerization.
9. The method of claim 8 , wherein the chain transfer agent and metal complex are present in a molar ratio ranging of greater than 1000:1.
10. A polycarbonate polyol composition comprising an epoxide CO 2 copolymer, characterized in that the copolymer has:
an Mn between about 400 and about 4,000 g/mol; and
greater than 99% carbonate linkages;
wherein the composition comprises epoxide CO 2 copolymer chains denoted P 1 that:
(i) have the formula:
wherein
each E comprises predominantly —CH 2 CH(CH 3 )— units derived from propylene oxide;
p ranges from 5 to 10,000; and
A- is
(mixture isomers); or
(ii) are derived from a diol chain transfer agent selected from dipropylene glycol; and
wherein the composition is characterized in that more than 99% of the epoxide CO 2 copolymer chains are of type P 1 .
11. The polycarbonate polyol composition of claim 10 , further comprising epoxide CO 2 copolymer chains denoted P 2 having a formula selected from the group consisting of:
wherein
X is a bound form of an anion capable of initiating only one polymer chain;
wherein the ratio of P 1 polymer chains to P 2 polymer chains is greater than 100:1.
12. The polycarbonate polyol composition of claim 11 , characterized in that the copolymer has an Mn of about 1,000 g/mol, about 2,000 g/mol, or about 3,000 g/mol.
13. The polycarbonate polyol composition of claim 12 , wherein the composition comprises epoxide CO 2 copolymer chains denoted P 1 that have the formula:
wherein
each E comprises predominantly —CH 2 CH(CH 3 )— units derived from propylene oxide;
p ranges from 5 to 10,000; and
-A- is
(mixture isomers).
14. The polycarbonate polyol composition of claim 12 , wherein the chains of type P 1 are derived from a diol chain transfer agent selected from dipropylene glycol.
15. The polycarbonate polyol composition of claim 13 , characterized in that:
the polydispersity index is less than about 1.1; and
more than 99% of linkages between adjacent epoxide monomer units are head-to-tail linkages.
16. The polycarbonate polyol composition of claim 14 , characterized in that:
the polydispersity index is less than about 1.1; and
more than 99% of linkages between adjacent epoxide monomer units are head-to-tail linkages.
17. A method for the synthesis of a polycarbonate polyol composition of claim 10 , the method comprising the step of:
a) providing a reaction mixture comprising:
(i) propylene oxide;
(ii) carbon dioxide;
(iii) a metallosalenate metal complex; and
(iv) a chain transfer agent selected from a dipropylene glycol;
wherein the chain transfer agent and metal complex are present in a molar ratio ranging of greater than 1000:1;
b) allowing the polymerization reaction to proceed; and
c) terminating the polymerization.
18. A polycarbonate polyol composition comprising an epoxide CO 2 copolymer, characterized in that the copolymer has:
an Mn between about 800 and about 4,000; and
greater than 99% carbonate linkages;
wherein the composition comprises epoxide CO 2 copolymer chains denoted P 1 that:
(i) have the formula:
wherein
each z is independently 0 or 1;
each E comprises predominantly —CH 2 CH(CH 3 )— units derived from propylene oxide;
p ranges from 5 to 10,000; and
A- is a polyether; or
(ii) are derived from a diol chain transfer agent selected from polypropylene oxide triol; and
wherein the composition is characterized in that more than 99% of the epoxide CO 2 copolymer chains are of type P 1 .
19. The polycarbonate polyol composition of claim 18 , further comprising epoxide CO 2 copolymer chains denoted P 2 having a formula selected from the group consisting of:
wherein
X is a bound form of an anion capable of initiating only one polymer chain;
wherein the ratio of P 1 polymer chains to P 2 polymer chains is greater than 100:1.
20. The polycarbonate polyol composition of claim 19 , characterized in that the copolymer has an Mn of about 1,000 g/mol, about 2,000 g/mol, or about 3,000 g/mol.
21. The polycarbonate polyol composition of claim 20 , wherein the composition comprises epoxide CO 2 copolymer chains denoted P 1 that have the formula:
wherein
each z is independently 0 or 1;
each E comprises predominantly —CH 2 CH(CH 3 )— units derived from propylene oxide;
p ranges from 5 to 10,000; and
-A- is a polyether.
22. The polycarbonate polyol composition of claim 20 , wherein the chains of type P 1 are derived from a diol chain transfer agent selected from polypropylene oxide triol.
23. A method for the synthesis of a polycarbonate polyol composition of claim 18 , the method comprising the step of:
a) providing a reaction mixture comprising:
(i) propylene oxide;
(ii) carbon dioxide;
(iii) a metallosalenate metal complex; and
(iv) a chain transfer agent selected from a polypropylene oxide triol;
b) allowing the polymerization reaction to proceed; and
c) terminating the polymerization.
24. The method of claim 23 , wherein the chain transfer agent and metal complex are present in a molar ratio ranging of greater than 1000:1.