Method of making polymers

Abstract

A method of making a polymer having the structure (I): ##STR00001##
wherein L is a linking group, R is a hydrocarbon group or a substituted-hydrocarbon group, and x is 2 or more, preferably from 2 to 100, more preferably from 2 to 50; and wherein each {Q} is an identical polymer block or contains a plurality of polymer blocks. The method comprises reacting a di-halo initiator with a selected monomer one or more times and then reacting the resulting moiety with a dithiol compound of the structure HS—R—SH.

Claims

1. A method of making a polymer having the structure (I): ##STR00015## wherein L is a linking group, R is a hydrocarbon group or a substituted-hydrocarbon group, and x is 2 or more; and wherein each {Q} contains a plurality of polymer blocks, such that the moiety {Q}-L-{Q} has the structure {P.sub.n . . . P.sub.2P.sub.1}-L-{P.sub.1P.sub.2, . . . P.sub.n} where each P.sub.n is an individual polymer block, the number of polymer blocks n in each {Q} being the same; wherein for each value of n the polymer blocks are identical; and wherein n is an integer of 2 or more; the method comprising: (i) reacting, in the presence of a catalyst comprising a transition metal-ligand complex, a di-halo initiator of the structure halo-L-halo, where halo is Br, Cl, or I, with a monomer of structure (II), or a mixture of two or more different monomers of structure (II): ##STR00016## wherein R.sub.1 or each R.sub.1 is independently hydrogen or methyl; wherein X or each X is independently a hydrocarbon group having from 1 to 50 carbon atoms, a substituted-hydrocarbon group having from 1 to 50 carbon atoms, COOR.sub.2, COSR.sub.2, CONR.sub.2R.sub.3, OCOR.sub.2, CONHR.sub.2, CN, COSiR.sub.2R.sub.3R.sub.4 or Cl, wherein R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, a hydrocarbon group having from 1 to 50 carbon atoms, or a substituted-hydrocarbon group having from 1 to 50 carbon atoms, to form a di-halo moiety with the structure halo-P.sub.1-L-P.sub.1-halo, where P.sub.1 is a polymer block formed from at least 3 monomers of structure (II); (ii) repeating step (i), between 1 and n times, each time n, reacting, in the presence of a catalyst as described in step (i), the di-halo moiety formed in the previous step with a further monomer of structure (II) and different from the monomer of structure (II) used in the previous step, or a mixture of two or more different monomers of structure (II) and different from the mixture of two or more different monomers of structure (II) used in the previous step, to form a di-halo moiety with the structure halo-{P.sub.n . . . P.sub.2P.sub.1}-L-{P.sub.1P.sub.2 . . . P.sub.n}-halo, where each P.sub.n is a polymer block formed from at least 3 monomers of structure (II), and n is an integer of 2 or more; and (iii) reacting the di-halo moiety formed in step (i) or if step (ii) is used, the moiety formed in step (ii), with a dithiol compound of the structure HS—R—SH.

2. A method according to claim 1, wherein each X is COOR.sub.2, wherein in at least one instance, R.sub.2 is a straight-chain or branched alkyl group, and wherein in at a least one other instance, R.sub.2 is a polyalkylene glycol residue of the formula —[(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is the average number of [(CR.sub.5H).sub.yO] moieties and is from 2 to 100, R.sub.5 is hydrogen or an alkyl group and R.sub.6 is hydrogen, an alkyl group or an aryl group.

3. A method according to claim 1, wherein step (ii) is repeated once and each X is COOR.sub.2, wherein in one instance, R.sub.2 is a branched alkyl group, and wherein in the other instance, R.sub.2 is a polyalkylene glycol residue of the formula —[(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is the average number of [(CR.sub.5H).sub.yO] moieties and is from 2 to 100, R.sub.5 is hydrogen or an alkyl group such as methyl or ethyl and R.sub.6 is hydrogen, an alkyl group or an aryl group.

4. A method according to claim 3, wherein the branched alkyl group is 2-ethylhexyl, and the polyalkylene glycol residue is of the formula —[(CH.sub.2).sub.yO].sub.zOMe where y is 2.

5. A method according to claim 4, wherein the branched alkyl group is 2-ethylhexyl, and the polyalkylene glycol residue is of the formula —[(CH.sub.2).sub.yO].sub.zOMe where y is 2 and z is an average value of 7 to 8.

6. A method according to claim 1, wherein step (ii) is repeated twice; wherein in one instance, R.sub.2 is a branched alkyl group and in the other two instances, R.sub.2 is a polyalkylene glycol residue of the formula —[(CR.sub.5H).sub.yO].sub.zOR.sub.6 where y is an integer from 2 to 4, and z is the average number of [(CR.sub.5H).sub.yO] moieties and is from 2 to 100, R.sub.5 is hydrogen or an alkyl group and R.sub.6 is hydrogen, an alkyl group or an aryl group.

7. A method according to claim 6, wherein the branched alkyl group is 2-ethylhexyl, and each polyalkylene glycol residue is the same and of the formula —[(CH.sub.2).sub.yO].sub.zOMe where y is 2.

8. A method according to claim 7, wherein the branched alkyl group is 2-ethylhexyl, and each polyalkylene glycol residue is the same and of the formula —[(CH.sub.2).sub.yO].sub.zOMe where y is 2 and z is an average value of 7 to 8.

9. A method according to claim 1, wherein the di-halo initiator of the structure halo-L-halo is: ##STR00017## where a is an integer from 1 to 10.

10. A method according to claim 1, wherein the dithiol compound of the structure HS—R—SH is: ##STR00018##

11. A method according to claim 1, wherein the transition metal-ligand complex is a copper-ligand complex.

12. A method according to claim 1, wherein the ligand used to form the transition metal-ligand complex is a nitrogen-containing ligand, more preferably a multidentate nitrogen-containing ligand.

13. A method according to claim 12, wherein the ligand used to form the transition metal-ligand complex is tris(2-dimethylaminoethyl)amine (Me.sub.6TREN).

14. A method according to claim 1, wherein the catalyst used in steps (i) and (ii) is a copper complex of tris(2-dimethylaminoethyl)amine (Me.sub.6TREN).

15. A method according to claim 1, wherein step (iii) is conducted in the presence of a base.

16. A method according to claim 15, wherein the base used in step (iii) is an alkylamine.

17. A method according to claim 1, wherein the catalyst used in steps (i) and (ii) is a copper complex of tris(2-dimethylaminoethyl)amine (Me.sub.6TREN) and step (iii) is conducted in the presence of triethylamine.

Description

WORKED EXAMPLES

(1) Synthesis of Polyacrylate Polymers

(2) The Table below details polymers made according to the method of the present invention. All were made using the reactants listed in the Table.

(3) Step (i)

(4) Monomer 1, ethylene glycol-derived bisinitiator [see below *] (1.00 equiv.), tris(2-dimethylaminoethyl)amine (Me.sub.6TREN) (0.36 equiv.), CuBr.sub.2 (0.10 equiv.) and DMSO (50% v/v) were charged to a Schlenk tube and sealed with a rubber septum. After degassing the reaction mixture for 30 minutes, a stirring bar wrapped with pre-activated copper wire (5 cm) was added to the reaction mixture in a counter-current of nitrogen. As described above, the copper species and the Me.sub.6TREN form a copper-ligand complex in situ. The tube was sealed again and the reaction mixture stirred at 25° C. until full conversion was observed (between 4 and 12 hours). Conversion was measured by 1H NMR spectroscopy and SEC analysis was carried out with samples diluted in THF which were filtered over basic alumina prior to analysis to remove residual copper species.

(5) Step (ii)

(6) Monomer 2 in DMSO (50% v/v) and another portion of Me.sub.6TREN (0.36 equiv.) and CuBr.sub.2 (0.10 equiv.) were added into a glass vial and degassed for 30 minutes before transferring to the reaction mixture from Stage 1. The tube was sealed again and the reaction mixture stirred at 25° C. until full conversion was observed.

(7) Step (iii)

(8) After full monomer conversion, a solution of bisthiol (1.00 equiv.) and triethylamine in DMF was added at ambient temperature to the reaction mixture. The mixture was then stirred overnight at room temperature before SEC analysis was carried out. The crude product was purified by filtration over basic alumina followed by precipitation from cold methanol to provide the pure polymer as a yellowish oil. The polymer obtained was characterised by 1H NMR and GPC with RI and UV detectors.

(9) The structures of the polymers obtained are given below the Table. In each case, the ethylene glycol derived bisinitiator was the following compound:

(10) ##STR00013##

(11) TABLE-US-00001 Monomer Monomer 1 2 bisthiol Mn(g/mol) Ð Polymer PEG EH 4,4′- 55900 2.42 1 thiodibenzenethiol Polymer PEG EH 4,4′- 74800 2.57 2 thiodibenzenethiol PEG: polyethylene glycol acrylate (Mn of polyethylene glycol group = 480 g/mol) EH: 2-ethylhexyl acrylate

(12) ##STR00014##