Block copolymers containing functional groups
View Patent ↗The present invention provides a block copolymer of styrene and an unsaturated cyclic anhydride, such as maleic anhydride, a process for making a copolymer using controlled free radical polymerization in which certain parameters are adjusted to control the microstructure and molecular weight of the copolymer, and a method for using the block copolymer, including as a compatibilizer. Microstructure and molecular weight in the block copolymer can be controlled by adjusting the ratio of stable free radical to initiator. The copolymer can be made in a one step process and has a controlled microstructure that allows one block to be reactive toward several chemical moieties available in engineering polymers and the other block to be fully miscible with polystyrene or polymers miscible with polystyrene or polymers miscible with polystyrene such as polyphenylene ether.
1. A process for producing a block copolymer, comprising:
heating a mixture of styrene and an unsaturated cyclic anhydride (UCA) in the presence of a free radical initiator and a stable free radical at temperatures between about 110 and about 200° C. to form a block copolymer in a single monomer-addition step, adjusting or setting the ratio of initiator to monomer in order to control the total length of the block copolymer, cooling the reaction mixture; and recovering the block copolymer by isolating the block copolymer from un-reacted monomer, wherein the composition of the block copolymer comprises:
a first block comprising a random copolymer of styrene and unsaturated cyclic anhydride having a total length between about 1 and about 720 monomeric units; and
a second block comprising an essentially pure polystyrene block having a length between about 100 and about 2000 monomeric units, wherein
the polydispersity of the block copolymer is between about 1.2 and about 3, and wherein
the resulting block copolymer has a number average molecular weight greater than about 25,000.
2. The process of claim 1 , wherein the first block has an alternating character given by the reactivity ratios of the monomers.
3. The process of claim 1 , wherein the number average molecular weight of the chain is controlled by adjusting or setting the molar concentration of initiator to a value of about
A−(5×108 −8 Mn) if the desired molecular weight is larger than or equal to 61500, and
B−(3.33×10 −7 Mn) if the desired molecular weight is smaller than 61500,
wherein Mn is a target value for number average molecular weight; A is between about 0.005 and about 0.01; and B is between about 0.016 and about 0.042.
4. The process of claim 1 , wherein the value of the molar ratio of stable free radical to initiator is at least about
1.3+0.10*(weight percentage of UCA with respect to total monomers).
5. The process of claim 1 , wherein the UCA is maleic anhydride.
6. The process of claim 1 , wherein the UCA is itaconic anhydride.
7. The process of claim 1 , wherein the temperature range is between about 120 and about 17° C.
8. The process of claim 1 , wherein the temperature range is between about 120 and about 150° C.
9. The process of claim 1 , wherein the proportion of UCA in the mixture of styrene and an UCA is in the range of about 0.09 to about 18% by weight.
10. The process of claim 1 , wherein the proportion of UCA in the mixture of styrene and an UCA is in the range of about 0.3 to about 10% by weight.
11. The process of claim 1 , wherein the proportion of UCA in the mixture of styrene and an UCA is in the range of about 0.9 to about 8% by weight.
12. The process of claim 1 , wherein the stable free radical is a nitroxyl free radical.
13. The process of claim 12 , wherein the nitroxyl free radical is selected from the group consisting of:
14. The process of claim 1 , wherein the free radical initiator is selected from the group consisting of: 2,2′-azobis (2-methylpropanenitrile), 2,2′-azobis(2-methylbutanenitrile), dibenzoyl peroxide (BPO), tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane and tert-butyl peroxydiethylacetate.
15. A process for producing a block copolymer, consisting essentially of:
heating styrene and an unsaturated cyclic anhydride in the presence of a free radical initiator and 4-hydroxy 2,2,6,6 tetramethyl-piperidine-N-oxyl and/or 4-oxo 2,2,6,6 tetramethyl-piperidine-N-oxyl stable free radical at temperatures between about 110 and about 200° C.;
cooling the reaction mixture; and recovering a block polymer by isolating the block copolymer ftom non-reacted monomer, wherein the block polymer comprises a first block that is a copolymer of the styrene and the unsaturated cyclic anhydride and a second block of polystyrene formed after the unsaturated cyclic anhydride is essentially depleted.
16. The process of claim 15 , wherein the number average molecular weight of the block copolymer is controlled by manipulating the molar concentration of initiator to have a value of about
A−(5×10 −8 Mn) if the desired molecular weight is larger than 61500, and
B−(3.33×10 −7 Mn) if the desired molecular weight is smaller than or equal to 61500,
in which Mn is a target value for number average molecular weight; A is between about 0.005 and about 0.01 and B is between about 0.016 and about 0.042.
17. A process for producing a block copolymer, comprising:
adding styrene monomer and an unsaturated cyclic anhydride monomer to a reactor in a single monomer-addition step;
heating the styrene monomer and the unsaturated cyclic anhydride monomer to a temperature range between about 110 and about 200° C.;
adding a free radical initiator to the reactor;
adding a stable free radical to the reactor; and
manipulating or adjusting or setting the molar ratio of free radical initiator to total monomer in order to recover a block copolymer having a number average molecular weight range of between about 25,000 and about 200,000.
18. The process of claim 17 , wherein the process is continuous.
19. The process of claim 17 , wherein a molar ratio of stable free radical to initiator is about: 1.3+0.10*(weight percentage of unsaturated cyclic anhydride with respect to total monomers).
20. The process of claim 17 , wherein the number average molecular weight of the block copolymer is controlled by setting the molar concentration of initiator to about
A minus (5×10 −8 ) times Mn, if the molecular weight is equal to or larger than 61500, and
B minus (3.33×10 −7 ) times Mn if the molecular weight is smaller than 61500,
where Mn is a desired number average molecular weight; A is between about 0.005 and about 0.01; and B is between about 0.016 and about 0.042.
21. A process comprising:
forming a block copolymer in essentially one step by heating styrene and unsaturated cyclic anhydride in the presence of a solvent, a free radical initiator and a stable free radical to a temperature ranging between about 110 and about 200° C. for more than about two hours,
wherein the number average molecular weight of the block copolymer lies in the range of between about 25,000 and about 200,000.
22. The process of claim 21 , wherein the block copolymer is formed in a reactor, and wherein the pressure in the reactor is adjusted to be above the vapor pressure of the reaction mixture.
23. The process of claim 21 , wherein the block copolymer is formed in a reactor, and wherein the pressure in the reactor is adjusted to be at least about that given by the formula
2.5 P o x s , if x s is less than or equal to 0.2 or
1.4 P o x s , if x s is equal to or greater than 0.2, where P o is the vapor pressure of the solvent at the temperature of the reaction, and x s is the mole fraction of solvent in the mixture of solvent and monomer.
24. The process of claim 21 , wherein the solvent is ethyl acetate, toluene, chloroform, xylene, acetone, ethyl benzene or mixtures thereof.
25. The process of claim 21 , wherein the solvent is present in an amount of 10-95% by weight based on the weight of monomers and solvent.
26. The process of claim 21 , wherein the solvent is present in an amount of 10-30% by weight based on the weight of monomers and solvent.
27. The process of claim 21 , wherein the solvent is present in an amount of 15-25% by weight based on the weight of monomers and solvent.
28. The process of claim 21 , wherein the solvent is present in an amount of 60-95% by weight based on the weight of monomers and solvent.
29. The process of claim 21 , wherein the solvent is present in an amount of 70-90% by weight based on the weight of monomers and solvent.
30. The process of claim 21 , wherein the solvent is present in an amount of 75-88% by weight based on the weight of monomers and solvent.
31. A process for producing a block copolymner, comprising:
heating to a temperature range between about 110 and about 200° C. in a reactor a mixture of styrene monomer and an unsaturated cyclic anhydride monomer wherein the proportion of unsaturated cyclic anhydride in the mixture styrene—unsaturated cyclic anhydride is in the range of about 0.09 to about 18 wt. %;
adding a free radical initiator to the reactor such that the molar ratio of monomer to initiator is about 100 to about 12000;
adding TEMPO or a derivative of TEMPO to provide a stable free radical such that the ratio of stable free radical to initiator is about 1.0 to about 3.0;
forming as a first block of a block copolymer a copolymer comprising styrene and unsaturated cyclic anhydride;
forming polystyrene as a second block of the block copolymer after the unsaturated cyclic anhydride monomer is essentially depleted;
cooling the reaction mixture; and
recovering the block copolymer by isolating the block copolymer from unreacted monomer, the block copolymer having a number avenge molecular weight greater than about 25,000 and consisting essentially of the first and second blocks.
32. The process of claim 31 , wherein the number average molecular weight of the block copolymer is between about 50,000 and about 100,000.
33. The process of claim 31 , wherein a solvent is added to the reaction mixture.
34. A process for producing a block copolymer of styrene and unsaturated cyclic anhydride without a prior step for making a homopolymer from the styrene or the unsaturated cyclic anhydride, comprising the steps of:
mixing styrene and an unsaturated cyclic anhydride in the presence of a solvent;
adding a free radical initiator to the mixture such that the molar ratio of monomer to initiator is about 100 to about 12000; and
adding as stable free radical 4-hydroxy 2,2,6,6 tetramethyl-piperidine-N-oxyl and/or 4-oxo 2,2,6,6 tetramethyl-piperidine-N-oxyl,
wherein a molar ratio of stable free radical to initiator is about 1.3±0.10*(weight percentage of UCA with respect to total monomers), and
wherein the weight percentage of UCA with respect to total monomers is between about 0.1 and about 16%.
35. The process of claim 34 , further comprising recovering the block copolymer, wherein the block copolymer has a number average molecular weight greater than about 35,000.
36. A process for controllably producing a diblock copolymer having a number average molecular weight greater than about 30,000 using living free radical polymerization, comprising the steps of:
maintaining styrene and an unsaturated cyclic anhydride (UCA) in a reactor at temperatures between about 110 and about 200°;
adding a free radical initiator to the reactor such that the molar ratio of monomer to initiator is about 100 to about 12000;
adding a stable free radical at a molar ratio of stable free radical to initiator of about 1.3+0.25*(weight percentage of UCA with respect to total monomers),
the weight percentage of UCA with respect to total monomers being between about 0.1 and about 6%;
forming initially a copolymer of styrene and UCA as a first block of a diblock copolymer; and
forming subsequently polystyrene as a second block of the diblock copolymer.
37. The process of claim 36 , wherein the stable free radical comprises 4-hydroxy 2,2,6,6 tetramethyl-piperidine-N-oxyl and/or 4-oxo 2,2,6,6 tetramethyl-piperidine-N-oxyl.
38. A process for producing a block copolymer, comprising:
reacting styrene monomer and an unsaturated cyclic anhydride monomer in the presence of a free radical initiator and a stable nitroxyl free radical and with a solvent having polarity at temperatures between about 110 and about 200° C.; and
recovering a block copolymer, wherein the composition of the block copolymer comprises:
a first block comprising a random copolymer of styrene and an unsaturated cyclic anhydride, with alternating character given by the reactivity ratios of the monomers, and a total length between about 1 and about 720 monomeric units; and
a second block comprising an essentially pure polystyrene block having a length between 100 and 2000 monomeric units, wherein
the polydispersity of the block copolymer is between about 1.2 and about 3.0, wherein
the resulting block copolymer has a number average molecular weight greater than about 25,000, and wherein
the second block is formed afier the first block is formed.
39. The process of claim 38 , wherein the molar ratio of nitroxyl radical to initiator is between about 1.3 and about 3.0.
40. The process of claim 38 , wherein the molar ratio of nitroxyl radical to initiator is between about 1.6 and about 2.5.
41. The process of claim 38 , wherein the molar ratio of nitroxyl radical to initiator is between about 1.9 and about 2.5.
42. The process of claim 38 , wherein the molar ratio of total monomer to initiator is in the range of about 100 to about 12,000.
43. The process of claim 38 , wherein the molar ratio of total monomer to initiator is in the range about 200 to about 3,000.
44. The process of claim 38 , wherein the molar ratio of total monomer to initiator is in the range about 600 to about 1,500, wherein the molar ratio of nitroxyl radical to initiator is between about 1.3 and about 3.0, and wherein the block copolymer consists essentially of the first and second blocks.
45. A process for making a copolymer, comprising:
heating styrene and an unsaturated cyclic anhydride in the presence of a free radical initiator and a stable free radical at temperatures between about 110 and about 200° C.;
agitating the reactants in a first reactor until a conversion of about 10 to about 50% is obtained;
maintaining the reactants in the first reactor or in a second reactor, without agitation, until a conversion of about 90 to about 100% is obtained; and
recovering a block copolymer, wherein the composition of the block copolymer comprises:
a first block comprising a random copolymer of styrene and an unsaturated cyclic anhydride, having a total length between about 1 and about 720 monomeric units; and
a second block comprising essentially pure polystyrene block having a length between about 100 and about 2000 monomeric units.
46. The process of claim 45 , wherein the block copolymer has a polydispersity between about 1.2 and about 3.0.
47. The process of claim 45 , wherein the unsaturated cyclic anhydride is maleic anhydride.
48. The process of claim 45 , wherein the unsaturated cyclic anhydride is itaconic anhydride.
49. A process for making a copolymer, comprising:
reacting styrene and an unsaturated cyclic anhydride (UCA) in the presence of a free radical initiator and a stable free radical to form a reaction mixture; and
recovering a block copolymer, wherein the composition of the block copolymer comprises:
a first block comprising a random copolymer of styrene and an unsaturated cyclic anhydride having a total length between about 1 and about 720 monomeric units; and
a second block of mostly polystyrene having a length between 100 and 2000 monomeric units, further comprising:
a) heating and passing the reaction mixture through a tubular reactor in which the exit fractional monomer conversion is numerically at least about twice the mass fraction of UCA in the feed (with respect to total monomer) to form a first intermediate;
b) passing the first intermediate into a continuous stirred tank reactor with exit conversions between about 10 and about 50% weight to form a second intermediate; and
c) passing the second intermediate through a tubular reactor in which the final conversion is between about 60 and about 100% by weight.
50. A process for making a copolymer, comprising:
reacting styrene and an unsaturated cyclic anhydride in the presence of a free radical initiator and a stable free radical to form a reaction mixture; and
recovering a block copolymer, wherein the composition of the block copolymer comprises:
a first block comprising a random copolymer of styrene and an unsaturated cyclic anhydride having a total length between about 1 and about 720 monomeric units; and
a second block of mostly polystyrene having a length between about 100 and about 2000 monomeric units, further comprising:
a) heating and passing the reaction mixture through a continuous stirred tank reactor with exit conversions between about 10 and about 50% by weight to form a first intermediate; and
b) passing the first intermediate through a tubular reactor in which the final conversion is between about 60 and about 100% by weight.
51. The process of claim 49 , wherein the unsaturated cyclic anhydride is maleic anhydride.
52. The process of claim 49 , further comprising recovering and recycling unreacted styrene monomer.
53. A process comprising:
forming a reaction mixture by heating styrene and unsaturated cyclic anhydride in the presence of a solvent, a free radical initiator and a stable free radical to a temperature ranging between about 110 and about 200 degrees C. in steps including:
a) heating and passing the reaction mixture through a first tubular reactor in which the exit fractional monomer conversion is numerically at least about twice the mass fraction of UCA in the feed (with respect to total monomer) to form a first intermediate; and
b) heating the first intermediate in a continuous stirred tank reactor with exit monomer conversion between about 10 and about 50% to form a second intermediate; and
c) passing the second intermediate through a second tubular reactor in order to obtain an exit monomer conversion between about 60 and about 100% by weight.
54. A process comprising:
forming a reaction mixture by heating styrene and unsaturated cyclic anhydride in the presence of a solvent, a free radical initiator and a stable free radical to a temperature ranging between about 110 and about 200° C. in steps including:
a) heating and passing the reaction mixture through a continuous stirred tank reactor with exit monomer conversion between about 10 and about 50% to form a first intermediate; and
b) passing the first intermediate through a tubular reactor in order to obtain an exit monomer conversion between about 60 and about 100% by weight.
55. The process of claim 53 , wherein the second tubular reactor is a vertical plug-flow reactor fed by the bottom.
56. The process of claim 53 , wherein the solvent is toluene, acetone, ethyl acetate, xylene, ethyl benzene or mixtures thereof.
57. The process of claim 53 , wherein the unsaturated cyclic anhydride is maleic anhydride.
58. The process of claim 53 , wherein the unsaturated cyclic anhydride is itaconic anhydride.
59. A process for making a block copolymer, comprising the steps of:
(a) making a first block by reacting styrene monomer, an unsaturated cyclic anhydride (UCA) monomer, a free radical initiator and a stable free radical;
(b) making a second block by continuing the reaction in step (a) after the UCA monomer is essentially depleted; and
(c) recovering a block copolymer consisting essentially of the first and second blocks, wherein the block copolymer has a number average molecular weight greater than about 25,000.
60. The process of claim 59 , wherein the fast block consists essentially of a copolymer of styrene and UCA and the second block consists essentially of polystyrene.
61. The process of claim 60 , wherein a temperature of at least about 110° C. is maintained while making the first and second blocks.
62. The process of claim 61 , wherein the block copolymer has a polydispersity between about 1.2 and about 3, wherein a molar ratio of total monomer to initiator is in the range of about 600 to about 1,500, and wherein a molar ratio of stable free radical to initiator is between about 1.3 and about 3.0.