SYNTHETIC METHOD FOR THE PREPARATION OF RHEOLOGICAL MODIFYING POLYMERS AND THE USE THEREOF

Abstract

The invention relates to a UV-initiated RAFT-type polymerization for producing hydrophobically associative terpolymers in an aqueous solution. The terpolymers produced by this method can be used as aqueous rheological modifiers. Specifically, the invention relates to a hydrophobically associating terpolymers and a method to produce same using a light initiated iniferter. The monomers used in the present invention are selected from: a monomer having a water-soluble monoethylenically unsaturated group; a monomer having an ionic water-soluble monoethylenically unsaturated group; and a monomer having a monoethylenically unsaturated monomer capable of forming hydrophobically associative bonds in aqueous medium. The iniferter is initiated with light of wavelength between 250-400 nm. The resultant terpolymer is produced in a cost-effective, simple, and one-step process and can be used to thicken aqueous mediums with less or equal amounts of polymer than currently available.

Claims

1. A terpolymer resulting from polymerization of a mixture of monomers selected from: i. monomer A, having a water-soluble monoethylenically unsaturated group; ii. monomer B, having an ionic water-soluble monoethylenically unsaturated group; and iii. monomer C, having a monoethylenically unsaturated monomer capable of forming hydrophobically associative bonds in aqueous medium and amenable to aqueous polymerization conditions.

2. The terpolymer of claim 1, having a viscosity greater than 1000 cP in fresh water.

3. The terpolymer of claim 1, having a weight average molecular weight ≥1.0×10.sup.6 g mol.sup.−1.

4. The terpolymer of claim 1, wherein monomer A is selected from a group consisting of R.sup.1—(C═C)—(C═O)—O—R.sup.2 or R.sup.1—(C═C)—(C═O)—N—(R.sup.3)—R.sup.4, in which: R.sup.1 is H or methyl; R.sup.2 is methyl, ethyl, propyl, butyl, epoxymethyl, methanol, ethanol, N,N-dimethylethyl, PEG (where the molecular weight is between 50-1000 g mol.sup.−1), benzyl, phenyl; R.sup.3 is H, methyl, or ethyl; and R.sup.4 is H, methyl, ethyl, isopropyl, propan-2-ol.

5. The terpolymer of claim 1, wherein monomer B is selected from a group consisting in the following monomers and the mixtures thereof B is R.sup.1—(C═C)—(C═O)—O—R.sup.5 or R.sup.1—(C═C)—(C═O)—N—(R.sup.6)—R.sup.7 or R.sup.1—(C═C)—(C═O)—R.sup.8, in which: R.sup.1 is H or methyl; R.sup.5 is H, methyl, ethyl, propyl, butyl, pentyl, hexyl, C9-C24 linear or branched chains; R.sup.6 is poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, wherein the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4-20 carbons in length; R.sup.7 is poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, wherein the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4-20 carbons in length; R.sup.8 poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl; and R.sup.2 is O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid.

6. The terpolymer of claim 1, wherein monomer C is selected from a group consisting in the following monomers and the mixtures thereof: R.sup.1—(C═C)—(C═O)—O—R.sup.9 or R.sup.3—(C═C)—(C═O)—N—(R.sup.10)—R.sup.11 or R.sup.1(C═C)—R.sup.12, in which: R.sup.1 is H or methyl; R.sup.9 is O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid, poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, wherein the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4 to 20 carbons in length; R.sup.10 is H, O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid; R.sup.11 is O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid; and R.sup.12 is poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, wherein the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4-20 carbons in length.

7. The terpolymer according to claim 1, wherein the monomer A in is present in an amount of from 25.0-99.9% by mol, the monomer B is present in an amount of from 25.0-99.9% by mol, and the monomer C is present in an amount of from 0.1-5.0% by mol, each based on the total molar amount of all components in the copolymer.

8. A process for preparation of a terpolymer comprising the steps of: i. combining of a mixture of monomers selected from the group comprising; monomer A, having a water-soluble monoethylenically unsaturated group, monomer B, having an ionic water-soluble monoethylenically unsaturated group, and monomer C, having a monoethylenically unsaturated monomer capable of forming hydrophobically associative bonds in aqueous medium and amenable to aqueous polymerization conditions; with an iniferter selected from the group comprising R.sup.1—(C═S)—S—Z.sup.1 or R.sup.2—S—(C═S)—S—Z.sup.2 in which; R.sup.1 is methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, t-butoxy, benzyl, phenyl, N-methylaniline, Z.sup.1 is propanoic acid, propanoate, phenylpropane-2-yl, cyanomethyl, cyanopropan-2-yl, R.sup.2 is a linear or branched alkyl chain (carbon length between C1-C12), benzyl, phenyl, isobutyronitrile, propanoate, propanoic acid, benzyl isobutyrate, 2-(pyridin-2-yldisulfanyl)ethyl propionate, Z.sup.2 is propanoate, propanoic acid, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, benzyl, benzyl isobutyrate, PEGylated 2-cyanopropanoic acid, to produce a reaction mixture; ii. sparging the reaction mixture with an inert gas; and iii. initiating the iniferter with light of wavelength between 250-400 nm.

9. The process according to claim 8 wherein the iniferter is initiated with light of wavelength 250-400 nm.

10. The process according to claim 8 wherein the preparation is conducted in a solvent system consisting of water and a polar protic or polar aprotic solvent with a range of water to polar protic or polar aprotic solvent between 100/0-51/49.

11. The process according to claim 8, wherein the terpolymer, is produced in the form of a gel.

12. A method comprising thickening a water-based solution by adding thereto a sufficient amount of the terpolymer according to claim 1 to thicken the water-based solution.

13. The method according to claim 12, wherein the solution is used to develop or exploit to completion subterranean mineral oil deposits or natural gas deposits.

14. The method according to claim 12, where the solution is used to transport a proppant, typically sand, treated sand, or man-made ceramic materials.

15. The method according to claim 14, wherein the proppant functions to keep an induced hydraulic fracture open.

16. The method according to claim 12, to enhance oil recovery by injecting the water-based solution in a concentration of 0.01-5% by weight through at least one injection well into a mineral oil deposit; and removing crude oil from the deposit through at least one production well.

17. The method according to claim 12, to increase viscosity of a mixture for use in the cosmetic industry.

18. The method according to claim 12, to create a viscous mixture for use as a pharmaceutical additive.

19. Use of the terpolymer according to claim 1 to enhance oil recovery by injecting the water-based solution comprising the terpolymer in a concentration of 0.01-5% by weight through at least one injection well into a mineral oil deposit; and removing crude oil from the deposit through at least one production well.

20. Use of the terpolymer according to claim 1, to adjust the viscosity of a cosmetic preparation.

21. Use of the terpolymer according to claim 1, to adjust viscosity of a pharmaceutical additive or preparation.

22. Use of the terpolymer according to claim 1, as a retention aid to incorporate fine fibers and pigments and as a dry-strength agent during paper making.

23. Use of the terpolymer according to claim 1, as a flocculating agent via charge neutralization and particle bridging in the treatment of water, waste water, or for the removal of unwanted impurities from a solution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The foregoing and other advantages of the disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.

[0032] FIG. 1: Example of synthetic method to produce hydrophobically associating terpolymers.

[0033] FIG. 2: .sup.1H-NMR of polymerization in deuterated water demonstrating the kinetics of the reaction.

[0034] FIG. 3: Pseudo-first-order kinetic plot indicating near-linear behaviour up to 120 mins (98% conversion).

[0035] FIG. 4: GPC traces of the RI response displaying molecular weight of polymers with different targeted weight average molecular weights for Examples 5, 6, and 7.

[0036] FIG. 5: (A) Frequency sweep test, (B) flow curve, and (C) strain sweep tests for all terpolymers aqueous solution. The squares and circles represent 25° C. and 70° C., respectively. The polymers analyzed include Example 9, Example 2, Example 8, and Example 4. All the rheological tests were carried out in triplicate or quadruplicate for each solution, and the average for each result is presented in this study. For figures in log-log scale, the errors are within the data point markers, and cannot be observed.

[0037] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in the detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of an invention as defined by the appended claims.

DETAILED DESCRIPTION

[0038] The object of embodiments of this invention is to provide a hydrophobically associating terpolymer that in a cost-effective, simple, and one-step process that can thicken aqueous medium with less or equal amounts of polymer than currently available.

[0039] This objective is achieved by using a water soluble, UV-initiated iniferter in a one-pot synthesis, at ambient temperature to give UHMW polymers, typically within 2 hours, consisting of: [0040] monomer A, having a water-soluble monoethylenically unsaturated group; [0041] monomer B, having an ionic water-soluble monoethylenically unsaturated group, different than monomer A; and [0042] monomer C, having a monoethylenically unsaturated monomer capable of forming hydrophobically associative bonds in aqueous medium and soluble in aqueous polymerization conditions, [0043] where monomer A is R.sup.1—(C═C)—(C═O)—O—R.sup.2 or R.sup.1—(C═C)—(C═O)—N—(R.sup.3)—R.sup.4 [0044] where monomer B is R.sup.1—(C═C)—(C═O)—O—R.sup.5 or R.sup.1—(C═C)—(C═O)—N—(R.sup.6)—R.sup.7 or R.sup.1—(C═C)—(C═O)—R.sup.8 [0045] where monomer C: R.sup.1—(C═C)—(C═O)—O—R.sup.9 or R.sup.3—(C═C)—(C═O)—N—(R.sup.10)—R.sup.11 or R.sup.1(C═C)—R.sup.12 [0046] R.sup.1 is H or methyl, [0047] R.sup.2 is methyl, ethyl, propyl, butyl, epoxymethyl, methanol, ethanol, N,N-dimethylethyl, PEG (where the molecular weight is between 50-1000 g/mol), benzyl, phenyl, [0048] R.sup.3 is H, methyl, or ethyl, [0049] R.sup.4 is H, methyl, ethyl, isopropyl, propan-2-ol, [0050] R.sup.5 is H, methyl, ethyl, propyl, butyl, pentyl, hexyl, C9-C24 linear or branched chains, [0051] R.sup.6 is poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, where the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4 to 20 carbons in length, [0052] R.sup.7 is poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, where the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4 to 20 carbons in length, [0053] R.sup.8 poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, where the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4 to 20 carbons in length, [0054] R.sup.9 is O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid, poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, where the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4 to 20 carbons in length, [0055] R.sup.10 is H, O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid, [0056] R.sup.11 is O.sup.−, OH, NH.sub.3.sup.+, sodium salt or neutral version of 2-amino-2-methylpropane-1-sulfonic acid, [0057] R.sup.12 is poly(ethylene glycol).sub.n (where n is between 2-20 units), PEGylated hydrocarbons, N-methoxyisobutyl, where the hydrocarbons are aromatic groups with linear or branch alkyl chains from 4 to 20 carbons in length.

[0058] The iniferter is selected from the group consisting of: [0059] R.sup.1—(C═S)—S—Z.sup.1 in which: [0060] R.sup.1 is methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, t-butoxy, benzyl, phenyl, N-methylaniline; [0061] Z.sup.1 is propanoic acid, propanoate, phenylpropane-2-yl, cyanomethyl, cyanopropan-2-yl, and [0062] R.sup.2—S—(C═S)—S—Z.sup.2 in which: [0063] R.sup.2 is a linear or branched alkyl chain (carbon length between C1-C12), benzyl, phenyl, isobutyronitrile, propanoate, propanoic acid, benzyl isobutyrate, 2-(pyridin-2-yldisulfanyl)ethyl propionate; [0064] Z.sup.2 is propanoate, propanoic acid, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, benzyl, benzyl isobutyrate, PEGylated 2-cyanopropanoic acid (PEG between 50-1000 g/mol).

[0065] The iniferter is initiated with light of wavelength between 250-400 nm, preferably 365 nm.

[0066] Concentration of the polymerization is 0.5-4.0 M

[0067] The general experimental procedure is as follows.

[0068] The reaction involves the combination of: monomer A, in a molar ratio percent of 10-98%, the monomer B is in a molar ratio of 5-90%, and the monomer C in a molar ratio of 0.05-10% and a water-soluble UV-initiated iniferter. The reaction mixture is sparged with an inert gas (i.e. nitrogen, argon, helium) for approximately 5-60 mins prior to initiation. The light source of initiation is between 250-400 nm, and temperature is between 5-95° C., and the solvent mixture is comprised of water with organic solvent preferably in a ratio of 100:0-1:99, where the secondary solvent is very to somewhat miscible with water and is polar protic or polar aprotic. The reaction typically takes between 1-12 hours depending on the types of monomers and ratio of monomers.

[0069] The following are to be regarded as non-limiting examples of terpolymer syntheses according to embodiments of the invention:

[0070] See FIG. 1. Example of synthetic method for the production of hydrophobically associating terpolymers.

Example 1

[0071] Monomer A 74.5 mmol, Monomer B is 25.0 mmol, and Monomer C 0.5 mmol, more specifically acrylamide (5.30 g) and sodium acrylate (2.42 g), and N-(isobutoxymethyl)acrylamide (0.08 g) were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 15 mins the mixture became a transparent viscous gel.

Example 2

[0072] Monomer A 74.0 mmol, Monomer B is 25.0 mmol, and Monomer C 1.0 mmol, where monomer A is acrylamide (5.26 g), monomer B is sodium acrylate (2.42 g), and N-(isobutoxymethyl)acrylamide (0.016 g) were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 30 mins the mixture became a transparent viscous gel.

Example 3

[0073] Monomer A 73.0 mmol, Monomer B is 25.0 mmol, and Monomer C 2.0 mmol, more specifically acrylamide (5.19 g) and sodium acrylate (2.42 g), and N-(isobutoxymethyl)acrylamide (0.324 g) were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 15 mins the mixture became a transparent viscous gel.

Example 4

[0074] Monomer A 71.0 mmol, Monomer B is 25.0 mmol, and Monomer C 4.0 mmol, more specifically acrylamide (5.05 g) and sodium acrylate (2.42 g), and N-(isobutoxymethyl)acrylamide (0.065 g) were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 30 mins the mixture became a transparent viscous gel.

[0075] See FIG. 2. .sup.1H-NMR of polymerization in deuterated water demonstrating the kinetics of the reaction based on Example 4. The progress of the reaction is from bottom to top with the time intervals of 0, 30, 60, 120, and 180 mins.

Example 5

[0076] Monomer A 37.25 mmol, Monomer B is 12.5 mmol, and Monomer C 0.25 mmol, more specifically acrylamide (2.65 g) and 2-acrylamido-2-methylpropane sulfonic acid sodium salt (4.75 mL of 50% solution in water), and N-(isobutoxymethyl)acrylamide (0.041 g), respectively, were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 30 mins the mixture became a transparent viscous gel.

Example 6

[0077] Monomer A 74.5 mmol, Monomer B is 25.0 mmol, and Monomer C 0.5 mmol, more specifically acrylamide (2.65 g) and 2-acrylamido-2-methylpropane sulfonic acid sodium salt (4.78 mL of 50% solution in water), and N-(isobutoxymethyl)acrylamide (0.405 g), respectively, were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 30 mins the mixture became a transparent viscous gel.

Example 7

[0078] Monomer A 74.9 mmol, Monomer B is 5.0 mmol, and Monomer C 0.1 mmol, more specifically acrylamide (10.60 g) and 2-acrylamido-2-methylpropane sulfonic acid sodium salt (19 mL of 50% solution in water), and N-(isobutoxymethyl)acrylamide (0.162 g), respectively, were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 30 mins the mixture became a transparent viscous gel.

Example 8

[0079] Monomer A 73.0 mmol, Monomer B is 25.0 mmol, and Monomer C 2.0 mmol, more specifically acrylamide (5.19 g) and acrylic acid (1.80 g), and N-(isobutoxymethyl)acrylamide (0.324 g) were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 6 hours. After 15 mins the mixture became a transparent viscous gel.

Example 9

[0080] Monomer A 74.5 mmol, Monomer B is 25.0 mmol, and Monomer C 0.5 mmol, more specifically acrylamide (5.30 g) and 2-acrylamido-2-methylpropane sulfonic acid (5.18 g), and N-(isobutoxymethyl)acrylamide (0.081 g), respectively, were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 3 hours. After 30 mins the mixture became a transparent viscous gel.

Example 10

[0081] Monomer A 74.9 mmol, Monomer B is 25.0 mmol, and Monomer C 0.1 mmol, more specifically acrylamide (5.33 g) and 2-acrylamido-2-methylpropane sulfonic acid (5.18 g), and poly(oxyethylene).sub.12 nonylphenylether acrylate (0.109 g), respectively, were used for the synthesis of a terpolymer. The monomers were dissolved in 50 mL of H.sub.2O in a 100 mL schlenk flask. Initiator stock solution (416 μL of 1 mg/mL in DMSO) was added to the monomer solution. The reaction mixture was sparged with N.sub.2 for 30 mins before it was irradiated with 365 nm wavelength light to initiate the reaction and left to stir for 3 hours. After 30 mins the mixture became a transparent viscous gel.

[0082] Surprisingly, embodiments of this invention were able to address all the desired properties of a hydrophobically associative terpolymer.

TABLE-US-00001 TABLE 1 Composition of monomers in mol during the polymerization over a period of 3 hours with monomer consumption based on monomer integration values relative to residual DOH. The experiment was based off a similar method to Example 4. Monomer Time Amount of monomer in (mol) consumption (min) Monomer A Monomer B Monomer C (%) 0 0.763 0.234 0.004 0 30 0.530 0.129 0.003 34 60 0.311 0.058 0.003 63 120 0.112 0.013 0.002 87 180 0.068 0.006 0.001 93

[0083] By monitoring the reaction kinetics by .sup.1H-NMR is deuterated water, a profile of the reactivity was able to be determined (FIG. 2, and

[0084] ). This invention demonstrates 98% conversion of monomers to polymers within 2 hours reaction time. The total consumption of the monomer based on moles in the reaction medium when plotted in a pseudo-first order reaction kinetic style demonstrates a near-linear behavior (Error! Reference source not found.).

[0085] FIG. 3 shows a pseudo-first-order kinetic plot indicating near-linear behaviour up to 120 mins, with reaction nearing completion at 180 mins (93%) and reaching full conversion at 300 min. The deviation from linearity is most likely due to lack of diffusion control of the reaction once a viscous gel is formed.

[0086] The reaction deviates from linearity after 120 mins, most likely due to the loss of diffusion control within the reaction medium due to the viscous nature of the polymers being synthesized. These results suggest that the RAFT reaction behaves as a controlled radical polymerization. This allowed the ability to control the molecular weight of the polymer to tailor the molecular weight to suit the viscosity requirements for our specific application.

[0087] To probe the molecular weight characteristics of these polymers triple detection gel permeation chromatography was used (TD-GPC). A Tosoh ambient GPC model 8220 with refractive index (RI) detector and dual-flow technology was used equipped with a Viscotek TDA 302 that included a viscometer, low-angle and right-angle light scattering detector (LALS and RALS, respectively), used to measure absolute molecular weights. The GPC was equipped with a TSKgel αM sample column and TSKgel superH-RC as reference columns. The sample flow rate was set to 0.750 mL/min, the reference flow rate was set to 0.325 mL/min, and the temperature of all the detectors was set to 30° C. The terpolymer samples were prepared in 2% KCl, dissolved for 24 hours on a rocker, filtered with a nylon 0.45 μm syringe filter. The TD-GPC was calibrated using a 20 kDa poly(ethyleneoxide) narrow standard and a 72 kDa dextran broad standard.

[0088] The viscosity measurements were acquired by diluting the terpolymer samples at a concentration of 3.5 g/L in fresh water. The dissolution process was expedited by mixing the solution in a stand mixer for 1-5 minutes, allowed to settle to remove air bubbles. The viscosity of the solution was measured by rotational viscometry using a Brookfield viscometer equipped with a spindle appropriate for the relative viscosities of the polymer solutions. The salt solutions of polymers were prepared by adding 2% KCl or 2% Sea water (w/w) to the dissolved fresh water solutions.

[0089] For Example 1, the polymer was dissolved at a concentration of 0.1 mg/mL in a 2% aqueous KCl solution and injected into a TD-GPC system the following absolute molecular weight parameters: Mw=2.20×10.sup.6 g mol.sup.−1, and a Ð=1.255. Based on GPC viscometry data, the intrinsic viscosity (IV) was measured to be 8.52 dl/g.

[0090] A terpolymer with a molar ratio of monomer A to monomer B to monomer C of 73.0:25.0:2.0 (Example 8) prepared for TD-GPC analysis at a concentration of 0.1 mg/mL and gave the following absolute molecular weight parameters: MW=4.62×10.sup.6 g mol.sup.−1, and a Ð=1.059. The IV of this terpolymer was measured to be 12.4 dl/g.

TABLE-US-00002 TABLE 2 Summary of molecular weight data and IV values for terpolymers from Examples 1-9. Example Mw (×10.sup.6 g mol.sup.−1) Ð IV (dl/g) 1 3.31 1.255 10.6 2 3.78 1.289 14.5 3 3.58 1.216 13.9 4 3.56 1.258 13.7 5 2.09 1.416 6.9 6 3.65 1.290 10.4 7 4.40 1.251 9.6 8 4.62 1.059 12.4 9 4.33 1.063 12.8 10 1.48 3.994 4.5

[0091] As demonstrated, embodiments of methods of this invention, can control the molecular weights consistent with a controlled radical polymerization using our specific combination of reagents, including monomer A, monomer B, monomer C, and the UV active iniferter, as well as conditions and concentration detailed above.

[0092] The storage modulus (G′), loss modulus (G″), and flow curves were analyzed for polymers in Examples 2, 9, 4, and 8. The samples were prepared by stirring the dried powder forms of the polymers at a concentration of 4000 ppm in water for 48 hours. The rheological measurements were carried out on an Anton Paar MCR302 rotational rheometer with a coaxial cylinder geometry and the Rheoplus/32 V3.62 software. Rotational rheometry enables us to subject a sample to either a dynamic (sinusoidal) or steady shear deformation and then measure the torque response to the applied deformation filed. The measuring bob and measuring cup had a radius of 13.329 mm OD and 14.463 mm ID, respectively. All the rheological measurements were done at a fixed temperature (T=25° C.). The temperature for high temperature solutions was at T=70° C. The frequency sweep test was performed within the linear viscoelastic region (LVR). The strain amplitude was set to 0.1% for frequency sweep tests over an angular frequency range of 0.1 rad/s-10 rad/s. The strain amplitude in oscillatory experiments was selected in a way to ensure that samples remain in the LVR all the time. On the other hand, strain amplitude test was done in both LVR and the nonlinear viscoelastic region (non-LVR). Strain amplitude sweep test was intended to investigate nonlinear viscoelasticity under large amplitude oscillatory shear (LAOS) flow. To avoid any flow instability, torque overload and wall-slip effects, angular frequency was set to 0.5 rad/s; and strain amplitude was varied between 1% and 1000%. Local elastic and viscous responses of a material at small and large instantaneous strains and strain-rates were collected after 5-7 cycles for each strain amplitude value to ensure a stationary viscoelastic response was achieved. The average of these measurements was reported by the rheometer software.

[0093] The data from FIG. 5 for Examples 2, 9, 4, and 8 show a G′>G″ for higher frequencies, and G″>G′ for lower frequencies, which shows they exhibit viscoelastic behaviors at 4000 ppm. To investigate the effect of a change in temperature of the polymers presented in Examples 2, 9, 4, and 8, frequency sweep, strain sweep and flow curve tests were conducted at two different temperatures (25° C. and 70° C.). The change in viscosity between 25° C. and 70° C. shows a decrease of about 10% between all the examples. These tests indicate that these polymers viscoelastic behaviour which is ideal for their potential application as a propagation agent.

[0094] To demonstrate control over molecular weight three experiments were performed by varying the maintaining the amount of iniferter (Example 5, 6, and 7) in the reaction mixture while varying the concentration of monomer A, monomer B, and monomer C in solution to 1.0, to 2.0, and 4.0 total mols present, respectively. These experiments yielded terpolymers with different experimental molecular weights, 2.09, 3.65, and 4.40×10.sup.6 g mol.sup.−1 for Examples 5, 6, and 7, respectively. These experiments demonstrate that this synthetic methodology gives the ability to tailor the molecular weight and therefore the rheological properties based on the desired function (Drawing 4).

[0095] FIG. 4 shows GPC traces of the RI response displaying molecular weight of polymers with different targeted weight average molecular weights for Examples 5 (black), 6 (dark gray), and 7 (light gray).

[0096] Viscometry data for the solution of the terpolymers were acquired by preparing solutions in deionized water at a concentration of 3.5 g/L using a Brookfield rotational viscometer. The terpolymer from Example 1 with a molar ratio of monomer A to monomer B to monomer C of 74.5:25.0:0.5 gave a value of 1100 cP at 0.1 s.sup.−1. When salt was introduced into the aqueous mixture with 2% KCl (w/w) and 2% sea water (w/w), it introduced a viscosity of 32 and 24 cP respectively.

TABLE-US-00003 TABLE 3 Viscosity measurements for Examples 1-10 at a rate of 0.1 s.sup.−1 using a Brookefield rotational viscometer. Viscosity (cP) Example Fresh water 2% KCl (w/w) Sea Water (2% w/w) 1 1100 32 24 2 1330 40 29 3 1200 36 29 4 1000 33 23 5 430 16 24 6 1400 28 24 7 2660 51 44 8 1010 33 28 9 1600 43 37 10 2660 12 12

[0097] Prior art in the field of rheological modifying polymers can produce polymers with similar composition, however the prior art does not address all the solutions that the many embodiments of the current invention encompasses.

[0098] Taton et al. described the synthesis of di- and tri-block copolymers with a system using a RAFT/MADIX technology. The inventors, however, were only able to produce polymers with molecular weight around 10,000 g mol.sup.−1. The embodiments of our invention are able to produce polymers with molecular weights ranging from 1 to 10×10.sup.6 g mol.sup.−1 with a faster reaction time and less reagents.

[0099] As described in the prior art by Carmean et al. they have shown the ability to synthesize a polymer with a UV initiated RAFT agent to produce a polymer with UHMW, although they do demonstrate the ability to change the types of monomers used and they do not demonstrate the synthesis of copolymers or terpolymer. One of the main difficulties of the aqueous synthesis of polymers designed to thicken aqueous solutions is the ability to process and characterize these macromolecules. Our invention details the synthesis of this difficult technique but also has allowed us to fully characterize the molecular weight properties of these terpolymers.

[0100] Previous inventions including Read et al. and Cadix et al. produced terpolymers with UHMW, however, these polymers required the use of reagents to create micelles to allow the inventors to integrate hydrophobic groups (as embodiments of our invention described Monomer C). These procedures also require low temperature and multi-component RED/OX initiator systems. These extra reagents and steps to produce micelles increase the cost and reduce the efficiency of their reactions.

[0101] The various embodiments of this invention afford advantages over prior inventions due to the novel methodology to produce the terpolymers. The specific combination of reagents and conditions allow this invention the ability to produce terpolymers of different targeted molecular weights, narrow PDIs, straightforward and relatively fast synthesis in aqueous media. Moreover, the iniferter system also allows the ability to incorporate different monomers at different molar ratios to create a terpolymer with the desired rheological properties in a one-pot synthetic strategy.

[0102] While particular implementations and applications of the present disclosure have been illustrated and described, it is to be understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of an invention as defined in the appended claims.