Process for rapid dissolution of powders containing low molecular weight acrylamide-based polymers

Abstract

A process for making down powder is provided, comprising making down a powder comprising one or more acrylamide-based polymers to form a made-down powder solution, and blending the mixture of powder and solvent for about 15 minutes or less to obtain the made-down powder solution, wherein the powder comprises particles dry-cut to a median particle size of about 200 microns to about 10,000 microns.

Description

[Technical field]

[0001] This application is an international (i.e., PCT) application that claims the benefit of U.S. Provisional Patent Application No. 62 / 539,323, filed July 31, 2017, the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] Relatively low molecular weight polymers (e.g., typically less than 2 million Daltons) are commonly used in many industrial processes (e.g., mining, textiles, paper). For example, some low molecular weight polymers can be used as strength aids in papermaking to help improve sheet strength, or in textiles to impart strength and finesse to fabrics. In addition, some low molecular weight polymers can be used in mining to improve wastewater recovery, reuse, and recycling.

[0003] Depending on the polymer structure, weight average molecular weight, and functionality, polymer products may exist and be sold as powders, liquids, or concentrated solutions. In many applications, polymer products must be dissolved and used as solution-based products. For example, to be effectively used, high and low molecular weight polymers need to be dissolved and diluted to less than about 1% by weight before being added to the paper machine / papermaking process.

[0004] When used in papermaking, powdered polymers are made down at low concentrations and under gentle mixing for extended periods of time. Although the above process is laborious, it ensures that the powdered polymer is completely dissolved without reducing the molecular weight and thereby performance. The drawback of this approach is that the demand for low concentration solutions generally requires large make-down equipment and therefore maintains a large spatial footprint.

[0005] One technique for accelerating the dissolution process and reducing the spatial footprint is to reduce the particle size of the powdered polymer. While this technique shortens dissolution times, particle size reduction tends to suffer from other drawbacks such as the costs, resources, and degradation associated with milling, "fish eyes" (i.e., caking of powder particles when wet), and safety and regulatory issues associated with dusting, packaging, and storage.

[0006] Another approach to addressing powder dissolution is disclosed by Sortwell et al. (U.S. Pat. No. 4,874,588). Sortwell et al. disclose a method for "wet-cutting" powdered polymers to reduce particle size and promote dissolution. The process consists of first forming a suspension of relatively large powder particles in water before cutting the wet powder with a bladed device suitable for particle size reduction. To reduce the size of the larger particles, Sortwell et al. subject them to instantaneous and temporary high cutting shear. This process intentionally avoids the problems associated with dusting of finely cut particles, but other potential drawbacks of this approach include equipment setup, high blade speeds (e.g., 10,000-13,000 rpm), blade wear, overheating, fisheyes, and the need for high motor capacity (see, e.g., Pich et al., U.S. Pat. No. 8,186,871).

[0007] Thus, there remains a need for a method of making low molecular weight powdered polymer products that does not require finely divided powders, low concentrations, and long mixing times. Summary of the Invention

[0008] A process is provided for making down a powder comprising one or more acrylamide-based polymers to form a made-down powder solution. The process includes blending a mixture of powder and solvent for about 15 minutes or less to obtain a made-down powder solution, the powder comprising dry cut particles with a median particle size of about 200 microns to about 10,000 microns. In certain aspects of the process, the powder solution made down at a tip speed of about 5 m / s to about 25 m / s has an intrinsic viscosity (dL / g) within about 20% deviation of the intrinsic viscosity (dL / g) of an identical solution made down on a cage stirrer with a tip speed of about 1.26 m / s and under otherwise identical conditions.

[0009] The present disclosure provides a unique approach to make down powders containing acrylamide-based polymers (e.g., strength aids). Using the blending techniques described herein, the need for low concentrations, small particle sizes, and long mixing times can be mitigated. [Brief description of the drawings]

[0010] [Figure 1] 1 is an exemplary 13C (nuclear magnetic resonance) NMR spectrum of the associative polymer described in Example 5.

[0011] [Diagram 2] The results of Experimental Example 10 are shown in the graph.

[0012] [Diagram 3] The results of Experimental Example 10 are shown in the graph.

[0013] [Figure 4] The results of Experimental Example 11 are shown in the graph.

[0014] [Diagram 5] The results of Experimental Example 13 are shown in the graph.

[0015] [Figure 6] The results of Experimental Example 14 are shown in the graph.

[0016] [Figure 7] The results of Experimental Example 15 are shown in the graph. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Generally, high and low molecular weight polymers are diluted, dissolved, and then added to their respective applications as aqueous solutions to avoid solubility issues and damage from high heat and / or shear. Common approaches to ensure complete dissolution of powder-based polymer products include, but are not limited to, reduced particle size, low powder concentration, and long mixing times. Attempts to speed up the process by increasing the shear of the make-down unit can result in irreparable polymer damage. The advantage of the process described herein is that it does not require powders with reduced particle size, diluted mix concentration, or long mixing times and does not damage the acrylamide-based polymers described herein. Thus, the process described herein can help reduce the costs associated with large make-down equipment and the time it takes to make-down and apply to industrial processes (e.g., mining, textile, or paper).

[0018] A process is provided for treating a powder comprising one or more acrylamide-based polymers to form a treated powder solution, the process comprising blending a mixture of powder and solvent for about 15 minutes or less at an impeller tip speed of about to obtain a made-down powder solution, the powder comprising particles dry cut to a median particle size of about 200 microns to about 10,000 microns.

[0019] The process includes blending a mixture of powder and solvent. As used herein, "blending" may refer to any process used to disperse the powder and solvent. For example, blending may mean mixing, stirring, whipping, shaking, pumping, or any combination thereof. Any equipment and / or make-down unit may be used to blend the powder and solvent, as long as the equipment and / or make-down unit meets the limitations described herein. An exemplary make-down unit for blending the powder and solvent is the IKA T25 digital ULTRA-TURRAX® high performance dispersion instrument available from IKA® (Wilmington, NC).

[0020] In some embodiments, the process includes blending the powder and solvent mixture at an impeller tip speed of about 5 m / s to about 25 m / s (e.g., about 5 m / s, about 6 m / s, about 7 m / s, about 8 m / s, about 9 m / s, about 10 m / s, about 11 m / s, about 12 m / s, about 13 m / s, about 14 m / s, about 15 m / s, about 16 m / s, about 17 m / s, about 18 m / s, about 19 m / s, about 20 m / s, about 21 m / s, about 22 m / s, about 23 m / s, about 24 m / s, or about 25 m / s). As used herein, "impeller tip speed" refers to the tangential velocity (m / s) of the impeller used in blending the powder and solvent in the stirred tank. In certain embodiments, the process includes blending the powder and solvent mixture at an impeller tip speed of about 10 m / sec to about 20 m / sec.

[0021] In some embodiments, the process includes blending the powder and solvent mixture at a rotor rotation frequency of about 4000 revolutions per minute ("rpm") to about 20,000 rpm (e.g., about 4,000 rpm, about 5,000 rpm, about 6,000 rpm, about 7,000 rpm, about 8,000 rpm, about 9,000 rpm, about 10,000 rpm, about 11,000 rpm, about 12,000 rpm, about 13,000 rpm, about 14,000 rpm, about 15,000 rpm, about 16,000 rpm, about 17,000 rpm, about 18,000 rpm, about 19,000 rpm, or about 20,000 rpm). In some embodiments, the process includes blending the powder and solvent mixture at a rotor rotation frequency of about 8,000 rpm to about 20,000 rpm. In certain embodiments, the process includes blending the mixture of powder and solvent at a rotor rotation frequency of about 8,000 rpm to about 16,000 rpm.

[0022] The mixture of powder and solvent can be blended for any period of time, so long as the period is sufficient to obtain a made-down powder solution. In some embodiments, the mixture of powder and solvent is blended for about 15 minutes or less to obtain a made-down powder solution. For example, the mixture of powder and solvent is blended for about 14 minutes, e.g., about 13 minutes, about 12 minutes, about 11 minutes, about 10 minutes, about 9 minutes, about 8 minutes, about 7 minutes, about 6 minutes, about 5 minutes, about 4 minutes, about 3 minutes, about 2 minutes, or about 1 minute to obtain a made-down powder solution. In some embodiments, the mixture of powder and solvent is blended for about 10 minutes or less to obtain a made-down powder solution. In certain embodiments, the mixture of powder and solvent is blended for about 5 minutes or less to obtain a made-down powder solution.

[0023] In some embodiments, the process is performed at about 10 batch volumes / minute to about 40 batch volumes / minute (e.g., about 10 batch volumes / minute, about 11 batch volumes / minute, about 12 batch volumes / minute, about 13 batch volumes / minute, about 14 batch volumes / minute, about 15 batch volumes / minute, about 16 batch volumes / minute, about 17 batch volumes / minute, about 18 batch volumes / minute, about 19 batch volumes / minute, about 20 batch volumes / minute, about 21 batch volumes / minute, about 22 batch volumes / minute, about 23 batch volumes / minute, about 24 batch volumes / minute, about 25 batch volumes / minute, about 26 batch volumes / minute, about 27 batch volumes / minute, about 28 batch volumes / minute, about 29 batch volumes / minute, about 30 batch volumes / minute, about 31 batch volumes / minute, about 32 batch volumes / minute, about 33 batch volumes / minute, about 34 batch volumes / minute, about 35 batch volumes / minute, about 36 batch volumes / minute, about 37 batch volumes / minute, about 38 batch volumes / minute, about 39 batch volumes / minute, about 40 batch volumes / minute, about 41 batch volumes / minute, about 42 batch volumes / minute, about 43 batch volumes / minute, about 44 batch volumes / minute, about 45 batch volumes / minute, about 46 batch volumes / minute, about 47 batch volumes / minute, about 48 batch volumes / minute, about 49 batch volumes / minute, about 50 batch volumes / minute, about 51 batch volumes / minute, about 52 batch volumes / minute, about 53 batch volumes / minute, about 54 batch volumes / minute, about 55 batch volumes / minute, about 56 batch volumes / minute, about 57 batch volumes / minute, about 58 batch volumes / minute, about 59 batch volumes / minute, about 60 batch volumes / minute, about 61 batch volumes / minute, about 62 batch volumes / minute, about The pumping rate may be from about 4 batch volumes / min, about 25 batch volumes / min, about 26 batch volumes / min, about 27 batch volumes / min, about 28 batch volumes / min, about 29 batch volumes / min, about 30 batch volumes / min, about 31 batch volumes / min, about 32 batch volumes / min, about 33 batch volumes / min, about 34 batch volumes / min, about 35 batch volumes / min, about 36 batch volumes / min, about 37 batch volumes / min, about 38 batch volumes / min, about 39 batch volumes / min, or about 40 batch volumes / min. As used herein, "pumping rate" refers to the turnover rate of making down a batch of powder and solvent. The batch volume is not particularly limited, as any batch volume may be used. In some embodiments, the process includes a pumping rate of about 15 batch volumes / min to about 40 batch volumes / min. In certain embodiments, the process includes a pumping rate of about 20 batch volumes / min to about 40 batch volumes / min.

[0024] Powders include particles that have been dry cut (e.g., cut or milled) to their median particle size. As used herein, the term "dry cut" refers to a process in which the cut used to achieve the median particle size described herein is not aided by the addition of water. Without being bound to any particular theory, it is believed that the processes described herein do not require fine particles that would require "wet cut" to avoid issues such as dusting.

[0025] The powder can have any suitable median particle size (i.e., median particle diameter). The median particle size can be determined by any suitable method known in the art. Typically, the median particle size is determined by a Horiba Laser Scattering Particle Size Distribution Analyzer LA-950. The powder can have a median particle size of about 200 microns or more, such as about 250 microns or more, about 300 microns or more, about 350 microns or more, about 400 microns or more, about 450 microns or more, or about 500 microns or more. Alternatively, or in addition, the powder can have a median particle size of about 10,000 microns or less, such as about 8,000 microns or less, about 6,000 microns or less, about 4,000 microns or less, about 2,000 microns or less, or about 1,000 microns or less. Thus, the powder can have a median particle size bounded by any two of the above endpoints. The powder may be about 200 microns to about 10,000 microns, for example, about 200 microns to about 8,000 microns, about 200 microns to about 6,000 microns, about 200 microns to about 4,000 microns, about 200 microns to about 2,000 microns, about 200 microns to about 1,000 microns, about 250 microns to about 10,000 microns, about 300 microns to about 10,000 microns, about 350 microns to about 10,000 microns, about 400 microns to about 500 microns, about 500 microns to about 6000 microns, about 600 microns to about 7000 microns, about 700 microns to about 8000 microns, about 800 microns to about 9000 microns, about 900 microns to about 10000 microns, about 1000 microns to about 1500 microns, about 1000 microns to about 2000 microns, about 1500 microns to about 2000 microns, about 1000 microns to about 2000 microns, about 1000 microns to about 3000 microns, about 10 ... The nanoparticles may have a median particle size of about 00 microns to about 10,000, about 450 microns to about 10,000 microns, about 500 microns to about 10,000 microns, about 250 microns to about 2,000 microns, about 300 microns to about 2,000 microns, about 350 microns to about 2,000 microns, about 400 microns to about 2,000 microns, about 450 microns to about 2,000 microns, or about 500 microns to about 2,000 microns.

[0026] In some embodiments, a powder with a median particle size of at least about 200 microns (e.g., at least 350 microns or at least 500 microns) as up to a 1 wt. % solution in water becomes a fully made down powder solution within about 10 minutes (e.g., within about 8 minutes or within about 5 minutes) at 25° C. and 1 atm while being stirred with an impeller having a tip speed of at least about 10 m / sec. In some embodiments, a powder with a median particle size of at least about 200 microns (e.g., at least 350 microns or at least 500 microns) as up to a 2 wt. % solution in water becomes a fully made down powder solution within about 10 minutes (e.g., within about 8 minutes or within about 5 minutes) at 25° C. and 1 atm while being stirred with an impeller having a tip speed of at least about 10 m / sec. In some embodiments, a powder with a median particle size of at least about 200 microns (e.g., at least 350 microns or at least 500 microns) as up to a 5% by weight solution in water becomes a fully made down powder solution within about 10 minutes (e.g., within about 8 minutes or within about 5 minutes) at 25° C. and 1 atm while being stirred with an impeller having a tip speed of at least about 10 m / sec. In some embodiments, a powder with a median particle size of at least about 200 microns (e.g., at least 350 microns or at least 500 microns) as up to a 10% by weight solution in water becomes a fully made down powder solution within about 10 minutes (e.g., within about 8 minutes or within about 5 minutes) at 25° C. and 1 atm while being stirred with an impeller having a tip speed of at least about 10 m / sec.

[0027] The solvent can be any solvent suitable for industrial processes (e.g., mining, textile, or paper) that does not interfere with the performance of the polymer. The solvent can be a single chemical or a mixture of two or more chemicals. In certain embodiments, the solvent is water. In some embodiments, the solvent is fresh water. The fresh water can be surface water or ground water. In certain embodiments, the fresh water is further treated before use in the methods provided herein. In certain embodiments, the solvent is process water. The process water can be obtained from any suitable step of an industrial process (e.g., cooling water). In some embodiments, the process water is further treated before use in the methods provided herein.

[0028] The dissolution level of the powder may be determined by any suitable method. In general, the dissolution levels provided herein are determined using the refractive index of the powder solution / suspension. A fully made-down powder solution of known concentration may be obtained (at 25° C. and 1 atmosphere ("atm") pressure) by mixing a predetermined amount of powder in a predetermined amount of water under shear with a cage stirrer at 400-800 rpm until the powder and water mixture can easily pass through a 100 mesh screen and only traces of insoluble residue (less than 0.05% by weight of the original powder added) remain on the screen. An aliquot of the filtered, made-down powder solution (i.e., filtrate) may be placed in the cell of an RM50 refractometer (Mettler Toledo) and the refractive index may be recorded. The refractive index of the made-down powder solution should be linearly correlated with the concentration of dissolved acrylamide-based polymer in the solution (see, e.g., FIG. 5). Thus, a fully made-down powder solution can be considered the point on the acrylamide-based polymer concentration curve where the refractive index is linearly correlated to the appropriate refractive index value, within error of the expected value (e.g., about ±5%).

[0029] Similarly, the dissolution level can be monitored as a function of time. A powder suspension can be obtained (at 25° C. and 1 atmosphere ("atm") pressure) by dispersing a given amount of powder in a given amount of solvent (up to 10% powder concentration by weight). Upon dispersion, the powder begins to hydrate, but it may take time to reach complete dissolution with sufficient mixing. Generally, a stable refractive index cannot be obtained for a powder suspension due to its inhomogeneous nature. However, the suspension can be filtered through a 100 mesh screen to remove undissolved powder, and the filtered acrylamide-based polymer solution can be placed in the cell of an RM50 refractometer (Mettler Toledo) and the refractive index recorded. Using the refractive index of the filtrate, the concentration of dissolved acrylamide-based polymer in the suspension can be calculated with a linear calibration curve (e.g., FIG. 5). To monitor the change in refractive index and concentration of dissolved powder during mixing of the powder suspension, small aliquots can be removed from the suspension at 30 second intervals and filtered through a 100 mesh screen. An aliquot of the filtrate can be placed onto the cell of an RM50 refractometer (Mettler Toledo) and the refractive index can be recorded. Once the refractive index reaches a plateau, the powder can be considered a fully made-down powder solution (see, e.g., FIG. 6 (comparison) and FIG. 7).

[0030] As mentioned above, conventional make-down processes of paper auxiliaries require low shear and long mixing times to avoid irreparable damage to the polymer. The advantage of the process described herein is that the polymer damage is minimal, if any. One way to evaluate the level of damage is to measure the change in intrinsic viscosity and / or viscosity of the polymer made down at high shear versus the powder made down at low shear and long mixing times. Without being bound to any particular theory, it is believed that as the polymer breaks down (e.g., becomes lower molecular weight), the intrinsic viscosity and / or viscosity decreases accordingly. Thus, if a polymer maintains a similar intrinsic viscosity and / or viscosity to the same polymer made down at low shear and long mixing times, the polymer can be considered capable of withstanding high shear make-down conditions.

[0031] Thus, in some embodiments, a fully made down powder solution of 1 wt % in water at 25° C. made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution has a viscosity (cps) within a deviation of about 20% (e.g., about 19%, about 18%, about 17%, about 16%, about 15%, about 14%, about 13%, about 12%, or about 11%) of the viscosity (cps) of the same solution, which is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution. In certain embodiments, a fully made down powder solution of 1 wt % in water at 25° C. made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution has a viscosity (cps) within a deviation of about 10% (e.g., about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, or about 1%) of the viscosity (cps) of an identical solution, which is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution.

[0032] Similarly, in some embodiments, a fully made down powder solution of 1 wt % in water at 25° C. made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution has an intrinsic viscosity (dL / g) within a deviation of about 20% (e.g., about 19%, about 18%, about 17%, about 16%, about 15%, about 14%, about 13%, about 12%, or about 11%) of the intrinsic viscosity (dL / g) of the same solution, which is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution. In certain embodiments, a fully made down powder solution of 1 wt % in water at 25° C. made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution has an intrinsic viscosity (dL / g) within a deviation of about 10% (e.g., about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, or about 1%) of the intrinsic viscosity (dL / g) of the same solution, which is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution.

[0033] The make-down powder solution can have any suitable intrinsic viscosity. For example, the make-down powder solution can have an intrinsic viscosity of about 0.05 dL / g to about 15 dL / g (e.g., about 0.05 dL / g to about 10 dL / g, about 0.05 dL / g to about 7 dL / g, about 0.05 dL / g to about 6 dL / g, about 0.05 dL / g to about 5 dL / g, about 0.05 dL / g to about 4 dL / g, about 0.05 dL / g to about 3 dL / g, about 0.05 dL / g to about 2 dL / g, about 0.05 The intrinsic viscosity may be from about 0.05 dL / g to about 0.5 dL / g, from about 0.1 dL / g to about 7 dL / g, from about 0.1 dL / g to about 6 dL / g, from about 0.5 dL / g to about 5 dL / g, from about 0.1 dL / g to about 10 dL / g, from about 0.5 dL / g to about 10 dL / g, from about 0.1 dL / g to about 15 dL / g, or from about 0.5 dL / g to about 15 dL / g. In some embodiments, the made-down powder solution has an intrinsic viscosity of from about 0.05 dL / g to about 7. In certain embodiments, the made-down powder solution has an intrinsic viscosity of from about 0.5 dL / g to about 5 dL / g.

[0034] Intrinsic viscosity ("IV") is defined by a series of reduced specific viscosity ("RSV") measurements extrapolated to the limit of infinite dilution, i.e., when the concentration of the powder equals zero. RSV is measured at a given polymer concentration and temperature and calculated as follows:

number

[0035] where η is the viscosity of the powder solution, η0 is the viscosity of the solvent at the same temperature, t is the dissolution time of the made-down powder solution, T0 is the dissolution time of the solvent, and c is the concentration of powder in solution (G / dL). Thus, intrinsic viscosity is defined in dL / g. The variables t and t0 are measured using a Cannon Ubbelohde semi-micro dilution viscometer (size 75) at 30±0.02° C. using the powder solution and solvent in 1.0 N sodium nitrate solution.

[0036] The make-down powder solution can have any suitable Huggins constant. For example, the make-down powder solution can have a Huggins constant of about 0.1 to about 20 (e.g., about 0.1 to about 15, about 0.1 to about 10, about 0.3 to about 10, about 0.1 to about 5, about 0.5 to about 20, about 0.5 to about 10, about 1 to about 20, about 1 to about 10, or about 1 to about 5). In some embodiments, the make-down powder solution can have a Huggins constant of about 0.3 to about 10, as determined by different concentrations of the make-down powder solution, the concentrations being selected to produce a (t / t0) value of about 1.2 to 2.2 in 1.0 N sodium nitrate solution. In some embodiments, the made down powder solution can have a Huggins constant of about 0.3 to about 5, as determined by different concentrations of powder, the concentrations selected to produce a (t / t0) value of about 1.2 to 2.2 in 1.0 N sodium nitrate solution. In one particular embodiment, the made down powder solution can have a Huggins constant of about 0.6 to about 3, as determined by different concentrations of powder, the concentrations selected to produce a (t / t0) value of about 1.2 to 2.2 in 1.0 N sodium nitrate solution. The Huggins constant is calculated as follows:

number

[0037] The make-down powder solution can be used in any suitable application where a powdered polymer needs to be converted into a solution-based polymer product. For example, the make-down powder solution can be used in the mining, textile, or paper industries. In some embodiments, the make-down powder solution is added to a paper sheet precursor. As used herein, the term "paper sheet precursor" refers to any component of the papermaking process upstream of the point where water removal begins (e.g., the table). As used herein, the terms "upstream" and "downstream" refer to components of the papermaking process that are procedurally toward the pulper and procedurally toward the reel, respectively. Thus, the make-down powder solution can be added to the pulp (e.g., virgin pulp, recycled pulp, or combinations thereof), pulp slurry, cellulose fibers, solutions used in any of the above components, and any combinations thereof, at various locations during the papermaking process leading up to and including the headbox. In certain embodiments, the made down powder solution may be added to the pulp slurry in a pulper, latency chest, reject refiner chest, disc filter or decker feed or accept, whitewater system, stock pulp storage chest (either low density ("LD"), medium consistency ("MC"), or high consistency ("HC")), blend chest, machine chest, headbox, save-all chest, or combinations thereof.

[0038] In some embodiments, the make-down powder solution is added to the paper sheet precursor upstream of the wet end of the paper machine (e.g., before the wet end). As used herein, the term "wet end" refers to any component of the papermaking process including the headbox and downstream thereof. Thus, the make-down powder solution may be added to any component of the papermaking process leading up to but not including the headbox. In certain embodiments, the make-down powder solution is added to the stock preparation section of the paper machine. As used herein, "stock preparation section" refers to any component of the papermaking process where the pulp is refined and / or blended. For example, the make-down powder solution may be added to a pulp stock storage chest (either low density ("LD"), medium consistency ("MC"), or high consistency ("HC")), a blend chest, a machine chest, a save-all chest, or a combination thereof.

[0039] In some embodiments, the pulp slurry includes recycled fibers. The recycled fibers may be obtained from various paper or fiber-containing products, such as paperboard, newsprint, printing grade, sanitary products, or other paper products. In some embodiments, these products may include, for example, old corrugated cardboard ("OCC"), old newsprint ("ONP"), mixed office waste ("MOW"), magazines, books, or combinations thereof. In some embodiments, the pulp slurry includes virgin fibers. In embodiments including virgin fibers, the pulp may be obtained from softwoods, hardwoods, or blends thereof. In certain embodiments, the virgin pulp may include bleached or unbleached kraft, sulfite or other chemical pulps, and groundwood pulps ("GW") or other mechanical pulps, such as, for example, thermomechanical pulps ("TMP").

[0040] The make-down powder solution can be added to an industrial process (e.g., a papermaking process) in any suitable amount to achieve a desired weight percent of polymer active. The make-down powder solution can be added to an industrial process (e.g., a papermaking process) in an amount to achieve about 0.01% by weight or more, for example, about 0.05% by weight or more, about 0.1% by weight or more, about 0.2% by weight or more, about 0.3% by weight or more, about 0.4% by weight or more, about 0.5% by weight or more, about 0.6% by weight or more, about 0.7% by weight or more, about 0.8% by weight or more, about 0.9% by weight or more, or about 1.0% by weight or more of the polymer active. Alternatively, or in addition, the made-down powder solution can be added to an industrial process (e.g., a papermaking process) in an amount to achieve about 10% by weight or less, e.g., about 9% by weight or less, about 8% by weight or less, about 7% by weight or less, about 6% by weight or less, about 5% by weight or less, about 4% by weight or less, about 3% by weight or less, about 2% by weight or less, or about 1% by weight or less of the polymer active material. Thus, the made-down powder solution can be added to an industrial process (e.g., a papermaking process) in any suitable amount bounded by any two of the above endpoints to achieve the desired weight percent of the polymer active material. The make-down powder solution may be about 0.01% by weight to about 10% by weight, for example, about 0.01% by weight to about 9% by weight, about 0.01% by weight to about 8% by weight, about 0.01% by weight to about 7% by weight, about 0.01% by weight to about 6% by weight, about 0.01% by weight to about 5% by weight, about 0.01% by weight to about 4% by weight, about 0.01% by weight to about 3% by weight, about 0.01% by weight to about 2% by weight, about 0.01% by weight to about 1% by weight, about 0.05% by weight to about 1% by weight, about 0.1% by weight to about 1% by weight, about 0.0 ... The composition may be added to an industrial process (e.g., a papermaking process) in an amount to achieve between 0.2% and about 1% by weight, between about 0.3% and about 1% by weight, between about 0.4% and about 1% by weight, between about 0.5% and about 1% by weight, between about 0.6% and about 1% by weight, between about 0.7% and about 1% by weight, between about 0.8% and about 1% by weight, between about 0.9% and about 1% by weight, between about 1% and about 10% by weight, between about 0.01% and about 2% by weight, or between about 0.01% and about 5% by weight of the polymer actives.

[0041] The make-down powder solution can have any suitable acrylamide-based polymer content before being subjected to an industrial process (e.g., a papermaking process). The make-down powder solution can have an acrylamide-based polymer content of about 10% by weight or less, for example, about 9% by weight or less, about 8% by weight or less, about 7% by weight or less, about 6% by weight or less, about 5% by weight or less, about 4% by weight or less, or about 3% by weight or less before being subjected to an industrial process (e.g., a papermaking process). Alternatively, or in addition, the make-down powder solution can have an acrylamide-based polymer content of about 0.1% by weight or more, for example, about 0.5% by weight or more, about 1% by weight or more, about 2% by weight or more, or about 3% by weight or more before being subjected to an industrial process (e.g., a papermaking process). Thus, the make-down powder solution can have an acrylamide-based polymer content bounded by any two of the aforementioned endpoints before being subjected to an industrial process (e.g., a papermaking process). The made-down powder solution can have an acrylamide-based polymer content of about 0.1% by weight to about 10% by weight, e.g., about 0.5% by weight to about 10% by weight, about 1% by weight to about 10% by weight, about 2% by weight to about 10% by weight, about 3% by weight to about 10% by weight, about 0.1% by weight to about 9% by weight, about 0.1% by weight to about 8% by weight, about 0.1% by weight to about 7% by weight, about 0.1% by weight to about 6% by weight, about 0.1% by weight to about 5% by weight, about 0.1% by weight to about 4% by weight, about 0.1% by weight to about 3% by weight, about 0.5% by weight to about 5% by weight, about 0.5% by weight to about 3% by weight, about 1% by weight to about 5% by weight, or about 1% by weight to about 4% by weight, before being subjected to an industrial process (e.g., a papermaking process).

[0042] The made-down powder solution can be added to an industrial process (e.g., a papermaking process) at any suitable dosage of acrylamide-based polymer (lbs / ton actives). As used herein, the term "lbs / ton actives" or "lb / ton actives" refers to pounds of acrylamide-based polymer actives per ton of fiber. The made-down powder solution can be added to an industrial process (e.g., a papermaking process) at a dosage of at least about 0.1 lbs / ton actives of acrylamide-based polymer. For example, the made down powder solution can be added to an industrial process (e.g., a papermaking process) at a dosage of acrylamide-based polymer of at least about 0.5 lbs / ton actives, at least about 1 lbs / ton actives, at least about 2 lbs / ton actives, at least about 3 lbs / ton actives, at least about 4 lbs / ton actives, at least about 5 lbs / ton actives, at least about 6 lbs / ton actives, at least about 7 lbs / ton actives, at least about 8 lbs / ton actives, at least about 9 lbs / ton actives, at least about 10 lbs / ton actives, at least about 11 lbs / ton actives, at least about 12 lbs / ton actives, at least about 13 lbs / ton actives, at least about 14 lbs / ton actives, or at least about 15 lbs / ton actives.

[0043] In some embodiments, the acrylamide-based polymer can improve the strength of the resulting product (e.g., paper product or fabric). In addition, in certain embodiments, the acrylamide-based polymer can improve one or more additional properties of the resulting product (e.g., paper product or fabric). For example, in addition to strength, the acrylamide-based polymer can improve opacity, smoothness, porosity, dimensional stability, pore size distribution, linting tendency, density, stiffness, forming, compressibility, or a combination thereof. Without being bound to any particular theory, it is believed that many of the above paper or fabric properties depend on the bonds that exist between the cellulose fibers of the paper or fabric. It is believed that the networking of these fibers can be enhanced by certain chemical auxiliaries and also by the mechanical beating and / or refining step(s) of the industrial process (e.g., papermaking process), during which the fibers become more flexible and the available surface area is increased.

[0044] In certain embodiments, the acrylamide-based polymer improves the dry strength of a product (e.g., a paper sheet or fabric), the wet or rewet strength of a product (e.g., a paper sheet or fabric), the wet web strength of a product (e.g., a paper sheet or fabric), or a combination thereof. In general, dry strength is recognized as the tensile strength exhibited by a dry product (e.g., a paper sheet or fabric), typically conditioned under uniform humidity and room temperature conditions before testing. Wet strength, or rewet strength, is recognized as the tensile strength exhibited by a paper sheet or fabric that has been completely dried and rewetted with water before testing. Wet web strength is recognized as the strength of a cellulose fiber mat before drying into a paper product.

[0045] In certain embodiments, the acrylamide-based polymer improves the dry strength of a product (e.g., a paper sheet or fabric). The acrylamide-based polymer can improve any suitable dry strength property of a product (e.g., a paper sheet or fabric). For example, the polymer can improve tensile strength, STFI ratio, burst strength ratio, ring crush, or a combination thereof.

[0046] In some embodiments, the acrylamide-based polymer increases the tensile strength (Nm / g) by at least about 0.5% per lb / ton actives. For example, the acrylamide-based polymer can increase the tensile strength (Nm / g) by at least about 1% per lb / ton actives, at least about 2% per lb / ton actives, at least about 3% per lb / ton actives, at least about 4% per lb / ton actives, or at least about 5% per lb / ton actives. In some embodiments, the acrylamide-based polymer increases the tensile strength (Nm / g) by at least about 2% per lb / ton actives. In certain embodiments, the acrylamide-based polymer increases the tensile strength (Nm / g) by at least about 3% per lb / ton actives.

[0047] In some embodiments, the acrylamide-based polymer increases the STFI ratio by at least about 0.5% per lb / ton actives on average. For example, the acrylamide-based polymer can increase the STFI ratio by at least about 1% per lb / ton actives, at least about 2% per lb / ton actives, at least about 3% per lb / ton actives, at least about 4% per lb / ton actives, or at least about 5% per lb / ton actives on average. In some embodiments, the acrylamide-based polymer increases the STFI ratio by about 2% per lb / ton actives on average. In certain embodiments, the acrylamide-based polymer increases the STFI ratio by about 3% per lb / ton actives on average.

[0048] In some embodiments, the acrylamide-based polymer has an average specific burst strength (PSI 1,000 ft) of at least about 0.5% per lb / ton of active material. 2For example, the acrylamide-based polymers increase, on average, the specific burst strength (PSI 1,000 ft 2 / lb) by at least about 1% per lb / ton actives, at least about 2% per lb / ton actives, at least about 3% per lb / ton actives, at least about 4% per lb / ton actives, or at least about 5% per lb / ton actives. 2 In some embodiments, the acrylamide-based polymer can, on average, increase the specific burst strength (PSI 1,000 ft lb / ton of active material) by about 2%. 2 In one particular embodiment, the acrylamide-based polymer increases, on average, the specific burst strength (PSI 1,000 ft ) by about 3% per lb / ton of active material. 2 / lb).

[0049] In some embodiments, the acrylamide-based polymer increases ring crush (kN / m) by at least about 0.5% per lb / ton actives. For example, the acrylamide-based polymer can increase ring crush (kN / m) by at least about 1% per lb / ton actives, at least about 2% per lb / ton actives, at least about 3% per lb / ton actives, at least about 4% per lb / ton actives, or at least about 5% per lb / ton actives. In some embodiments, the acrylamide-based polymer increases ring crush (kN / m) by at least about 2% per lb / ton actives. In certain embodiments, the acrylamide-based polymer increases ring crush (kN / m) by at least about 3% per lb / ton actives.

[0050] Acrylamide-based polymers can improve the dry strength of any suitable product, such as paper sheets or fabrics. In some embodiments, the acrylamide-based polymers improve the dry strength of kraft paper, tissue paper, testliner paper, mated topside white paper, cardboard and shaped or formed paperboard, or combinations thereof. In certain embodiments, the acrylamide-based polymers do not require a supplemental strength aid.

[0051] In some embodiments, the made-down powder solution is used with any suitable conventional papermaking product. For example, the made-down powder solution may be used with one or more inorganic fillers, dyes, retention aids, drainage aids, sizing agents, coagulants, or combinations thereof.

[0052] In some embodiments, the make-down powder solution is used with one or more inorganic fillers. The inorganic filler can be any suitable inorganic filler that can increase opacity or smoothness, reduce the cost per mass of paper, or a combination thereof. For example, the make-down powder solution can be used with kaolin, chalk, limestone, talc, titanium dioxide, calcined clay, urea formaldehyde, aluminates, aluminosilicates, silicates, calcium carbonate (e.g., ground and / or precipitated), or a combination thereof.

[0053] In some embodiments, the make-down powder solution is used with one or more dyes. The dyes can be any suitable dye capable of controlling the coloration of the paper. For example, the dyes can be direct dyes, cationic direct dyes, acid dyes, basic dyes, insoluble color pigments, or combinations thereof.

[0054] In some embodiments, the made-down powder solution is used with one or more drainage and / or retention aids. The drainage and / or retention aids can be any suitable drainage and / or retention aids that can help improve uniformity and retain additives while maintaining industrial process efficiency and drainage. For example, the drainage and / or retention aids can be cationic polyacrylamide ("PAM") polymers, anionic polyacrylamide ("PAM") polymers, cationic polyethyleneimine ("PEI") polymers, polyamines, ammonium-based polymers (e.g., polydiallyldimethylammonium chloride ("DADMAC"), colloidal silica, bentonite, polyethylene oxide ("PEO"), starch, polyaluminum sulfate, polyaluminum chloride, or combinations thereof.

[0055] In some embodiments, the make-down powder solution is used with one or more sizing agents. The sizing agent can be any suitable sizing agent capable of increasing the resistance to water and other liquids exhibited by a product (e.g., a paper sheet or fabric). For example, the sizing agent can be rosin, alkenyl succinic anhydride ("ASA"), alkyl ketene dimer ("AKD"), or a combination thereof.

[0056] In some embodiments, the made-down powder solution is used with one or more coagulants. The coagulant can be any suitable coagulant. In the context of this application, "coagulant" refers to a water treatment chemical used in the solid-liquid separation stage to neutralize the charge of suspended particles so that the particles can flocculate. In general, coagulants can be classified as cationic, anionic, amphoteric, or zwitterionic. Furthermore, coagulants can be classified as inorganic coagulants, organic coagulants, and blends thereof. Exemplary inorganic coagulants include, for example, aluminum or iron salts such as aluminum sulfate, aluminum chloride, ferric chloride, ferric sulfate, polyaluminum chloride, and / or aluminum chloride hydrate. Exemplary organic coagulants include, for example, diallyldimethylammonium chloride ("DADMAC"), dialkylaminoalkyl acrylates, and / or dialkylaminoalkyl methacrylates, or quaternary or acid salts thereof.

[0057] In some embodiments, the powder comprises one or more acrylamide-based polymers. For example, the powder can comprise a plurality of acrylamide-based polymers (e.g., at least two polymer molecules), where the acrylamide-based polymer(s) have the same molecular structure (i.e., one acrylamide-based polymer), or the powder can comprise a plurality of acrylamide-based polymers, where the acrylamide-based polymer(s) have different molecular structures (i.e., two or more acrylamide-based polymers). The one or more acrylamide-based polymers can be any suitable polymer. For example, the one or more acrylamide-based polymers can be homopolymers, copolymers, terpolymers, or higher, or combinations thereof. In certain embodiments, the one or more acrylamide-based polymers are terpolymers.

[0058] The acrylamide-based polymer(s) may be cationic, anionic, amphoteric, nonionic, or zwitterionic. In some embodiments, the acrylamide-based polymer(s) are cationic. As used herein, a "cationic" polymer refers to a polymer that contains cationic monomer units, or a combination of cationic and nonionic monomer units. In some embodiments, the acrylamide-based polymer(s) are anionic. As used herein, an "anionic" polymer refers to a polymer that contains anionic monomer units, or a combination of anionic and nonionic monomer units. In some embodiments, the acrylamide-based polymer(s) are amphoteric. As used herein, an "amphoteric" polymer refers to a polymer that contains cationic and anionic monomer units, or cationic, anionic, and nonionic monomer units. In some embodiments, the acrylamide-based polymer(s) are nonionic. As used herein, a "nonionic" polymer refers to a polymer that contains nonionic monomer units. In some embodiments, the acrylamide-based polymer(s) are zwitterionic. As used herein, a "zwitterionic" polymer refers to a polymer that contains zwitterionic monomer units, or a combination of zwitterionic and cationic, anionic, and / or nonionic monomer units.

[0059] The acrylamide-based polymer(s) can be present as any suitable structural type. For example, the acrylamide-based polymer(s) can be present as alternating polymers, random polymers, block polymers, graft polymers, linear polymers, branched polymers, cyclic polymers, or combinations thereof. The acrylamide-based polymer(s) can contain a single monomer unit, or any suitable number of different monomer units. For example, the acrylamide-based polymer(s) can contain two different monomer units, three different monomer units, four different monomer units, five different monomer units, or six different monomer units. The monomer units of the acrylamide-based polymer(s) can be present in any suitable concentration and any suitable ratio.

[0060] In certain embodiments, the powder comprises one or more acrylamide-based polymers, and the acrylamide-based polymer(s) (i.e., no networking) have a weight average molecular weight of about 10 kDa to about 5,000 kDa. The acrylamide-based polymer(s) can have a weight average molecular weight of about 5,000 kDa or less, for example, about 4,000 kDa or less, about 3,000 kDa or less, about 2,500 kDa or less, about 2,000 kDa or less, about 1,800 kDa or less, about 1,600 kDa or less, about 1,400 kDa or less, about 1,200 kDa or less, about 1,000 kDa or less, about 900 kDa or less, about 800 kDa or less, about 700 kDa or less, about 600 kDa or less, or about 500 kDa or less. Alternatively, or in addition, the acrylamide-based polymer(s) can have a weight average molecular weight of about 10 kDa or more, e.g., about 50 kDa or more, about 100 kDa or more, about 200 kDa or more, about 300 kDa or more, or about 400 kDa or more. Thus, the acrylamide-based polymer(s) can have a weight average molecular weight bounded by any two of the above endpoints.For example, the acrylamide-based polymer(s) may be from about 10 kDa to about 500 kDa, from about 50 kDa to about 500 kDa, from about 100 kDa to about 500 kDa, from about 200 kDa to about 500 kDa, from about 300 kDa to about 500 kDa, from about 400 kDa to about 500 kDa, from about 400 kDa to about 600 kDa, from about 400 kDa to about 700 kDa, About 400kDa to about 800kDa, about 400kDa to about 900kDa, about 400kDa to about 1,000kDa, about 400kDa to about 1,200kDa, about 400kDa to about 1,400kDa, about 400kDa to about 1,600kDa, about 400kDa to about 1,800kDa, about 400kDa to about 2,000kDa, about 10kDa to about 2 ,000kDa, about 200kDa to about 2,000kDa, about 500kDa to about 2,000kDa, about 800kDa to about 2,000kDa, about 200kDa to about 2,500kDa, about 500kDa to about 2,500kDa, about 800kDa to about 2,500kDa, about 200kDa to about 3,000kDa, about 500kDa to about 3,000kDa Da, about 800 kDa to about 3,000 kDa, about 200 kDa to about 4,000 kDa, about 500 kDa to about 4,000 kDa, about 800 kDa to about 4,000 kDa, about 200 kDa to about 5,000 kDa, about 500 kDa to about 5,000 kDa, or about 800 kDa to about 5,000 kDa.

[0061] The weight average molecular weight may be determined by any suitable technique. Although alternative techniques are envisioned, in some embodiments, the weight average molecular weight is determined using size exclusion chromatography (SEC) equipped with a set of TSKgel PW columns (TSKgel Guard+GMPW+GMPW+G1000PW), Tosoh Bioscience LLC, Cincinnati, Ohio), and a Waters 2414 (Waters Corporation, Milford, Massachusetts) refractive index detector, or a DAWN HELEOS II multi-angle light scattering (MALS) detector (Wyatt Technology, Santa Barbara, California). Additionally, the weight average molecular weight is determined either from calibration with polyethylene oxide / polyethylene glycol standards ranging from 150 to 875,000 daltons, or from direct use of light scattering data with known refractive index increments ("dn / dc").

[0062] In certain embodiments, the weight average molecular weight is determined by hydrolysis of the acrylamide-based polymer to remove hydrolyzable side chains, which are then further analyzed by size exclusion chromatography (SEC). The acrylamide-based polymer may be hydrolyzed by any suitable technique. For example, the acrylamide-based polymer may be hydrolyzed by treatment with a 0.1 wt% solution of NaOH at pH 12 for 1 hour using a cage stirrer at 400 rpm. As used herein, "hydrolyzable side chain" refers to any side chain on the associative monomer unit or additional monomer unit that can be cleaved by hydrolysis. Without being bound to any particular theory, acrylamide-based polymers containing associative monomer units may need to be hydrolyzed prior to size exclusion chromatography due to low recovery from the column. In general, hydrolysis of the acrylamide-based polymer does not cleave the polymer backbone and preserves the degree of polymerization of the acrylamide-based polymer(s).

[0063] In certain embodiments, the associative monomer unit does not contain hydrolyzable side chains. In embodiments in which the associative monomer unit does not contain hydrolyzable side chains, the weight average molecular weight can be determined by analyzing a substitute for the acrylamide-based polymer. For example, the weight average molecular weight can be determined by synthesizing a polymer using the exact same recipe in the absence of the associative monomer unit. Without being bound by any particular theory, the polymer synthesized with the same recipe maintains a similar degree of polymerization and results in a similar weight average molecular weight to the acrylamide-based polymer in which the associative monomer unit is present.

[0064] Exemplary embodiments of the acrylamide-based polymer(s) generally include one or more associative monomer units and one or more additional monomer units. As used herein, "additional monomer units" refers to any monomer unit other than the associative monomer unit. In certain embodiments, the one or more additional monomer units are derived from a water-soluble monomer (e.g., acrylamide, diallyldimethylammonium chloride ("DADMAC"), 2-(acryloyloxy)-N,N,N-trimethylethanaminium chloride ("DMAEA.MCQ"), etc.). As used herein, "derived" when referring to a monomer unit means that the monomer unit has substantially the same structure as the monomer from which it was made, and the terminal olefin has been converted during the polymerization process. In some embodiments, the acrylamide-based polymer(s) include one or more associative monomer units, monomer units derived from a monomer of formula I, and one or more additional monomer units. In certain embodiments, the acrylamide-based polymer(s) include one or more associative monomer units, monomer units derived from a monomer of formula I, and additional monomer units.

[0065] In some embodiments, the one or more associative monomer units and the one or more additional monomer units may be incorporated into the acrylamide-based polymer(s) using monomers, dimers, trimers, oligomers, adducts, or combinations thereof of the monomer structures from which they are derived. For example, the one or more associative monomer units or the one or more additional monomer units may be present as dimers, trimers, oligomers, or adducts prior to incorporation into the acrylamide-based polymer(s).

[0066] The acrylamide-based polymer(s) can include any one or more suitable additional monomer units selected from cationic monomer units, anionic monomer units, nonionic monomer units, zwitterionic monomer units, and combinations of two or more thereof. For example, the acrylamide-based polymer(s) can include cationic and anionic monomer units, anionic and nonionic monomer units, cationic and nonionic monomer units, or cationic, anionic, and nonionic monomer units. In certain embodiments, the acrylamide-based polymer(s) can include and / or further include zwitterionic monomer units. The acrylamide-based polymer(s) can be synthesized by any suitable polymerization method. For example, the acrylamide-based polymer(s) can be made by free radical polymerization, addition polymerization, free radical addition polymerization, cationic addition polymerization, anionic addition polymerization, emulsion polymerization, solution polymerization, suspension polymerization, precipitation polymerization, or combinations thereof. In certain embodiments, the polymerization occurs by free radical polymerization.

[0067] Thus, suitable additional monomer units may be derived from any one or more suitable monomers capable of participating in free radical polymerization. For example, an acrylamide-based polymer(s) may be prepared by reacting a monomer of formula I, 2-(dimethylamino)ethyl acrylate ("DMAEA"), 2-(dimethylamino)ethyl methacrylate ("DMAEM"), 3-(dimethylamino)propyl methacrylamide ("DMAPMA"), 3-(dimethylamino)propyl acrylamide ("DMAPA"), 3-methacrylamidopropyl-trimethyl-ammonium chloride ("MAPTAC"), 3-acrylamidopropyl-trimethyl-ammonium chloride ("APTAC"), N-vinylpyrrolidone ("NVP"), N-vinylacetamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, diallyldimethylammonium chloride ("DADMAC"), diallylamine, vinylformamide, 2-(acryloyl The monomer unit may include one or more additional monomer units derived from a monomer selected from: 2-(methacryloyloxy)-N,N,N-trimethylethanaminium chloride ("DMAEA.MCQ"), 2-(methacryloyloxy)-N,N,N-trimethylethanaminium chloride ("DMAEM.MCQ"), N,N-dimethylaminoethyl acrylate benzyl chloride ("DMAEA.BCQ"), N,N-dimethylaminoethyl methacrylate benzyl chloride ("DMAEM.BCQ"), 2-acrylamido-2-methylpropanesulfonic acid ("AMPS"), 2-acrylamido-2-methylbutanesulfonic acid ("AMBS"), [2-methyl-2-[(1-oxo-2-propenyl)amino]propyl]-phosphonic acid, methacrylic acid, acrylic acid, salts thereof, and combinations thereof.

[0068] In some embodiments, the acrylamide-based polymer(s) comprise monomer units derived from a monomer of formula I, [ka] wherein R1 is H or C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), and each R2 is independently H or an organic group. As used herein, the term "organic group" refers to an alkyl group, an aryl group, a fluoroalkyl group, or a fluoroaryl group. In certain embodiments, a monomer unit derived from a monomer of formula I is considered an additional monomer unit.

[0069] In certain embodiments of the substituent R2, the organic group is a C1-C6 alkyl group (i.e., 1, 2, 3, 4, 5, or 6 carbon units in length). In some embodiments, the C1-C6 alkyl group is saturated, unsaturated, branched, straight-chained, cyclic, or a combination thereof. An exemplary list of C1-C6 alkyl groups is methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, neo-pentyl, or hexyl. In certain embodiments, the C1-C6 alkyl group is substituted with one or more alkyl substituents, aryl substituents, heteroatoms, or combinations thereof (e.g., benzyl, phenylethyl, phenylpropyl, etc.). In some embodiments, the C1-C6 alkyl group can be a C1-C6 heteroalkyl group (i.e., 1, 2, 3, 4, 5, or 6 carbon units in length). As used herein, a "heteroalkyl group" refers to a saturated or unsaturated, substituted or unsubstituted, straight-chain, branched, or cyclic aliphatic group that contains at least one heteroatom (e.g., O, S, N, and / or P) in the core (i.e., carbon backbone) of the molecule.

[0070] In certain embodiments of the substituent R2, the organic group is an aryl group. The aryl group can be any substituted or unsubstituted aryl or heteroaryl group, and the heteroaryl group is an aromatic 5- or 6-membered monocyclic group having at least one heteroatom (e.g., O, S, or N) in at least one of the rings. The heteroaryl group can contain 1 or 2 oxygen or sulfur atoms and / or 1 to 4 nitrogen atoms, provided that the total number of heteroatoms in the ring is 4 or less and the ring has at least one carbon atom. Optionally, the nitrogen, oxygen, and sulfur atoms can be oxidized (i.e., undergoing a process that loses electrons), and the nitrogen atom can be optionally quaternized. In some embodiments, the aryl compound is phenyl, pyrrolyl, furanyl, thiophenyl, pyridyl, isoxazolyl, oxazolyl, isothiazolyl, thiazolyl, imidazolyl, thiadiazolyl, tetrazolyl, triazolyl, oxadiazolyl, pyrazolyl, pyrazinyl, triazinyl, pyrimidinyl, or pyridazinyl.

[0071] In certain embodiments of the substituent R2, the organic group is a C1-C6 fluoroalkyl group or a C1-C6 fluoroaryl group. As used herein, the terms "fluoroalkyl" and "fluoroaryl" refer to any alkyl or aryl group, respectively, having one or more fluorine atoms.

[0072] In certain embodiments, the monomer of formula I is an acrylamide or a methacrylamide.

[0073] The acrylamide-based polymer(s) can include one or more additional monomer units in any suitable concentration, so long as the acrylamide-based polymer(s) include a suitable portion of one or more associative monomer units provided herein. The acrylamide-based polymer(s) can include a total of about 90 mol% or more, e.g., about 91 mol% or more, about 92 mol% or more, about 93 mol% or more, about 94 mol% or more, about 95 mol% or more, about 96 mol% or more, about 97 mol% or more, about 98 mol% or more, or about 99 mol% or more of the one or more additional monomer units. Alternatively, or in addition, the acrylamide-based polymer(s) can comprise a total of about 99.995 mol% or less, e.g., about 99.99 mol% or less, about 99.9 mol% or less, about 99.75 mol% or less, about 99.5 mol% or less, about 99.4 mol% or less, about 99.3 mol% or less, about 99.2 mol% or less, or about 99.1 mol% or less of one or more additional monomer units. Thus, the acrylamide-based polymer(s) can comprise one or more additional monomer units in a total concentration bounded by any two of the above endpoints. The acrylamide-based polymer(s) may be from about 90 mol% to about 99.995 mol%, for example, from about 91 mol% to about 99.995 mol%, from about 92 mol% to about 99.995 mol%, from about 93 mol% to about 99.995 mol%, from about 94 mol% to about 99.995 mol%, from about 95 mol% to about 99.995 mol%, from about 97 mol% to about 99.995 mol%, from about 98 mol% to about 99.995 mol%, from about 9 ... mol%, from about 99 mol% to about 99.995 mol%, from about 99 mol% to about 99.99 mol%, from about 99 mol% to about 99.99 mol%, from about 99 mol% to about 99.99 mol%, from about 99 mol% to about 99.99 mol%, from about 99 mol% to about 99.99 mol%, from about 99 mol% to about 99.99 mol%, from about 99 mol% to about 99.99 mol%, from about The copolymer may comprise a total of about 99.9 mol%, about 99 mol% to about 99.75 mol%, about 99 mol% to about 99.5 mol%, about 99 mol% to about 99.4 mol%, about 99 mol% to about 99.3 mol%, about 99 mol% to about 99.2 mol%, about 99 mol% to about 99.1 mol%, about 99.5 mol% to about 99.99 mol%, about 99.5 mol% to about 99.995 mol%, about 99.75 mol% to about 99.99 mol%, or about 99.75 mol% to about 99.995 mol% of one or more additional monomer units.

[0074] Acrylamide-based polymer(s) can include one or more associative monomer units of any suitable type(s). As described herein, "associative monomer unit" refers to any monomer unit that can coordinate with itself, other associative monomer units, surfactants, or combinations thereof. Coordination can occur through any suitable interaction. For example, coordination can occur through ionic bonds, hydrogen bonds, hydrophobic interactions, dipole interactions, van der Waals forces, or a combination of two or more such coordination types.

[0075] In some embodiments, the associative monomer unit is formed after polymerization by attaching an associative moiety to the polymer. As used herein, "associative moiety" refers to any pendant chemical structure capable of coordinating with itself, other associative monomer units, surfactants, or combinations thereof. Coordination can occur through any suitable interaction. For example, coordination can occur through ionic bonds, hydrogen bonds, hydrophobic interactions, dipole interactions, van der Waals forces, or a combination of two or more such coordination types. In some embodiments, the associative moiety is attached directly to the end of the polymer, attached to the end of the polymer via a linker, attached directly to the polymer backbone, attached to the polymer backbone via a linker, or a combination thereof.

[0076] In certain embodiments, one or more associative monomer units of one or more acrylamide-based polymers are structurally similar. As used herein, "structurally similar" means that the associative monomer unit(s) have similar chemical functional groups. In some embodiments, the associative monomer unit(s) each comprise at least one hydroxyl substituent. In some embodiments, the associative monomer unit(s) each comprise at least one amine substituent. In some embodiments, the associative monomer unit(s) each comprise a polyether chain. In some embodiments, the associative monomer unit(s) each comprise a polyether chain, and the length of the polyether chains are separated by no more than 6 carbon units (i.e., 6, 5, 4, 3, 2, 1, or 0). For example, if an associative monomer unit has a polyether chain length of 16 carbon units, a structurally similar associative monomer unit has a polyether chain length of 10 to 22 carbon units (i.e., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22). In certain embodiments, the polyether chains each comprise the same number of carbon units. In some embodiments, the associative monomer unit(s) each comprise an alkyl chain. In some embodiments, the associative monomer unit(s) each comprise an alkyl chain, and the alkyl chains are separated by 6 carbon units or less (i.e., 6, 5, 4, 3, 2, 1, or 0) in length. For example, if an associative monomer unit has an alkyl chain length of 16 carbon units, a structurally similar associative monomer unit will have an alkyl chain length of 10 to 22 carbon units (i.e., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22). In certain embodiments, the alkyl chains each contain the same number of carbon units. In certain embodiments, the associative monomer unit(s) are the same.

[0077] In certain embodiments, one or more associative monomer units are incorporated into the polymer by polymerization with one or more associative monomers. Thus, one or more associative monomer units can be derived from any one or more suitable associative monomers selected from nonionic associative monomers, cationic associative monomers, anionic associative monomers, zwitterionic associative monomers, and combinations thereof. One or more associative monomers are capable of participating in polymerization. In certain embodiments, one or more associative monomers, apart from the associative moiety, include unsaturated subunits (e.g., acrylates, acrylamides, etc.) capable of participating in free radical polymerization. Generally, one or more associative monomers are selected from acrylates, acrylamides, or combinations thereof.

[0078] In one embodiment, the associative monomer unit is a non-ionic associative monomer unit. Generally, the non-ionic associative monomer unit is derived from an acrylate and / or acrylamide monomer of formula II: [ka] In the formula, R3 is H or C1-C 10 Alkyl (e.g., (CH2) k CH3), k is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), X is O or NH, m, n, and o are independently integers from 0 to 100, and if (n+o) is 3 or less, then m is at least 7, and each Y1 and Y2 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), and R4 is H or a hydrophobic group. In some embodiments, "C1-C4 alkyl" is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), X is O or NH, m, n, and o are independently integers from 0 to 100, and if (n+o) is 3 or less, then m is at least 7, and each Y1 and Y2 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), and R4 is H or a hydrophobic group. 10 "Alkyl" is a branched C1-C 10In certain embodiments, each Y1 and Y2 is independently selected to produce a block or random copolymer of ethylene oxide ("EO"), propylene oxide ("PO"), or a combination thereof. In some embodiments, m, n, and o refer to the average (rounded to the nearest integer) chain length of the specified subunits (i.e., average carbon chain length or average EO / PO chain length). As used herein, the term "hydrophobic group" refers to an alkyl group, an aryl group, a fluoroalkyl group, or a fluoroaryl group.

[0079] In certain embodiments of the substituent R4, the hydrophobic group is a C1-C 32 In some embodiments, the alkyl group is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32 carbon units in length. 32 The alkyl group may be saturated, unsaturated, branched, straight chain, cyclic, or a combination thereof. 32 An exemplary list of alkyl groups is methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, neo-pentyl, hexyl, heptyl, octyl, nonyl, lauryl, stearyl, cetyl, behenyl, cyclopentyl, cyclohexyl, propenyl, 2-butenyl, 3-butenyl, 2-pentenyl, 3-pentenyl, or 4-pentenyl. In certain embodiments, C1-C 32 The alkyl carbon group is further substituted with one or more alkyl substituents, aryl substituents, heteroatoms, or combinations thereof. In some embodiments, C1-C 32 The alkyl group is C1-C 32Heteroalkyl groups can be (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32 carbon units in length). As used herein, "heteroalkyl group" refers to a saturated or unsaturated, substituted or unsubstituted, straight-chain, branched, or cyclic aliphatic group that contains at least one heteroatom (e.g., O, S, N, and / or P) in the core (i.e., carbon backbone) of the molecule.

[0080] As used herein, the term "substituted" means that one or more hydrogens on the specified atom or group are replaced with another group, provided that the normal valence of the specified atom is not exceeded. For example, if the substituent is oxo (i.e., =O), two hydrogens on the carbon atom are replaced. Combinations of substituents are permitted, provided that the substituents do not significantly adversely affect the synthesis or use of the acrylamide-based polymer.

[0081] In certain embodiments of the substituent R4, the hydrophobic group is an aryl group. The aryl group can be any substituted or unsubstituted aryl or heteroaryl group, and the heteroaryl group is an aromatic 5- or 6-membered monocyclic group, a 9- or 10-membered bicyclic group, or an 11- to 14-membered tricyclic group having at least one heteroatom (e.g., O, S, or N) in at least one of the rings. Each ring of the heteroaryl group containing a heteroatom can contain one or two oxygen or sulfur atoms and / or one to four nitrogen atoms, provided that the total number of heteroatoms in each ring is four or less and each ring has at least one carbon atom. The fused rings completing the bicyclic and tricyclic groups may contain only carbon atoms and may be saturated, partially saturated, or unsaturated. The nitrogen, oxygen, and sulfur atoms may be optionally oxidized, and the nitrogen atoms may be optionally quaternized. Heteroaryl groups that are bicyclic or tricyclic must contain at least one complete aromatic ring, but the other fused ring or rings can be aromatic or non-aromatic. In some embodiments, the aryl group is phenyl, naphthyl, pyrrolyl, isoindolyl, indolizinyl, indolyl, furanyl, benzofuranyl, benzothiophenyl, thiophenyl, pyridyl, acridinyl, naphthyridinyl, quinolinyl, isoquinolinyl, isoxazolyl, oxazolyl, benzoxazolyl, isothiazolyl, thiazolyl, benzthiazolyl, imidazolyl, thiadiazolyl, tetrazolyl, triazolyl, oxadiazolyl, benzimidazolyl, purinyl, pyrazolyl, pyrazinyl, pteridinyl, quinoxalinyl, phthalazinyl, quinazolinyl, triazinyl, phenazinyl, cinnolinyl, pyrimidinyl, or pyridazinyl.

[0082] In certain embodiments of the substituent R4, the hydrophobic group is a C1-C 32 Fluoroalkyl group or C1-C 32 A fluoroaryl group. As used herein, the terms "fluoroalkyl" and "fluoroaryl" refer to any alkyl or aryl group, respectively, having one or more fluorine atoms.

[0083] In certain embodiments, the nonionic associative monomer units are derived from acrylate monomers comprising an acrylate head group of formula III: [ka] In the formula, R5 is -CH2(CH2) p CH 3であり , R3 is H or C1-C 10 Alkyl (e.g., (CH2) k CH3), k is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), and p is an integer from 3 to 100 (e.g., 4 to 50, 6 to 50, 8 to 50, 10 to 50, 12 to 50, 16 to 50, or 18 to 50). In some embodiments, the acrylate monomer of formula III is a mixture of two or more such acrylates, such that the average (rounded to the nearest integer) value of ... 10 "Alkyl" is a branched C1-C 10 R5 refers to an alkyl group. In certain embodiments, R5 is a branched alkyl group of 3 to 100 carbon units in length. Generally, the nonionic associative monomer is selected from lauryl acrylate, cetyl acrylate, stearyl acrylate, behenyl acrylate, or combinations thereof. In certain embodiments, the nonionic associative monomer unit is lauryl acrylate, i.e., R3=H and p=10.

[0084] In certain embodiments, the nonionic associative monomer units are derived from acrylate monomers comprising an acrylate head group of formula IV: [ka] In the formula, R3 is H or C1-C 10 Alkyl (e.g., (CH2) kCH3), k is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), q is an integer from 2 to 100 (e.g., 4 to 50, 6 to 50, 8 to 50, 10 to 50, 12 to 50, 16 to 50, 18 to 50, 16 to 100, 18 to 100, or 50 to 100), r is an integer from 0 to 30 (e.g., 2 to 30, 4 to 30, 6 to 30, 8 to 30, 10 to 30, 12 to 30, 16 to 30, 18 to 30, 20 to 30, 22 to 30, or 24 to 30), and each Y is independently H or CH3. 10 "Alkyl" is a branched C1-C 10refers to an alkyl group. In certain embodiments, each Y is selected to produce a block or random copolymer of ethylene oxide ("EO"), propylene oxide ("PO"), or a combination thereof. In some embodiments, the acrylate monomer of formula IV is a mixture of two or more such acrylates such that the average (rounded to the nearest integer) value of q is an integer between 2 and 100 (e.g., 4-50, 6-50, 8-50, 10-50, 12-50, 16-50, 18-50, 16-100, 18-100, or 50-100) and the average (rounded to the nearest integer) value of r is an integer between 0 and 30 (e.g., 2-30, 4-30, 6-30, 8-30, 10-30, 12-30, 16-30, 18-30, 20-30, 22-30, or 24-30). In some embodiments, the acrylate monomer of formula IV is lauryl polyethoxy (25) methacrylate, cetyl polyethoxy (25) methacrylate, stearyl polyethoxy (25) methacrylate, behenyl polyethoxy (25) methacrylate, or a combination thereof. In certain embodiments, the nonionic associative monomer unit is VISIOMER® ether methacrylate, available from Evonik Industries, Essen, Germany. In some embodiments, the nonionic associative monomer unit is cetyl and / or stearyl polyethoxy (25) methacrylate, available from Evonik Industries, Essen, Germany, sold under the product name Methacrylic acid ester (25 EO) C16-C18 fatty alcohol ("C18PEG1105MA").

[0085] In certain embodiments, the nonionic associative monomer units are derived from acrylate monomers comprising an acrylate head group of formula V: [ka] In the formula, R3 is H or C1-C 10 Alkyl (e.g., (CH2) kCH3), k is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), each Y1 and Y2 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), n and o are independently integers ranging from 0 to about 100 (e.g., from about 0 to about 90, from about 0 to about 80, from about 0 to about 70, from about 0 to about 60, from about 0 to about 50, from about 10 to about 100, or from about 10 to about 50), and R4' is a C8-C 30 In some embodiments, "C1-C4" is an alkyl group (i.e., 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 carbon units in length), and n and o cannot both be 0. 10 "Alkyl" is a branched C1-C 10 refers to an alkyl group. In certain embodiments, each Y1 and Y2 is independently selected to produce a block or random copolymer of ethylene oxide ("EO"), propylene oxide ("PO"), or a combination thereof. In some embodiments, the acrylate monomer of formula V is a mixture of two or more such acrylates, such that the average (rounded to the nearest integer) values ​​of n and o are independently integers between 0 and 100 (e.g., 0-50, 6-50, 8-50, 10-50, 12-50, 16-50, 18-50, 16-100, 18-100, 50-100). In certain embodiments, the acrylate monomer of formula V contains a side chain derived from Plurafac® surfactants, commercially available from BASF Corporation, Florham Park, New Jersey.

[0086] In another embodiment, the associative monomer unit is a cationic associative monomer unit. Generally, the cationic associative monomer unit is derived from an acrylate salt monomer and / or an acrylamide salt monomer of formula VI, [ka] In the formula, R6 and R7 are each independently H or C1 to C 10 Alkyl (e.g., (CH2) t CH3), t is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), X is O or NH, s is an integer from 0 to 20 (e.g., 2 to 20, 4 to 20, 6 to 20, 8 to 20, 5 to 10, 10 to 20, 5 to 15, 12 to 20, 0 to 10, 0 to 8, 0 to 6, or 0 to 4), Z is any anion, and R8 is a hydrophobic group. In some embodiments, the acrylate and / or acrylamide salt of formula VI is a mixture of two or more such acrylates and / or acrylamides, such that the average (rounded to the nearest integer) value of s is an integer between 0 and 20 (e.g., 2-20, 4-20, 6-20, 8-20, 5-10, 10-20, 5-15, 12-20, 0-10, 0-8, 0-6, or 0-4). 10 "Alkyl" is a branched C1-C 10 As used herein, the term "hydrophobic group" refers to an alkyl group, an aryl group, a fluoroalkyl group, or a fluoroaryl group.

[0087] In certain embodiments of the substituent R8, the hydrophobic group is C1-C 32 In some embodiments, the alkyl group is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32 carbon units in length. 32 The alkyl group may be saturated, unsaturated, branched, straight chain, cyclic, or a combination thereof. 32An exemplary list of alkyl groups is methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, neo-pentyl, hexyl, heptyl, octyl, nonyl, lauryl, stearyl, cetyl, behenyl, cyclopentyl, cyclohexyl, propenyl, 2-butenyl, 3-butenyl, 2-pentenyl, 3-pentenyl, or 4-pentenyl. In certain embodiments, C1-C 32 The alkyl group is further substituted with one or more alkyl substituents, aryl substituents, heteroatoms, or combinations thereof. In some embodiments, C1-C 32 The alkyl group is C1-C 32 Heteroalkyl groups can be (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32 carbon units in length). As used herein, "heteroalkyl group" refers to a saturated or unsaturated, substituted or unsubstituted, straight-chain, branched, or cyclic aliphatic chain that contains at least one heteroatom (e.g., O, S, N, and / or P) in the core (i.e., carbon backbone) of the molecule.

[0088] In certain embodiments of the substituent R8, the hydrophobic group is an aryl group. The aryl group can be any substituted or unsubstituted aryl or heteroaryl group, with the heteroaryl group being an aromatic 5- or 6-membered monocyclic group, a 9- or 10-membered bicyclic group, and an 11- to 14-membered tricyclic group having at least one heteroatom (e.g., O, S, or N) in at least one of the rings. Each ring of the heteroaryl group containing a heteroatom can contain one or two oxygen or sulfur atoms and / or one to four nitrogen atoms, provided that the total number of heteroatoms in each ring is four or less and each ring has at least one carbon atom. The fused rings completing the bicyclic and tricyclic groups may contain only carbon atoms and may be saturated, partially saturated, or unsaturated. The nitrogen, oxygen, and sulfur atoms may be optionally oxidized, and the nitrogen atoms may be optionally quaternized. Heteroaryl groups that are bicyclic or tricyclic must contain at least one complete aromatic ring, but the other fused ring or rings can be aromatic or non-aromatic. In some embodiments, the aryl compound is phenyl, naphthyl, pyrrolyl, isoindolyl, indolizinyl, indolyl, furanyl, benzofuranyl, benzothiophenyl, thiophenyl, pyridyl, acridinyl, naphthyridinyl, quinolinyl, isoquinolinyl, isoxazolyl, oxazolyl, benzoxazolyl, isothiazolyl, thiazolyl, benzthiazolyl, imidazolyl, thiadiazolyl, tetrazolyl, triazolyl, oxadiazolyl, benzimidazolyl, purinyl, pyrazolyl, pyrazinyl, pteridinyl, quinoxalinyl, phthalazinyl, quinazolinyl, triazinyl, phenazinyl, cinnolinyl, pyrimidinyl, or pyridazinyl.

[0089] In certain embodiments of the substituent R8, the hydrophobic group is C1-C 32 Fluoroalkyl group or C1-C 32 A fluoroaryl group. As used herein, the terms "fluoroalkyl" and "fluoroaryl" refer to any alkyl or aryl group, respectively, having one or more fluorine atoms.

[0090] The ammonium salt of formula VI can have any suitable anionic counterion (i.e., "Z"). In some embodiments, the anionic counterion ("Z") comprises an element selected from halogen (e.g., fluoride, chloride, bromide, or iodide), sulfur, carbon, nitrogen, phosphorus, and combinations thereof. An exemplary list of anions includes fluoride, chloride, bromide, iodide, sulfide, sulfite, sulfate, sulfonate, bisulfate, bisulfite, thiosulfate, carbonate, bicarbonate, nitrate, nitrite, phosphate, hydrogen phosphate, dihydrogen phosphate, phosphite, dihydrogen phosphite, hexafluorophosphate, carboxylate, acetate, mesylate, tosylate, or triflate. In certain embodiments, Z is selected from fluoride, chloride, bromide, mesylate, tosylate, or combinations thereof.

[0091] In certain embodiments, the cationic associative monomer unit is derived from an acrylamide salt monomer of formula VII: [ka] In the formula, R6 is H or C1-C 10 Alkyl (e.g., (CH2) t CH3), t is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), and u is an integer from 0 to 30 (e.g., 2 to 30, 4 to 30, 6 to 30, 8 to 30, 5 to 25, 10 to 30, 12 to 30, 15 to 25, 16 to 30, 18 to 30, 20 to 30, 22 to 30, or 24 to 30). 10 "Alkyl" is a branched C1-C 10refers to an alkyl group. In some embodiments, the acrylamide salt of formula VII is a mixture of two or more such acrylamides, such that the average (rounded to the nearest integer) value of u is an integer between 0 and 30 (e.g., 2-30, 4-30, 6-30, 8-30, 5-25, 10-30, 12-30, 15-25, 16-30, 18-30, 20-30, 22-30, or 24-30). In certain embodiments, the acrylamide salt of formula VII is a "MAPTAC-C12 derivative" (i.e., where R6 is CH3 and u is 10).

[0092] In another embodiment, the associative monomer units are anionic associative monomer units. Generally, the anionic associative monomer units are derived from acrylate and / or acrylamide monomers of formula VIII: [ka] In the formula, R9 is H or C1 to C 10 Alkyl (e.g., (CH2) v CH3), v is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), X is O or NH, M is any cation, and each R 10 are independently H or a hydrophobic group. In some embodiments, 10 "Alkyl" is a branched C1-C 10 As used herein, the term "hydrophobic group" refers to an alkyl group, an aryl group, a fluoroalkyl group, or a fluoroaryl group.

[0093] Substituent R 10 In certain embodiments, the hydrophobic group is C 32 In some embodiments, the alkyl group is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32 carbon units in length. 32The alkyl group may be saturated, unsaturated, branched, straight chain, cyclic, or a combination thereof. 32 An exemplary list of alkyl groups is methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, sec-pentyl, neo-pentyl, hexyl, heptyl, octyl, nonyl, lauryl, stearyl, cetyl, behenyl, cyclopentyl, cyclohexyl, propenyl, 2-butenyl, 3-butenyl, 2-pentenyl, 3-pentenyl, or 4-pentenyl. In certain embodiments, C1-C 32 The alkyl group is further substituted with one or more alkyl substituents, aryl substituents, heteroatoms, or combinations thereof. In some embodiments, C1-C 32 The alkyl group is C1-C 32 Heteroalkyl groups can be (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32 carbon units in length). As used herein, "heteroalkyl group" refers to a saturated or unsaturated, substituted or unsubstituted, straight-chain, branched, or cyclic aliphatic group that contains at least one heteroatom (e.g., O, S, N, and / or P) in the core (i.e., carbon backbone) of the molecule.

[0094] Substituent R 10In certain embodiments, the hydrophobic group is an aryl group. The aryl group can be any substituted or unsubstituted aryl or heteroaryl group, with the heteroaryl group being an aromatic 5- or 6-membered monocyclic group, a 9- or 10-membered bicyclic group, and an 11- to 14-membered tricyclic group having at least one heteroatom (e.g., O, S, or N) in at least one of the rings. Each ring of the heteroaryl group containing a heteroatom can contain one or two oxygen or sulfur atoms and / or one to four nitrogen atoms, provided that the total number of heteroatoms in each ring is four or less and each ring has at least one carbon atom. The fused rings completing the bicyclic and tricyclic groups may contain only carbon atoms and may be saturated, partially saturated, or unsaturated. The nitrogen, oxygen, and sulfur atoms may be optionally oxidized, and the nitrogen atoms may be optionally quaternized. Heteroaryl groups that are bicyclic or tricyclic must contain at least one complete aromatic ring, but the other fused ring or rings can be aromatic or non-aromatic. In some embodiments, the aryl compound is phenyl, naphthyl, pyrrolyl, isoindolyl, indolizinyl, indolyl, furanyl, benzofuranyl, benzothiophenyl, thiophenyl, pyridyl, acridinyl, naphthyridinyl, quinolinyl, isoquinolinyl, isoxazolyl, oxazolyl, benzoxazolyl, isothiazolyl, thiazolyl, benzthiazolyl, imidazolyl, thiadiazolyl, tetrazolyl, triazolyl, oxadiazolyl, benzimidazolyl, purinyl, pyrazolyl, pyrazinyl, pteridinyl, quinoxalinyl, phthalazinyl, quinazolinyl, triazinyl, phenazinyl, cinnolinyl, pyrimidinyl, or pyridazinyl.

[0095] Substituent R 10 In certain embodiments, the hydrophobic group is C 32 Fluoroalkyl group or C1-C 32 A fluoroaryl group. As used herein, the terms "fluoroalkyl" and "fluoroaryl" refer to any alkyl or aryl group, respectively, having one or more fluorine atoms.

[0096] The sulfonate salt can have any suitable cationic counterion (i.e., "M"). For example, the cationic counterion ("M") can be a proton, ammonium, a quaternary amine, an alkali metal cation, an alkaline earth metal cation, a transition metal cation, a rare earth metal cation, a main group element cation, or a combination thereof. In some embodiments, the cationic counterion is a proton or cation of lithium, sodium, potassium, magnesium, calcium, manganese, iron, zinc, or a combination thereof. In certain embodiments, M is selected from hydrogen, lithium, sodium, potassium, or a combination thereof.

[0097] One or more associative monomer units can be present in any suitable amount in the acrylamide-based polymer.The acrylamide-based polymer can comprise a total of about 10 mol% or less, for example about 9 mol% or less, about 8 mol% or less, about 7 mol% or less, about 6 mol% or less, about 5 mol% or less, about 4 mol% or less, about 3 mol% or less, about 2 mol% or less, or about 1 mol% or less of one or more associative monomer units.Alternatively or in addition, the acrylamide-based polymer can comprise about 0.005 mol% or more, for example about 0.01 mol% or more, about 0.1 mol% or more, about 0.25% or more, about 0.3 mol% or more, about 0.4 mol% or more, or about 0.5 mol% or more of one or more associative monomer units.Thus, the acrylamide-based polymer can comprise one or more associative monomer units at a concentration bounded by any two of the above endpoints. The acrylamide polymer is about 0.005 mol% to about 10 mol%, for example, about 0.005 mol% to about 9 mol%, about 0.005 mol% to about 8 mol%, about 0.005 mol% to about 7 mol%, about 0.005 mol% to about 6 mol%, about 0.005 mol% to about 5 mol%, about 0.005 mol% to about 4 mol%, about 0.005 mol% to about 3 mol%, about 0.005 mol% to about 2 mol%, about It may contain one or more associative monomer units at 0.005 mol% to about 1 mol%, about 0.01 mol% to about 1 mol%, about 0.1 mol% to about 1 mol%, about 0.25 mol% to about 1 mol%, about 0.3 mol% to about 1 mol%, about 0.4 mol% to about 1 mol%, about 0.5 mol% to about 1.0 mol%, about 0.01 mol% to about 0.5 mol%, or about 0.01 mol% to about 0.25 mol%.

[0098] In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional cationic monomer unit. In some embodiments, the acrylamide-based polymer(s) comprises an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from DMAEA.MCQ. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ.

[0099] In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional anionic monomer unit. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from sodium acrylate. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate.

[0100] In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional cationic monomer unit. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from DMAEA.MCQ. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VI, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ.

[0101] In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional anionic monomer unit. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from sodium acrylate. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VI, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate.

[0102] In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VIII, a monomer unit derived from a monomer of formula I, and an additional cationic monomer unit. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VIII, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from DMAEA.MCQ.

[0103] In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VIII, a monomer unit derived from a monomer of formula I, and an additional anionic monomer unit. In some embodiments, the acrylamide-based polymer comprises an associative monomer unit derived from a monomer of formula VIII, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from sodium acrylate.

[0104] In some embodiments, the acrylamide-based polymer has the formula AP1: [ka] wherein E is one or more associative monomer units, F is one or more additional monomer units, G is one or more monomer units derived from a monomer of formula I, and H is optionally present and is one or more piperidine-2,6-dione units, wherein the one or more piperidine-2,6-diones are formed by cyclization of an acrylamide nitrogen of one or more monomer units ("G") derived from a monomer of formula I on the carbonyl of the additional monomer unit ("F"), and the acrylamide-based polymer has a weight average molecular weight of from about 10 kDa to about 2,000 kDa.

[0105] In some embodiments, the acrylamide-based polymer has the formula AP2: [ka] where E is one or more associative monomer units, E' is a molar percentage value of about 0.005 to about 10, F is one or more additional monomer units, F' is a molar percentage value of about 0.005 to about 90, G is one or more monomer units derived from a monomer of formula I, G' is a molar percentage value of about 10 to about 99.99. The monomer units E are defined by the associative monomer units described herein. The monomer units F and G are defined by the additional monomer units and the monomer units derived from a monomer of formula I, respectively, described herein.

[0106] As described herein, the acrylamide-based polymer of formula AP2 can exist as an alternating polymer, a random polymer, a block polymer, a graft polymer, a linear polymer, a branched polymer, a cyclic polymer, or a combination thereof. Thus, E, F, and G can exist in any suitable order (e.g., EGF, EFG, GEF, GFE, FEG, or FGE), including repeating individual units (e.g., EEFFFGG, EFGGEFEE, EFGEEE, EEEEFG, etc.).

[0107] The amount of the one or more associative monomer units ("E'") and the sum of the one or more additional monomer units ("F'" + "G'") are as previously described for the sum of the one or more associative monomer units and the one or more additional monomer units.

[0108] In some embodiments, an acrylamide-based polymer of formula AP2 undergoes charge decomposition to provide an acrylamide-based polymer of formula AP3: [ka] wherein E is one or more associative monomer units, E″ is from about 0.005 to about 10 mole percent; F is one or more additional monomer units, F″ is from about 0.005 to about 90 mole percent; G is one or more monomer units derived from a monomer of formula I, G″ is from about 10 to about 99.99 mole percent; and H is one or more piperidine-2,6-dione units, the one or more piperidine-2,6-diones being formed by cyclization of the acrylamide nitrogen of one or more monomer units (“G”) derived from a monomer of formula I on the carbonyl of the additional monomer unit (“F”), H″ is from about 0 (i.e., a trace amount) to about 10 mole percent. As used herein, "charge decomposition" refers to a process in which a monomer unit derived from a monomer of formula I cyclizes onto a charged additional monomer unit (i.e., a cationic and / or anionic monomer unit), thereby displacing the charged substituent of the additional monomer unit, such that the polymer has fewer cationic and / or anionic monomer units. Without being bound to any particular theory, it is believed that charge decomposition can occur spontaneously or can be facilitated by one or more components in the polymer solution.

[0109] In certain embodiments, the acrylamide-based polymer(s) have the formula AP3: [ka] where E is one or more associative monomer units, E″ is a mole percent value of about 0.005 to about 10, F is one or more additional monomer units, F″ is a mole percent value of about 0.005 to about 90, G is one or more monomer units derived from a monomer of formula I, G″ is a mole percent value of about 10 to about 99.99, and H is one or more units of formula H, where R1 is H or C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), R2 is H or an organic group, and H″ is a mole percent value of about 0 (i.e., trace amounts) to about 10. In certain embodiments, R1 and R2 are hydrogen. [ka]

[0110] As described herein, the acrylamide-based polymer of formula AP3 can be present as alternating, random, block, graft, linear, branched, cyclic, or combinations thereof. Thus, E, F, G, and H can be present in any suitable order (e.g., EGFH, EGHF, EHFG, EHGF, EFGH, EFHG, FEGH, FEHG, FHEG, FHGE, FGEH, FGHE, GHFE, GHEF, GEFH, GEHF, GFHE, GFEH, HEFG, HEGF, HGEF, HGFE, HFEG, or HFGE), including repeating individual units (e.g., EEFFFGGHHH, EFGGEFEEH, EFGEEEHH, HHHEEEEFG, etc.).

[0111] In certain embodiments, the acrylamide-based polymer has the formula AP4: [ka] wherein each R1 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), each R2 is independently H or an organic group, and R3 is independently H or a C1-C4 alkyl group. 10 Alkyl (e.g., (CH2) k CH3), k is an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), X is O or NH, m, n, and o are independently integers from 0 to 100, and if (n+o) is 3 or less, then m is at least 7, each Y1 and Y2 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), R4 is H or hydrophobic, E″ is a mole percent value from about 0.005 to about 10, F is one or more additional monomeric units, F″ is a mole percent value from about 0.005 to about 90, G″ is a mole percent value from about 10 to about 99.99, and H″ is a mole percent value from about 0 (i.e., trace amounts) to about 10. 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0112] In certain embodiments of an acrylamide-based polymer of formula AP4, F is derived from a diallyldimethylammonium chloride ("DADMAC") monomer. In certain embodiments of an acrylamide-based polymer of formula AP4, F is derived from a 2-(acryloyloxy)-N,N,N-trimethylethanaminium chloride ("DMAEA.MCQ") monomer.

[0113] In certain embodiments, the acrylamide-based polymer has the formula AP5: [ka] wherein each R1 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), each R2 is independently H or an organic group, and R3 is independently H or a C1-C4 alkyl group. 10 Alkyl (e.g., (CH2) k CH3), k is an integer from 0 to 9, q is an integer from 2 to 100, r is an integer from 0 to 30, each Y is independently H or CH3, E'' is from about 0.005 to about 10 mole percent, F'' is from about 0.005 to about 90 mole percent, G'' is from about 10 to about 99.99 mole percent, and H'' is from about 0 (i.e., trace amounts) to about 10 mole percent. In some embodiments, "C1-C 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0114] In certain embodiments, the acrylamide-based polymer has the formula AP6: [ka] wherein r is an integer from 0 to 30 (e.g., 2 to 30, 4 to 30, 6 to 30, 8 to 30, 10 to 30, 12 to 30, 16 to 30, 18 to 30, 20 to 30, 22 to 30, or 24 to 30), each Y is independently H or CH3, E" is a mole percent value from about 0.005 to about 10, F" is a mole percent value from about 0.005 to about 90, G" is a mole percent value from about 10 to about 99.99, and H" is a mole percent value from about 0 (i.e., trace amounts) to about 10. In certain embodiments, r is an integer from 14 to 16.

[0115] In certain embodiments, the acrylamide-based polymer has the formula AP7: [ka] wherein each R1 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), each R2 is independently H or an organic group, and each R6 and R7 is independently H or a C1-C4 alkyl group. 10 Alkyl (e.g., (CH2) t CH3), t is an integer from 0 to 9, X is O or NH, s is an integer from 0 to 20, Z is any anion, R8 is a hydrophobic group, E″ is from about 0.005 to about 10 mole percent, F is one or more additional monomer units, F″ is from about 0.005 to about 90 mole percent, G″ is from about 10 to about 99.99 mole percent, and H″ is from about 0 (i.e., trace amounts) to about 10 mole percent. In some embodiments, “C1-C 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0116] In certain embodiments, the acrylamide-based polymer has the formula AP8: [ka] wherein each R1 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), each R2 is independently H or an organic group, and R6 is independently H or a C1-C4 alkyl group. 10 Alkyl (e.g., (CH2) t CH3), t is an integer from 0 to 9, u is an integer from 0 to 30, E″ is from about 0.005 to about 10 molar percent, F″ is from about 0.005 to about 90 molar percent, G″ is from about 10 to about 99.99 molar percent, and H″ is from about 0 (i.e., trace amounts) to about 10 molar percent. In some embodiments, “C1-C 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0117] In certain embodiments, the acrylamide-based polymer has the formula AP9: [ka] In the formula, R6 is H or C1-C 10 Alkyl (e.g., (CH2) t CH3), t is an integer from 0 to 9, u is an integer from 0 to 30, E″ is from about 0.005 to about 10 molar percent, F″ is from about 0.005 to about 90 molar percent, G″ is from about 10 to about 99.99 molar percent, and H″ is from about 0 (i.e., trace amounts) to about 10 molar percent. In some embodiments, “C1-C 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0118] formula AP 7~9 In certain embodiments of the acrylamide-based polymers (i.e., AP7, AP8, or AP9), F is derived from one or more monomers selected from acrylic acid, methacrylic acid, or salts thereof.

[0119] In certain embodiments, the acrylamide-based polymer has the formula AP 10 having [ka] wherein each R1 is independently H or a C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), each R2 is independently H or an organic group, and R9 is independently H or a C1-C4 alkyl group. 10 Alkyl (e.g., (CH2) v CH3), v is an integer from 0 to 9, X is O or NH, M is any cation, and each R 10are independently H or a hydrophobic group, E″ is from about 0.005 to about 10 mole percent, F is one or more additional monomeric units, F″ is from about 0.005 to about 90 mole percent, G″ is from about 10 to about 99.99 mole percent, and H″ is from about 0 (i.e., trace amounts) to about 10 mole percent. In some embodiments, “C1-C 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0120] In certain embodiments, the acrylamide-based polymer has the formula AP 11 having [ka] In the formula, R9 is H or C1 to C 10 Alkyl (e.g., (CH2) v CH3), v is an integer from 0 to 9, X is O or NH, M is any cation, and each R 10 are independently H or a hydrophobic group, E″ is from about 0.005 to about 10 mole percent, F is one or more additional monomeric units, F″ is from about 0.005 to about 90 mole percent, G″ is from about 10 to about 99.99 mole percent, and H″ is from about 0 (i.e., trace amounts) to about 10 mole percent. In some embodiments, “C1-C 10 "Alkyl" is a branched C1-C 10 Refers to an alkyl group.

[0121] As described herein, the formulae AP4 to AP 11 (i.e. AP4, AP5, AP6, AP7, AP8, AP9, AP 10 , or AP 11 The acrylamide-based polymers of can be present as alternating, random, block, graft, linear, branched, cyclic, or combinations thereof. Thus, the monomer units can be present in any suitable order, including repeating individual units.

[0122] The presence of monomer unit H can be detected by any suitable method. In some embodiments, monomer H is 13 CNMR, 1 HNMR, IR spectroscopy, or a combination thereof.

[0123] The abundance of monomer unit H can be determined by any suitable method. In some embodiments, the abundance of monomer unit H is 13 C NMR spectrum, 1 The peak integrals of the H NMR spectrum, the IR spectrum, or a combination thereof may be determined by a relative comparison.

[0124] formula AP 3~11 (i.e. AP3, AP4, AP5, AP6, AP7, AP8, AP9, AP 10 , or AP 11In some embodiments of the acrylamide-based polymer, E″ is about 0.005 mol % to about 10 mol % (e.g., about 0.005 mol % to about 9 mol %, about 0.005 mol % to about 8 mol %, about 0.005 mol % to about 7 mol %, about 0.005 mol % to about 6 mol %, about 0.005 mol % to about 5 mol %, about 0.005 mol % to about 4 mol %, about 0.005 mol % to about 3 mol %, or about 0.005 mol % to about 2 mol %), and F″ is about 0.005 mol % to about 90 mol % (e.g., about 0.005 mol % to about 80 mol %). ol%, about 0.005 mol% to about 70 mol%, about 0.005 mol% to about 60 mol%, about 0.005 mol% to about 50 mol%, about 0.005 mol% to about 40 mol%, about 0.005 mol% to about 35 mol%, about 0.005 mol% to about 30 mol%, about 0.005 mol% to about 25 mol%, about 0.005 mol% to about 20 mol%, about 0.005 mol% to about 16 mol%, about 0.005 mol% to about 12 mol%, about 0.005 mol% to about 10 mol%, about 2 mol% to about 20 mol%, about 4 mol% to about 20 mol%, about 6 mol% G'' is about 10 mol% to about 99.99 mol% (e.g., about 10 mol% to about 99.99 mol%, about 20 mol% to about 16 mol%, about 4 mol% to about 12 mol%, or about 4 mol% to about 10 mol%), and G'' is about 10 mol% to about 99.99 mol% (e.g., about 10 mol% to about 99.99 mol%, about 20 mol% to about 99.99 mol%, about 30 mol% to about 99.99 mol%, about 40 mol% to about 99.99 mol%, about 50 mol% to about 99.99 mol%, about 60 mol% to about 99.99 mol%, about 70 mol% to about 99.99 mol%, about 80 mol% to about 99.99 mol%, about 80 mol% to about 99.99 mol%, about 99.95 mol%, about 80 mol% to about 99.9 mol%, about 80 mol% to about 99.5 mol%, about 80 mol% to about 99 mol%, about 80 mol% to about 97 mol%, about 80 mol% to about 95 mol%, about 80 mol% to about 92 mol%, about 80 mol% to about 90 mol%, about 84 mol% to about 99 mol%, about 84 mol% to about 94 mol%, about 84 mol% to about 95 mol%, about 84 mol% to about 92 mol%, or about 84 mol% to about 90 mol%, and H'' is about 0 mol% (i.e., a trace amount) to about 10 mol% (e.g., about 0.The concentration is about 0.001 mol% to about 10 mol%, about 0.001 mol% to about 9 mol%, about 0.001 mol% to about 8 mol%, about 0.001 mol% to about 7 mol%, about 0.001 mol% to about 6 mol%, about 0.001 mol% to about 5 mol%, about 0.001 mol% to about 4 mol%, about 0.001 mol% to about 3 mol%, or about 0.001 mol% to about 2 mol%.

[0125] Expression(AP 3~11 ) (i.e. AP3, AP4, AP5, AP6, AP7, AP8, AP9, AP 10 , or AP 11In certain embodiments of the acrylamide-based polymer, E″ is from about 0.005 mol % to about 1 mol % (e.g., from about 0.01 mol % to about 1 mol %, from about 0.1 mol % to about 1 mol %, from about 0.25 mol % to about 1 mol %, from about 0.3 mol % to about 1 mol %, from about 0.4 mol % to about 1 mol %, from about 0.5 mol % to about 1.0 mol %, from about 0.01 mol % to about 0.5 mol %, or from about 0.01 mol % to about 0.25 mol %) and F″ is from about 4 mol % to about 10 mol %. 1% (e.g., about 4 mol% to about 9 mol%, about 4 mol% to about 8 mol%, about 4 mol% to about 7 mol%, about 4 mol% to about 6 mol%, about 4 mol% to about 5 mol%, about 5 mol% to about 10 mol%, about 6 mol% to about 10 mol%, about 7 mol% to about 10 mol%, about 8 mol% to about 10 mol%, about 9 mol% to about 10 mol%, or about 6 mol% to about 8 mol%), and G'' is about 84 mol% to about 90 mol% (e.g., about 85 mol% to about 90 mol%, about 86 mol% to about 90 mol%, about 87 mol% to about 90 mol%, about 88 mol% to about 90 mol%, about 89 mol% to about 90 mol%, about 84 mol% to about 89 mol%, about 84 mol% to about 88 mol%, about 84 mol% to about 87 mol%, about 84 mol% to about 86 mol%, about 84 mol% to about 85 mol%, or about 86 mol% to about 88 mol%, and H'' is about 0 mol% (i.e., a trace amount) to about 6 mol% (e.g., about 0.001 mol% to about 5 mol%, about 0. 001 mol% to about 4 mol%, about 0.001 mol% to about 3 mol%, or about 0.001 mol% to about 2 mol%, about 0.001 mol% to about 1 mol%, about 0.01 mol% to about 1 mol%, about 0.1 mol% to about 1 mol%, about 0.2 5 mol% to about 1 mol%, about 0.3 mol% to about 1 mol%, about 0.4 mol% to about 1 mol%, about 0.5 mol% to about 1.0 mol%, about 0.01 mol% to about 0.5 mol%, or about 0.01 mol% to about 0.25 mol%).

[0126] In some embodiments, the process for making the powder includes networking one or more acrylamide-based polymers. As used herein, "networking" refers to the chemical coordination of one polymer chain to an adjacent polymer chain to promote different physical properties. The networking technique can include any suitable chemical coordination. In general, the networking of one or more acrylamide-based polymers does not include covalently bonding adjacent polymer chains. For example, the chemical coordination can occur through ionic bonds, hydrogen bonds, hydrophobic interactions, dipole interactions, van der Waals forces, or a combination thereof.

[0127] In one embodiment, at least a portion of the networking occurs between associative monomer units of different polymer chains (i.e., intermolecular interactions). Without being bound to any particular theory, it is believed that the associative monomer units instantaneously interact through weak chemical interactions (i.e., ionic bonds, hydrogen bonds, hydrophobic interactions, dipole interactions, van der Waals forces, or a combination thereof), resulting in a temporary networking of adjacent acrylamide-based polymer(s). As used herein, "temporary networking of adjacent acrylamide-based polymer(s)" refers to interactions that can be controlled by dilution levels, the presence of surfactants, or a combination thereof. Thus, the networking of the acrylamide-based polymer(s) is reversible, thereby allowing for the preparation of powders, gels, or low-viscosity liquid media and / or subsequent dispersion in solvents.

[0128] In another embodiment, at least a portion of the networking occurs between the associative monomer unit and one or more surfactants. Without being bound to any particular theory, it is believed that the associative monomer unit can momentarily interact with one or more surfactants via weak chemical interactions (i.e., ionic bonds, hydrogen bonds, hydrophobic interactions, dipole interactions, van der Waals forces, or a combination thereof), resulting in a temporary networking of the acrylamide-based polymer(s) and surfactant(s). As used herein, "temporary networking of adjacent acrylamide-based polymer(s) and surfactant(s)" refers to an interaction that can be controlled by the dilution level, the amount of surfactant, or a combination thereof. Thus, the networking of the acrylamide-based polymer(s) and surfactant(s) is reversible, thereby allowing the preparation of powders, gels, or low-viscosity liquid media and / or subsequent dispersion in a solvent.

[0129] In some embodiments, at least a portion of the networking occurs by micellar copolymerization. As used herein, "micellar copolymerization" refers to the simultaneous formation of micelles comprising associative monomers and / or surfactant(s) and associative polymer(s) comprising associative monomer units. As used herein, "micellar copolymerization" refers to the simultaneous formation of micelles comprising associative monomers and / or surfactant(s) and associative polymer(s) comprising associative monomer units.

[0130] As used herein, "transient networking" refers to associative interactions (e.g., within solutions, wet gels, and powders of acrylamide-based polymer(s)) that can be controlled by dilution levels, the presence of surfactants, or a combination thereof. In contrast to more permanent crosslinking practices known in the art, such as crosslinking via covalent bonds, transient networking can be instantaneous. As used herein, "transient" can refer to any length of time ranging from the initial formation of a solution of acrylamide-based polymer(s) to the dispersion of the powder in the solution. For example, transient networking provides sufficient structure of the wet gel to allow machining and conversion to a powder. In addition, transient networking is useful for producing powders that are stable but still maintain a reasonable level of water solubility. Upon dilution in water, the associative interactions (i.e., transient networking) are reduced and the powder is dispersed in water or other solvents.

[0131] In certain embodiments, the process for making the powder comprises networking one or more acrylamide-based polymers and one or more surfactants, wherein the one or more associative monomer units and the one or more surfactants are structurally similar. As used herein, "structurally similar" means that the associative monomer unit(s) and the surfactant(s) have the same or similar chemical functional groups. In some embodiments, the associative monomer unit(s) and the surfactant(s) each comprise at least one hydroxyl substituent. In some embodiments, the associative monomer unit(s) and the surfactant(s) each comprise at least one amine substituent. In some embodiments, the associative monomer unit(s) and the surfactant(s) each comprise a polyetherether chain. In some embodiments, the associative monomer unit(s) and the surfactant(s) each comprise a polyether chain, wherein the length of the polyether chain is separated by no more than 6 carbon units (i.e., 6, 5, 4, 3, 2, 1, or 0). For example, if the associative monomer unit has a polyether chain length of 16 carbon units, the structurally similar surfactant has a polyether chain length of 10 to 22 carbon units (i.e., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22). In certain embodiments, the polyether chain comprises the same number of carbon units. In some embodiments, the associative monomer unit(s) and the surfactant(s) each comprise an alkyl chain. In some embodiments, the associative monomer unit(s) and the surfactant(s) each comprise an alkyl chain, and the alkyl chain lengths are separated by 6 carbon units or less (i.e., 6, 5, 4, 3, 2, 1, or 0). For example, if an associative monomer unit has an alkyl chain length of 16 carbon units, a structurally similar surfactant has an alkyl chain length of 10 to 22 carbon units (i.e., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22). In certain embodiments, the alkyl chains each contain the same number of carbons. In certain embodiments, the associative monomer unit(s) and the surfactant(s) contain the same structural subunits.

[0132] In some embodiments, the process for making the powder further comprises one or more surfactants. The surfactant can be any suitable surfactant selected from anionic surfactants, cationic surfactants, nonionic surfactants, and combinations thereof. In some embodiments, one or more surfactants can exist as dimers. For example, the surfactant can have one polar head group and two non-polar tails, or two polar head groups and one non-polar tails, or two polar head groups and two non-polar tails. Without being bound to any particular theory, it is believed that the surfactant provides structure to the wet gel and increases the solubility of the resulting powder upon dilution in water or other solvent.

[0133] In one embodiment, the surfactant is a cationic surfactant. In one particular embodiment, the cationic surfactant is an ammonium salt of formula IX: [ka] Each R 11 are independently H or C1-C 10 Alkyl (e.g., (CH2) e CH 3) In some embodiments, "C1 to C2 are each an integer from 0 to 9 (i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9), A is any anion, and d is an integer from 6 to 34 (e.g., 6 to 30, 6 to 24, 6 to 20, 6 to 16, 6 to 12, 5 to 25, 10 to 20, 15 to 25, 10 to 24, or 10 to 30). 10 "Alkyl" is a branched C1-C 10refers to an alkyl group. In some embodiments, the ammonium salt of formula IX is a mixture of two or more such ammonium salts, such that the average (rounded to the nearest integer) value of d is an integer between 6 and 34 (e.g., 6 to 30, 6 to 24, 6 to 20, 6 to 16, 6 to 12, 5 to 25, 10 to 20, 15 to 25, 10 to 24, or 10 to 30). In certain embodiments, the cationic surfactant is hexadecyltrimethylammonium p-toluenesulfonate or hexadecyltrimethylammonium chloride.

[0134] The ammonium salt can have any suitable anionic counterion (i.e., "A"). In some embodiments, the anionic counterion ("A") comprises an element selected from halogen (i.e., fluoride, chloride, bromide, or iodide), sulfur, carbon, nitrogen, phosphorus, and combinations thereof. An exemplary list of anions includes fluoride, chloride, bromide, iodide, sulfite, sulfate, bisulfate, bisulfite, thiosulfate, carbonate, bicarbonate, nitrate, nitrite, phosphate, hydrogen phosphate, dihydrogen phosphate, phosphite, dihydrogen phosphite, hexafluorophosphate, carboxylate, acetate, mesylate, tosylate, or triflate. In certain embodiments, A is selected from fluoride, chloride, bromide, mesylate, tosylate, or combinations thereof.

[0135] In some embodiments, the surfactant is an anionic surfactant. In certain embodiments, the anionic surfactant is a sulfate salt of formula X: [ka] where B is any cation and f is an integer between 7 and 35 (e.g., 7 to 29, 7 to 23, 7 to 19, 7 to 15, 7 to 11, 11 to 19, 11 to 23, or 11 to 29). In some embodiments, the sulfate of formula X is a mixture of two or more such sulfates such that the average (rounded to the nearest integer) value of f is an integer between 7 and 35 (e.g., 7 to 29, 7 to 23, 7 to 19, 7 to 15, 7 to 11, 11 to 19, 11 to 23, or 11 to 29). In certain embodiments, the anionic surfactant is sodium dodecyl sulfate (i.e., f is 11).

[0136] The sulfate salt can have any suitable cationic counterion (i.e., "B"). For example, the cationic counterion ("B") can be a proton, ammonium, a quaternary amine, an alkali metal cation, an alkaline earth metal cation, a transition metal cation, a rare earth metal cation, a main group element cation, or a combination thereof. In some embodiments, the cationic counterion is hydrogen or a cation of lithium, sodium, potassium, magnesium, calcium, manganese, iron, zinc, or a combination thereof. In certain embodiments, B is selected from hydrogen, lithium, sodium, potassium, or a combination thereof.

[0137] In some embodiments, the surfactant is a non-ionic surfactant.The non-ionic surfactant can be any suitable non-ionic surfactant.In some embodiments, the non-ionic surfactant comprises ethylene oxide, propylene oxide, or ethylene oxide and propylene oxide repeating units.In certain embodiments, the surfactant comprises block or random copolymers of ethylene oxide ("EO"), propylene oxide ("PO"), or combinations thereof.

[0138] In certain embodiments, the nonionic surfactant has the formula XI: [ka] wherein a, b, and c are independently integers ranging from about 2 to about 200 (e.g., from about 2 to about 175, from about 2 to about 150, from about 2 to about 125, from about 2 to about 100, from about 50 to about 200, from about 50 to about 150, or from about 50 to about 100), and a, b, and c are the same or different. In some embodiments, the nonionic surfactant of formula X is a mixture of two or more such surfactants, where a, b, and c refer to the average (rounded to the nearest integer) chain length of the designated subunits (i.e., the average chain length of the EO and PO), and a, b, and c are independently integers ranging from about 2 to about 200 (e.g., from about 2 to about 175, from about 2 to about 150, from about 2 to about 125, from about 2 to about 100, from about 50 to about 200, from about 50 to about 150, or from about 50 to about 100). In certain embodiments, the nonionic surfactant is PLURONIC® F-127 surfactant, i.e., HO(CHO), sold by BASF Corporation (Florham Park, New Jersey). 101 (C3H6O) 56 (C2H4O) 101 It's H.

[0139] In some embodiments, the nonionic surfactant has formula XII: [ka] In the formula, g is an integer ranging from about 6 to about 50 (e.g., from about 6 to about 42, from about 6 to about 36, from about 6 to about 30, from about 6 to about 24, from about 6 to about 18, from about 6 to about 12, from about 8 to about 30, from about 12 to about 50, from about 12 to about 36, or from about 12 to about 24), and each R 12 and R 13is independently H or C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), and h and i are independently an integer in the range of 0 to about 100 (e.g., about 0 to about 90, about 0 to about 80, about 0 to about 70, about 0 to about 60, about 0 to about 50, about 10 to about 100, or about 10 to about 50). In some embodiments, the surfactant of formula XII is a mixture of two or more such surfactants, where g, h, and i refer to the average (rounded to the nearest integer) chain length of the designated subunits (i.e., the average carbon chain or average EO (or substituted EO) chain length), where g is an integer from about 6 to about 50 (e.g., from about 6 to about 42, from about 6 to about 36, from about 6 to about 30, from 6 to about 24, from about 6 to about 18, from about 6 to about 12, from about 8 to about 30, from about 12 to about 50, from about 12 to about 36, or from about 12 to about 24), and h and i are independently integers in the range of 0 to about 100 (e.g., from about 0 to about 90, from about 0 to about 80, from about 0 to about 70, from about 0 to about 60, from about 0 to about 50, from about 10 to about 100, or from about 10 to about 50).

[0140] In certain embodiments, the nonionic surfactant has formula XII: [ka] In the formula, g is an integer ranging from about 6 to about 50 (e.g., from about 6 to about 42, from about 6 to about 36, from about 6 to about 30, from about 6 to about 24, from about 6 to about 18, from about 6 to about 12, from about 12 to about 50, from about 12 to about 36, or from about 12 to about 24), and R 12 and R 13 is H, and h and i are independently an integer ranging from 0 to about 100 (e.g., from about 0 to about 90, from about 0 to about 80, from about 0 to about 70, from about 0 to about 60, from about 0 to about 50, from about 10 to about 100, or from about 10 to about 50). In certain embodiments, the surfactant is BRIJ® S20, i.e., a surfactant of formula C, sold by Croda International PLC (East Yorkshire, United Kingdom). 18 H 37 (OC2H4) h’OH, where h' is an integer ranging from about 2 to about 200.

[0141] In certain embodiments, the nonionic surfactant has formula XII: [ka] In the formula, g is an integer ranging from about 6 to about 50 (e.g., from about 6 to about 42, from about 6 to about 36, from about 6 to about 30, from about 6 to about 24, from about 6 to about 18, from about 6 to about 12, from about 12 to about 50, from about 12 to about 36, or from about 12 to about 24), i is 0, and R 12 is H, where h is an integer ranging from about 2 to about 30 (e.g., 2-30, 4-30, 6-30, 8-30, 10-30, 12-30, 16-30, 18-30, 20-30, 22-30, or 24-30). In certain embodiments, the surfactant is Lutensol® fatty alcohol ethoxylate, available from BASF Corporation, Florham Park, New Jersey. More preferably, the surfactant is polyethoxy (25) cetyl and / or stearyl alcohol, available under the product name (25 EO) C16-C18 fatty alcohol ("Lutensol AT® 25"), available from BASF Corporation, Florham Park, New Jersey.

[0142] In certain embodiments, the nonionic surfactant has formula XII: [ka] In the formula, g is an integer ranging from about 8 to about 30 (e.g., 10 to 30, 12 to 30, 16 to 30, 18 to 30, 20 to 30, 22 to 30, or 24 to 30), and each R 12 and R 13is independently H or C1-C4 alkyl (e.g., methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, or tert-butyl), and h and i are independently integers ranging from 0 to about 50 (e.g., from about 0 to about 40, from about 0 to about 30, from about 0 to about 20, from about 10 to about 50, from about 10 to about 40, from about 10 to about 30, or from about 10 to about 20). In certain embodiments, the surfactant is a Plurafac® surfactant, commercially available from BASF Corporation (Florham Park, New Jersey).

[0143] In certain embodiments, the nonionic surfactant has formula XIII: [ka]

[0144] wherein w, x, y, and z are integers from about 0 to about 50 (e.g., from about 0 to about 40, from about 0 to about 30, from about 0 to about 20, from about 0 to about 16, from 0 to about 12, or from about 0 to about 8), and w, x, y, and z are the same or different. In some embodiments, the nonionic surfactant of formula XIII is a mixture of two or more such surfactants, where w, x, y, and z refer to the average (rounded to the nearest integer) chain length of the specified subunits (i.e., the average chain length of the EO), and w, x, y, and z are integers from about 0 to about 50 (e.g., from about 0 to about 40, from about 0 to about 30, from about 0 to about 20, from about 0 to about 16, from about 0 to about 12, or from about 0 to about 8). In one particular embodiment, the non-ionic surfactant is TWEEN® 20 surfactant, i.e., w+x+y+z=20, sold by Croda International PLC (East Yorkshire, United Kingdom).

[0145] When one or more surfactants are present in the powder, the one or more surfactants can be present in the powder at any suitable concentration. The powder can include a total of about 20% by weight or less, for example, about 15% by weight or less, about 10% by weight or less, about 9% by weight or less, 8% by weight or less, about 7% by weight or less, about 6% by weight or less, or about 5% by weight or less of the surfactant(s). Alternatively, or in addition, the powder can include a total of about 0.001% by weight or more, for example, about 0.01% by weight, about 0.1% by weight, about 0.25% by weight or more, about 0.5% by weight or more, about 1% by weight or more, about 2% by weight or more, about 3% by weight or more, or about 4% by weight or more of the surfactant(s). Thus, the powder can include one or more surfactants at a concentration bounded by any two of the above endpoints. The powder may be about 0.001% by weight to about 5% by weight, about 0.01% by weight to about 5% by weight, about 0.1% by weight to about 5% by weight, for example, about 0.25% by weight to about 5% by weight, about 0.5% by weight to about 5% by weight, about 1% by weight to about 5% by weight, about 2% by weight to about 5% by weight, about 3% by weight to about 5% by weight, about 4% by weight to about 5% by weight, about 4% by weight to about 10% by weight, about 4% by weight to about 9% by weight, about 4% by weight to about 8% by weight, about 4% by weight to about 7% by weight, about 4% by weight to about The surfactant may comprise a total of about 6% by weight, about 0.001% to about 10% by weight, about 0.01% to about 10% by weight, about 0.1% to about 10% by weight, about 0.001% to about 15% by weight, about 0.01% to about 15% by weight, about 0.1% to about 15% by weight, about 0.001% to about 20% by weight, about 0.01% to about 20% by weight, about 0.1% to about 20% by weight, or about 0.001% to about 1% by weight.

[0146] In one embodiment, one or more surfactants are added prior to the formation of the powder (e.g., to a polymer solution before or after polymerization, or to a wet gel). When the surfactant(s) are added prior to the formation of the powder, the surfactant(s) are incorporated into the wet gel and thereby into the powder. Generally, the surfactant(s) improve the processability of the wet gel into a powder. Typically, the surfactant(s) further improves the solubility or dispersibility of the resulting powder in aqueous media or other solvents.

[0147] In some embodiments, one or more surfactants are added to the powder after it has been processed from the wet gel. In some embodiments, one or more surfactants are not necessary for the wet gel to be processed. In particular, the chemical interaction of the associative monomer units may be strong enough to network the acrylamide-based polymer(s) in the absence of the surfactant(s). Although a surfactant is not necessarily required for the formation of the powder, the resulting powder (absent one or more surfactants) is generally less soluble in aqueous media. For example, one or more surfactants tend to promote the rewetting of the acrylamide-based polymer(s) and accelerate the process of forming a solution in water. Thus, a surfactant may be added after the formation of the powder to improve the solubility and dispersibility of the resulting powder in aqueous media or other solvents.

[0148] The polymerization to form the acrylamide-based polymer(s) can be carried out according to any suitable polymerization known in the art. For example, the acrylamide-based polymer(s) can be made by emulsion polymerization, dispersion polymerization, solution polymerization, gel polymerization, or a combination thereof. The polymerization to form the acrylamide-based polymer(s) can occur by any suitable mechanism. For example, the polymerization can occur by cationic polymerization, anionic polymerization, free radical polymerization, coordination polymerization, or a combination thereof. Typically, the polymerization occurs by free radical polymerization.

[0149] In some embodiments, the polymerization to form the acrylamide-based polymer(s) includes one or more polymerization components. In certain embodiments, one or more of the polymerization components are not removed from the reaction mixture such that one or more of the polymerization components remain in the polymer solution, polymer wet gel, and / or powder. In other embodiments, one or more of the polymerization components are removed such that one or more of the polymerization components are not present in the polymer solution, polymer wet gel, and / or powder. In some embodiments, one or more of the polymerization components are converted such that one or more converted polymerization components are present in the polymer solution, polymer wet gel, and / or powder. An exemplary list of polymerization components is an initiator, a chain transfer agent, a chelating agent, an oxidation reducing agent, a buffering agent, and combinations thereof.

[0150] In some embodiments, the polymerization comprises one or more initiators. The initiator can be any suitable initiator. In some embodiments, the initiator is a free radical initiator. In certain embodiments, the initiator is selected from the group of azobis compounds. An illustrative list of initiators is 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (anhydrous), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane].

[0151] In some embodiments, the polymerization comprises one or more chain transfer agents. The chain transfer agent can be any suitable chain transfer agent. An exemplary list of chain transfer agents is carbon tetrachloride, carbon tetrabromide, bromotrichloromethane, pentaphenylethane, sodium formate, sodium hypophosphite, thiophenol, 4,4'-thiobisbenzenethiol, 4-methylbenzenethiol, and aliphatic thiols such as isooctyl 3-mercaptopropionate, tert-nonyl mercaptan, and N-acetyl-L-cysteine, N-(2-mercaptoethyl)acetamide, glutathione, N-(2-mercaptopropionyl)glycine, and 2-mercaptoethanol.

[0152] In some embodiments, the polymerization includes one or more chelating agents. The chelating agent can be any suitable chelating agent. In certain embodiments, the chelating agent is a polydentate organic compound. An exemplary list of chelating agents is diethylenetriaminepentaacetic acid ("DTPA"), ethylenediaminetetraacetic acid ("EDTA"), nitrilotriacetic acid ("NTA"), diethylenetriaminepentaacetic acid, N,N-bis(carboxymethyl)-L-glutamic acid, trisodium N-(hydroxyethyl)-ethylenediaminetriacetate, adipic acid, and salts thereof.

[0153] In some embodiments, the polymerization includes one or more redox agents. The redox agent can be any suitable redox agent. In some embodiments, the redox agent assists in terminating the polymerization. In certain embodiments, the redox reagent is an organic peroxide, an inorganic peroxide, or a combination thereof. An exemplary list of redox agents is sodium bisulfite, thiosulfate, ferrous ammonium sulfate; ascorbic acid, amines, hypophosphites, sodium bromate, chlorate, permanganate, ammonium persulfate, potassium persulfate, sodium persulfate, t-butyl hydrogen peroxide, hydrogen peroxide, ozone, and salts thereof. In some embodiments, the redox agent is added as a redox pair, such that one agent is involved in reduction and one agent is involved in oxidation. In certain embodiments, the redox agent is an initiator.

[0154] In some embodiments, the polymerization includes a buffer system. The buffer system can be any suitable organic and / or inorganic buffer system. In certain embodiments, the buffer system includes organic and / or inorganic acids and / or bases capable of controlling the pH below about 6 (e.g., about 0 to about 6, about 1 to about 6, about 2 to about 6, about 3 to about 6, about 4 to about 6, about 5 to about 6, about 0 to about 1, about 0 to about 2, about 0 to about 3, about 0 to about 4, or about 0 to about 5). An exemplary list of buffering agents is adipic acid, pimelic acid, glutaric acid, citric acid, acetic acid, inorganic acids (e.g., phosphoric acid), amines, and salts thereof.

[0155] The solution of one or more acrylamide-based polymers and, optionally, one or more surfactants, may be converted to a wet gel by any suitable technique. In some embodiments, the solution of one or more acrylamide-based polymers and, optionally, one or more surfactants, spontaneously becomes a wet gel. For example, a solution-based monomer can be polymerized in the presence of one or more surfactants, and the polymerization results in a transition from the solution-based monomer to a solution-based polymer, which spontaneously begins to solidify to form a polymeric wet gel. In some embodiments, the solution of one or more acrylamide-based polymers and, optionally, one or more surfactants may need to be dried prior to the formation of a wet gel. For example, the solution of one or more acrylamide-based polymers and, optionally, one or more surfactants may be converted to a wet gel through drying (e.g., placement in an oven and / or evaporation at ambient temperature), cooling, a change in pressure, or a combination thereof. As used herein, "wet gel" refers to any material produced when a solution of one or more acrylamide-based polymers and, optionally, one or more surfactants, transitions from a fluid-like state to a solid-like state. In certain embodiments, the wet gel maintains a taffy-like consistency and is not sticky.

[0156] The wet gel comprises the resulting acrylamide-based polymer(s), optionally one or more surfactants, and a solvent. Generally, the wet gel comprises about 20% to about 80% by weight of the acrylamide-based polymer. In one embodiment, the polymer wet gel comprises about 25% to about 50% by weight of the polymer. In one particular embodiment, the polymer wet gel comprises about 30% to about 40% by weight of the polymer.

[0157] The wet gel may be processed into a powder by any suitable process. In some embodiments, the wet gel is processed into a powder by cutting the wet gel to form granules, drying the granules, and converting the dried granules to form a powder. In some embodiments, the wet gel is processed into a powder by drying the wet gel, cutting the dried wet gel into granules, and converting the granules to a powder. In some embodiments, the wet gel is processed into a powder by drying the wet gel, cutting the dried wet gel into granules, drying the granules, and converting the dried granules to form a powder. The wet gel may be cut by any suitable method. In certain embodiments, the wet gel is mechanically processed (e.g., using a Retsch Mill Cutter) to form wet gel granules. In certain embodiments, the wet gel is cut with a lubricant. The lubricant may be any suitable lubricant (e.g., a petroleum-based lubricant). The wet gel granules may be converted into a powder by any suitable method. In some embodiments, "converting granules to form a powder" refers to a process of, for example, optionally further drying the granules, grinding the granules, or drying and grinding the granules to produce a powder, although the conversion may include other processing steps. For example, converting the granules to a powder can further include sieving.

[0158] The powder can have any suitable particle shape. In some embodiments, the powder particles are non-spherical. Without wishing to be bound by any particular theory, it is believed that non-spherical particles are generally formed when the powder is produced by a gel, spray, or drum-based process (e.g., via cutting and drying). In some embodiments, the powder particles are spherical. Without wishing to be bound by any particular theory, it is believed that spherical particles are generally formed when the powder is produced by a bead-based process.

[0159] The powder can have any suitable moisture content. Generally, the moisture content is about 0% to about 30% by weight (e.g., about 0.01% to about 30% by weight, about 0.1% to about 30% by weight, or about 1% to about 30% by weight). In certain embodiments of the powder, the moisture content is about 0% to about 25% by weight (e.g., about 0.01% to about 25% by weight, about 0.1% to about 25% by weight, or about 1% to about 25% by weight). In certain embodiments of the powder, the moisture content is about 0% to about 20% by weight (e.g., about 0.01% to about 20% by weight, about 0.1% to about 20% by weight, about 1% to about 20% by weight, about 0.01% to about 15% by weight, about 0.1% to about 15% by weight, about 1% to about 15% by weight, about 0.01% to about 12% by weight, about 0.1% to about 12% by weight, about 1% to about 12% by weight, about 0.01% to about 10% by weight, about 0.1% to about 10% by weight, or about 1% to about 10% by weight). In certain embodiments, the moisture content is about 10% by weight.

[0160] The powder can have any suitable intrinsic viscosity. For example, the powder can have an intrinsic viscosity of about 0.05 dL / g to about 15 dL / g (e.g., about 0.05 dL / g to about 10 dL / g, about 0.05 dL / g to about 7 dL / g, about 0.05 dL / g to about 6 dL / g, about 0.05 dL / g to about 5 dL / g, about 0.05 dL / g to about 4 dL / g, about 0.05 dL / g to about 3 dL / g, about 0.05 dL / g to about 2 dL / g, about 0.05 dL / g to about 1 ...2 dL / g, about 0.05 dL / g to about 2 dL / g, about 0.05 dL / g to about 2 dL / g, about 0.05 dL / g to about 2 dL / g, about 0.05 dL / g to about 2 The powder may have an intrinsic viscosity of about 1 dL / g, about 0.05 dL / g to about 0.5 dL / g, about 0.1 dL / g to about 7 dL / g, about 0.1 dL / g to about 6 dL / g, about 0.5 dL / g to about 5 dL / g, about 0.1 dL / g to about 10 dL / g, about 0.5 dL / g to about 10 dL / g, about 0.1 dL / g to about 15 dL / g, or about 0.5 dL / g to about 15 dL / g. In some embodiments, the powder has an intrinsic viscosity of about 0.05 dL / g to about 7. In certain embodiments, the powder has an intrinsic viscosity of about 0.5 dL / g to about 5 dL / g.

[0161] The resulting powder can have any suitable Huggins constant. For example, the resulting powder can have a Huggins constant of about 0.1 to about 20 (e.g., about 0.1 to about 15, about 0.1 to about 10, about 0.3 to about 10, about 0.1 to about 5, about 0.5 to about 20, about 0.5 to about 10, about 1 to about 20, about 1 to about 10, or about 1 to about 5). In some embodiments, the powder can have a Huggins constant of about 0.3 to about 10, as determined by different concentrations of the powder, the concentrations selected to produce a (t / t0) value of about 1.2 to 2.2 in a 1.0 N sodium nitrate solution. In some embodiments, the powder can have a Huggins constant of about 0.3 to about 5, as determined by different concentrations of the powder, the concentrations selected to produce a (t / t0) value of about 1.2 to 2.2 in a 1.0 N sodium nitrate solution. In one particular embodiment, the powder has a Huggins constant of about 0.6 to about 3, as determined by different concentrations of the powder, the concentrations selected to produce values ​​of (t / t0) of about 1.2 to 2.2 in a 1.0 N sodium nitrate solution. The Huggins constant is calculated as follows:

[0162] In some embodiments, the powder comprises one or more acrylamide-based polymers comprising one or more associative monomer units and one or more monomer units selected from at least one of cationic monomer units, anionic monomer units, nonionic monomer units, zwitterionic monomer units, or combinations thereof, and optionally one or more surfactants, wherein the acrylamide-based polymer(s) have a weight average molecular weight of about 10 kDa to about 2,000 kDa. In some embodiments, the powder comprises one or more low molecular weight acrylamide-based polymers that are reversibly associated in a polymer network, the association being controllable by the degree of dilution in the aqueous medium or the amount of surfactant present.

[0163] In some embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional cationic monomer unit. In some embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from DMAEA.MCQ. In some embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the powder comprises a nonionic surfactant of formula XII and an acrylamide-based polymer comprising an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the powder comprises PLURONIC® F-127 surfactant and / or Lutensol AT® 25 surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ.

[0164] In some embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional anionic monomer unit. In some embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from sodium acrylate. In some embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula II, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises a non-ionic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises a nonionic surfactant of formula XII and an acrylamide-based polymer comprising an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises PLURONIC® F-127 surfactant and / or Lutensol AT® 25 surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from VISIOMER® monomer C18PEG1105MA, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate.

[0165] In some embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional cationic monomer unit. In some embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from DMAEA.MCQ. In some embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula VI, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the powder comprises a cationic surfactant of formula IX and an acrylamide-based polymer comprising an associative monomer unit derived from a MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ. In certain embodiments, the powder comprises cetyltrimethylammonium chloride and / or hexadecyltrimethylammonium p-toluenesulfonate and an acrylamide-based polymer comprising an associative monomer unit derived from a MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from DMAEA.MCQ.

[0166] In some embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional anionic monomer unit. In some embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula VI, a monomer unit derived from a monomer of formula I, and an additional monomer unit derived from sodium acrylate. In some embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a monomer of formula VI, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises a cationic surfactant and an acrylamide-based polymer comprising an associative monomer unit derived from a MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises a cationic surfactant of formula IX and an acrylamide-based polymer comprising an associative monomer unit derived from the MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate. In certain embodiments, the powder comprises cetyltrimethylammonium chloride and / or hexadecyltrimethylammonium p-toluenesulfonate and an acrylamide-based polymer comprising an associative monomer unit derived from the MAPTAC-C12 derivative of formula VII, an additional monomer unit derived from acrylamide, and an additional monomer unit derived from sodium acrylate.

[0167] In some embodiments, the powder comprises an anionic surfactant and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, monomer units derived from a monomer of formula I, and additional cationic monomer units. In some embodiments, the powder comprises an anionic surfactant and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, monomer units derived from a monomer of formula I, and additional monomer units derived from DMAEA.MCQ. In some embodiments, the powder comprises an anionic surfactant and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, additional monomer units derived from acrylamide, and additional monomer units derived from DMAEA.MCQ. In some embodiments, the powder comprises an anionic surfactant of formula X and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, additional monomer units derived from acrylamide, and additional monomer units derived from DMAEA.MCQ. In one particular embodiment, the powder comprises sodium dodecyl sulfate and an acrylamide-based polymer comprising associative monomer units derived from a monomer of Formula VIII, additional monomer units derived from acrylamide, and additional monomer units derived from DMAEA.MCQ.

[0168] In some embodiments, the powder comprises an anionic surfactant and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, monomer units derived from a monomer of formula I, and additional anionic monomer units. In some embodiments, the powder comprises an anionic surfactant and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, monomer units derived from a monomer of formula I, and additional monomer units derived from sodium acrylate. In some embodiments, the powder comprises an anionic surfactant and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, additional monomer units derived from acrylamide, and additional monomer units derived from sodium acrylate. In some embodiments, the powder comprises an anionic surfactant of formula X and an acrylamide-based polymer comprising associative monomer units derived from a monomer of formula VIII, additional monomer units derived from acrylamide, and additional monomer units derived from sodium acrylate. In one particular embodiment, the powder comprises sodium dodecyl sulfate and an acrylamide-based polymer comprising associative monomer units derived from a monomer of Formula VIII, additional monomer units derived from acrylamide, and additional monomer units derived from sodium acrylate.

[0169] The individual components of the powder, for example, the one or more acrylamide-based polymers and the one or more optional surfactants, are as defined by the parameters described herein.

[0170] The individual structures of the one or more acrylamide-based polymers, e.g., the one or more acrylamide-based polymers and the one or more monomer units selected from at least one of a cationic monomer unit, anionic monomer unit, nonionic monomer unit, zwitterionic monomer unit, or combinations thereof, are as defined by the parameters described herein.

[0171] The individual structures of the one or more surfactants are as defined by the parameters described herein.

[0172] The amounts of the individual components of the powder, for example the amount of one or more acrylamide-based polymers and optionally one or more surfactants, are as defined by the parameters described herein.

[0173] The amounts of the individual monomer units of the acrylamide-based polymer(s), e.g., one or more associative monomer units, as well as one or more monomer units selected from at least one of a cationic monomer unit, anionic monomer unit, nonionic monomer unit, zwitterionic monomer unit, or combinations thereof, are as defined by the parameters described herein.

[0174] In certain embodiments, the physical characteristics of the powder are as defined by the parameters described herein.

[0175] The present invention is further illustrated by the following embodiments.

[0176] (1) A process for making down a powder comprising one or more acrylamide-based polymers to form a made-down powder solution, comprising blending a mixture of powder and solvent for about 15 minutes or less to obtain the made-down powder solution, wherein the powder comprises particles that have been dry cut to a median particle size of about 200 microns to about 10,000 microns.

[0177] (2) The process of embodiment (1), wherein the solvent is water.

[0178] (3) The process of embodiment (1) or (2), wherein the particles have a median particle size of from about 350 microns to about 10,000 microns.

[0179] (4) The process of embodiment (3), wherein the particles have a median particle size of from about 500 microns to about 10,000 microns.

[0180] (5) The process of any one of embodiments (1) to (4), wherein the mixture of powder and solvent is blended at an impeller tip speed of about 5 m / sec to about 25 m / sec.

[0181] (6) The process of embodiment (5), wherein the mixture of powder and solvent is blended at an impeller tip speed of about 10 m / sec to about 20 m / sec.

[0182] (7) The process of embodiment (6), wherein the mixture of powder and solvent is blended at an impeller tip speed of about 15 m / sec.

[0183] (8) The process of any one of embodiments (1) to (7), wherein the mixture of powder and the solvent is blended for about 10 minutes or less to obtain a made-down powder solution.

[0184] (9) The process of embodiment (8), wherein the mixture of powder and solvent is blended for about 5 minutes or less to obtain a made-down powder solution.

[0185] (10) The process of any one of embodiments (1) to (9), wherein a fully made down powder solution of 1 wt. % in water at 25° C. has a viscosity (cps) within about 20% deviation of the viscosity (cps) of the identical solution, which is made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution, and the identical solution is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution.

[0186] (11) The process of embodiment (10), wherein a fully made down powder solution of 1 wt. % in water at 25° C. has a viscosity (cps) within about 10% deviation of the viscosity (cps) of the identical solution, which is made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution, and the identical solution is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution.

[0187] (12) The process according to any one of embodiments (1) to (11), wherein a fully made down powder solution of 1 wt. % in water at 25° C., made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution, has an intrinsic viscosity (dL / g) within about 20% deviation of the intrinsic viscosity (dL / g) of the same solution, and the same solution is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution.

[0188] (13) The process of embodiment (12), wherein a fully made down powder solution of 1 wt. % in water at 25° C., made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution, has an intrinsic viscosity (dL / g) within about 10% deviation of the intrinsic viscosity (dL / g) of the same solution, and the same solution is made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain a fully made down powder solution.

[0189] (14) The process of any one of embodiments (1) to (13), wherein the made-down powder solution has an intrinsic viscosity of from about 0.05 dL / g to about 15 dL / g.

[0190] (15) The process of embodiment (14), wherein the made down powder solution has an intrinsic viscosity of about 0.05 dL / g to about 7 dL / g.

[0191] (16) The process of any one of embodiments (1) to (15), wherein the one or more acrylamide-based polymers have a weight average molecular weight of from about 10 kDa to about 5,000 kDa.

[0192] (17) The process of embodiment (16), wherein the one or more acrylamide-based polymers have a weight average molecular weight of about 200 kDa to about 2,000 kDa.

[0193] (18) The process of embodiment (17), wherein the one or more acrylamide-based polymers have a weight average molecular weight of about 800 kDa to about 2,000 kDa.

[0194] (19) The process of any one of embodiments (1) to (18), wherein the made-down powder solution comprises at least about 0.25 wt.% of one or more acrylamide-based polymers.

[0195] (20) The process of embodiment (19), wherein the made-down powder solution comprises at least about 0.5 wt.% of one or more acrylamide-based polymers.

[0196] (21) The process of embodiment (20), wherein the made-down powder solution comprises at least about 1 wt.% of one or more acrylamide-based polymers.

[0197] (22) The process of any one of embodiments (1) to (21), wherein the powder further comprises one or more surfactants.

[0198] (23) The process of any one of embodiments (1) to (22), wherein the made-down powder solution further comprises one or more surfactants.

[0199] (24) At least one of the one or more acrylamide-based polymers has the formula AP1: [ka] wherein E is one or more associative monomer units, F is one or more additional monomer units, and G is one or more additional monomer units of formula I; [ka] The process of any one of embodiments (1) to (23), wherein R1 is H or a C1-C4 alkyl, each R2 is independently H, or an alkyl group, an aryl group, a fluoroalkyl group, or a fluoroaryl group, and H is optionally present, and one or more piperidine-2,6-dione units, wherein the one or more piperidine-2,6-diones are formed by cyclization of an acrylamide nitrogen of an additional monomer unit ("G") of formula I onto the carbonyl of an additional monomer unit ("F").

[0200] (25) The process of any one of embodiments (1) to (24), wherein the powder comprises one or more acrylamide-based polymers and one or more surfactants that are associatively networked.

[0201] (26) The process of embodiment (25), wherein at least one of the one or more acrylamide-based polymers has one or more monomer units structurally similar to a surfactant(s).

[0202] below Experimental Example further illustrates the present invention but, of course, should not be construed as in any way limiting its scope.

[0203] Experimental Example 1 This served as a control Experimental Example demonstrates the effect on the inability to be machinable into powder exhibited by low molecular weight polymers without associative monomer units or surfactant-mediated networking.

[0204] Polymer 1 (control) containing 95 / 5 mol% acrylamide / DMAEA.MCQ was synthesized in the following manner.

[0205] A 1,000 g aqueous solution containing a 34 wt% monomer mixture of 95 / 5 mol% acrylamide / DMAEA.MCQ, azo initiator, chain transfer agent, buffer, and chelating agent at pH 2-5 was cooled to approximately -5 °C and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until monomer conversion reached >99.99%, resulting in a 1 × 10 6 The target molecular weight in g / mol was obtained. The resulting polymer gel was too soft and sticky to be processed with 1 wt% (relative to the weight of the polymer gel) petroleum lubricant in a cutting mill (Restch Mill Cutter) at 1500 rpm. The resulting polymer gel was manually divided into small pieces on a tray, dried in an oven at 85°C to remove moisture, and then ground into a powder with an intrinsic viscosity of 3.20 dg / L and a Huggins constant of 0.31 in 1.0 N NaNO3 solution at 30°C. The weight average molecular weight was determined by hydrolysis of the resulting polymer (using 0.1 wt% NaOH solution at pH 12 with a cage stirrer at 400 rpm for 1 hour) followed by size exclusion chromatography.

[0206] As is evident from the results listed in Table 1, the low molecular weight polymer 1, lacking temporary networking via the associative monomer, could not be machined to form a powder, which was further evidenced by the procedure requiring manual breaking up of the soft and sticky polymer. [Table 1]

[0207] Experimental Example 2 this Experimental Example demonstrate the effect on the ability to be machined into powder exhibited by low molecular weight polymers containing associative monomer units and transient networking via surfactants.

[0208] Polymer 2, containing 94.94 / 5 / 0.06 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA, was synthesized in the following manner.

[0209] A 1,000 g aqueous solution containing a 34 wt% monomer mixture of 94.94 / 5 / 0.06 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA (VISIOMER® monomer; 55% active; Evonik Industries, Essen, Germany), 1 wt% PLURONIC® F127 surfactant (BASF Corporation, Florham Park, New Jersey), azo initiator, chain transfer agent, buffer, and chelating agent at pH 2-5 was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until monomer conversion reached >99.99%, at 1×10 6 The target molecular weight in g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed in a Retsch Mill Cutter at 1500 rpm using 1 wt% (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85°C to reduce the moisture content to about 10 wt%, and then ground in 1N NaNO3 solution at 30°C to a powder with an intrinsic viscosity of 2.91 dg / L and a Huggins constant of 1.05. The weight average molecular weight was determined by hydrolysis of the resulting polymer (using a 0.1 wt% NaOH solution at pH 12 with a cage stirrer at 400 rpm for 1 hour) followed by size exclusion chromatography.

[0210] As is evident from the results reported in Table 1, the low molecular weight polymer 2 containing the temporary network could be machined to form a powder. This was further demonstrated by the procedure where the use of a cutting mill allowed the wet gel to be processed.

[0211] Experimental Example 3 this Experimental Example demonstrate the effect on the ability to be processed into powders exhibited by low molecular weight polymers containing associative monomer units and temporary networking via surfactants.

[0212] Polymer 3, containing 94.84 / 5 / 0.12 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA, was synthesized in the following manner.

[0213] A 1,000 g aqueous solution containing a 34 wt% monomer mixture of 94.8 / 5 / 0.12 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA (VISIOMER® monomer; 55% active; Evonik Industries, Essen, Germany), 1 wt% PLURONIC® F127 surfactant (BASF Corporation, Florham Park, New Jersey), azo initiator, chain transfer agent, buffer, and chelating agent at pH 2-5 was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until monomer conversion reached >99.99%, at 0.5×10 6 The target molecular weight in g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed in a Retsch Mill Cutter at 1500 rpm using 1 wt% (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85°C to reduce the moisture content to about 10 wt%, and then ground in 1N NaNO3 solution at 30°C to a powder with an intrinsic viscosity of 1.96 dg / L and a Huggins constant of 1.36. The weight average molecular weight was determined by hydrolysis of the resulting polymer (using a 0.1 wt% NaOH solution at pH 12 with a cage stirrer at 400 rpm for 1 hour) followed by size exclusion chromatography.

[0214] As is evident from the results reported in Table 1, the low molecular weight polymer 3 containing temporary networking could be machined to form a powder. This was further demonstrated by the procedure where the use of a cutting mill allowed the wet gel to be processed.

[0215] Experimental Example 4 this Experimental Example demonstrate the effect on the ability to be machinable into powder exhibited by low molecular weight polymers that contain transient networking solely via associative monomer units (i.e., no additional surfactant in the monomer phase).

[0216] Polymer 4, containing 89.965 / 10 / 0.035 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA, was synthesized in the following manner.

[0217] A 1,000 g aqueous solution containing a 37 wt% monomer mixture of 89.965 / 10 / 0.035 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA (VISIOMER® monomer; 55% active; Evonik Industries, Essen, Germany), azo initiator, chain transfer agent, buffer, and chelating agent at pH 2-5 was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until monomer conversion reached >99.99%, yielding a 1.0×10 6The target molecular weight of g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed with difficulty in a Retsch Mill Cutter at 1500 rpm using 1 wt% (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85°C to reduce the moisture content to approximately 10 wt% and then ground into powder. The resulting powder had a median particle size of 568.9 microns (mean particle size was 634.4) as measured using a Horiba Laser Scattering Particle Size Distribution Analyzer LA-950 with the powder refractive index set to 1.5000. The powder did not completely dissolve as a 1 wt% solution in synthetic tap water within 1 hour with agitation on a cage stirrer at 400 rpm. The powder as a 1 wt% solution in synthetic tap water had a viscosity of 744 cps as measured on a Brookfield Model DV-E Viscometer equipped with a Spindle 62 at 30 rpm. The weight average molecular weight was determined by hydrolysis of the resulting polymer (using a 0.1 wt% NaOH solution at pH 12 using a cage stirrer at 400 rpm for 1 hour) followed by size exclusion chromatography.

[0218] As is evident from the results reported in Table 2, the surfactant-free low molecular weight polymer 4 could be just barely machined to form a powder. The resulting powder was poorly soluble in water (i.e., it did not completely dissolve as a 1 wt % solution in local tap water within 1 hour with cage stirrer agitation at 400 rpm). [Table 2]

[0219] Experimental Example 5 this Experimental Example demonstrate the effect on the ability to be machined into powder exhibited by low molecular weight polymers containing associative monomer units and transient networking via surfactants.

[0220] Polymer 5, containing 89.965 / 10 / 0.035 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA, was synthesized in the following manner.

[0221] A 1,000 g aqueous solution of pH 2-5 containing a 37 wt% monomer mixture of 89.965 / 10 / 0.035 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA (VISIOMER® monomer; 55% active; Evonik Industries, Essen, Germany), 1 wt% Lutensol AT® 25 surfactant, or ethoxylated (25 mol EO) C16-18 fatty alcohol (BASF Corporation, Florham Park, New Jersey), azo initiator, chain transfer agent, buffer, and chelating agent was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until the monomer conversion reached >99.99%, at 1.0×10 6The target molecular weight in g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed in a Retsch Mill Cutter at 1500 rpm using 1 wt % (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85° C. to reduce the moisture content to about 10 wt % and then ground into powder. The resulting powder had a median particle size of 559.7 microns (mean particle size was 609.3) as measured using a Horiba Laser Scattering Particle Size Distribution Analyzer LA-950 with the powder refractive index set to 1.5000. The powder was completely dissolved within 1 hour as a 1 wt % solution in synthetic tap water with agitation on a cage stirrer at 400 rpm. The powdered polymer as a 1 wt% solution in synthetic tap water had a viscosity of 317 cps as measured on a Brookfield Model DV-E Viscometer equipped with a Spindle 62 at 30 rpm. The weight average molecular weight was determined by hydrolysis of the resulting polymer (using a 0.1 wt% NaOH solution at pH 12 using a cage stirrer at 400 rpm for 1 hour) followed by size exclusion chromatography. The structure of Polymer 5 was 13 Further analysis was performed by C NMR spectroscopy (Figure 1 ) to quantify the amount of piperidine-2,6-dione present in the polymer. 13 C NMR samples were prepared in deuterium oxide and carbon spectra were obtained using an Agilent Inova 500 Mhz spectrometer equipped with a Z gradient and a broadband 10 mm probe.

[0222] As is evident from the results set forth in Table 2, the surfactant-containing low molecular weight polymer 5 was easily machined to form a powder. In addition, the resulting powder containing 2.2 wt % surfactant was completely soluble as a 1 wt % solution in local tap water within 1 hour with cage stirrer agitation at 400 rpm.

[0223] In addition, the presence of piperidine-2,6-dione monomer units 13C NMR spectrum has a characteristic peak at 177 ppm 13 The relative amount of piperidine-2,6-dione monomer units can be verified by C NMR spectroscopy (Figure 1). The relative amount of piperidine-2,6-dione monomer units can be determined by the integration of the peak at 177 ppm, followed by other peaks indicating other monomer units. 13 The associative monomer units can be quantified by comparison with the integrals of the C NMR signals. The integrated analysis demonstrates that polymer 5 contains 7.8 / 90 / 2.1 mol% DMAEA.MCQ-acrylamido-piperidine-2,6-dione. The associative monomer units are characterized by the presence of peaks characteristic of the associative monomer units. 13 Note that it is present in concentrations so low that it is not visible by C NMR spectroscopy.

[0224] Experimental Example 6 This served as a control Experimental Example demonstrates the effect on the inability to be machinable into powder exhibited by low molecular weight polymers without associative monomer units or surfactant-mediated networking.

[0225] Polymer 6 (control), containing 50 / 50 mol % acrylamide / sodium acrylate, was synthesized in the following manner.

[0226] A 1,000 g aqueous solution at neutral pH containing a 37 wt % monomer mixture of 50 / 50 mol % acrylamide / sodium acrylate, an azo initiator, a chain transfer agent, and a chelating agent was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until the monomer conversion reached >99.99%, resulting in a polymerization of 1.0×10 6The target molecular weight in g / mol was obtained. The resulting polymer wet gel was too soft and sticky to be processed with 1 wt% (based on the weight of the polymer gel) petroleum-based lubricant in a Retsch Mill Cutter at 1500 rpm. The resulting wet gel was manually divided into small pieces on a tray, dried in an oven at 85°C to remove moisture, and then ground into a powder with an intrinsic viscosity of 5.80 dg / L and a Huggins constant of 0.24 in 1N NaNO3 solution at 30°C. The weight average molecular weight was determined by size exclusion chromatography.

[0227] As evident from the results reported in Table 3, the low molecular weight polymer 6, lacking temporary networking via associative monomer units, could not be machined to form a powder, as further evidenced by the procedure requiring manual breaking up of the soft and sticky polymer. [Table 3]

[0228] Experimental Example 7 this Experimental Example demonstrate the effect on the ability to be machined into powder exhibited by low molecular weight polymers containing associative monomer units and transient networking via surfactants.

[0229] Polymer 7, containing 49.9 / 50 / 0.1 mol% acrylamide / sodium acrylate / MAPTAC-C12 derivative, was synthesized in the following manner.

[0230] A 1,000 g aqueous solution at neutral pH containing a 37 wt% monomer mixture of 49.9 / 50 / 0.1 mol% acrylamide / sodium acrylate / MAPTAC-C12 derivative, 0.5 wt% hexadecyltrimethylammonium p-toluenesulfonate (Sigma-Aldrich, St. Louis, MO), azo initiator, chain transfer agent, and chelating agent was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until the monomer conversion reached >99.99%, yielding 1.0×10 6 The target molecular weight in g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed in a Retsch Mill Cutter at 1500 rpm using 1 wt % (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85° C. to reduce the moisture content to about 10 wt % and then ground into powder. The resulting powder had a median particle size of 357.1 microns (mean particle size was 420.1) as measured using a Horiba Laser Scattering Particle Size Distribution Analyzer LA-950 with the powder refractive index set to 1.5000. The powder had an intrinsic viscosity of 5.83 dg / L and a Huggins constant of 0.84 in a 1.0 N NaNO3 solution at 30° C. The powder was completely dissolved within 1 hour as a 1 wt % solution in synthetic tap water with agitation of a cage stirrer at 400 rpm. The powder as a 1 wt % solution in synthetic tap water had a viscosity of 1976 cps as measured on a Brookfield Model DV-E Viscometer equipped with Spindle 63 at 30 rpm. The weight average molecular weight was determined by size exclusion chromatography using Alternative Polymer 6.

[0231] The surfactant-containing low molecular weight polymer 7 was easily machined to form a powder, as evidenced by the results set forth in Table 3. In addition, Table 4 shows that the resulting powder containing 1.3 wt % surfactant was completely soluble as a 1 wt % solution in local tap water within 1 hour with cage stirrer agitation at 400 rpm.

[0232] Experimental Example 8 this Experimental Example demonstrate the effect on the ability to be machined into powder exhibited by low molecular weight polymers containing associative monomer units and transient networking via surfactants.

[0233] Polymer 8, containing 89.9 / 10 / 0.1 mol% acrylamide / sodium acrylate / MAPTAC-C12 derivative, was synthesized in the following manner.

[0234] A 1,000 g aqueous solution at neutral pH containing a 33 wt% monomer mixture of 89.9 / 10 / 0.1 mol% acrylamide / sodium acrylate / MAPTAC-C12 derivative, 0.5 wt% hexadecyltrimethylammonium p-toluenesulfonate (Sigma-Aldrich, St. Louis, MO), azo initiator, chain transfer agent, and chelating agent was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until the monomer conversion reached >99.99%, yielding a 1.0×10 6The target molecular weight in g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed in a Retsch Mill Cutter at 1500 rpm using 1 wt % (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85° C. to reduce the moisture content to about 10 wt % and then ground into powder. The resulting powder had a median particle size of 396.2 microns (mean particle size was 463.6) as measured using a Horiba Laser Scattering Particle Size Distribution Analyzer LA-950 with the powder refractive index set to 1.5000. The powder had an intrinsic viscosity of 3.49 dg / L and a Huggins constant of 2.49 in a 1N NaNO3 solution at 30° C. The powder was completely dissolved within 1 hour as a 1 wt % solution in synthetic tap water with agitation of a cage stirrer at 400 rpm. The powder as a 1 wt% solution in tap water had a viscosity of 2748 cps as measured on a Brookfield Model DV-E Viscometer equipped with Spindle 63 at 30 rpm. The weight average molecular weight was determined by size exclusion chromatography using an alternative polymer formed by the same synthetic procedure containing 90 / 10 mol% acrylamide / sodium acrylate in the absence of the MAPTAC-C12 derivative.

[0235] The surfactant-containing low molecular weight polymer 8 was easily machined to form a powder, as evidenced by the results set forth in Table 3. In addition, Table 4 shows that the resulting powder containing 1.3 wt % surfactant was completely soluble as a 1 wt % solution in local tap water within 1 hour with cage stirrer agitation at 400 rpm. [Table 4]

[0236] Experimental Example 9 this Experimental Exampledemonstrate the effect on the ability to be machinable into powder exhibited by low molecular weight polymers containing transient networking via associative monomers only (i.e., no additional surfactant in the monomer phase).

[0237] Polymer 9, containing 49.9 / 50 / 0.1 mol% acrylamide / sodium acrylate / MAPTAC-C12 derivative, was synthesized by the following method.

[0238] A 1,000 g aqueous solution at neutral pH containing a 37 wt% monomer mixture of 49.9 / 50 / 0.1 mol% acrylamide / sodium acrylate / MAPTAC-C12 derivative, an azo initiator, a chain transfer agent, and a chelating agent was cooled to approximately −5° C. and degassed with nitrogen. Polymerization was initiated with a redox couple and proceeded adiabatically until the monomer conversion reached >99.99%, resulting in a polymerization of 1.0×10 6The target molecular weight in g / mol was obtained. The resulting wet gel (which maintained a taffy-like consistency and was not sticky) was processed in a Retsch Mill Cutter at 1500 rpm using 1 wt % (relative to the weight of the polymer gel) petroleum-based lubricant to form granules. The wet gel granules were dried on mesh trays in an oven at 85° C. to remove moisture (i.e., to achieve a moisture content of about 10 wt %) and then ground into powder. The resulting powder had a median particle size of 385.4 microns (mean particle size was 446.4) as measured using a Horiba Laser Scattering Particle Size Distribution Analyzer LA-950 with the powder refractive index set to 1.5000. The powder had an intrinsic viscosity of 5.84 dg / L and a Huggins constant of 0.98 in 1N NaNO3 solution at 30° C. The powdered polymer did not completely dissolve as a 1 wt% solution in synthetic tap water within 1 hour with cage stirrer agitation at 400 rpm. The powder as a 1 wt% solution in synthetic tap water had a viscosity of 1588 cps as measured with a Brookfield Model DV-E Viscometer equipped with Spindle 63 at 30 rpm. The weight average molecular weight was determined by size exclusion chromatography using Alternative Polymer 6.

[0239] As is evident from the results set forth in Table 4, the surfactant-free low molecular weight polymer 9 could be machined to form a powder. The resulting powder was poorly soluble in water (i.e., did not completely dissolve as a 1 wt % solution in local tap water within 1 hour with cage stirrer agitation at 400 rpm).

[0240] Experimental Example 10 this Experimental Example demonstrate the effect on paper dry strength shown by sheets of paper treated with a powder containing acrylamide-based polymer(s) networked via associative monomer units and surfactants.

[0241] Polymer 2( Experimental Example 2) and polymer 3 ( Experimental Example 3) was dissolved in water and dosed at various concentrations into a cellulose fiber slurry. The treated fibers were then added to a handsheet form and discharged through a screen to form a wet fiber pad. The pad was strained through the screen, pressed, and dried to obtain a finished paper sheet. The sheets were tested for tensile and compressive strength and the results are set forth in Figures 2 and 3, respectively. Additionally, tensile and compressive strength results for an established commercial paper strength agent, Nalco 64114 (i.e., a glyoxylated polyacrylamide polymer), are provided for comparison.

[0242] As demonstrated by Figures 2 and 3, Polymer 2 and Polymer 3 exhibit sufficient strength properties, superior to standard Nalco 64114 (ie, a glyoxylated polyacrylamide polymer) (the control) in both tensile and compressive strength.

[0243] Experimental Example 11 this Experimental Example demonstrate the effect on paper dry strength shown by sheets of paper treated with a powder containing acrylamide-based polymer(s) networked via associative monomer units and surfactants.

[0244] Polymer 1( Experimental Example 1) and polymer 2 ( Experimental Example 2) was dissolved in water and dosed at various concentrations into a cellulose fiber slurry. The treated fibers were then added to a handsheet form and discharged through a screen to form a wet fiber pad. The pad was strained through the screen, pressed, and dried to obtain a finished paper sheet. The sheets were tested for tensile strength and the results are shown in Figure 4.

[0245] As demonstrated by FIG. 4, Polymer 2 exhibited improved tensile strength compared to the low molecular weight Polymer 1 (control), which lacked networking via associative monomer units.

[0246] Experimental Example 12 this Experimental Example demonstrates the effect on polymer quality exhibited by Polymer 5 made down with high and low shear mixing compared to a high molecular weight conventional dry powder flocculant made down with high and low shear mixing ("Flocculant Comparison 1").

[0247] Flocculant Comparison 1 was prepared comprising 90 / 10 acrylamide / DMAEA.MCQ (median particle size of approximately 990±386 microns) with a molecular weight of approximately 10,000 kDa and a reduced specific viscosity ("RSV") of 19 dL / g at 450 ppm and pH 4.

[0248] Polymer 5 was prepared comprising 89.965 / 10 / 0.035 mol% acrylamide / DMAEA.MCQ / C18PEG1105MA (median particle size of approximately 560 microns) with a molecular weight of approximately 1,000 kDa and a reduced specific viscosity ("RSV") of 4 dL / g at 3,000 ppm and pH 12.

[0249] Two 1 wt% solutions of Polymer 5 were made down to form a fully made down powder solution. The first solution was made down using a cage stirrer at 800 rpm (tip speed of 1.26 m / s) for 1 hour. The second solution was made down using an IKA T25 digital ULTRA-TURRAX® high performance dispersion instrument equipped with an S25N-25F dispensing element at 8,000 rpm (tip speed of 10.47 m / s) for 4 minutes.

[0250] For comparison, two 0.25 wt. % solutions of Flocculant Comparison 1 were made down to form a fully made down powder solution. The first solution was made down using a cage stirrer at 400 rpm (tip speed of 0.63 m / sec) for 1 hour. The second solution was made down using an IKA T25 digital ULTRA-TURRAX® high performance dispersion instrument equipped with an S25N-25F dispensing element at 8,000 rpm (tip speed of 10.47 m / sec) for 4 minutes.

[0251] The viscosity, intrinsic viscosity, and Huggins constant of the resulting made down powder solutions were measured and the results are listed in Table 1. [Table 5]

[0252] As is evident from the results set forth in Table 1, Comparative Flocculant 1 broke down into lower molecular weight polymers when made down at high shear using an IKA T25 digital ULTRA-TURRAX® high performance dispersing instrument, as evidenced by the reduction in viscosity and intrinsic viscosity. Polymer 5, however, maintained its molecular weight when made down at high shear using an IKA T25 digital ULTRA-TURRAX® high performance dispersing instrument, as evidenced by the relatively similar reduction in viscosity and intrinsic viscosity compared to solutions made down at low shear using a cage stirrer.

[0253] Experimental Example 13 this Experimental Example demonstrates the refractive index of a series of acrylamide-based polymer solutions as measured by an RM50 refractometer (Mettler Toledo) at 25° C. and 1 atmosphere ("atm") pressure.

[0254] Completely dissolved acrylamide-based polymer solutions of known concentrations were obtained by mixing a weighed amount of powder and a weighed amount of water under shear using a cage stirrer at 400-800 rpm (tip speeds of 0.63 m / s to approximately 1.26 m / s) until the mixture of powder and water could easily pass through a 100 mesh screen and only traces of insoluble gel residue (less than 0.05% by weight of the original powder added) remained on the screen. An aliquot of the resulting filtered acrylamide-based polymer solution was placed in the cell of an RM50 refractometer (Mettler Toledo) and the refractive index was recorded. The procedure was repeated for different concentrations of acrylamide-based polymer solution, and the refractive index was plotted as a function of concentration.

[0255] As demonstrated by Figure 5, the refractive index of an acrylamide-based polymer solution is linearly correlated with concentration. Therefore, a refractive index calibration curve can be used to estimate the concentration of an acrylamide-based polymer in solution.

[0256] Experimental Example 14 this Experimental Example demonstrates the mixing progress of a powder suspension (1 wt%) made down using a cage stirrer at 800 rpm (tip speed of 1.26 m / sec) as measured by refractive index.

[0257] A powder (polymer 5; median particle size approximately 560 microns) suspension was obtained by dispersing a weighed amount of powder into a weighed amount of water (1% powder content by weight) either manually or using a powder feeder, e.g., a Norchem POWDERCAT™ feeder (Norchem Industries, Mokena, IL). The resulting mixture was blended using a cage stirrer at 800 rpm (tip speed of 1.26 m / sec). Small aliquots of the suspension were filtered through a 100 mesh screen at 1 minute intervals to remove undissolved powder. The refractive index of the filtrate was measured using an RM50 refractometer (Mettler Toledo) and the refractive index was recorded. The concentration of dissolved acrylamide-based polymer in the solution was determined by: Experimental Example13 and the calibration curve outlined in Figure 5. To determine the mixing progress of the powder suspensions, the refractive index (or acrylamide-based polymer concentration) was plotted as a function of time.

[0258] As demonstrated by Figure 6, the mixing curve of the 1 wt% powder suspension plateaus at a refractive index of about 1.33425 after about 15 minutes of mixing. Experimental Example By 15 minutes mixing, it can be considered a completely made down powder solution.

[0259] Experimental Example 15 this Experimental Example demonstrates the mixing progress of a powder suspension (1 wt%) made down using an IKA T25 digital ULTRA-TURRAX® dispersion instrument at 8,000 rpm (tip speed of 10.47 m / sec) as measured by refractive index.

[0260] A powder (polymer 5; median particle size approximately 560 microns) suspension was obtained by dispersing a weighed amount of powder into a weighed amount of water (1% powder content by weight) either manually or using a powder feeder, e.g., a Norchem POWDERCAT™ feeder (Norchem Industries, Mokena, IL). The resulting mixture was blended using an IKA T25 digital ULTRA-TURRAX® high performance dispersion instrument at 8,000 rpm (10.47 m / sec tip speed). Small aliquots of the suspension were filtered through a 100 mesh screen at 30 second intervals to remove undissolved powder. The refractive index of the filtrate was measured using an RM50 refractometer (Mettler Toledo) and the refractive index was recorded. The concentration of dissolved acrylamide-based polymer in the solution was determined by: Experimental Example 13 and the calibration curve outlined in Figure 5. To determine the mixing progress of the powder suspensions, the refractive index (or acrylamide-based polymer concentration) was plotted as a function of time.

[0261] As demonstrated by Figure 7, the mixing curve of the 1 wt% powder suspension plateaus at a refractive index of about 1.33425 after about 4 minutes of mixing. Experimental Example By 100%, it can be considered a completely made down powder solution after about 4 minutes of mixing.

[0262] All references cited in this specification, including publications, patent applications, and patents, are hereby incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety.

[0263] In the context of describing the present invention (particularly in the context of the claims which follow), the use of the terms "a," "an," "the," "at least one," and similar referents are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B") should be construed as meaning one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including but not limited to"), unless otherwise indicated. The recitation of numerical ranges herein is intended to serve as a shorthand method of individually referring to each individual value falling within the range, unless otherwise stated herein, and each individual value is incorporated herein as if it were individually recited herein. All methods described herein may be performed in any suitable order, unless otherwise stated herein or clearly contradicted by context. Any and all examples provided herein, or the use of exemplary language (e.g., "etc.") are intended only to better illustrate the invention, and do not limit the scope of the invention unless otherwise claimed. No term in this specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0264] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors expect that such variations will be adopted appropriately by those skilled in the art, and intend that the invention be practiced otherwise than as specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Also, any combination of the above-described elements in all possible variations thereof is encompassed by the present invention unless otherwise indicated herein or clearly contradicted by context.

Claims

1. 1. A process for making down a powder comprising one or more acrylamide-based polymers to form a fully made down powder solution, comprising blending said powder and solvent mixture at an impeller tip speed of about 5 m / sec to about 25 m / sec for about 10 minutes or less to obtain said fully made down powder solution; the powder comprises particles dry cut to a median particle size of about 200 microns to about 10,000 microns; At least one of the one or more acrylamide-based polymers has the formula AP 1 : wherein E is one or more associative monomer units, F is one or more additional monomer units, and G is one or more additional monomer units of formula I; wherein R 1 is H or C 1 -C 4 alkyl, and each R 2 is independently H, or an alkyl group, an aryl group, a fluoroalkyl group, or a fluoroaryl group; wherein H is one or more piperidine-2,6-dione units; wherein said one or more piperidine-2,6-diones are formed by cyclization of the acrylamide nitrogen of said additional monomer unit ("G") of formula I onto the carbonyl of said additional monomer unit ("F").

2. The process of claim 1 , wherein the solvent is water.

3. 3. The process of claim 1 or 2, wherein the particles have a median particle size of about 350 microns to about 10,000 microns.

4. 4. The process according to any one of claims 1 to 3, wherein a fully made down powder solution of 1 wt% in water at 25°C made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution has a viscosity (cps) within about 20% deviation of the viscosity (cps) of an identical solution made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain said fully made down powder solution.

5. 5. The process according to any one of claims 1 to 4, wherein a fully made down powder solution of 1 wt% in water at 25°C made down at a tip speed of about 5 m / s to about 25 m / s to obtain a fully made down powder solution has an intrinsic viscosity (dL / g) within about 20% deviation of the intrinsic viscosity (dL / g) of an identical solution made down in a cage stirrer at a tip speed of about 1.26 m / s and under otherwise identical conditions to obtain said fully made down powder solution.

6. 6. The process of any one of claims 1 to 5, wherein the fully made down powder solution has an intrinsic viscosity of about 0.05 dL / g to about 15 dL / g.

7. 7. The process of any one of claims 1 to 6, wherein the one or more acrylamide-based polymers have a weight average molecular weight of from about 10 kDa to about 5,000 kDa.

8. 8. The process of any one of claims 1 to 7, wherein the fully made-down powder solution comprises from about 0.1% to about 10% by weight of the one or more acrylamide-based polymers.

9. The process of any one of claims 1 to 8, wherein the powder further comprises one or more surfactants.

10. The process of any one of claims 1 to 9, wherein the fully made-down powder solution further comprises one or more surfactants.

11. 11. The process of any one of claims 1 to 10, wherein the powder comprises one or more acrylamide-based polymers and one or more surfactants that are associatively networked.

12. 12. The process of claim 11, wherein at least one of the one or more acrylamide-based polymers has one or more monomer units structurally similar to the surfactant.

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