Apparatus and method for effectively controlling the production of multi-stage polymer production

Abstract

To provide an apparatus and a method for actively controlling the production of multistage and multimodal polymers.SOLUTION: The apparatus can include a reaction vessel configured to contain a polymer solution and to conduct a polymer reaction in at least two stages, and one or more detectors configured to monitor at least one reaction characteristic of the polymer solution contained in the reaction vessel. The apparatus can further include a control element coupled with the reaction vessel and the one or more detectors, wherein the control element is configured to actively control the development of the predetermined reaction characteristic by modifying at least one process control variable based on at least one reaction characteristic monitored by the detector.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Patent Application No. 62 / 382,062, filed August 31, 2016, entitled "Device and Methods to Actively Control Multi-Stage Polymer Production," which is incorporated herein by reference in its entirety for all purposes.

[0002] This application is directed to controlling the production of polymers. In particular, the present disclosure relates to an apparatus and method for actively controlling the production of multi-stage and multimodal polymers. [Background technology]

[0003] In laboratory and polymer fabrication, modified polymers and polymer blends are frequently produced. Modified polymers can be produced in stages. As a non-limiting example, polyacrylamide homopolymer can be produced in the first stage by free radical polymerization and then hydrolyzed with a base such as NaOH to form a copolymer polyelectrolyte consisting of neutral Am groups and anionic COO- groups. There are many other examples of modified polymers that utilize two or more process steps. Modifications include, but are not limited to, sulfonation, PEGylation, amination, quaternization, hydroxylation, branching, multiblock extension, grafting, crosslinking, dendrimerization, the creation of star-shaped and other branched structures with well-defined architectures, and hybridization of polymers with nanoparticles and microparticles, such as, but not limited to, silica, titanium dioxide, pure metals, metal oxides, clays, and other materials.

[0004] Multimodal polymers can resemble blends, produced in two or more stages, each resulting in a unique polymer with its own properties and distribution. For example, a high molecular weight mode of polymer can impart mechanical strength to a product such as a plastic, while a significantly lower molecular weight second mode can be combined to aid in multimodal polymer fabrication processes such as extrusion. Other examples of multimodal polymers include plasticizers, compatibilizers, and viscosity and combustion by-product control agents frequently found in motor oil formulations. Still other examples include blends of incompatible polymers that result in the formation of desired nano- or microstructures or macroscopic phase separation. An example is high-impact polystyrene, where incompatible polybutadiene, with or without polystyrene grafts, is present with polystyrene to form rubbery microinclusions that impart impact, flexibility, and crack resistance.

[0005] Embodiments of the present application will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0006] [Figure 1] 1 shows experimental results of automatic control of monomer concentration using sinusoidal control of monomer concentration during free radical polymerization compared to monomer trajectory for a batch reaction with no monomer feed, according to an exemplary embodiment of the present disclosure. [Figure 2] FIG. 10 shows the results of the automatic Mw control element as the reactor temperature is changed, according to an exemplary embodiment of the present disclosure, including a target trajectory for Mw,t(t), which increases linearly in time with a slope of 50.0 g / mol-s. [Figure 3] 1 shows Mw(Cp) and Mw,inst(Cp) for reactions using the Mw control elements of the present disclosure along with the addition of a CTA to lower Mw and produce a multimodal population according to an exemplary embodiment of the present disclosure. [Figure 4]4 shows a calculation of MWD from the data of FIG. 3 according to an exemplary embodiment of the present disclosure, where bimodality is seen in the sum of all 14 instantaneous MWDs, weighted by the amplitude of the inset histogram, using the inset histogram mass to calculate the lognormal instantaneous MWD, and showing the 14 lognormal instantaneous MWDs. [Figure 5] 1 shows the synthesis of a bimodal population using the automatic Mw control element of the present disclosure, using sodium formate as a CTA to produce a significant reduction in Mw,inst, creating a second, lower molecular weight mode, according to an exemplary embodiment of the present disclosure. [Figure 6] 5 shows the calculated MWD using Mw,inst for the bimodal polymer final product from FIG. 5 and the log-normal distribution (dashed line), and the PEO equivalent MWD by GPC where the column was calibrated with PEO molecular weight standards, according to an exemplary embodiment of the present disclosure. [Figure 7] 10 shows the synthesis of a trimodal population using the automated Mw control element of the present disclosure to produce two large reductions in Mw,int using the automated addition of sodium formate as a CTA, according to an exemplary embodiment of the present disclosure. [Figure 8] FIG. 8 shows the MWD of the final product of the trimodal polymer from FIG. 7 as determined by model-based non-chromatographic calculation based on GPC and Mw,inst (smooth curve), according to an exemplary embodiment of the present disclosure. [Figure 9] 1 illustrates an ACOMP system and method according to an exemplary embodiment of the present disclosure. [Figure 10] 1 shows an isomorphous reaction pair according to an exemplary embodiment of the present disclosure, in which a target trajectory was established by polymerization of Am at an upward increment of T from 45° C. to 65° C. with a fixed initiator [KPS], as shown by the dashed line, and a second reaction followed this latter trajectory at a fixed T=45° C. with active manual pumping of initiator into the reactor (the second reaction trajectory was always within 3% of the first trajectory). [Figure 11]An isomorphous Mw reaction pair is shown in which a target trajectory was established by polymerization of Am at an upward increment of T from 5°C to 65°C with a fixed initiator [KPS]. A second reaction followed this latter at a fixed T = 45°C while actively manually pumping initiator into the reactor. The second reaction trajectory, according to exemplary embodiments of the present disclosure, was always within 10% of that of the first reaction. [Figure 12] 1 illustrates an apparatus and system that includes, at least in part, the ACOMP method and system, according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007] It should be understood that the various aspects are not limited to the arrangements and instrumentality shown in the drawings.

[0008] overview The present disclosure provides an apparatus and method for actively controlling the production of multi-stage and multimodal polymers. According to the present disclosure, actively controlled multi-stage polymer production can produce polymers of increasing complexity, as well as coexisting multimodal polymers. In the first state, active control allows for a continuous process that adds or modifies polymer characteristics with each new stage. For simplicity, we refer to the polymer as a "modified polymer." In the second state, the actively controlled stages produce a "multimodal polymer," a mixture of polymers with distinctly different properties that must typically be produced by blending different polymer lots together. The two states can also coexist when a continuously produced modified polymer coexists with a multimodal polymer.

[0009] When a multimodal polymer is produced, there is an associated multimodal distribution. Multimodal distributions may include, but are not limited to, molecular weight (MWD), intrinsic viscosity (IVD), composition (CD), stereoregularity (TD), branching (BD), and the like. Modified and multimodal polymers are produced continuously in batch or semi-batch reactions, where the desired properties of each mode of the modified polymer are identified, and then active control elements guide the production of each mode in turn. Active control elements may be manual or fully automated. The disclosed method involves the use of equipment capable of frequently providing values ​​for the modal properties being produced, such as molecular weight, IV, and composition. In some cases, multimodal polymers are equivalent to blends of different types of polymers. Because the multimodal process is carried out entirely in a single reactor or series of reactors, it does not require the energy- and time-intensive steps associated with blending polymers from different batches. In contrast, the modified polymers produced by this method cannot be achieved simply by blending different polymers together.

[0010] Detailed Description It should be understood that, for simplicity and clarity of description, reference numerals have been repeated, where appropriate, among the different figures to indicate corresponding or similar elements. Furthermore, numerous specific details have been set forth in order to provide a thorough understanding of the embodiments described herein. However, those skilled in the art will understand that the embodiments described herein may be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the relevant features being described. Those skilled in the art will understand that other components and configurations may be used without departing from the spirit and scope of the present disclosure. Initially, exemplary implementations of one or more embodiments are described below; however, it should be understood that the disclosed apparatus and method may be implemented using any number of techniques. The present disclosure should in no way be limited to the exemplary implementations, figures, and techniques shown herein, but may be modified within the scope of the appended claims, along with the full range of equivalents thereof. Furthermore, this description should not be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale, and proportions of certain parts may be exaggerated to better illustrate the details and features of the present disclosure.

[0011] Some definitions that apply throughout this disclosure are now presented. The term "coupled" is defined as connected directly or indirectly through intervening components, and is not necessarily limited to a physical connection. The term "communicatively coupled" is defined as connected directly or indirectly through intervening components, and is not necessarily limited to a physical connection, but is a connection that allows for the transfer of data between the aforementioned components. A connection may be one in which objects are permanently connected or removably connected. The terms "comprise," "include," and "have" are used interchangeably in this disclosure. The terms "comprise," "include," and "have" mean including, but not necessarily limited to, what is so set forth.

[0012] As used herein, the term "polymer reaction" refers to any type of chemical or physical reaction involving polymers. The term "polymer reaction" includes, but is not limited to, covalently forming polymers from monomers or comonomers (statistically or randomly forming copolymers), branching or crosslinking reactions, cleaving polymer bonds to form smaller polymers, forming block copolymers, forming star-shaped, comb-shaped, dendrimer-shaped, cyclic, or other highly specific polymer architectures, any type of reaction that results in chemical modification of a polymer, such as, but not limited to, impregnating polymers with negative and / or positive charges, zwitterions, polar groups, impregnating polymers with acid or base properties, linking polymers to or growing polymers from nano- or microparticles, such as silica, metals, such as silver or gold, gels, metal oxides, such as titanium dioxide, clay, etc., and reversible or irreversible supramolecular assembly of polymers and other particles.

[0013] There are no limitations on the type of polymerization mechanism used to produce polymers from monomers. This includes chain-growth and step-growth reactions. The former includes free radical and controlled radical polymerization. Controlled radical polymerization can include, but is not limited to, methods such as ring-opening metathesis polymerization (ROMP), atom transfer radical polymerization (ATRP), reversible addition-fragmentation transfer polymerization (RAFT), and nitroxide-mediated polymerization (NMP). Polymer reactions can occur in solvent, bulk, or in heterogeneous phases such as micelles, emulsions, inverse emulsions, and dispersions. This includes metallocene-based chain growth, such as that used in polyolefins. Step-growth reactions include polycondensation reactions, such as those used in the production of polypeptides, polynucleotides, polyimides, polyamides, and polyurethanes.

[0014] The present disclosure does not impose any fundamental limitations on the type of polymer reactor to which it is applicable. As used herein, the term "polymer reactor," also referred to as a "polymer reaction vessel," refers to a reactor or reaction vessel that can be as small as submilliliters or as large as tens or hundreds of thousands of liters. They can be made of many different materials, including, but not limited to, metals such as stainless steel or aluminum, glass, porcelain, and ceramic. They can be batch-type, reagent-feeding types sometimes referred to as "semi-batch," or continuous. When a continuous reactor is used, the apparatus and methods of the present disclosure may be applied differently depending on the type of continuous reactor. For example, in a long tubular continuous reactor, different actively controlled process stages can occur at different points along the trajectory of the reaction fluid through the reactor. In a continuous stirred tank reactor, a steady state can be reached in the reactor, and multiple CSTRs can be arranged in continuous flow to reach different stages of an actively controlled multi-stage process.

[0015] As used herein, a "multi-stage polymer" is a polymer whose properties are modified in two or more processing steps. It may also be referred to as a "modified polymer." A multi-stage polymer acquires different properties in each step, but is remodeled from the polymer in the previous step. This distinguishes a "multi-stage polymer" from a "multimodal polymer," in which a separate new polymer is produced in a subsequent process step and coexists with the polymer produced in the previous step. Of course, in some cases, both multi-stage and multimodal polymers can be produced in the same set of processes, for example, when a subsequent process step not only produces a new polymer but also modifies a previously produced polymer.

[0016] As used herein, the term "mode" refers to a unimodal distribution of a property, such as molecular weight (MW) or composition. According to the present disclosure, the concentration of a polymer population, the mass of a population, or the fraction of the mass of a population is a function of the property. For example, x can be a property, and C p(x) can be the concentration of polymer with that property. One may consider unimodal MWDs, such as those arising from geometric chain length distributions. Typically, a unimodal continuous distribution has two inflection points in the distribution, i.e., d 2 C(x) / dx 2 =0.

[0017] As used herein, "multimodality" occurs when at least two modes exist in a polymer population. According to the present disclosure, the requirement for multimodality is that there are at least two different processes that produce two different modes, and each mode of polymer is distinguishable from the other modes. It is not necessary for the modes of the combined polymers to be physically separable from each other; they simply need to exist together due to their sequential generation. In other words, there may be no physical separation method to physically separate the modes, but rather two separate processes create each mode that they coexist.

[0018] There are numerous methods for separating polymers according to properties such as molecular weight, composition, and branching. These methods include, but are not limited to, gel permeation chromatography (GPC), size exclusion chromatography (SEC), field-flow fractionation (FFF), matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF), Fourier transform mass spectrometry, and coupled methods such as, but not limited to, two-dimensional GPC / SEC, and variations of chromatography such as CRYSTAF and temperature-rising elution fractionation (TREF).

[0019] The present disclosure provides apparatus and methods for actively controlling the production of multi-stage and multimodal polymers. In particular, the present disclosure provides apparatus and methods for producing multimodal polymers in a single reactor without the need to blend different polymer lots together. The present disclosure also provides apparatus and methods for sequentially producing modified or multi-stage polymers.

[0020] To achieve the active control necessary to produce modified and multimodal polymers, it is necessary to be able to monitor the reaction characteristics to be controlled and to monitor them frequently enough to enable control. If composition is to be controlled, it is necessary to be able to distinguish and monitor the course of the comonomer conversion involved. In some instances, sufficiently frequent measurements can be made by in-reactor spectroscopic probes such as Raman scattering and infrared. Within the ACOMP platform, comonomer differentiation has been achieved by refractive index, UV absorption, near-IR, NMR, and conductivity. When chiral molecules are mixed with achiral molecules, the former can be distinguished using polarimetry or other sensors of optical activity such as circular dichroism or circular birefringence.

[0021] To measure molecular weight, the ACOMP utilizes total intensity light scattering, multi-angle when necessary (i.e., when the z-average root-mean-square radius of the polymer is a significant fraction of the wavelength of the incident light), in conjunction with determining the polymer concentration. Intrinsic viscosity (IV) is also related to molecular weight, and capillary viscometers are frequently used in conjunction with ACOMP detectors. When IV is combined with molecular weight, it can also be used to assess branching. The simultaneous measurement of low and high shear viscosity with the ACOMP can also be used to assess branching due to non-Newtonian shear behavior.

[0022] To perform active control, information about the reaction characteristic must be available frequently enough to allow control actions to be taken within a short time interval compared to the overall reaction time. In other words, the frequency of data acquisition must be such that control of the desired reaction characteristic is performed in a time interval much shorter than the time during which significant deviations of the controlled characteristic can occur. "Significant deviation" depends on the degree of control desired. For example, and without limitation, in some cases it may be acceptable to control the desired characteristic to within 35% of the target trajectory, while in other cases control to within 10%, 5%, or even less than 1% deviation may be required. Thus, the sufficient frequency of reaction characteristic information must be frequent enough to control the characteristic within the desired range of deviation from the target trajectory. w Target trajectories for reaction properties such as IV, or composition are typically established offline to optimize the final product properties and the processes leading to them. The target trajectories are then executed, followed by active control measures during the polymer reaction process.

[0023] For example, a typical ACOMP system is w Multiple reaction characteristics, such as viscosity drop, conversion, monomer and polymer concentrations, and comonomer composition, are measured once per second. While faster and slower rates are possible, this generally gives a rough sense of frequency for reactions lasting tens of minutes or hours. In fact, when the period (the inverse of frequency) of data measurements is sufficiently within the time scale required to control deviations, such measurements are often referred to as "continuous," as in the term "Automated Continuous Online Monitoring of Polymerization Reactions (ACOMP)." Manual sampling methods, such as those widely employed in both the polymer production industry and research laboratories, rarely have a sufficiently high frequency for active control. Similarly, online chromatographic methods generally lack sufficient frequency, although they can be employed in accordance with the present disclosure.

[0024] Control of the trajectory of one or more reaction properties (e.g., molecular weight, composition, branching, degree of hydrolysis, and chemical substitution) can be controlled by process control variables, also referred to as "reaction control variables," including, but not limited to, temperature and the mixing and feeding of at least one of the following to the reactor: monomers, comonomers, branching agents, crosslinking agents, chain transfer agents, inhibitors, gases such as air, O2, N2, and argon, acids, bases, redox agents, and catalysts.

[0025] Active control of one or more reaction variables during a reaction phase can be achieved by one of three means according to the present disclosure. First, in "manual active control," a human has access to data of sufficient frequency of appropriate characteristics, where the human follows a particular reaction target trajectory for one or more appropriate characteristics by manually controlling one or more process control variables as described above. Second, a computational algorithm can be used to direct which control variables an operator should manually control, enabling "computation-assisted active control." Third, process control variables can be automatically controlled by computation-based control elements, enabling automatic active control.

[0026] The process control variable may also be controlled based on the reaction trajectory as determined by monitoring the reaction characteristics. As used herein, the term "reaction trajectory" refers to the relationship between the M W The term "reaction trajectory" refers to a specific mathematical form of a reaction property, such as IV, or composition. The most common dependent variables in a polymerization reaction are time and polymer concentration, but can include others, such as composition and degree of branching. The reaction trajectory determines the final properties of the polymer, including all of its unimodal or multimodal properties. Therefore, by controlling the reaction trajectory, the properties of the final polymer are controlled.

[0027] Typically, reaction trajectories are actively controlled to follow a target trajectory as closely as possible. While a target trajectory is often thought of as including reaction characteristics over time, concentration, or other variables in batch or semi-batch reactors, this concept also applies to continuous reactions. Continuous reactors typically operate at a steady state to continuously produce a consistent grade of polymer, i.e., a polymer with defined physical and chemical properties. When a reactor changes polymer grades during production, "grade" is equivalent to "mode" as used in this disclosure, and transitions from one steady state to another are required, requiring various operating conditions, such as comonomer feed rate, catalyst, other reagents, temperature, pressure, etc. Similar to producing polymers in different modes during transitions, polymers produced between two grades are often rejected because they do not meet the specifications for either grade, resulting in significant waste of energy, raw materials, and time. The optimal crossover target trajectory can be determined offline and implemented online, resulting in active control minimizing the time, materials, and energy used for grade crossover.

[0028] Certain reaction characteristics, such as, but not limited to, cumulative weight average molecular weight M, which can be measured frequently or continuously during polymer synthesis by methods such as ACOMP, w can be considered and a general property X can be further considered. Online monitoring of the reactor contents can be performed to determine the reactor X c The accumulation of X and the resulting distribution produce the instantaneous value of X, i.e., X inst , and X inst The concentration of polymers depends on how much is added to the cumulative population. Specifically, X c and X inst The relationship is, by definition, as follows: TIFF2026001067000002.tif2061 (1)

[0029] M w (C p) is measured directly from the light scattering and concentration detectors of the ACOMP system. w,inst (C p ) is calculated by the following formula according to Eq. w (C p ) can be calculated from the ACOMP value. TIFF2026001067000003.tif1763(2)

[0030] M w and C p From the primary ACOMP value of M w,inst Calculating X in Equation 1 allows us to track the average instantaneous weight of the MWD and create a histogram representation of the MWD as the synthesis progresses. c can represent any property of the other IVs, compositions, etc. Up to this point, all quantities are model independent and based on primary detector measurements.

[0031] The disclosed apparatus and method may include two or more reactors to achieve the desired modified polymer, multimodal polymer, or a mixture of both. While a single reactor may often be provided to provide all the reaction control variables needed to produce the desired polymer, two or more reactors are often used, each performing one or more different stages of the process. For example, the second stage of the process may involve temperatures, pressures, or reagents that the first vessel cannot withstand, necessitating the need for a second reactor. The second reactor may be constructed with materials and specifications to withstand higher temperatures, pressures, corrosive materials, and have higher viscosity mixing capabilities. Multiple such stages may require more than two reactors. Intermediate or final polymer products in subsequent stages may also require special handling measures. For example, in the first or early stages, the polymer intermediate may be sufficiently low in viscosity to be pumped, but in later or final stages, the viscosity may be high and may require skimming or scraping. Economies of scale, production throughput, quality, and reduced maintenance needs are often achieved by having multiple polymer reactors, each dedicated to one or more stages of the process.

[0032] When more than one reactor is used, the present disclosure provides that at least one of the reactors is equipped for active control. Active control of all stages is not necessary, and in some examples, active control brings the polymer into a particular state, such as a mass distribution or composition distribution, and then utilizes stages that do not require active control, such as polymerizing remaining monomer or monitoring small amounts of remaining monomer.

[0033] Examples of multimodal polymers include, but are not limited to, 1) compositional blends, 2) molecular weight blends, 3) multimodal polymers produced by controlled radical polymerization, and 4) multimodal stimuli-responsive polymers produced by controlled radical polymerization. A compositional blend can be a bimodal blend of homopolymer A and homopolymer B, produced by first feeding monomer A until the desired MWD (i.e., C(M), where M is the molar mass) is achieved. The MWD is produced by active control. Monomer B is then fed until the desired C(M) for homopolymer B is achieved using active control. If some copolymer is produced during the production of the second mode, it constitutes a third copolymer mode with unique properties. The latter is a modified (or multistage) polymer as defined above. The blend then becomes one of bimodal homopolymer A and homopolymer B, and a modified polymer, copolymer AB.

[0034] Multimodal polymers can also contain a blend of molecular weights. It is often desirable to have more than one molecular weight mode. For example, long chains can impart tensile strength to a polymer, which can be blended with short chains to enhance processability. In this case, each MWD mode is produced sequentially.

[0035] For example, a high MW mode can be generated first by having a high monomer-to-initiator ratio. The details of the mode, i.e., the details of the MW trajectory, can be controlled by variables such as the monomer and / or initiator flow through the reactor and changes in temperature. In principle, in free radical polymerization, increasing the concentration of monomer increases the MW, while increasing T and initiator decreases the MW. In the latter case, increasing T and initiator also increases the reaction rate, which may or may not be desirable depending on the desired outcome of the reaction. An active control element ensures that the MW follows the desired path. Once the concentration of a certain amount of Mode 1 polymer reaches C1, a second mode can be initiated. This creates a much lower molecular weight mode, M w Increasing the temperature and initiator may decrease the molecular weight, but increasing the M w If a change in M ​​is desired that approaches one or more orders of magnitude, the effect is usually not large enough. In this case, a chain transfer agent (CTA) can be added, which has the advantage that the conversion kinetics are not altered, no temperature change is required, and M w A significant reduction in M ​​can then be achieved. The trajectory of this second mode can then be controlled as desired until the concentration of polymer in this mode reaches C2. More modes can be added, for example, by adding more CTAs to decrease M until the concentration of the third mode, C3, is reached. w can be further significantly reduced.

[0036] It is also possible to provide target trajectories for two or more properties and provide a means to simultaneously control the reaction trajectories to closely match each individual target trajectory. w And the composition of a given mode can have its own specific target trajectory, each of which is followed by active control during the process. Each subsequent mode is M w and a new set of target trajectories for the composition.

[0037] In other examples, separate Mw It may be desirable to establish a target trajectory for the M and IV. w and IV are deterministically linked according to their architecture, e.g., linear polymer, simply branched polymer, comb-branched polymer, dendrimer, etc. w In order to follow a path where the IV is not deterministically connected (this point is M w (This means that the orbital population of IV must be set so that it remains unchanged, and vice versa.) This can be done by adding reagents such as branching agents, capping agents, inhibitors, crosslinkers, etc. Also, by adding the comonomer supply to one control variable relative to another, it is possible to control the target orbital and simultaneously control more than two properties, e.g., M w It is possible to impose control over the IV and composition. w,inst and instantaneous IV, IV inst The instantaneous relationship between IV and RV is used to establish each target trajectory and control the process variables. Intrinsic viscosity (IV) is the limit of viscosity drop (RV) at zero polymer concentration and zero shear rate. Branching, crosslinking, and other architectural features control the high shear, non-Newtonian behavior of polymer solutions. Therefore, simultaneous measurements at low shear (resulting in an RV very close to IV) and high shear can be used as an indication of the architecture as it follows the target trajectory.

[0038] In the final mode, it may be advantageous and often necessary to reduce the monomer concentration to a very low residual value, such as 100 parts per million (ppm), regardless of how much is produced. Some products, such as human-grade acrylamide-based polymers, require 10 ppm or less of residual monomer, and for some very demanding applications, such as electronic and optical coatings, the required amount may be less than 1 ppm. To achieve low ppm, it may be sufficient to simply maintain the reaction conditions the same as in the final mode and monitor the monomer depletion to the ppm setpoint. Alternatively, adding more initiator and / or increasing the temperature may allow the reaction to reach the ppm setpoint more quickly.

[0039] It may be desirable to modify the polymer at some stage before continuing with the next mode of synthesis or as a final step. Modifications can be of many types, including but not limited to sulfonation, amination, PEGylation, acid or base hydrolysis, carbonation, hydroxylation, quaternization, and phosphorylation. Modifications can be carried out using active control until the desired stage of modification is reached and the next mode of synthesis can begin.

[0040] An example is the hydrolysis of polyacrylamide with NaOH to produce a charged polymer with the charged moiety COO-, i.e., a polyelectrolyte. The amount of NaOH, temperature, and time of hydrolysis determine which portion of the monomers in the chain are modified to COO-. Conductivity, viscosity, and light scattering all show significant changes as the charge of the modifying polymer increases, and active control can be used to vary the modification conditions to optimize the target modification properties. Once the modification is complete, the next mode can be produced. An example is the continued synthesis of a neutral polymer, such as polyvinylpyrrolidone or polyacrylamide, thereby producing a blend of the polyelectrolyte and the neutral polymer.

[0041] An additional mode that may be added includes multimodal polymers produced by controlled radical polymerization. In controlled radical polymerization, molecular weight is frequently controlled by the ratio of monomer to CRP agent (e.g., RAFT agent). In this case, molecular weight only needs to be monitored, not actively controlled, provided the desired molecular weight path is not violated. In contrast, composition can be actively controlled by comonomer feed. This forms an interesting class of multimodal polymers, as each final polymer chain can have a multimodal signature imbued into the chain by various process steps. This results in multicomponent chains, sometimes referred to as "gradient copolymers." However, the present invention does not require the creation of a gradient by passively introducing different concentrations of two or more comonomers, with the natural reactivity ratio determining the composition gradient. Rather, according to the present disclosure, it is possible to arbitrarily impart specific compositions along a polymer by actively controlling the comonomer feed. Thus, while this does not necessarily result in a smooth "gradient," it can produce segments along a polymer chain of specific composition with sharp transitions between various desired composition sequences. In this example, the polymer itself is multimodal, whereas in free radical polymerization there is a blend of subpopulations of polymers, each with its own properties.

[0042] Another example of a multimodal polymer is a multimodal stimulus-responsive polymer produced by controlled radical polymerization. Regarding this last example, a class of polymers that can result from CRP and related methods are stimulus-responsive polymers, sometimes referred to as "smart materials." These are characterized by specific copolymer compositions, often achieved by producing polymers of specific architectures, frequently more complex than simple linear chains. Such architectures can include cyclic polymers, stars, dendrimers, and cavitands. The present invention actively controls composition and monitors molecular weight to ensure desired composition and molecular weight characteristics are achieved within the desired architectural framework.

[0043] Control variables include, but are not limited to, monomers, comonomers, initiators, quenchers, chain transfer agents, redox reagents, branching agents, crosslinking agents, agents that serve both branching and crosslinking, inert gases, e.g., N2, O2, and other gases that affect free radical reactions, as well as changes in temperature and the addition of agitation. Control schemes for each of these can be developed.

[0044] According to the present disclosure, but not limited to, M w A method for active control of polymerization is provided. The method can include a control element that is based on two basic principles or can include any detailed kinetic or inferential model with many parameters. The free radical polymerization of acrylamide (Am) combined with the ACOMP system (automated, continuous, online monitoring of the polymerization reaction) and both manual and fully automated active control were used to validate the control element comprising the two basic principles.

[0045] Instantaneous kinetic mass of the chain M v is the concentration of the monomer, C m is proportional to the instantaneous weight average molecular weight M w,inst is the kinetic mass M v is proportional to. TIFF2026001067000004.tif1263(3)

[0046] The proportionality constant, p, encompasses all the complex parameters that make up the relationship in Equation 3 without the need to explicitly know any of them. For example, in a typical standard free radical kinetic model, p is given by: TIFF2026001067000005.tif2165 (4)

[0047] In the formula, k p is the propagation constant, k tis the termination constant, k3 is the chain transfer constant, [R] is the free radical concentration, [CTA] is the concentration of the chain transfer agent, and d is a dimensionless constant whose order depends on how much of the termination is due to disequilibrium and how much is due to recombination and on the instantaneous relationship between the weight-average chain length and the most probable (kinetic) chain length.

[0048] Each of these parameters can be a steep function of temperature, and to further increase the complexity of p, [R] is composed of additional terms. In the quasi-steady-state approximation (QSSA) of free radical polymerization, for example, TIFF2026001067000006.tif2145 (5)

[0049] where F is the efficiency of the initiator, k d is the initiator decomposition rate constant, and [I2] is the initiator concentration. (See Dotson, N.A.; Galvan, R.; Laurence, R.L.; Tirrel, M. Polymerization Process Modelling; VCH Pub.: New York, 1996.) These can also have a steep temperature dependence, and [I2] is generally time dependent.

[0050] The rate of polymerization of the monomer is proportional to the concentration of the monomer, i.e. TIFF2026001067000007.tif1845 (6)

[0051] The proportional parameter α(t) can vary with time. For free radical polymerization, α(t) encompasses several other parameters. For example, in a typical kinetic model, TIFF2026001067000008.tif1343 (7)

[0052] where [R] can change over time due to parameter changes, e.g., changes in the parameters of Equation 5, and k pcan vary with both temperature, chain length, viscosity of the reaction environment, and other quantities.

[0053] The control elements of the present disclosure are robust because, after a hypothetical value of C(t) is used, as determined, for example, in a previously monitored batch reaction, α can be recalculated at intervals during the reaction, and the new value will encompass all parameter changes in this single experimentally measured parameter. Recalculating α(t) during the reaction also corrects for errors in the hypothetical value. In some cases, the hypothetical value is not used, and the reaction is allowed to proceed under initial conditions (e.g., temperature and reagent concentrations) until α(t) (or any other measurable parameter needed for control) is measured for the first time during the reaction.

[0054] In this particular control element, a single control variable is used, the flow rate of monomer from a concentrated monomer reservoir (51% Am) to the reactor, i.e., semi-batch operation.

[0055] This flow velocity is expressed as Q(t), which is used for automatic calculation of Q(t) and target trajectory M w, M required to trace (t) w The automatic setting of the reservoir pump to the calculated value that realizes the control of the ACOMP. The ACOMP extraction rate from the reactor is q(t), which is usually small, between 0.25 and 0.5 cm. 3 / min and is kept constant. It is treated as negligible below. This outflow from the reactor provides a continuous sample stream that is diluted and adjusted for the measurement of ACOMP. V(t) is the liquid volume of the reactor and V o is the initial volume.

[0056] Monomer concentration dC over the interval dt m The change in is given by the following formula: TIFF2026001067000009.tif1669 (8)

[0057] C m' is the concentration of monomer in the reservoir and V(t) is the volume of the reactor as a function of time.

[0058] This control element can be extended to other control variables, including but not limited to, feeding multiple monomers to simultaneously control both composition and molecular weight, feeding initiators to increase the reaction rate and decrease molecular weight, feeding inhibitors such as air or O2 to slow or stop the reaction, feeding chain transfer agents to low molecular weight, feeding surfactants to interact or encapsulate the polymer, feeding branching and crosslinking reagents, and using temperature variations.

[0059] Equation 8 is the monomer concentration C m It allows (t) to be a process characteristic under control, which can frequently be valuable in itself, and once p is introduced, M w Just one step away from control of C m,t (t) is C m (t) shows the target trajectory. At that time, the goal is to m (t) to C m,t (t) is to be made to comply with it.

[0060] This control element then limits the reaction to a finite control interval Δt i Divide into Δt i is the duration of the i-th control interval, and Δt i is very short compared to the duration of the entire reaction, allowing the changes in variables and properties to be approximated as linear over short intervals. i At the beginning of control interval i, which begins with m,t,i, is t i +Δt i From the target trajectory value at the current measurement value C m (t i ) is subtracted. TIFF2026001067000010.tif1182 (9)

[0061] In Equation 8, dt is replaced by Δt iand using Equation 9, the required flow rate Q(t i ) is calculated using the following formula: TIFF2026001067000011.tif1984 (10)

[0062] Next, the control element is t i The monomer supply pump is Q(t i )

[0063] In Equation 10, α(t i ) is the most recent value of α(t). Over any preceding time interval Δτ during the reaction, α(t i ) can be calculated. The rate at which polymer is produced is TIFF2026001067000012.tif2037 (11)

[0064] and as a result, by mass balance, the concentration of polymer at any time is TIFF2026001067000013.tif1795 (12)

[0065] In the formula, C m,o is the initial amount of monomer in the reactor. C m (t) is measured directly by ACOMP, TIFF2026001067000014.tif1018 is found by automatic integration of the pump flow rate, and V(t) is given by TIFF2026001067000015.tif1570 (13)

[0066] where q is the constant ACOMP release rate. Therefore, α(t i ) is calculated by the following formula: i can be calculated over any preceding time interval Δτ earlier than TIFF2026001067000016.tif1856 (14)

[0067] The actual value of Δτ used depends on signal / noise considerations and the value of the control interval Δt i There is no need to respond to.

[0068] Figure 1 shows an example of controlling the monomer concentration using the above method. m,t The non-monotonic trajectory for σ was chosen to strongly depart it from the simple exponential decay in the corresponding batch reaction. TIFF2026001067000017.tif12108 (15)

[0069] is used, where ω=2.5×10 -4 ×π radians / sec. The reaction was carried out at T = 55°C.

[0070] The control element results are very good, well within 2% error from the target trajectory, and in fact indistinguishable from the target trajectory during the first half of the cycle. Also shown in Figure 1 is the monomer concentration trajectory for an equivalent pure batch reaction without monomer feed.

[0071] M w To control M, it is necessary to use the proportionality parameter p(t) introduced in Eq. 3. First, w,inst or M w In the former case, the target trajectory is M w,inst,t (t). Next, M w,t (C p ) The control trajectory is calculated according to Equation 3. C p Since (t) is known, here we use M w,inst,t Expressions related to (t) are used.

[0072] Considering time t to future time Δt, M w,t (t+Δt) can be written as follows: TIFF2026001067000018.tif22108(16)

[0073] In the formula, M w,t (t+Δt) is the experimental M w,e is the value that should be at t+Δt, where M w,e (t) is the experimentally measured value from ACOMP. Expanded to first order, TIFF2026001067000019.tif18100 (17)

[0074] Then, Equation 16 can be written as: TIFF2026001067000020.tif21116 (18)

[0075] This requires some C to justify the series of truncations. p is applied after it has been accumulated, i.e., C p >>ΔC p In addition, the ACOMP light scattering detector w,e To obtain an accurate measurement of (t), a finite C p It is also necessary to accumulate

[0076] where the first integral is the target M w,t (C p ) should be t, but the target M w,t (t+Δt) is preferably achieved at t+Δt. Therefore, to achieve this, the trajectory must be corrected from t to t+Δt, and the interval is the actual experimentally measured M w,e It starts from (t). Therefore, 0~C p The first integral up to M w,e (t) is replaced by the concentration interval C p (t) to C p Average M over (t+Δt) w,inst of <M w,inst,t By calling it >, we can recall the mean theorem for the second integral in Equation 18. As a result, TIFF2026001067000021.tif17103 (19)

[0077] In the formula, ΔC p =C p (t+Δt)-C p (t) and experimental M w,t (t) by M w According to the above substitution of (t), M w,t (t) is the experimental instantaneous weighted average M w,inst,e (t) TIFF2026001067000022.tif2258 (20)

[0078] ΔC p / C p Retaining terms to first order only in gives TIFF2026001067000023.tif1799 (twenty one)

[0079] At this time, ΔM w,t (t) is M w,e (t+Δt) is M w,t M is forced to evolve over time Δt so that it is equal to (t + Δt) w is defined as the increment of TIFF2026001067000024.tif1083 (twenty two)

[0080] This allows us to rewrite equation 21 as follows: TIFF2026001067000025.tif1788 (twenty three)

[0081] spanning the interval from t to t+Δt <M w,inst,t > and the average monomer concentration <C m Using the relationship between TIFF2026001067000026.tif1171 (twenty four)

[0082] and TIFF2026001067000027.tif1163 (twenty five)

[0083] is expressed as follows: TIFF2026001067000028.tif16104(26)

[0084] and obtain the following quadratic equation: TIFF2026001067000029.tif17102 (27)

[0085] This means: TIFF2026001067000030.tif20114 (28) The solution is obtained.

[0086] This control element assumes that the control interval is short enough that the quantity changes linearly over the control interval Δt, which is much shorter than the duration of the reaction. TIFF2026001067000031.tif1772 (29)

[0087] and therefore, TIFF2026001067000032.tif1081 (30)

[0088] and C over the control interval Δt m The required change in TIFF2026001067000033.tif1067 (31)

[0089] And TIFF2026001067000034.tif1890 (32)

[0090] is used to obtain the flow rate Q(t), for which the monomer feed pump is TIFF2026001067000035.tif1678 (33)

[0091] or TIFF2026001067000036.tif1592 (34)

[0092] and in the formula <C m > comes from Equation 28.

[0093] The value of p can be recalculated over any interval Δτ before t. TIFF2026001067000037.tif1893 (35)

[0094] In the formula, ΔM w,exp (t) is M w,e (t) and M w,e (t-Δτ). TIFF2026001067000038.tif1093 (36)

[0095] Figure 2 shows the M w,t The target trajectory of (t) is shown, increasing linearly with time with a slope of 50.0 g / mol-s. To verify the robustness of the control elements, the temperature was increased stepwise from 45 °C to 57 °C during the reaction. p and α were recalculated to obtain the linear M w,t As can be seen by the dark black dots across (t), excellent performance of the control element was obtained. The automatically calculated value of α was 1.0×10 -4 s -1 ~2.5×10 -4 s -1 and p is in the range of 4.0 × 10 7 ~9.0×10 7 These data demonstrate how the control elements continue to function even when the reactor temperature changes significantly during the reaction, without the need for detailed kinetic models.

[0096] According to at least one aspect of the present disclosure, a method for active composition and molecular weight control during free radical polymerization is provided. The method includes a control element that extends the approach of the molecular weight homopolymerization control element described above to control the composition of comonomers A and B during free radical copolymerization using the ACOMP platform. This therefore allows for simultaneous control of molecular weight and copolymer composition. Therefore, any M in each mode can be controlled. w The properties and compositional characteristics can be specified. For example, but not by way of limitation, the first mode can have a constant M w and a constant composition, and the second mode has a different constant M w and a different constant composition, and the third mode can have yet another constant M w and composition. As another example, but not by way of limitation, any mode may have a constant M w It is possible to increase, decrease, or maintain a constant composition of that mode while increasing, decreasing, or maintaining the ratio of the modal composition of the modal composition, and similarly for two or more subsequent modes. The model-agnostic approach described above does not require, but is not limited to, a kinetic model or kinetic model parameters such as reaction rate ratios. It is also possible to use control elements incorporating kinetic models at any level of complexity deemed most appropriate for a given application in generating multimodal polymers.

[0097] Of particular note, composition control applies equally well to living reactions, such as controlled radical polymerization (RADT, ATRP, NMP, ROMP, etc.). The difference between free radical and living copolymerizations in the generation of composition distributions is as follows: In free radical polymerization, polymer chains initiate, propagate, and terminate very rapidly compared to the overall length of the reaction (e.g., within milliseconds between the generation of individual polymers in a reaction lasting tens of minutes). Therefore, the controlling factor generates a distribution of chains with various compositions. In the living case, each growing polymer ideally continues to grow until all monomers are consumed or the reaction otherwise terminates. Therefore, a composition trajectory is generated along the length of each chain; that is, a composition gradient exists along each individual chain. Controlling the latter allows for the generation of materials with significantly different properties, since the manner in which two or more comonomers interact along the chain can result in many different types of conformations, phases, and morphologies.

[0098] For the homopolymer case described above, a single rate constant α and a molecular weight proportionality constant ρ are required, each of which can be recalculated during the reaction. To extend this to copolymer systems, the rate α A and α B Introducing the formula, the amounts of A and B converted to polymer over the interval Δt are: TIFF2026001067000039.tif3036 (37a, b)

[0099] In the formula, A and B represent the concentrations of monomers A and B. A and α B may change throughout the reaction and should therefore be recalculated during the reaction, but α A and α BIt has been found that in some cases, the ρ remains constant (see AM Alb, P. Enohnyaket, R. Shunmugam, GN Tew, WF Reed, "Quantitative contrasts in the copolymerization of acrylate and methacrylate monomers", Macromolecules, 39, 8283-8292, 2006).

[0100] Monomer concentration and instantaneous molecular weight M w,inst The question of the relationship between p and p can be more complicated. For homopolymers, the proportionality constant collapses all the underlying rates and parameters into a single, recalculatable constant, p. TIFF2026001067000040.tif1343 (38)

[0101] where m is the monomer concentration.

[0102] For copolymers, the total monomer concentration m is TIFF2026001067000041.tif1137 (39) is obtained by

[0103] Equation 38 holds over any relatively short interval, but now the dependency of p is extended to implicitly include any underlying relative reactivity and ratio A / B. Since the values ​​of A and B are only known up to their ratio A / B at any time for a given target trajectory, the sum of Equation 44 can have any value of m. Using Equation 38 and the value of p at any time during the reaction, M w,inst can be identified, which fixes the value of m at that time and specifies the set of three variables A, B, and m, and thus the target trajectory M w,inst can be defined simultaneously with the target composition trajectory.

[0104] Since p(A,B) can be measured throughout the reaction, simultaneous control of composition and molecular weight is possible. If the comonomers in the copolymer have significantly different dn / dc in the solvent used, when there is a significant range in the composition distribution, the M of the copolymer can be measured by light scattering. w Note that the calculation of becomes much more complex. This problem has been solved using ACOMP, but requires a specific implementation. (See P. Enohnyaket, T. Kreft, AM Alb, M. Drenski, WF Reed, “Determination of molecular mass during online monitoring of copolymerization reactions”, Macromolecules, 40, 8040-8049, 2007.)

[0105] The control element of this disclosure relies on feeding separate semi-batches of comonomer to the reactor. There are two reservoirs, one at concentration C A one for monomer A at concentration C B The flow rates from reservoirs A and B can be controlled independently, and at any time t, each has a flow rate Q A (t) and Q B The control element aims to control the required flow rate Q throughout the reaction. A (t) and Q B (t) is automatically calculated and adjusted. A (t) and Q B The solution to (t) can be found by the following expansion:

[0106] According to at least one embodiment of the present disclosure, cumulative and instantaneous fractional composition may be required control elements. The primary quantities that the ACOMP system measures in terms of conversion are the concentrations of each monomer, A and B. The polymer forms A at any point in the reaction. p and B p Each model The amount of monomer can be found from a mass balance using the following formula: TIFF2026001067000042.tif2046 (40a, b)

[0107] The cumulative fraction of polymer consisting of A is f A and the cumulative fraction of B is f B is. TIFF2026001067000043.tif3651 (41a, b)

[0108] In the formula, f A (t)+f B (t)=1 and the total concentration of polymer is: TIFF2026001067000044.tif1139 (42)

[0109] The most probable fraction of A instantaneous in a polymer chain generated at any time t is: TIFF2026001067000045.tif1755 (43)

[0110] dA p =-dA=α A Since Adt, F A teeth, TIFF2026001067000046.tif1845 (44) It can be written as:

[0111] Equation 44 not only determines the consumption of each comonomer but also the most probable composition F A Since we also need α A and α B F B =1-F A Therefore, F A It is sufficient to focus on finding and controlling F B Therefore, the controlling factor for the composition is the α measured during the reaction. A and α BIt is possible to base this directly on the value of F. Naturally, there is a distribution of compositions around the most probable value. Here, F A The most likely instantaneous value of F will be referred to as the "mean value of the composition." Model distributions were previously used in ACOMP to create a complete composition distribution from the most likely values. Thus, F A Based on the measured values ​​and any suitable composition distribution model, the complete composition distribution can be generated online in real time (see A. Giz, A. Oncul Koc, H. Giz, A. M. Alb, W. F. Reed, "Online monitoring of reactivity ratios, composition, sequence length, and molecular weight distributions during free radical copolymerization," Macromolecules, 35, 6557-6571, 2002).

[0112] In at least some instances, the control element may be configured to control the target composition trajectory f A,t (t) and the target total monomer trajectory m t (t). Together with the measurement of Equation 38 and p, the target M w The trajectory can be followed simultaneously with the target composition trajectory. The control element is the final composition distribution C(F A ), where C(F A )dF A is F A From F A +dF A Monomers A and F in the section up to A is the concentration of chains with fractional composition of . The average of the instantaneous values ​​F A With regard to, it becomes as follows: TIFF2026001067000047.tif2275 (45)

[0113] From this, apart from Equation 44, f A (t), A p , and C pDirect F from ACOMP measurements A (t) can also be calculated. TIFF2026001067000048.tif1840 (46)

[0114] Operationally, C(F A ) is established offline by an optimization program, e.g., gPROMS, and the desired pathway f A,t (t) is established. This means that t, A, and C p Since all are recognized at the same time as ACOMP, f A (A) or f A (C p ) can also be expressed as

[0115] compositional orbital f A (t) is defined as the total monomer concentration m t The basis for this is to determine the rate and amount of comonomer produced, and to map the desired or theoretical molecular weight trajectory to M if p(A / B) is known or approximate. w,t (t) can be established. In this latter case, it is therefore possible to simultaneously control both the composition and molecular weight trajectories (this latter via Eq. 38). Furthermore, α can be remeasured as frequently as necessary during the reaction. A and α B The value of F in Equation 44 A can be used to directly determine , thus enabling the desired target composition trajectory to be followed.

[0116] In further detail, a control interval is set such that the values ​​of the trajectory at Δt and t+Δt are as follows: TIFF2026001067000049.tif2170 (47)

[0117] This is ΔC p Expanding this to first order gives us the following equation: TIFF2026001067000050.tif2185 (48)

[0118] Using the mean theorem, the second integral is F over the period t to t+Δt. A Regarding the average value of <F A > TIFF2026001067000051.tif1457 (49)

[0119] Therefore, ΔC p To first order, we have TIFF2026001067000052.tif1678 (50)

[0120] Control increment Δf A (t) is f at t+Δt A The desired value of and the actual measured value at time t A (t) is the difference between TIFF2026001067000053.tif1066 (51)

[0121] and therefore, TIFF2026001067000054.tif1671 (52)

[0122] and using equations 37a and 37b we get: TIFF2026001067000055.tif1796 (53)

[0123] Therefore, the important control parameters <F A > is a directly measurable quantity and the required control increment Δf A This can be seen from the combination with (t).

[0124] The control interval Δt is then taken to be short enough so that the change in quantity is linear over the interval, so that: TIFF2026001067000056.tif1457 (54)

[0125] This determines which F to use to follow the target trajectory. A A condition arises to find whether (t+Δt) is necessary. TIFF2026001067000057.tif966 (55)

[0126] In the formula, F A (t) is known at t according to Equation 49. F A (t+Δt) can be written as follows: TIFF2026001067000058.tif1687 (56)

[0127] The total monomer trajectory can be used to express ΔB as follows: TIFF2026001067000059.tif841 (57)

[0128] where Δm is the desired total monomer trajectory m t (t) is the difference in total monomer concentration from t to t + Δt. TIFF2026001067000060.tif960 (58)

[0129] Substituting this into Equation 57, solving for ΔA, and simplifying yields: TIFF2026001067000061.tif1584 (59a)

[0130] A similar procedure is used to obtain ΔB. TIFF2026001067000062.tif1584 (59b)

[0131] The total change ΔA over Δt is then due to the loss of A due to polymerization over Δt and the amount of A pumped over Δt, TIFF2026001067000063.tif1767 (60)

[0132] This automatically reduces the pump speed Q A After setting (t), the desired result is obtained. TIFF2026001067000064.tif1655 (61a)

[0133] Similarly, the pump rate Q from the monomer B reservoir B (t) is as follows: TIFF2026001067000065.tif1657 (61b)

[0134] V(t) is the volume of the reactor at time t, calculated taking into account both the fluid inflow from reservoirs A and B and the outflow from the ACOMP recovery q. TIFF2026001067000066.tif1393 (62)

[0135] where V0 is the initial volume of the reactor.

[0136] Composition, f A,t (t), and the total monomer concentration m t The desired target trajectory for (t) should be established and implemented offline. Alternatively, simultaneous composition and M w,inst,t To achieve control, the composition and M w,inst The target trajectory of M is determined offline. w,inst,t At the beginning of the control interval t, the following characteristics are measured to determine the control elements A(t), B(t), M w (t). The control element sends its latest value α A and α B Calculate the amounts of A and B using

[0137] This process can be extended to copolymers with three of the comonomers. For example, a terpolymer contains three comonomers A, B, and C, each f A , f B , and f C The cumulative fractional composition of is found by successive measurements of concentrations A(t), B(t), and C(t). The latter time-dependent concentrations can also be calculated for any time interval α A (t), α B (t), and α C Over time (t), the corresponding rate constants are generated. A (t), F B (t), and F C (t) is calculated at any time t by the following equation, similar to equation 49: TIFF2026001067000067.tif1694 (63)

[0138] Also, F B (t), and F C The same applies to (t), and the normalization condition is F A (t)=1-F B (t)-F C (t). In such a case, p can be measured and m(t) = A(t) + B(t) + C(t), so M w,inst Simultaneous control of (t) can also be achieved by Equation 49. This procedure is w,inst With control, it can be extended to any number N of comonomers.

[0139] The previously outlined approach to composition control involves the target composition trajectory F according to Eq. A,t and α A and α B F calculated directly from measurements of A,t Note that this can be rationalized by using the measurements of and.

[0140] Example 1 - Multimodal Polymer: Bimodal MWD for Polyacrylamide An example of the actively controlled production of trimodal polymers is the M mentioned above, with the automatic addition of a chain transfer agent (CTA), sodium formate. w This involves the free radical polymerization of Am using a control element, leading to the production of a low molecular weight population in the second stage of the reaction, and an even lower molecular weight population in the third stage. w (C p ) and M w,inst (C p ) are shown along with the points where two additions of CTA were made. w,inst decreases sharply.

[0141] The inset in Figure 4 shows the M obtained from Figure 3. w,inst A histogram of the values ​​is shown, and the main graph in Figure 4 shows the MWD calculated from this histogram using a log-normal distribution of the form TIFF2026001067000068.tif1699 (64)

[0142] It is fully characterized by the most probable (peak) molecular weight M0 and the width σ of the MWD. n , M w , and M z The value of is related to these two parameters by the following equation: TIFF2026001067000069.tif2934 (65)

[0143] M w / M n For an expected instantaneous MWD width of σ = 2, 2 = In(2) = 0.6931, which gives the instantaneous M o M w,inst It becomes possible to correlate with TIFF2026001067000070.tif1049 (66)

[0144] A portion of the 14 instantaneous MWDs are shown in Figure 4 along with the sum of all 14 instantaneous MWDs. The net result is bimodal (the MWD resulting from the two additions of CTAs seen in Figure 3). w The effect of the reduction in smears out together in the single low-mass mode in Fig. 4).

[0145] Another example similar to the above is shown in Figure 5, where CTA was added only once and bimodality was measured by gel permeation chromatography (GPC). w increases for the first 40% of the reaction, at which point CTA is added, and then M w In contrast, M w,inst is 10 for the first 40% 6 g / mol, and then after the addition of CTA, the 6 During the first 40%, the automatic control element adjusts M to keep it constant at this value. w,inst The CTA was then automatically injected at 40% and then M was administered for the remaining 60% of the response. w,inst was kept constant.

[0146] Figure 6 also shows M w / M n Using =2, M in Figure 5 w,inst Figure 6 also shows the PEO equivalent MWD determined by GPC. To this end, a Shimadzu chromatographic refractive index detector was used to measure the concentration of polymer eluting from a Polymer Standard Services (Amherst, MA) Linear XL column, and a Shimadzu high-pressure liquid chromatography pump was used to drive the GPC flow. The column was calibrated using poly(ethylene oxide), PEO, molecular weight standards provided by Polymer Standard Services.

[0147] The agreement between the calculated MWD and the MWD measured by GPC is good, and the following points must be considered: (1) The PEO standard only measures the "PEO equivalent" mass in pAm, not the absolute molecular weight. In contrast, the M w and M w (2) The molecular weight used to calculate M is from light scattering, which is an absolute method that does not rely on calibration with standards; (3) GPC resolution is not perfect and depends heavily on column details, injection concentration, etc. Columns with better molecular weight resolution may exhibit a deeper trough between the high and low molecular weight modes. This can be seen, for example, in the calculation of MWD in Figure 6; (4) ACOMP to M w,inst Since obtaining MWD is not yet an exact science, there will always be some error in the calculated MWD; (5)M w / M n A log-normal distribution with σ = 2 underlies the calculation of MWD.

[0148] Figure 7 shows another example of synthesizing a trimodal molecular weight polymer to automatically produce approximately equal concentrations of each of the three MWD modes in the final product. w is controlled by adding Am from the reservoir to the reactor, and in the following two MWD modes, M w,inst Two automatic additions of CTA were added to reduce the mass of the final product. w The cumulative weight average molecular weight M w shows only a measurable discontinuity whenever CTA is automatically added, while M w,inst The value of decreases sharply. The first mode M w,inst So it's about 1.5 x 10 6 g / mol and 2×10 for the second mode. 5 g / mol, and the third mode is 4 × 10 4g / mol. Thus, the final product contains polymeric MWD modes separated in their peak molecular weights by a factor of 75.

[0149] Figure 8 shows the M w / M n The calculated MWD using a log-normal distribution with =2, and the M of the final product w,inst Figure 7 shows the GPC-based MWD of the resulting trimodal polymer final product, along with the spectrum of σ (the smoother of the two curves). While the MWDs generated by each method are in good agreement, neither method can resolve all three MWDs. This is due to the fact that, even with well-separated mode peaks, the distributions are so broad and overlap with each other that resolution of all three modes is prevented. (A similar situation occurs in diffraction, for example, in the so-called "Rayleigh criterion," where two separate, overlapping light intensity distributions cannot be resolved from each other until a certain minimum angular separation between their sources is met.) The fact that the online ACOMP method of determining MWD (Figure 7) shows all three MWD modes without relying on physical separation, such as GPC, demonstrates the power of the ACOMP method and its ability to resolve the multimodal populations generated by the disclosed method.

[0150] Example 2 - Apparatus for generating multimodal populations An apparatus capable of producing modified (or multistage) and multimodal polymers was built by Advanced Polymer Monitoring Technologies, Inc. (New Orleans, Louisiana). The apparatus included an ACOMP system and control interface. Operators interacted with the ACOMP / CI system through a custom-designed human-machine interface (HMI) built using the Rockwell Factory Talk View SE environment of Logix5000 programming software. This interfaced with all ACOMP hardware through a Rockwell Control Logix PLC. All sensor and detector signals were compiled locally into Rockwell database tables and then sent to the ACOMP Analysis package via an Open Platform Communications gateway (OPC). The ACOMP Analysis software was written in C++, and it interpreted all appropriate sensor and detector signals for characterization of reaction and polymer properties. The ACOMP Controller software, which received online analytical data and sent control signals to adjust various process variables, was developed in Python 3.5 and also communicated with Rockwell Automation via the OPC gateway. In this application, the control element regulated the flow rate of Am from the enrichment reservoir to the reactor.

[0151] 9 illustrates an exemplary ACOMP system and method in accordance with at least an exemplary embodiment of the present disclosure. The sample was measured between 0.25 and 0.50 cm depending on the experiment. 3The sample was continuously extracted from the reactor recirculation loop by an extraction pump at a rate of 1 / min, immediately quenched with solvent (distilled water in these experiments) from a solvent pump, diluted 80-fold, and homogenized in a mixing chamber, from which the sample flowed through a four-wavelength UV / Vis 159 detector by Gilson (Middelton, WI), which continuously monitored the monomer absorption during polymerization. Polymer conversion was calculated using a wavelength of 245 nm. After flowing past the UV / Vis detector, a fraction of the sample stream was diverted by an isocratic pump to achieve continuous, pulse-free flow through the remaining detector array, which included a custom-built multi-angle laser light scattering (MALS) detector at four angles: 65°, 90°, 115°, and 130°, and a custom-built single capillary viscometer. Based on the reaction and polymer properties determined by the ACOMP / CI, the reactor temperature, nitrogen, and monomer or initiator feeds could be adjusted to control the desired aspect of the polymerization. In this study, total C m and M w The trajectory of C is controlled by manual active control using temperature and initiator flow in batch mode. m and M w Fully automatic active control of the monomer flow was achieved in semi-batch mode. There are many other specific embodiments for the ACOMP system beyond that shown in Figure 9. ACOMP systems with other configurations are within the spirit and scope of the present disclosure.

[0152] The delay from the reactor to the first detector, the UV detector, was 85 seconds. To account for this delay in the control calculations, a forward linear regression was performed from 30 seconds ago to the current real-time instant t, C m was used for.

[0153] Monomer and polymer concentration, viscosity reduction, η r , M w and rotation 2 ​The use of UV absorbance, viscosity, and MALS to calculate the z-average root mean square radius >z has been detailed in a previous ACOMP publication. For the latter, the usual Zimm equation was used, where IR(θ) is the excess Rayleigh scattering ratio from the polymer solution at scattering angle θ, and TIFF2026001067000071.tif1674 (67)

[0154] In the formula, C p is the polymer concentration and q s is the magnitude of the scattering vector: TIFF2026001067000072.tif1437 (68)

[0155] K is an optical constant given for vertically polarized incident light by: TIFF2026001067000073.tif1853 (69)

[0156] In the formula, dn / dC p is the differential refractive index of the polymer in a solvent of refractive index n, and N A is Avogadro's number, and λ is the vacuum wavelength of the incident laser. For Am in water, dn / dc=0.181 cm 3 / g, with n = 1.333 and λ = 660 nm from a 35 mW Laser Max linearly polarized miniature diode laser. (See Zimm, B.H. The Scattering of Light and the Radial Distribution Function of High Polymer Solutions. J. Chem. Phys. 1948, 16, 1093-1099; Zimm, B.H. Apparatus and Methods for Measurement and Interpretation of the Angular Variation of Light Scattering; Preliminary Results on Polystyrene Solutions. J. Chem. Phys. 1948, 16, 1099-1115).

[0157] In Equation 67, A2 is the composite average of the second virial coefficients. For the polyacrylamide final product, it is 3.29 x 10 -4 cm 3 -mol / g 2 + / - 20%, M w The maximum concentration of pAm in the detector column was 4 × 10 -4 g / cm 3 This is the estimated value of M w is about 10 6 For g / mol values, 2A2M w About C p This leads to a correction factor in Equation 72 of approximately 0.26. With a 20% error bar in A2, this is due to the Mw at the highest concentration and the high M w This results in a maximum systematic error of about 5%.

[0158] Example 3 - Manual Active Control Example Both manual active control and automatic control have been implemented with the APMT ACOMP / CI system. m,t (t) or M w,tA target trajectory of (t) was established, and an operator manually manipulated the controlled variables to follow the target trajectory. This may be useful in R&D labs or manufacturing facilities where it may be desirable to maintain human operator involvement for safety or other reasons. This also illustrates the use of temperature and initiator as controlled variables, which are not addressed in the fully automated version above.

[0159] FIG. 10 shows the target trajectory for the Am free radical polymerization of 30 g of Am with 0.45 g / L of KPS in a 1 L reactor, where the fractional conversion of Am, C m (t) / C m,o is the target trajectory, where C m,o is the starting concentration of Am. The target trajectory was obtained by increasing the reactor temperature stepwise from 45 °C to 62 °C over approximately 8,000 seconds. The subsequent reaction was followed by the control trajectory C. m (t) / C mo The objective was to follow the model pathway, which was carried out isothermally at 45°C, with initiator added via a pump whose flow rate was controlled at the discretion of the operator. The operator managed to control the monomer concentration (expressed as fractional conversion) to within 3% of the model pathway. These two reactions can be called an "isomorphic reaction pair" with respect to temperature and initiator conversion. "Isomorphic" indicates that the trajectories are (essentially) the same, but that temperature and initiator are two different control variables for reaching the same trajectory.

[0160] Figure 11 shows the M w The control trajectory is the M generated from the step-temperature model reaction in Figure 10. w The second reaction, intended to follow the first, was isothermal, held at 45°C, with initiator flow at the operator's discretion. Figure 11 shows that the latter trajectory follows within 10% of the control trajectory, indicated by the gray shaded area.

[0161] The monomer concentration pathway in Figure 8 is based on basic kinetic considerations, as M wNote that this does not lead to an isomorphic reaction pair at C m is the same in both reactions, then according to equation 3 (where [CTA]=0), p is the same for both, which means that k p / k t M if and only if [R] is the same for both w is required to be the same for both. However, as T increases, [R] decreases with the k d increases rapidly due to the exponential dependence of k on temperature. p and k t Because is temperature dependent, p cannot be the same for the isothermal and temperature-graded reactions, and therefore separate control reactions were required to produce the results in Figure 11 .

[0162] According to at least one embodiment of the present disclosure, the above techniques and methods can be used in the system and apparatus shown in FIG. 12 or any portion thereof. As shown in FIG. 12, pump 200 is capable of handling high viscosities. Pump 200 can be a gear, screw, or lobe pump. For moderate viscosities, a peristaltic pump can also be used. Pump 200 extracts reactor fluid (having a solute concentration Cr) from reactor 201 via inlet line 202 at a flow rate Qr. The majority of this flow is recycled to reactor 201 via recycle line 204, while a desired fraction is fed to mixing chamber 208 via outlet 206 and / or flow divider 210 at an average flow rate Qc. Flow divider 210 can be either active or passive. A passive type can simply be a "Y" where the length and inner diameter of the capillary tube from the "Y" back to the reactor and into mixing chamber 208 controls the division of the fluid flow. Active flow diverter 210 may be a three-way solenoid valve that normally returns flow to the reactor but can be actuated by a programmable logic control element (PLC) 212 or similar electronic device to periodically divert flow to mixing chamber 208 to achieve an average Qc. Pump 214 draws solvent from solvent reservoir 215 at a rate Qs1 and delivers it via outlet 218 to mixing chamber 208 where both the reactor fluid and solvent are mixed, resulting in the following concentrations: TIFF2026001067000074.tif1851(74)

[0163] At this point, the single-stage mixer simply delivers fluid at concentration Cc to detector column 240 via line 222 and pump 220 at a flow rate Qp2. In a two-stage diluter, the secondary stage S of the compound includes an additional pump 226 that pumps solvent from solvent reservoir 215 at a rate Qs2 via line 228. The liquid streams from the outlets (224 and 230, respectively) of pumps 220 and 226 are mixed in, for example, an ultra-small volume, microbore, high-pressure "T" mixer 232 (e.g., Upchurch, Inc.) or other passive or active mixing device. Thus, the flow rate from mixer 232 to detector column 240 via line 234 is Q=Qs2+Qp2, and the concentration of solute reaching detector column 240 is TIFF2026001067000075.tif1951 (75) is.

[0164] In this embodiment, detector array 240 consists of a single or multi-angle light scattering detector 242 (LS), a refractometer 244 (RI), a viscometer 246 (V), and an ultraviolet / visible spectrophotometer 248 (UV). Other types and combinations of detectors are possible. For example, one or more of these measurement devices can be omitted. Fluid exiting detector array 240 passes to waste container 249.

[0165] The non-recirculating embodiment just withdraws reactor fluid at rate Qc and feeds the mixing chamber 208 directly. All other flow rates and concentrations remain as above. The main difference with this approach is the longer delay between sampling the fluid element and its measurement by the detector array.

[0166] An active mixing element 250 in the mixing chamber 208, e.g., a rotary vane rotated by a small motor, is shown in Figure 12. For low-viscosity fluids, a passive element can be substituted. The mixing chamber 208 is typically vented to the atmosphere to expel any air bubbles coming from the reactor and prevent them from being drawn into the detector flow. An active or passive overflow 252(O) and / or a level sensor are preferably included in the system (see Figure 12). In the latter case, the level sensor cooperates with the PLC 212 to control the active flow diverter 210. In this case, a solvent recirculation loop may be introduced, whereby a second active flow diverter, also operated by the PLC 212, periodically delivers the desired average flow Qs1. In the case of an active overflow without a level sensor, a fixed volume of mixed fluid from the mixing chamber 208 is pumped out by another low-viscosity pump at a rate Qw, such that Qw + Qp2 = Qc + Qs1. The volume V of fluid in the mixing chamber 208, together with the combined flow rates Qs1+Qc, is determined by the mean residence time t of the fluid elements in the mixing chamber according to: r (hence, the chamber's reaction time). TIFF2026001067000076.tif2764 (76)

[0167] t r sets a lower limit for the time it takes for a reaction to develop that can still be monitored by ACOMP. Typically, t r is on the order of tens to hundreds of seconds. When the mixing chamber 208 is pulsed by the active shunt 204(s) for a period of Δt, the mixing chamber 208 r >>Δt, facilitating separate injection of reactor fluids and / or solvents. Commercially available solenoid-type flow dividers typically have response times on the order of milliseconds or tens of milliseconds, so meeting the latter criterion is not difficult, and thus the total solute concentration in the mixing chamber 208 can be maintained constant, so that the detector signal does not exhibit peaks or pulsations due to concentration fluctuations in the mixing chamber 208.

[0168] Pumps 214, 220, 226 do not need to pump highly viscous liquids, and pump 200 is the only high-viscosity pump in this embodiment. Because mixing chamber 208 is vented to atmosphere, pump 214 does not need to operate against any significant backpressure, so very inexpensive peristaltic, piston, diaphragm, or other types of pumps can be used. Pumps 220, 226 must be capable of pumping the low-viscosity sample fluids to be mixed against the backpressure of detector column 240, typically on the order of 20 psi to 1000 psi. Many commercially available piston pumps exist for this application.

[0169] 12, conditioning module 256 is in line with outlet 206 of pump 200. Conditioning module 256 can perform functions such as heating the reactor fluid to evaporate solvent and / or monomer, or filtering the reactor fluid. Conditioning module 256 can also be located elsewhere on the diagram, such as at outlet 218 of mixing chamber 208.

[0170] Incorporated Statement of the Disclosure Statement 1: A method for producing a multimodal polymer in a single reaction vessel, the method comprising: conducting a polymer reaction in the reaction vessel in at least two stages to produce a multimodal polymer; monitoring at least one reaction characteristic in at least one stage; and actively controlling modal evolution during said production of a polymer in at least one of said at least two stages by modifying at least one process control variable based on said at least one monitored reaction characteristic.

[0171] Statement 2: The method of statement 1, further comprising determining a reaction trajectory based on the at least one monitored reaction characteristic, wherein the process control variable is modified based on the determination of the reaction trajectory to follow a target trajectory.

[0172] Statement 3: The method of statement 1 or statement 2, further comprising: determining an optimal crossover second target trajectory associated with switching of a continuous reactor from the evolution of a first mode to a second mode; and actively controlling the evolution of the second mode by modifying at least one process control variable, wherein the process control variable is modified based on the second target trajectory.

[0173] Statement 4: The method of statement 2 or statement 3, wherein the reaction property on which the target trajectory is based is molecular weight.

[0174] Statement 5: The method of statement 2 or statement 3, wherein the reaction property on which the target trajectory is based is the composition of the copolymer.

[0175] Statement 6: The method of statement 2 or statement 3, wherein the reaction property on which the target trajectory is based is intrinsic viscosity (IV).

[0176] Statement 7: The method of any one of the preceding statements 2-6, further comprising simultaneously determining a plurality of reaction trajectories, each of the plurality of reaction trajectories being based on at least one monitored reaction characteristic.

[0177] Statement 8: The method of any one of the preceding statements 2-7, further comprising modifying one or more process control variables based on the plurality of reaction trajectories so that the trajectories of multiple monitored reaction characteristics are simultaneously controlled.

[0178] Statement 9: The multiple simultaneously controlled trajectories are M w 9. The method of any one of the preceding statements 2 to 8, wherein the viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution are selected from the group consisting of: viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0179] Statement 10: The method of any one of the preceding statements 1-9, wherein actively controlling includes automatic active control.

[0180] Statement 11: The method of any one of the preceding statements 1-10, wherein actively controlling includes manual active control.

[0181] Statement 12: The method of any one of the preceding statements 1-11, wherein actively controlling includes computationally assisted active control.

[0182] Statement 13: The method of any one of the preceding statements 1-12, wherein at least one or more of the at least two stages comprises a form of controlled radical polymerization.

[0183] Statement 14: The method of any one of the preceding statements 1-13, wherein the multimodal polymer comprises a multimodal stimuli-responsive polymer.

[0184] Statement 15: The characteristics of the modes are w 15. The method of any one of the preceding statements 1 to 14, wherein the effect of the polymerization on the polymerization is selected from the group consisting of viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0185] Statement 16: The method of any one of the preceding statements 1-15, wherein said monitoring at least one reaction property comprises measuring at least one selected from the group consisting of Raman scattering, infrared spectroscopy, refractive index, ultraviolet absorption, conductivity, optical activity, circular dichroism, circular birefringence, NMR, total intensity light scattering, multi-angle total intensity light scattering, dynamic light scattering, capillary viscometry, and simultaneous measurement of low and high shear viscosity.

[0186] Statement 17: The method of any one of the preceding statements 1-16, wherein the reaction characteristic is the conversion of comonomer monitored by a Raman scattering or infrared spectroscopy probe of the reaction vessel.

[0187] Statement 18: The method of any one of the preceding statements 1-17, wherein the reaction characteristic is molecular weight monitored by total intensity light scattering or multi-angle total intensity light scattering.

[0188] Statement 19: The method of any one of the preceding statements 1-18, wherein the reaction characteristic is intrinsic viscosity (IV) monitored by a capillary viscometer.

[0189] Statement 20: The method of any one of the preceding statements 1-19, wherein the reaction characteristic is a branch monitored by simultaneous measurement of low and high shear viscosity.

[0190] Statement 21: The reaction characteristic is M w 21. The method of any one of the preceding statements 1-20, wherein the branching is monitored by simultaneous measurement of IV and IV.

[0191] Statement 22: The method of any one of the preceding statements 1-21, wherein the process control variables are selected from the group consisting of temperature, agitation rate, mixing rate, stirring, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst.

[0192] Statement 23: The method of any one of the preceding statements 1-22, wherein monitoring at least one reaction characteristic includes taking measurements at least once every 0.1 seconds to about once every 30 seconds.

[0193] Statement 24: A method for sequentially modifying a polymer, the method comprising: conducting a polymer reaction in a reaction vessel in at least two stages to produce a modified polymer; monitoring at least one reaction characteristic in at least one stage; and actively controlling the evolution of a predetermined reaction characteristic during the production of the polymer in at least one of the at least two stages by modifying at least one process control variable based on the at least one monitored reaction characteristic.

[0194] Statement 25: The method of statement 24, further comprising determining a reaction trajectory based on the at least one monitored reaction characteristic, wherein the process control variable is modified based on the determination of the reaction trajectory.

[0195] Statement 26: The method of statement 24 or statement 25, wherein the predetermined reaction characteristic on which the target trajectory is based is molecular weight.

[0196] Statement 27: The method of statement 24 or statement 25, wherein the predetermined reaction characteristic on which the target trajectory is based is a copolymer composition.

[0197] Statement 28: The method of statement 24 or statement 25, wherein the predetermined reaction characteristic on which the target trajectory is based is intrinsic viscosity (IV).

[0198] Statement 29: The method of any one of the preceding statements 24-28, further comprising simultaneously determining a plurality of reaction trajectories, each of the plurality of reaction trajectories being based on at least one monitored reaction characteristic.

[0199] Statement 30: The method of any one of the preceding statements 24-29, further comprising modifying one or more process control variables based on the plurality of reaction trajectories so that the trajectories of multiple monitored reaction characteristics are simultaneously controlled.

[0200] Statement 31: The multiple simultaneously controlled trajectories are M w 31. The method of any one of the preceding statements 24 to 30, wherein the viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution are selected from the group consisting of: viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0201] Statement 32: The method of any one of the preceding statements 24-31, wherein actively controlling includes automatic active control.

[0202] Statement 33: The method of any one of the preceding statements 24-32, wherein actively controlling includes manual active control.

[0203] Statement 34: The method of any one of the preceding statements 24-33, wherein actively controlling includes computationally assisted active control.

[0204] Statement 35: The method of any one of the preceding statements 24-34, wherein at least one or more of the at least two stages comprises a form of controlled radical polymerization.

[0205] Statement 36: The method of any one of the preceding statements 24-35, wherein the modified polymer comprises a stimulus-responsive polymer.

[0206] Statement 37: The reaction characteristic is M w 37. The method of any one of the preceding statements 24 to 36, wherein the effect of the polymerization on the polymerization is selected from the group consisting of viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0207] Statement 38: The method of any one of the preceding statements 24-37, wherein said monitoring at least one reaction property comprises measuring at least one selected from the group consisting of Raman scattering, infrared spectroscopy, refractive index, ultraviolet absorption, conductivity, optical activity, circular dichroism, circular birefringence, NMR, total intensity light scattering, multi-angle light scattering, capillary viscometry, and simultaneous measurement of low and high shear viscosity.

[0208] Statement 39: The method of any one of the preceding statements 24 to 38, wherein the reaction characteristic on which the target trajectory is based is the comonomer conversion monitored by a Raman scattering or infrared spectroscopy probe of the reaction vessel.

[0209] Statement 40: The method of any one of the preceding statements 24-39, wherein the reaction property on which the target trajectory is based is molecular weight monitored by total intensity light scattering or multi-angle light scattering.

[0210] Statement 41: The method of any one of the preceding statements 24-40, wherein the reaction characteristic on which the target trajectory is based is intrinsic viscosity (IV) monitored by a capillary viscometer.

[0211] Statement 42: A method according to any one of the preceding statements 24 to 41, wherein the reaction characteristic on which the target trajectory is based is a branch monitored by simultaneous measurement of low and high shear viscosity.

[0212] Statement 43: The method of any one of the preceding statements 24-42, wherein the process control variables are selected from the group consisting of temperature, agitation rate, mixing rate, stirring, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst.

[0213] Statement 44: The method of any one of the preceding statements 24-43, wherein monitoring at least one reaction characteristic includes taking measurements at least once every 0.1 seconds to about once every 30 seconds.

[0214] Statement 45: The method of any one of the preceding statements 24-44, wherein the modified polymer comprises a combination of a multimodal polymer and a modified polymer.

[0215] Statement 46: The method of any one of the preceding statements 24 to 45, further comprising: determining an optimal crossover second target trajectory associated with switching of a continuous reactor from the evolution of a first mode to a second mode; and actively controlling the evolution of the second mode by modifying at least one process control variable, wherein the process control variable is modified based on the second target trajectory.

[0216] Statement 47: An apparatus comprising: a reaction vessel configured to contain a polymer solution and to cause a polymer reaction in at least two stages; one or more detectors configured to monitor at least one reaction characteristic of the polymer solution contained in the reaction vessel; and a control element coupled to the reaction vessel and the one or more detectors, the control element configured to actively control the development of a predetermined reaction characteristic by modifying at least one process control variable based on the at least one reaction characteristic monitored by the detector.

[0217] Statement 48: The apparatus of statement 47, wherein the control element further includes an interface configured to allow an operator to cause the control element to actively control the development of the predetermined response characteristic.

[0218] Statement 49: The apparatus of statement 47 or statement 48, wherein the control element is further configured to determine a reaction trajectory based on the at least one reaction characteristic monitored by the detector, and the process control variable is modified based on the determination of the reaction trajectory.

[0219] Statement 50: The apparatus of any one of the preceding statements 47-49, wherein the predetermined reaction characteristic on which the target trajectory is based is molecular weight.

[0220] Statement 51: The apparatus of any one of the preceding statements 47-49, wherein the predetermined reaction characteristic on which the target trajectory is based is a copolymer composition.

[0221] Statement 52: The apparatus of any one of the preceding statements 47-49, wherein the predetermined reaction characteristic on which the target trajectory is based is intrinsic viscosity (IV).

[0222] Statement 53: The apparatus of any one of preceding statements 47-52, wherein the control element is further configured to simultaneously determine multiple reaction trajectories, each of the multiple reaction trajectories being based on at least one monitored reaction characteristic.

[0223] Statement 54: The apparatus of any one of preceding statements 47-53, wherein the control element is further configured to modify one or more process control variables based on the plurality of reaction trajectories so that the trajectories of multiple monitored reaction characteristics are simultaneously controlled.

[0224] Statement 55: The multiple simultaneously controlled trajectories are M w 55. The apparatus of any one of the preceding statements 47-54, wherein the characteristics of the polymer are selected from the group consisting of viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0225] Statement 56: The reaction characteristic is M w 56. The apparatus of any one of the preceding statements 47-55, wherein the effects of the polymerization are selected from the group consisting of viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0226] Statement 57: The apparatus of any one of the preceding statements 47-56, wherein the one or more detectors are configured to measure at least one selected from the group consisting of Raman scattering, infrared spectroscopy, refractive index, ultraviolet absorption, conductivity, optical activity, circular dichroism, circular birefringence, NMR, total intensity light scattering, multi-angle light scattering, capillary viscometry, and simultaneous measurement of low and high shear viscosity.

[0227] Statement 58: The apparatus of any one of the preceding statements 47-57, wherein the reaction characteristic is the conversion rate of comonomer and the detector is a Raman scattering or infrared spectroscopy probe coupled to the reaction vessel.

[0228] Statement 59: The apparatus of any one of the preceding statements 47-58, wherein the reaction characteristic is molecular weight monitored by total intensity light scattering or multi-angle light scattering.

[0229] Statement 60: The apparatus of any one of the preceding statements 47-58, wherein the response characteristic is intrinsic viscosity (IV) and the detector is a capillary viscometer.

[0230] Statement 61: An apparatus according to any one of the preceding statements 47-58, wherein the reaction characteristic is monitored by simultaneous measurement of low and high shear viscosity.

[0231] Statement 62: The apparatus of any one of the preceding statements 47-61, wherein the process control variables are selected from the group consisting of temperature, agitation rate, mixing rate, agitation, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst.

[0232] Statement 63: The apparatus of any one of the preceding statements 47-62, wherein the detector is configured to take measurements at least once every 0.1 seconds to about once every 30 seconds.

[0233] Statement 64: The apparatus of any one of the preceding statements 47 to 63, wherein the detector and control element are components of an ACOMP system.

[0234] Statement 65: The apparatus described in any one of the preceding statements 47 to 64, further comprising a second reaction vessel, wherein the reaction vessel and the second reaction vessel are each configured to cause a polymer reaction in at least one of the at least two stages.

[0235] Statement 66: The apparatus of any one of the preceding statements 47-65, wherein the control element is further configured to determine an optimal crossover second target trajectory associated with switching of the continuous reactor from the evolution of a first mode to a second mode, and to actively control the evolution of the second mode by modifying at least one process control variable, wherein the process control variable is modified based on the second target trajectory.

[0236] Statement 67: A method for producing a multimodal polymer in a single reaction vessel, the method comprising: conducting a polymer reaction in a reaction vessel in at least two stages to produce a multimodal polymer; monitoring at least one reaction characteristic in at least one stage; actively controlling the evolution of a first mode by modifying at least one process control variable based on the at least one monitored reaction characteristic during the production of a polymer in at least one of the at least two stages; determining a reaction trajectory based on the at least one monitored reaction characteristic, wherein the process control variable is modified based on the determination of the reaction trajectory to follow a first target trajectory; determining a second target trajectory of optimal crossover associated with switching of a continuous reactor from the evolution of a first mode to a second mode; and actively controlling the evolution of a second mode by modifying at least one process control variable, wherein the process control variable is modified based on the second target trajectory.

[0237] Statement 68: The characteristic of the mode is M w 68. The method of claim 67, wherein the effect of the polymerization on the polymerization is selected from the group consisting of viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

[0238] Statement 69: The method of statement 67 or statement 68, wherein said monitoring at least one reaction property comprises measuring at least one selected from the group consisting of Raman scattering, infrared spectroscopy, refractive index, ultraviolet absorption, conductivity, optical activity, circular dichroism, circular birefringence, NMR, total intensity light scattering, multi-angle total intensity light scattering, dynamic light scattering, capillary viscometry, and simultaneous measurement of low and high shear viscosity.

[0239] Statement 70: The method of any one of the preceding statements 67-69, wherein the process control variables are selected from the group consisting of temperature, agitation rate, mixing rate, stirring, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst. Further included within this disclosure are the following: (1) 1. A method for producing a multimodal polymer in a single reaction vessel, comprising: producing a multimodal polymer by conducting a polymer reaction in at least two stages, each of which produces a modal polymer, each modal polymer having unique properties, and wherein the polymer reaction occurs in a single reaction vessel; monitoring at least one reaction characteristic of said mode of polymer at at least one stage; actively controlling said mode of polymer evolution by modifying at least one process control variable during said polymer reaction in at least one of said at least two stages based on said at least one monitored reaction characteristic. The method comprising: (2) 10. The method of claim 1, further comprising determining a reaction trajectory based on the at least one monitored reaction characteristic, wherein the process control variable is modified based on the determination of the reaction trajectory to follow a target trajectory. (3) The method of (2), wherein the reaction characteristic on which the target trajectory is based is molecular weight, copolymer composition, or intrinsic viscosity (IV). (4) The method according to (1), wherein the polymer reaction occurs as a first step in a free radical polymerization reaction and as a second step in the production of low molecular weight populations. (5) simultaneously determining a plurality of reaction trajectories, each of the plurality of reaction trajectories being based on at least one monitored reaction characteristic; modifying one or more process control variables based on the plurality of reaction trajectories so that the trajectories of the plurality of monitored reaction properties are simultaneously controlled; further comprising The plurality of simultaneously controlled trajectories are M w , viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution. (6) The method of (1), wherein the multimodal polymer comprises a multimodal stimuli-responsive polymer. (7) The characteristics of the mode are M w , viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution. (8) 10. The method of claim 1, wherein the process control variables are selected from the group consisting of temperature, stirring rate, mixing rate, agitation, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst. (9) 10. The method of claim 1, wherein the reaction characteristic on which the target trajectory is based is molecular weight, the process control variable is the introduction of a chain transfer agent, and the multimodal polymer is produced from polyacrylamide. (10) a reaction vessel configured to contain a polymer solution and to carry out a polymer reaction in at least two stages to produce a multimodal polymer, each of the at least two stages producing a polymer with unique properties; one or more detectors configured to monitor at least one reaction property of the polymer solution contained in the reaction vessel; and a control element coupled to the reaction vessel and the one or more detectors, the control element configured to actively control the evolution of a predetermined reaction characteristic by modifying at least one process control variable based on the at least one reaction characteristic monitored by the detector; An apparatus comprising: (11) 11. The apparatus of claim 10, wherein the control element further comprises an interface configured to allow an operator to cause the control element to actively control the development of the predetermined response characteristic. (12) 12. The apparatus of claim 11, wherein the control element is further configured to determine a reaction trajectory based on the at least one reaction characteristic monitored by the detector, and the process control variable is modified based on the determination of the reaction trajectory. (13) 11. The apparatus of claim 10, wherein the control element is further configured to simultaneously determine multiple reaction trajectories, each of the multiple reaction trajectories being based on at least one monitored reaction characteristic. (14) 14. The apparatus of claim 13, wherein the control element is further configured to modify one or more process control variables based on the plurality of reaction trajectories such that the trajectories of multiple monitored reaction properties are simultaneously controlled. (15) The plurality of simultaneously controlled trajectories are M w , viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution. (16) The reaction characteristic is M w , viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution. (17) 11. The apparatus of claim 10, wherein the process control variables are selected from the group consisting of temperature, agitation rate, mixing rate, agitation, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst. (18) The device described in (10), wherein the detector and control element are components of an ACOMP system. (19) The apparatus of (10), further comprising a second reaction vessel, wherein the reaction vessel and the second reaction vessel are each configured to cause a polymer reaction in at least one of the at least two stages. (20) 13. The apparatus of claim 12, wherein the control element is further configured to determine an optimal crossover second target trajectory associated with switching of the continuous reactor from the evolution of a first mode to a second mode, and to actively control the evolution of the second mode by modifying at least one process control variable, the process control variable being modified based on the second target trajectory. (twenty one) The apparatus according to (10), wherein the polymer reaction occurs as a first step in a free radical polymerization reaction and as a second step in the production of low molecular weight populations. (twenty two) 11. The apparatus of claim 10, wherein the reaction characteristic on which the target trajectory is based is molecular weight, the process control variable is the introduction of a chain transfer agent, and the multimodal polymer is produced from polyacrylamide. The following items are also included in the present disclosure: (A-1) 1. A method for producing a multimodal polymer in a single reaction vessel, comprising: producing a multimodal polymer by conducting a polymer reaction in at least two stages, the at least two stages producing a first mode and a second mode polymer, each of the first mode and second mode polymers having unique properties, the polymer reaction occurring in a single reaction vessel; monitoring at least one reaction characteristic of said first mode polymer at at least one stage; determining a reaction trajectory based on at least one monitored reaction characteristic, wherein at least one of a plurality of process control variables is modified based on the reaction trajectory to follow a first target trajectory; actively controlling the evolution of the polymer in the first mode by modifying at least one of a plurality of process control variables based on the at least one monitored reaction characteristic during the polymer reaction in at least one of the at least two stages; determining a second target trajectory associated with the second mode; actively controlling the evolution of the second mode by modifying at least one of the process control variables. The method comprising: (A-2) The method of (A-1), wherein the at least one monitored reaction characteristic on which the first target trajectory or the second target trajectory is based is molecular weight, copolymer composition, or intrinsic viscosity (IV). (A-3) The method according to (A-1), wherein the polymer reaction occurs as a free radical polymerization reaction as a first step of the at least two steps and as a production of a low molecular weight population as a second step of the at least two steps. (A-4) simultaneously determining a plurality of reaction trajectories, each of the plurality of reaction trajectories being based on at least one monitored reaction characteristic; Simultaneously modifying at least two or more process control variables based on the plurality of reaction trajectories so that the trajectories of the plurality of monitored reaction properties are simultaneously controlled. further comprising Multiple simultaneously controlled trajectories are w The method according to (A-1), wherein the viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution are selected from the group consisting of: (A-5) The method of (A-1), wherein at least one of the multimodal polymers comprises a multimodal stimuli-responsive polymer. (A-6) The at least one monitored response characteristic of the first mode or the second mode is M w The method according to (A-1), wherein the effect of the polymerization is selected from the group consisting of viscosity reduction, conversion rate, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution. (A-7) The method of (A-1), wherein the at least one monitored reaction characteristic on which the first target trajectory or the second target trajectory is based is molecular weight, at least one of the process control variables is the introduction of a chain transfer agent, and the multimodal polymer is produced from polyacrylamide. (A-8) The method of (A-1), wherein the process control variables are selected from the group consisting of temperature, stirring speed, mixing speed, stirring, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst. (A-9) The method of (A-1), further comprising determining, by a control element, an optimal crossover target trajectory associated with switching of the continuous reactor from the development of the first mode to the second mode. (A-10) a reaction vessel configured to contain a polymer solution and to carry out a polymer reaction in at least two stages to produce a multimodal polymer, each of the at least two stages producing a polymer with unique properties; one or more detectors configured to monitor at least one reaction property of the polymer solution contained in the reaction vessel; and a control element coupled to the reaction vessel and the one or more detectors, the control element configured to actively control the evolution of a predetermined reaction characteristic by modifying at least one of a plurality of process control variables based on the at least one reaction characteristic monitored by the one or more detectors. Equipped with the control element is further configured to determine a reaction trajectory based on the at least one reaction characteristic monitored by the one or more detectors, and at least one of the process control variables is modified based on the reaction trajectory to follow a first target trajectory; The apparatus, wherein the control element is further configured to determine a second target trajectory of a crossover associated with switching of the continuous reactor from the evolution of a first mode to a second mode, and to actively control the evolution of the second mode by modifying at least one of the process control variables. (A-11) The device described in (A-10), wherein the control element further includes an interface configured to allow an operator to cause the control element to actively control the development of the predetermined reaction characteristic. (A-12) The apparatus described in (A-10), wherein the control element is further configured to simultaneously determine multiple reaction trajectories, each of the multiple reaction trajectories being based on at least one monitored reaction characteristic. (A-13) The apparatus described in (A-12), wherein the control element is further configured to modify one or more process control variables based on the plurality of reaction trajectories so that the trajectories of the plurality of monitored reaction characteristics are simultaneously controlled. (A-14) The plurality of simultaneously controlled trajectories are M w The apparatus described in (A-13), wherein the viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution are selected from the group consisting of: (A-15) The at least one reactive property is M w The apparatus described in (A-10), wherein the viscosity reduction, conversion rate, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution are selected from the group consisting of: (A-16) The apparatus described in (A-10), wherein the one or more detectors and control elements are components of an ACOMP system. (A-17) The apparatus described in (A-10), further comprising a second reaction vessel, wherein the reaction vessel and the second reaction vessel are each configured to cause a polymer reaction in at least one of the at least two stages. (A-18) The apparatus described in (A-10), wherein the polymer reaction occurs as a free radical polymerization reaction as the first step of the at least two steps and as the production of a low molecular weight population as the second step of the at least two steps. (A-19) The apparatus described in (A-10), wherein the at least one reaction characteristic on which the first target trajectory is based is molecular weight, at least one of the process control variables is the introduction of a chain transfer agent, and the multimodal polymer is produced from polyacrylamide. (A-20) The apparatus described in (A-10), wherein the process control variables are selected from the group consisting of temperature, stirring speed, mixing speed, stirring, introduction of monomer, introduction of comonomer, introduction of initiator, introduction of quencher, introduction of branching agent, introduction of crosslinking agent, introduction of chain transfer agent, introduction of inhibitor, introduction of air, introduction of O2 gas, introduction of N2 gas, introduction of argon gas, introduction of acid, introduction of base, introduction of redox agent, and introduction of catalyst.

Claims

1. 1. A method for producing a multimodal polymer in a single reaction vessel, comprising: producing a multimodal polymer by conducting a polymer reaction in at least two stages, a first stage and a second stage of the at least two stages producing a first mode and a second mode polymer, respectively, each of the first mode and the second mode polymer having unique properties, the polymer reaction occurring in a single reaction vessel, including a continuous reactor; monitoring at least one response characteristic of the first mode polymer during the first stage; monitoring a reaction trajectory based on at least one monitored reaction characteristic, wherein at least one of a plurality of process control variables is modified based on monitoring the reaction trajectory to follow a first target trajectory; actively controlling the evolution of the polymer in the first mode by modifying at least one of a plurality of process control variables based on at least one monitored reaction characteristic during the polymer reaction in at least one of the at least two stages; tracing a target crossover trajectory relating to crossover in the continuous reactor from evolution of the first mode to the second mode; actively controlling the evolution of the second mode by modifying at least one of a plurality of process control variables based on monitoring the reaction trajectory to follow the target crossover trajectory. The method comprising:

2. 10. The method of claim 1, wherein the at least one reaction characteristic on which the first target trajectory or the target crossover trajectory is based is molecular weight, copolymer composition, or intrinsic viscosity (IV).

3. 10. The method of claim 1, wherein the polymer reaction occurs with a free radical polymerization reaction as the first step and with the production of a low molecular weight population as the second step.

4. simultaneously determining a plurality of reaction trajectories, each of the plurality of reaction trajectories being based on at least one monitored reaction characteristic; Simultaneously modifying at least two or more process control variables based on the plurality of reaction trajectories so that the plurality of trajectories of the plurality of monitored reaction properties are simultaneously controlled. further comprising Multiple simultaneously controlled trajectories are ｗ , viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

5. The method of claim 1 , wherein the multimodal polymer comprises a multimodal stimulus-responsive polymer.

6. At least one reaction characteristic of the first stage mode is M ｗ 10. The method of claim 1, wherein the effect of the polymerization on the polymerization is selected from the group consisting of viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

7. The process control variables include temperature, agitation rate, mixing rate, agitation, monomer introduction, comonomer introduction, initiator introduction, quencher introduction, branching agent introduction, crosslinking agent introduction, chain transfer agent introduction, inhibitor introduction, air introduction, O ２ Gas introduction, N ２ 2. The method of claim 1, wherein the introduction of the catalyst is selected from the group consisting of introducing a gas, introducing argon gas, introducing an acid, introducing a base, introducing an oxidation-reduction agent, and introducing a catalyst.

8. 10. The method of claim 1, wherein the at least one reaction characteristic on which the first target trajectory or the target crossover trajectory is based is molecular weight, at least one of a plurality of process control variables is the introduction of a chain transfer agent, and the multimodal polymer is produced from polyacrylamide.

9. The method of claim 1 , wherein at least one of the process control variables is modified based on a difference between the reaction trajectory and the target crossover trajectory.

10. a reaction vessel configured to contain a polymer solution and to carry out a polymer reaction in at least two stages to produce a multimodal polymer, each of the at least two stages producing a polymer with unique properties; one or more detectors configured to monitor at least one reaction property of the polymer solution contained in the reaction vessel, including a continuous reactor; and a control element coupled to the reaction vessel and the one or more detectors, the control element configured to actively follow a target trajectory for the reaction characteristic by modifying at least one of a plurality of process control variables based on the at least one reaction characteristic monitored by the one or more detectors. Equipped with the control element is further configured to follow a reaction trajectory based on at least one reaction characteristic monitored by the one or more detectors, and at least one of a plurality of process control variables is modified based on monitoring the reaction trajectory to follow a first target trajectory; The apparatus, wherein the control element is further configured to follow a target crossover trajectory associated with a crossover from a first mode evolution in a first stage to a second mode evolution in a second stage in the continuous reactor, and to actively control the evolution of the second mode by modifying at least one of a plurality of process control variables based on monitoring the reaction trajectory to follow the target crossover trajectory.

11. 11. The apparatus of claim 10, wherein the control element further comprises an interface configured to allow an operator to cause the control element to actively control the development of the predetermined response characteristic.

12. The apparatus of claim 10 , wherein the control element is further configured to simultaneously determine multiple reaction trajectories, each of the multiple reaction trajectories being based on at least one monitored reaction characteristic.

13. 13. The apparatus of claim 12, wherein the control element is further configured to modify one or more process control variables based on the plurality of reaction trajectories such that multiple trajectories of multiple monitored reaction properties are simultaneously controlled.

14. Multiple simultaneously controlled trajectories are ｗ , viscosity reduction, IV, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

15. The at least one reactive property is M ｗ 11. The device of claim 10, wherein the viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution are selected from the group consisting of: viscosity reduction, conversion, monomer and polymer concentration, comonomer composition, branching, degree of hydrolysis, and chemical substitution.

16. The process control variables include temperature, agitation rate, mixing rate, agitation, monomer introduction, comonomer introduction, initiator introduction, quencher introduction, branching agent introduction, crosslinking agent introduction, chain transfer agent introduction, inhibitor introduction, air introduction, O ２ Gas introduction, N ２ 11. The apparatus of claim 10, wherein the introduction of the gas is selected from the group consisting of introduction of argon gas, introduction of an acid, introduction of a base, introduction of an oxidation-reduction agent, and introduction of a catalyst.

17. The apparatus of claim 10 , wherein the one or more detectors and the control element are components of an ACOMP system.

18. 11. The apparatus of claim 10, further comprising a second reaction vessel, said reaction vessel and said second reaction vessel each configured to cause a polymer reaction to occur in at least one of said at least two stages.

19. 11. The apparatus of claim 10, wherein the polymer reaction occurs with a free radical polymerization reaction as the first step and with the production of a low molecular weight population as the second step.

20. 11. The apparatus of claim 10, wherein the at least one reaction characteristic on which the first target trajectory is based is molecular weight, at least one of the process control variables is the introduction of a chain transfer agent, and the multimodal polymer is produced from polyacrylamide.

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