Method for controlling the conjugated polymer molecular weight using flow reactor

Abstract

The present invention discloses a method for controlling the molecular weight of a conjugated polymer. A method for controlling the molecular weight of a conjugated polymer using a flow reactor having a first linear flow path capable of inducing an elongational flow of the conjugated polymer, comprising: a step of inducing chain cleavage of at least a portion of the conjugated polymer by introducing a conjugated polymer solution, an inert gas, and a carrier solvent into the inlet of the linear flow path to induce an elongational flow of the conjugated polymer; and a step of recovering the conjugated polymer discharged from the linear flow path; wherein the conjugated polymer solution comprises a conjugated polymer having a number average molecular weight (Mn) of 30 to 130 kDa.

Description

Technology Field

[0001] The present invention relates to a method for controlling the molecular weight of a conjugated polymer using a flow reactor. Background Technology

[0002] Conjugated polymers are mechanically flexible, solution-processable, and tunable, making them applicable to various electronic and optoelectronic devices, including solar panels, transistors, light-emitting diodes, and sensors. However, the most significant limitation of conjugated polymers is that their molecular weight and molecular weight dispersion vary significantly from batch to batch, leading to variations in device performance. Therefore, it is crucial to synthesize conjugated polymers with a desired molecular weight. One method for obtaining polymers with a desired molecular weight is synthesis using a flow reactor. However, with the discovery of chain cleavage in conjugated polymers within flow reactors, controlling this phenomenon is essential for controlling molecular weight.

[0003] Research on polymer chain cleavage has been an active field for over 90 years, and it is known that various types of flow, such as turbulent, laminar, counter-jet flow, transient elongation flow, and cavitation-induced flow, degrade polymers. Generally, these methods mechanically stretch polymer chains and induce bond separation. The chain cleavage rate varies depending on experimental conditions and polymer properties. For example, linear polymers generally cleave more rapidly as their length increases. However, research on the chain cleavage of conjugated polymers is still limited.

[0004] Flow reactors allow for precise control of reaction conditions during polymer synthesis, and their uniformity enhances the reproducibility of polymerization results. Additionally, they offer advantages such as rapid polymerization times, improved safety, easy optimization, and the potential for scalability and automation. In the case of polymer synthesis using a flow reactor, it was found that while molecular weight increased with increasing residence time, chain cleavage occurred within the reactor after a few minutes, preventing further increase in the polymer's molecular weight. Therefore, it is anticipated that flow reactors can be applied to research on conjugated polymer chain cleavage. Prior art literature

[0005] Republic of Korea Registered Patent No. 10-1187346 The problem to be solved

[0006] One objective of the present invention is to study the chain cleavage phenomenon of conjugated polymers using a flow reactor and to provide a method for controlling molecular weight. means of solving the problem

[0007] To achieve the above objective, a method for controlling the molecular weight of a conjugated polymer using a flow reactor having a first linear flow path capable of inducing an elongational flow of the conjugated polymer comprises: a step of inducing chain cleavage of at least some of the conjugated polymers by introducing a conjugated polymer solution, an inert gas, and a carrier solvent into the inlet of the linear flow path to induce an elongational flow of the conjugated polymer; and a step of recovering the conjugated polymer discharged from the linear flow path; wherein the conjugated polymer solution has a number average molecular weight (M n A method for controlling the molecular weight of a conjugated polymer comprising a conjugated polymer having a molecular weight of 30 to 130 kDa is provided. Effects of the invention

[0008] According to the present invention, a conjugated polymer having a desired molecular weight can be produced by the method for controlling the molecular weight of a conjugated polymer according to the present invention. In addition, the extension and cleavage of polymer chains can be controlled using a flow reactor. Brief explanation of the drawing

[0009] FIG. 1 is a flowchart of a method for controlling the molecular weight of a conjugated polymer according to one embodiment of the present invention. FIG. 2 is a schematic diagram of a method for controlling the molecular weight of a conjugated polymer according to one embodiment of the present invention. Figure 3 shows the change in conjugated polymer molecular weight according to the residence time of the flow reactor. Figure 4 is the ultraviolet-visible (UV-vis) absorption spectrum of the conjugated polymer before and after the flow reactor operation. Figure 5 shows the change in the molecular weight of the conjugated polymer according to the operating temperature of the flow reactor. Figure 6 shows the results of molecular weight loss according to the molecular weight of the polymer. Figure 7 shows the change in the molecular weight of the conjugated polymer according to the concentration of the conjugated polymer introduced into the fluidized reactor. Figure 8 shows the change in molecular weight of polystyrene (PS). Figure 9 shows the change in molecular weight of the conjugated polymer (N2200). Specific details for implementing the invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. Since the present invention is susceptible to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. Similar reference numerals have been used for similar components in the description of each drawing. In the attached drawings, the dimensions of the structures are shown enlarged compared to the actual dimensions for the clarity of the present invention.

[0011] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0012] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0013] Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0015] FIG. 1 is a flowchart of a method for controlling the molecular weight of a conjugated polymer according to an embodiment of the present invention. Referring to FIG. 1, a method for controlling the molecular weight of a conjugated polymer using a flow reactor having a first linear flow path capable of inducing an elongational flow of the conjugated polymer comprises: a step (S110) of inducing chain cleavage of at least a portion of the conjugated polymer by introducing a conjugated polymer solution, an inert gas, and a carrier solvent into the inlet of the linear flow path to induce an elongational flow of the conjugated polymer; and a step (S120) of recovering the conjugated polymer discharged from the linear flow path, wherein the conjugated polymer solution has a number average molecular weight (M n It may include a conjugated polymer having a viscosity of about 30 to 130 kDa.

[0016] In one embodiment, to induce elongational flow of the conjugated polymer, the first linear channel may be formed in a coil shape, but is not limited thereto.

[0017] In one embodiment, the temperature of the first linear flow channel may be controlled to about 100 to 150°C, but is not limited thereto. For example, the temperature of the first linear flow channel may be controlled to about 110 to 130°C. The chain cleavage of the conjugated polymer may be influenced by thermal energy supplied in the first linear flow channel in addition to the elongation flow.

[0018] In one embodiment, the conjugated polymer solution may be flowable by the carrier solvent. An inert gas may be positioned between the conjugated polymer solution and the carrier solvent so that the polymer solution may flow through the flow reactor by the carrier solvent and the inert gas, and diffusion between the conjugated polymer solution and the carrier solvent may be prevented by the inert gas.

[0019] In one embodiment, the inert gas may be nitrogen gas, but is not limited thereto. Due to the nitrogen gas, mixing and diffusion of the conjugated polymer solution and the carrier solvent do not occur, so that the conjugated polymer solution can flow through the first linear channel at a constant concentration and speed.

[0020] In one embodiment, the carrier solvent may flow the conjugated polymer solvent at a speed of about 0.05 to 0.5 ml / min, but is not limited thereto. The carrier solvent may flow the conjugated polymer solvent at a speed of about 0.20 to 0.30 ml / min.

[0021] In one embodiment, the conjugated polymer solution may flow through the first linear channel for about 1 to 10 minutes. If the conjugated polymer solution flows through the first linear channel for less than about 1 minute, the elongation of the conjugated polymer due to the flow may not occur sufficiently, and the chains of the conjugated polymer may not be cut. If the conjugated polymer solution flows through the first linear channel for more than about 10 minutes, the cut chains of the conjugated polymer may rejoin, or the occurrence of additional chain cutting may be significantly reduced.

[0022] In one embodiment, the conjugated polymer solution may contain about 0.5 to 7 mg of conjugated polymer per about 1 ml of solvent. If the conjugated polymer solution contains less than about 0.5 mg of conjugated polymer per about 1 ml of solvent or more than about 7 mg, the chain cleavage efficiency of the conjugated polymer by the flow reactor may decrease.

[0023] In one embodiment, the flow reactor further comprises the second linear channel, and the second linear channel is positioned adjacent to the first linear channel so that the conjugated polymer solution can flow through the second linear channel and the first linear channel. For example, the outlet of the second linear channel may be connected to the inlet of the first linear channel.

[0024] In one embodiment, the second linear channel may be formed in a coil shape, and an inert gas may be disposed between the conjugated polymer solution and the carrier solvent in the second linear channel. The conjugated polymer solution, the inert gas, and the carrier solvent may be arranged in that order in the second linear channel and supplied to the first linear channel. Depending on the arrangement of the inert gas, the diffusion of the conjugated polymer solution by the carrier solvent in the first linear channel may be prevented.

[0026] Hereinafter, the present invention will be described in detail with reference to examples to aid in understanding. However, the following examples are merely illustrative of the content of the present invention and the scope of the present invention is not limited to the following examples. The examples of the present invention are provided to more completely explain the present invention to those with average knowledge in the art.

[0028] <Preparation Example 1> Preparation of Conjugated Polymer

[0029] The inside of the fluidized reactor was washed with anhydrous toluene and heated to approximately 120 °C. The inside of the fluidized reactor was pressurized with nitrogen gas at approximately 40 psi, and chlorobenzene was injected as a carrier solution into a syringe pump. Monomer solutions and catalyst solutions were prepared by dissolving each monomer and catalyst in chlorobenzene. 2-ethylhexyl-4,6-dibromo-3-fluorothieno[3,4-b]thiophene-2-carboxylate (TT) and 4,8-bis[(2-ethylhexyl)oxy]-2,6-bis(trimethyltanyl)benzo[1,2-b:4,5-b']dithiophene (BDT) were used as monomers, and Pd2(dba)3 and P(o-tolyl)3 were used as catalysts. The monomer solutions and catalyst solutions were injected into a gastight syringe. The nitrogen gas valve was closed, and the monomer solution and catalyst solution were introduced into the reactor to produce a reaction mixture (0.015 M). Nitrogen gas and a carrier solution were introduced sequentially to set the reaction time to approximately 3 to 30 minutes to synthesize polymers with various molecular weights, and the reaction mixture, nitrogen gas, and carrier solvent were arranged in that order in the layer-forming section of the reactor. The reaction mixture was transported by nitrogen and the carrier solvent to a collection chamber filled with methanol at a flow rate of approximately 0.25 ml / min. After collecting the precipitate in the collection chamber, it was filtered and dried in a vacuum oven for approximately 6 hours. Depending on the reaction time, conjugated polymers (PTB7) with molecular weights of approximately 113, 67, 47, and 31 kDa were obtained. The conjugated polymers corresponding to each molecular weight were named P113, P67, P47, and P31.

[0031] <Examples 1 to 16> Conjugated Polymer Chain Cleavage

[0032] FIG. 2 is a schematic diagram of a method for controlling the molecular weight of a conjugated polymer according to an embodiment of the present invention. According to FIG. 2, the conjugated polymer prepared in the preparation example was introduced into a flow reactor to cut the polymer chains.

[0033] The inside of the fluidized reactor was washed with anhydrous toluene and heated to approximately 120 °C. The inside of the fluidized reactor was pressurized with nitrogen gas at approximately 40 psi, and chlorobenzene was injected as a carrier solution into a syringe pump. Conjugated polymer solutions of various concentrations were prepared by dissolving the conjugated polymers prepared in Preparation Examples 1 to 4 in chlorobenzene. The conjugated polymer solutions were injected into a gastight syringe. The nitrogen gas valve was closed, and the conjugated polymer solutions were introduced into the reactor at a flow rate of approximately 0.25 mL / min. Nitrogen gas and the carrier solution were introduced sequentially so that the layers in the layer-forming section of the reactor were arranged in the order of nitrogen gas, the polymer solution, nitrogen gas, and the carrier solvent. The conjugated polymer solutions were transported by the nitrogen and carrier solution to a collection chamber filled with methanol. The carrier solution, chlorobenzene, flowed at a flow rate of approximately 2.5 mg / mL. After obtaining the precipitate from the collection chamber, it was filtered and dried in a vacuum oven for approximately 6 hours. The type of conjugated polymer, the concentration of the conjugated polymer solution, and the residence time were performed according to Table 1 below.

[0034] Conjugated polymer Conjugated polymer solution concentration (mg / ml) Time of stay Example 1 P113 2.5 30 Example 2 P67 1 3 Example 3 1 30 Example 4 1 60 Example 5 1 90 Example 6 2.5 3 Example 7 2.5 30 Example 8 2.5 60 Example 9 2.5 90 Example 10 5 3 Example 11 5 30 Example 12 5 60 Example 13 5 90 Example 14 P47 2.5 30 Example 15 P31 2.5 30 Example 16 N2200 1 30

[0035] <Comparative Example 1>

[0036] The same method as in Example 1 was performed, except that the procedure was carried out at room temperature without heating to about 120°C.

[0038] <Comparative Example 2>

[0039] The same method as in Example 1 was performed, except that polystyrene (PS) was used instead of P113 in Example 1.

[0041] <Experimental Example 1>

[0042] Table 2 below shows the number average molecular weight (M) of the conjugated polymer prepared in Preparation Example 1. n ), weight-average molecular weight (M wThe molecular weight and dispersion (D) were shown. The molecular weight was analyzed for polystyrene standard material dissolved in chlorobenzene solvent at approximately 60 °C using Schambeck SFD GmbH size exclusion chromatography (SEC) with an S9425 HPLC pump, S 2020 RI detector, and Canatech TL105 HPLC column heater.

[0043] polymer M n (kDa) M w (kDa) Ð P113 112.5 256.6 2.28 P67 67.1 133.1 1.98 P47 47.4 86.7 1.83 P31 31.1 57.0 1.84

[0044] Figure 3 shows the change in molecular weight of the conjugated polymer according to the residence time in the fluidized reactor. In Comparative Example 2 and Examples 6 to 9, P67 was introduced as the conjugated polymer and retained in the fluidized reactor for up to approximately 90 minutes to confirm the change in molecular weight of the conjugated polymer according to the residence time. At a residence time of approximately 3 minutes, the number average molecular weight (M n It was confirmed to be about 54 kDa, a decrease of about 19%, and about 40 kDa, a decrease of about 40%, at a residence time of about 90 minutes.

[0045] Figure 4 shows the ultraviolet-visible (UV-vis) absorption spectra of the conjugated polymer before and after the flow reactor operation. The UV-visible absorption spectra were measured using a UV-visible spectrophotometer (Perkin-Elmer model Lambda 25). To identify the cause of the decrease in polymer molecular weight, the UV-visible absorption spectra of Comparative Example 2 and Example 6 were compared, and it was confirmed that the conjugated polymer of Example 6 shifted to blue. While a red shift occurs when side chain cleavage occurs, a blue shift occurs when chain cleavage occurs. Through this, it was confirmed that the molecular weight decreased due to chain cleavage in the flow reactor.

[0046] Figure 5 shows the change in the molecular weight of the conjugated polymer according to the operating temperature of the flow reactor. In Example 1 and Comparative Example 1, P113 was introduced as the conjugated polymer and retained for approximately 3 minutes to confirm the amount of polymer reduction according to temperature. M of P113 performed in Example 1 nIt was confirmed to have decreased by approximately 49% to approximately 68 kDa, and M of P113, which performed Comparative Example 1, was n This resulted in a decrease of only about 19% to approximately 108 kDa. This result not only demonstrates the importance of temperature but also suggests that most chain cleavage is likely to occur in the heating coil of the flow reactor. Through this, the examples indicated that, overall, the decomposition of conjugated polymers promotes chain bond disintegration due to a combination of mechanical (polymer chain elongation by flow) and thermal energy transfer processes. It was determined that polymer cleavage through a flow reactor is distinct from the polymer chain cleavage patterns that generally occur in flow systems with narrow nozzles.

[0047] Figure 6 shows the results of molecular weight loss according to the molecular weight of the polymer. To determine the molecular weight loss according to the initial molecular weight of the conjugated polymer, the molecular weights of Examples 1, 7, 14, and 15 were compared. Polymers with higher molecular weights generally undergo faster chain cleavage. Similarly, in Figure 6, molecular weight loss increased as the initial molecular weight increased. In other words, polymers with larger molecular weights degraded more rapidly. This is consistent with most elongated flow techniques used in the study of mechanochemical degradation of polymers. Furthermore, these results supported the fact that when the side chain length of the polymer is constant, mechanochemical side chain cleavage is independent of molecular weight, and therefore chain degradation occurs through chain breakdown rather than side chain cleavage.

[0048] Figure 7 shows the change in molecular weight of the conjugated polymer according to the concentration of the conjugated polymer introduced into the flow reactor. By varying the concentration of P67 to approximately 1.0, 2.5, or 5.0 mg / mL, it was confirmed that the decomposition rate increased as the concentration decreased. This supports the possibility that the conjugated polymer is undergoing flow-induced elongation, which leads to stress accumulation and chain rupture at high temperatures.

[0049] Figure 8 shows the change in molecular weight of polystyrene (PS). Polystyrene (PS) with a molecular weight of approximately 833 kDa was fed into a fluidized reactor to check whether the polymer chains were cleaved. In Figure 8, it was confirmed that the change in molecular weight of polystyrene is minimal even when treated in a fluidized reactor.

[0050] Figure 9 shows the change in molecular weight of the conjugated polymer (N2200). It was verified whether the polymer chains of N2200, a representative donor-acceptor type conjugated polymer, are cleaved through a flow reactor. The initial M of N2200 n was approximately 85 kDa, and through the flow reactor M n This was reduced by approximately 24% to about 65 kDa. It was determined that the flow decomposition of N2200 is likely due to chain cleavage being a competitive side reaction in the flow polymerization of conjugated polymers. It was speculated that the decomposition of conjugated polymers may be partly due to an increase in stiffness.

[0052] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

Claim 1 A method for controlling the molecular weight of a conjugated polymer using a flow reactor having a first linear flow path capable of inducing an elongational flow of the conjugated polymer, comprising: a step of inducing chain cleavage of at least a portion of the conjugated polymer by introducing a conjugated polymer solution, an inert gas, and a carrier solvent into the inlet of the linear flow path to induce an elongational flow of the conjugated polymer; and a step of recovering the conjugated polymer discharged from the linear flow path; wherein the conjugated polymer solution has a number average molecular weight (M n A method for controlling the molecular weight of a conjugated polymer, comprising a conjugated polymer having a molecular weight of 30 to 130 kDa. Claim 2 A method for controlling the molecular weight of a conjugated polymer, wherein, in claim 1, the temperature of the first linear flow path is controlled to 100 to 150 ℃. Claim 3 A method for controlling the molecular weight of a conjugated polymer, wherein, in claim 1, the conjugated polymer solution flows through the carrier solvent. Claim 4 A method for controlling the molecular weight of a conjugated polymer, wherein the carrier solvent flows the conjugated polymer solvent at a rate of 0.05 to 0.5 ml / min. Claim 5 A method for controlling the molecular weight of a conjugated polymer, wherein the conjugated polymer solution flows through the first linear channel for 1 to 90 minutes. Claim 6 A method for controlling the molecular weight of a conjugated polymer, wherein the conjugated polymer solution comprises mixing 0.5 to 7 mg of the conjugated polymer per 1 ml of solvent. Claim 7 A method for controlling the molecular weight of a conjugated polymer, wherein, in claim 1, the flow reactor further comprises a second linear flow path, and the second linear flow path is arranged adjacent to the first linear flow path so that the conjugated polymer solution flows through the second linear flow path and the first linear flow path. Claim 8 A method for controlling the molecular weight of a conjugated polymer, wherein, in claim 7, an inert gas is disposed between the conjugated polymer solution and the carrier solvent in the second linear flow path. Claim 9 A method for controlling the molecular weight of a conjugated polymer, wherein, in claim 7, the first linear channel and the second linear channel are in the form of coils.

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