Method for testing performance of polymer liquid

Abstract

The invention provides a polymer liquid performance testing method which comprises the following steps: transferring a to-be-detected polymer liquid into a preset container, weighing the sum of the mass of the to-be-detected polymer liquid and the mass of the preset container, and determining the sum as a first mass; dipping a preset mass of to-be-detected polymerization liquid and transferring the to-be-detected polymerization liquid to a preset support plate for coating to form a polymerization liquid film; weighing the sum of the mass of the residual to-be-detected polymerization liquid after dipping and the mass of the preset container, and determining the sum as a second mass; the preset supporting plate is immersed in preset liquid, the polymer liquid film is separated from the preset supporting plate, and the polymer liquid film is dried and weighed to be determined as third mass; and determining the solid content in the polymerization liquid according to the first mass, the second mass and the third mass. According to the method for testing the performance of the polymerization liquid, the solid content of the dipped to-be-detected polymerization liquid is obtained, then the solid content of the polymerization liquid is determined, and the method is small in error, easy to operate, low in equipment cost and suitable for online monitoring of the solid content of the polymerization liquid in the polymerization reaction process.

Description

Technical Field

[0001] The present disclosure relates to the technical field of carbon fiber production and testing, and in particular to a method for testing the properties of a polymer solution. Background Art

[0002] Polyacrylonitrile-based carbon fiber has the characteristics of high strength, high modulus, corrosion resistance, and fatigue resistance. It is not only an irreplaceable strategic basic material for the cutting-edge defense industry, but also a new material for the upgrading of civilian industries.

[0003] Combining the current status of high-performance polyacrylonitrile-based carbon fiber technology at home and abroad, we analyzed that due to the limitation of homogeneous solution, in order to obtain a higher conversion rate, the polymerization reaction time is relatively long, generally between 18 and 30 hours. Although the conversion rate can be improved by increasing the ratio of initiator to monomer, increasing the reaction temperature, and extending the polymerization time, these three methods will reduce the relative molecular weight of the polymer to a certain extent and make the molecular weight distribution wider. The relative molecular weight and molecular weight distribution indicators have a serious impact on the performance of high-performance polyacrylonitrile-based carbon fibers. Therefore, in the polymerization process, it is particularly important to quickly and efficiently determine the conversion rate and solid content of the polymerization solution. Summary of the Invention

[0004] To solve the problems existing in the related art, the present disclosure provides a method for testing the performance of a polymer solution, the testing method comprising:

[0005] Transferring the polymer solution to be tested into a preset container, and weighing the sum of the masses of the polymer solution to be tested and the preset container to determine the sum as the first mass;

[0006] Dipping a predetermined mass of the polymer solution to be tested and transferring it to a predetermined support plate for coating to form a polymer liquid film;

[0007] Weighing the sum of the mass of the remaining polymer solution to be tested and the mass of the preset container after dipping, and determining it as the second mass;

[0008] immersing the preset support plate in a preset liquid, separating the polymer liquid film from the preset support plate, drying and weighing the polymer liquid film to determine a third mass;

[0009] The solid content in the polymerization solution is determined based on the first mass, the second mass, and the third mass.

[0010] In some embodiments of the present disclosure, the step of dipping a predetermined mass of the polymer liquid to be detected and transferring the polymer liquid to a predetermined support plate for coating to form a polymer liquid film comprises:

[0011] The dipping member is used to dip a preset mass of the polymer liquid to be tested and transfer it to a preset position on the preset support plate, and the dipping member is used to rotate along the same direction on the preset support plate to spread the polymer liquid to be tested on the preset support plate to form the polymer liquid film.

[0012] In some embodiments of the present disclosure, determining the solid content in the polymer solution based on the first mass, the second mass, and the third mass includes:

[0013] The solid content in the polymer solution is determined according to the following formula:

[0014]

[0015] Wherein, c is the solid content, in %; m1 is the first mass, in g; m2 is the second mass, in g; and m3 is the third mass, in g.

[0016] In some embodiments of the present disclosure, drying and weighing the polymer liquid film to determine the third mass includes:

[0017] The polymer liquid film is dried and weighed under preset conditions for multiple times until the difference between two adjacent weighings is no greater than a preset value, and the value of the last weighing is determined as the third mass.

[0018] In some embodiments of the present disclosure, the preset conditions include:

[0019] The preset temperature is 100-110°C, and the preset time is 50-70 minutes.

[0020] In some embodiments of the present disclosure, before drying the polymer liquid film, the testing method further comprises:

[0021] The polymer liquid film is washed.

[0022] In some embodiments of the present disclosure, the testing method further comprises:

[0023] After the polymerization reaction of the polymerizable monomers, a sample is immediately taken to form the polymer solution to be tested.

[0024] In some embodiments of the present disclosure, the preset support plate is a glass plate.

[0025] In some embodiments of the present disclosure, the testing method further comprises:

[0026] The conversion rate of the polymerization solution is determined according to the solid content.

[0027] In some embodiments of the present disclosure, determining the conversion rate of the polymerization solution according to the solid content includes:

[0028] The conversion rate of the polymer solution was determined according to the following formula:

[0029]

[0030] Wherein, a is the conversion rate, in %; b is the concentration of the total polymerized monomers before the polymerization reaction, in %; and c is the solid content, in %.

[0031] The beneficial effects of the present disclosure include but are not limited to: the testing method for the performance of the polymer liquid provided by the present disclosure obtains the solid content of the dipped polymer liquid to be tested through an integrated method of precise weighing, film coating and stripping, and rapid drying, and then determines the solid content in the polymer liquid. The testing method has small error, simple operation, and low equipment cost, and is suitable for online rapid monitoring of the solid content in the polymer liquid during the polymerization reaction.

[0032] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, are used to explain the principles of the embodiments of the present disclosure. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present disclosure, not all embodiments. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0034] Figure 1 Schematic diagram of a method for testing the performance of a polymer solution according to an exemplary embodiment of the present disclosure;

[0035] Figure 2 This is a schematic diagram of a dipping member according to an exemplary embodiment of the present disclosure rotating in the same direction on a preset support plate. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the technical solutions of the present disclosure will be clearly and completely described below in conjunction with the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure. It should be noted that, in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other.

[0037] In the preparation process of polyacrylonitrile-based carbon fibers, it is particularly important to quickly and efficiently determine the conversion rate and solid content of the polymerization solution during the polymerization reaction.

[0038] In order to solve the above technical problems, the present disclosure provides a method for testing the performance of a polymerization liquid. Through an integrated method of precise weighing, film coating and stripping, and rapid drying, the solid content of the dipped polymerization liquid to be tested is obtained, and then the solid content in the polymerization liquid is determined. This testing method has small error, simple operation, and low equipment cost, and is suitable for online rapid monitoring of the solid content in the polymerization liquid during the polymerization reaction.

[0039] The present disclosure provides a method for testing the performance of a polymer solution. Figure 1 As shown, the test method includes:

[0040] S100 , transferring the polymer solution to be tested into a preset container, and weighing the sum of the masses of the polymer solution to be tested and the preset container to determine the sum as the first mass.

[0041] Exemplarily, the preset container may be a weighing bottle.

[0042] S200 , dipping a preset mass of the polymer liquid to be tested and transferring it to a preset support plate for coating to form a polymer liquid film.

[0043] In this embodiment, the polymer solution to be tested is a uniform dispersed phase. Therefore, the solid content of the predetermined mass of the polymer solution to be tested can represent the solid content of the total polymer solution to be tested. In this step, a predetermined mass of the polymer solution to be tested is transferred to a predetermined support plate for coating. The resulting polymer film represents the solid components in the predetermined mass of the polymer solution to be tested.

[0044] S300 , weighing the sum of the mass of the remaining polymer solution to be tested after dipping and the mass of the preset container, and determining the sum as the second mass.

[0045] The preset mass of the polymer solution to be tested dipped in step S200 is inconvenient to weigh, or directly weighing it is prone to errors due to residual material in the container. The difference between the sum of the mass of the remaining polymer solution to be tested and the preset container (i.e., the second mass) and the first mass after dipping can be determined as the preset mass of the polymer solution to be tested dipped in step S200.

[0046] S400 , immersing a preset support plate in a preset liquid, separating the polymer liquid film from the preset support plate, drying the polymer liquid film, and weighing the polymer liquid film to determine the third mass.

[0047] The polymer liquid film on the preset support plate is the solid component in the preset mass of the polymer liquid to be tested, and the dry weight of the polymer liquid film (ie the third mass) is the solid mass in the preset mass of the polymer liquid to be tested.

[0048] For example, the predetermined liquid can be a liquid that can dissolve the polymerizable monomer or solvent but does not react with the polymeric liquid film. For example, the predetermined liquid can be water. To prevent the introduction of impurities, the predetermined liquid can be secondary water. When the predetermined support plate is immersed in the predetermined liquid, the polymeric liquid film does not react with the predetermined liquid and can be separated from the predetermined support plate to form an independent polymeric liquid film for subsequent weighing.

[0049] S500 : Determine the solid content in the polymerization solution according to the first mass, the second mass, and the third mass.

[0050] The difference between the sum of the mass of the remaining polymeric liquid to be tested and the mass of the preset container (i.e., the second mass) and the first mass can be determined as the preset mass of the polymeric liquid to be tested sampled in step S200. The ratio of the dry weight of the polymeric liquid film to the preset mass of the sampled polymeric liquid to be tested is the solid content of the sampled polymeric liquid to be tested. As previously mentioned, the polymeric liquid to be tested is a uniform dispersed phase, so the solid content of the sampled preset mass of the polymeric liquid to be tested can be representative of the solid content of the total polymeric liquid to be tested.

[0051] In this embodiment, the solid content of the dipped polymer liquid to be tested is obtained through an integrated method of precise weighing, film coating and stripping, and rapid drying, and then the solid content in the polymer liquid is determined. This test method has small error, simple operation, and low equipment cost, and is suitable for online rapid monitoring of the solid content in the polymer liquid during the polymerization reaction.

[0052] For example, at least two parallel samples of the polymer solution to be tested may be provided for each test to improve the accuracy of the test results.

[0053] In one embodiment, a preset mass of the polymer liquid to be detected is dipped and transferred to a preset support plate for coating to form a polymer liquid film, including: dipping a preset mass of the polymer liquid to be detected by a dipping component and transferring it to a preset position of the preset support plate, and rotating the dipping component along the same direction on the preset support plate to spread the polymer liquid to be detected on the preset support plate to form a polymer liquid film.

[0054] Exemplarily, the dipping member may be a glass rod, and the preset mass may be 0.5 to 1.0 g.

[0055] refer to Figure 2 , the polymer solution to be tested of a preset mass is dipped by the dipping member 10 and transferred to a preset position of the preset support plate 20, for example, the preset position can be the center of the preset support plate 20. The dipping member 10 is moved in the same direction, for example Figure 2The dipping member 10 rotates in a clockwise direction 30 as shown in the figure, spreading the polymer solution to be tested on the predetermined support plate 20 to form a polymer film. Because the formed polymer film is spread by the dipping member 10, it ensures a uniform thickness throughout the polymer film, preventing localized excessive thickness of the polymer film from causing incomplete subsequent drying and resulting in test errors. The dipping member 10 spreads the polymer solution to be tested on the predetermined support plate 20 in the same direction, reducing operator variability and improving the reproducibility of test results.

[0056] In one embodiment, the support plate is a glass plate, which has a smooth surface, is easy to remove the film, and is easy to clean. In addition, the glass plate is chemically stable and does not react with the polymer solution, thus ensuring the integrity of the polymer solution film and the accuracy of the test results.

[0057] In one embodiment, determining the solid content of the polymerization liquid according to the first mass, the second mass, and the third mass includes determining the solid content of the polymerization liquid according to the following formula:

[0058]

[0059] Wherein, c is the solid content, in %; m1 is the first mass, in g; m2 is the second mass, in g; m3 is the third mass, in g.

[0060] The sum of the masses of the remaining polymer liquid to be detected and the preset container after dipping (i.e., the second mass), and the difference between the first mass, i.e., m1-m2, can be determined as the preset mass of the polymer liquid to be detected dipped in step S200. The ratio of the dry weight of the polymer liquid film to the preset mass of the dipped polymer liquid to be detected is the solid content of the dipped polymer liquid to be detected. The polymer liquid to be detected is a uniform dispersed phase, so the solid content in the preset mass of the dipped polymer liquid to be detected can represent the solid content in the total polymer liquid to be detected. In this embodiment, the solid content of the dipped polymer liquid to be detected can be obtained by calculating through a clear formula, and then the solid content in the total polymer liquid to be detected can be determined. There is no need for complicated conversion, which reduces the risk of calculation errors and can also meet the requirements of online rapid monitoring of the solid content in the polymer liquid during the polymerization reaction.

[0061] In one embodiment, the polymer liquid film is dried and weighed to determine the third mass, including: drying and weighing the polymer liquid film under preset conditions multiple times until the difference between two adjacent weighings is no greater than a preset value, and determining the last weighed value as the third mass.

[0062] Exemplarily, the preset value can be a value that ensures the degree of drying of the polymer liquid film. When the difference between two consecutive weighings is no greater than the preset value, it indicates that the polymer liquid film is nearly completely dried. Further extension of the drying time will have little effect on drying the polymer liquid film and will extend the test time and reduce test efficiency. For example, the preset value can be 0.3-0.5 mg, such as 0.3 mg, 0.4 mg, or 0.5 mg. The preset value can also be any value between the exemplary preset values, such as 0.35-0.45 mg.

[0063] In this embodiment, by repeatedly drying and weighing the polymer liquid film under preset conditions until a constant weight is reached, interference from volatile components such as moisture in the polymer liquid film can be eliminated, thereby avoiding the third mass of the weighed polymer liquid film being too high due to insufficient drying, and thus avoiding the test result of solid content being too high.

[0064] In one embodiment, the preset conditions include: a preset temperature of 100-110° C., and a preset duration of 50-70 minutes.

[0065] In this embodiment, the polymer liquid film is dried at a preset temperature of 100-110°C for 50-70 minutes to ensure that the moisture and other substances in the polymer liquid film are fully volatilized while preventing the polymer liquid film from being decomposed by excessively high temperatures. For example, the preset temperature can be 100°C, 105°C, or 110°C. The preset temperature can also be any value between the exemplary preset temperatures, for example, the preset temperature can also be any value between 102-108°C. For example, the preset duration can be 50 minutes, 60 minutes, or 70 minutes. The preset duration can also be any value between the exemplary preset durations, for example, the preset duration can also be any value between 55-65 minutes.

[0066] In one embodiment, before drying the polymer liquid film, the testing method further includes: washing the polymer liquid film.

[0067] For example, the polymer liquid membrane can be cleaned by soaking it in secondary water for 10 minutes. After cleaning, the polymer liquid membrane is taken out and placed on filter paper to absorb moisture from the surface of the polymer liquid membrane.

[0068] In this embodiment, the polymer liquid film is washed before being dried to remove unreacted monomers or residual solvents in the polymer liquid film, thereby preventing them from being counted in the third mass of the polymer liquid film and affecting the accuracy of the solid content test results.

[0069] In one embodiment, the testing method further comprises: immediately sampling the polymerizable monomer after the polymerization reaction to form a polymer solution to be tested.

[0070] In this embodiment, after the polymerization reaction of the polymerizable monomer, sampling is immediately performed to quickly obtain the solid content data of the current polymerization reaction state, providing a basis for adjusting process parameters, such as reaction time or reaction stop time, and avoiding the reaction-test interval being too long, so that the polymer solution to be tested can no longer represent the immediate polymerization reaction situation.

[0071] In one embodiment, the testing method further comprises: determining the conversion rate of the polymerization solution based on the solid content.

[0072] The reactant monomers in the polymerization reaction of the polymerization liquid are liquid, and the polymerization reaction product polymer is solid. That is, the conversion rate of the polymerization liquid can be determined according to the solid content after the polymerization reaction. Therefore, the solid content in the polymerization liquid can be directly related to the conversion rate of the polymerization reaction, providing a basis for the process optimization of the polymerization reaction.

[0073] In one embodiment, determining the conversion rate of the polymerization solution based on the solid content includes:

[0074] The conversion rate of the polymerization solution was determined according to the following formula:

[0075]

[0076] Wherein, a is the conversion rate, unit is %; b is the concentration of total polymerized monomers before polymerization, unit is %; c is the solid content, unit is %.

[0077] The reactant monomers in the polymerization solution are liquid, while the polymer product is solid. This means that the solids content of the polymerization solution after the polymerization reaction is the concentration of the polymer produced. Therefore, the conversion rate (a) of the polymerization solution can be determined based on the ratio of the solids content (c) after the polymerization reaction to the total monomer concentration (b) before the polymerization reaction.

[0078] In this embodiment, by correlating the solid content c with the concentration b of the total polymerized monomers before the polymerization reaction, the conversion rate a of the polymerization reaction is determined, which can intuitively reflect the progress of the polymerization reaction and provide a basis for the process optimization of the polymerization reaction. For example, the end time of the polymerization reaction can be judged in real time by the conversion rate to avoid excessive polymerization or insufficient reaction and improve the quality of the carbon fiber precursor.

[0079] In order to more clearly explain the technical solution of the present disclosure, a specific example of a method for testing the properties of a polymer solution provided by an exemplary embodiment of the present disclosure is given.

[0080] After the polymerization reaction of the polymerizable monomer, a sample is immediately taken to form a polymer solution to be tested, and the polymer solution to be tested is transferred to a weighing bottle. The sum of the masses of the polymer solution to be tested and the weighing bottle is weighed and determined as the first mass m1.

[0081] Use a glass rod to dip 0.5-1.0 g of the polymer solution to be tested and transfer it to a 22×22 cm2 In the center of the glass plate, the glass rod rotates several times in the same direction along the glass plate to evenly spread the polymer liquid to be tested on the glass plate to form a polymer liquid film.

[0082] The sum of the mass of the remaining polymer solution to be tested after dipping and the mass of the weighing bottle is weighed and determined as the second mass m2.

[0083] Immerse the glass plate with the polymer liquid film in a tray filled with secondary water. The polymer liquid film will separate from the glass plate. Soak the polymer liquid film in secondary water for 10 minutes, then wash it and take it out and place it on filter paper.

[0084] Place the polymer film in a vacuum drying oven and adjust the vacuum drying oven to a non-vacuum state. When the temperature reaches 105°C, dry it for 60 minutes, then weigh the polymer film. Repeat the drying and weighing process until the difference between the two weighings is no greater than 0.4 mg. The final polymer film mass is used as the third mass m3. At least two replicate samples should be prepared for each set of polymer solutions to be tested.

[0085] Determine the solid content in the polymer solution according to the following formula, take the average value of the result, and retain 2 decimal places:

[0086]

[0087] The conversion rate of the polymerization solution was determined according to the following formula, and the results were averaged, with one decimal place retained:

[0088]

[0089] Wherein, a is the conversion rate, in %; b is the concentration of the total polymerized monomers before the polymerization reaction, in %; and c is the solid content, in %.

[0090] Two groups of polymer solutions were tested using the above polymer solution performance test method. Two parallel samples were set up in each group. The test results are recorded in Table 1.

[0091] Table 1

[0092]

[0093] As can be seen from Table 1, the test method for the performance of the polymer liquid provided in the above exemplary embodiment of the present disclosure obtains the solid content of the dipped polymer liquid to be tested through an integrated method of precise weighing, film coating and stripping, and rapid drying, and then determines the solid content in the polymer liquid and the conversion rate of the polymer liquid. The test error is small and the results are accurate, which can provide a basis for the process optimization of the polymerization reaction.

[0094] The contents described above can be implemented individually or in combination in various ways, and these variations are all within the scope of protection of the present disclosure.

[0095] Finally, it should be noted that in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0096] The above embodiments are intended only to illustrate the technical solutions of the present disclosure and are not intended to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents; and such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.

Claims

1. A method for testing the properties of a polymer solution, characterized in that: The test method includes: Transferring the polymer solution to be tested into a preset container, and weighing the sum of the masses of the polymer solution to be tested and the preset container to determine the sum as the first mass; Dipping a predetermined mass of the polymer solution to be tested and transferring it to a predetermined support plate for coating to form a polymer liquid film; Weighing the sum of the mass of the remaining polymer solution to be tested and the mass of the preset container after dipping, and determining it as the second mass; immersing the preset support plate in a preset liquid, separating the polymer liquid film from the preset support plate, drying and weighing the polymer liquid film to determine a third mass; The solid content in the polymerization solution is determined based on the first mass, the second mass, and the third mass.

2. The method for testing the performance of a polymer solution according to claim 1, wherein: The step of dipping a predetermined mass of the polymer liquid to be tested and transferring the polymer liquid to a predetermined support plate for coating to form a polymer liquid film comprises: The dipping member is used to dip a preset mass of the polymer liquid to be tested and transfer it to a preset position on the preset support plate, and the dipping member is used to rotate along the same direction on the preset support plate to spread the polymer liquid to be tested on the preset support plate to form the polymer liquid film.

3. The method for testing the performance of a polymer solution according to claim 1, wherein: Determining the solid content in the polymer solution according to the first mass, the second mass, and the third mass includes: The solid content in the polymer solution is determined according to the following formula: Wherein, c is the solid content, in %; m1 is the first mass, in g; m2 is the second mass, in g; and m3 is the third mass, in g.

4. The method for testing the performance of a polymer solution according to claim 1, wherein: The step of drying and weighing the polymer liquid film to determine the third mass includes: The polymer liquid film is dried and weighed under preset conditions for multiple times until the difference between two adjacent weighings is no greater than a preset value, and the value of the last weighing is determined as the third mass.

5. The method for testing the performance of a polymer solution according to claim 4, wherein: The preset conditions include: The preset temperature is 100-110°C, and the preset time is 50-70 minutes.

6. The method for testing the performance of a polymer solution according to claim 1, wherein: Before drying the polymer liquid film, the testing method further comprises: The polymer liquid film is washed.

7. The method for testing the performance of a polymer solution according to claim 1, wherein: The test method further comprises: After the polymerization reaction of the polymerizable monomers, a sample is immediately taken to form the polymer solution to be tested.

8. The method for testing the performance of a polymer solution according to claim 1, wherein: The preset supporting plate is a glass plate.

9. The method for testing the performance of a polymer solution according to any one of claims 1 to 8, characterized in that: The test method further comprises: The conversion rate of the polymerization solution is determined according to the solid content.

10. The method for testing the performance of a polymer solution according to claim 9, wherein: Determining the conversion rate of the polymer solution according to the solid content includes: The conversion rate of the polymer solution was determined according to the following formula: Wherein, a is the conversion rate, in %; b is the concentration of the total polymerized monomers before the polymerization reaction, in %; and c is the solid content, in %.

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