Method for testing content of resin

Abstract

The invention provides a resin content testing method which comprises the following steps: respectively decomposing a prepreg with a first preset weight, a fiber with a second preset weight and a resin with a third preset weight under the same preset condition to obtain the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin; wherein the prepreg comprises fibers and resin; and determining the content of the resin in the prepreg according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin. According to the testing method, the prepreg, the fiber and the resin are decomposed under the same preset condition, the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin are obtained, and then the content of the resin in the prepreg can be determined. The test method can quickly determine the content of the resin in the prepreg, does not need to use a solvent, reduces the cost, and is environment-friendly.

Description

Technical Field

[0001] The present disclosure relates to the technical field of composite materials, and in particular to a method for testing resin content. Background Art

[0002] Prepreg is a combination of resin matrix and reinforcing material made by impregnating continuous fibers or fabrics in a resin matrix under strictly controlled conditions. It is an intermediate material before composite materials are formed into parts, and its performance directly affects the quality of composite products. Resin content is the main technical indicator in the prepreg manufacturing process and is a key characteristic parameter that affects the molding processability, performance and quality of resin-based composite materials. Therefore, the determination of resin content is of great significance in prepreg production. At present, traditional prepreg resin content testing processes such as dissolution and extraction methods are time-consuming and have chemical solvent pollution, and cannot reflect the distribution of resin content in a timely manner. Summary of the invention

[0003] In order to solve the problems existing in the related art, the present disclosure provides a test method for resin content, the test method comprising:

[0004] Decomposing a prepreg of a first preset weight, a fiber of a second preset weight, and a resin of a third preset weight under the same preset conditions respectively to obtain a weight loss rate of the prepreg, a weight loss rate of the fiber, and a weight loss rate of the resin; wherein the prepreg includes the fiber and the resin;

[0005] The content of the resin in the prepreg is determined according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin.

[0006] In some embodiments of the present disclosure, determining the content of the resin in the prepreg according to the weight loss rate of the prepreg, the weight loss rate of the fiber, and the weight loss rate of the resin comprises:

[0007] According to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin, the content of the resin in the prepreg is determined by the following calculation:

[0008]

[0009] Wherein, Rc is the content of resin in the prepreg, in %; A is the weight loss rate of the resin, in %; B is the weight loss rate of the fiber, in %; C is the weight loss rate of the prepreg, in %.

[0010] In some embodiments of the present disclosure, the decomposing of the prepreg of the first preset weight, the fiber of the second preset weight, and the resin of the third preset weight under the same preset conditions respectively comprises:

[0011] A prepreg of a first preset weight, a fiber of a second preset weight, and a resin of a third preset weight are respectively placed in a thermogravimetric analyzer under the same preset conditions for decomposition to obtain a weight-temperature relationship curve of the prepreg, a weight-temperature relationship curve of the fiber, and a weight-temperature relationship curve of the resin.

[0012] In some embodiments of the present disclosure, obtaining the weight loss rate of the prepreg, the weight loss rate of the fiber, and the weight loss rate of the resin comprises:

[0013] Determining the weight loss rate of the prepreg according to the weight and temperature relationship curve of the prepreg;

[0014] Determining the weight loss rate of the fiber according to the weight-temperature relationship curve of the fiber;

[0015] The weight loss rate of the resin is determined according to the relationship curve between the weight and temperature of the resin.

[0016] In some embodiments of the present disclosure, the weight loss rate of the prepreg is determined according to the ratio between the weight reduction of the prepreg during the decomposition process and the first preset weight; and / or,

[0017] determining the weight loss rate of the fiber according to the ratio between the weight reduction of the fiber during the decomposition process and the second preset weight; and / or,

[0018] The weight loss rate of the resin is determined according to the ratio between the weight reduction of the resin during the decomposition process and the third preset weight.

[0019] In some embodiments of the present disclosure, the first preset weight is 1-5 mg; the second preset weight is 1-5 mg; and the third preset weight is 1-5 mg.

[0020] In some embodiments of the present disclosure, the first preset weight is less than or equal to the second preset weight.

[0021] In some embodiments of the present disclosure, the first preset weight is less than or equal to the third preset weight.

[0022] In some embodiments of the present disclosure, the preset conditions include:

[0023] The preset temperature is 25-700°C, and during the decomposition process, the preset temperature is increased at a rate of 10-30°C / min.

[0024] In some embodiments of the present disclosure, the preset conditions also include a nitrogen atmosphere.

[0025] The beneficial effects of the present disclosure include but are not limited to: in the test method for resin content provided by the present disclosure, by decomposing the prepreg, fiber and resin under the same preset conditions, the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin are obtained, and then according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin, the content of the resin in the prepreg can be determined. This test method can quickly determine the content of the resin in the prepreg, and does not require the use of solvents, reduces costs, and is environmentally friendly.

[0026] 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 present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings incorporated into the specification and constituting a part of the specification illustrate embodiments of the present disclosure and are used together with the description 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, rather than all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The figure is a schematic flow chart of a method for testing resin content according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present disclosure clearer, the technical solution of the present disclosure will be clearly and completely described in combination with the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other without conflict.

[0030] As the main technical index in the prepreg manufacturing process, resin content is a key characteristic parameter that affects the molding processability, performance and quality of resin-based composite materials. Therefore, the determination of resin content is of great significance in prepreg production. At present, the traditional prepreg resin content testing process such as solvent washing method and extraction method is time-consuming and has chemical solvent pollution, and cannot reflect the distribution of resin content in time.

[0031] Based on this, the exemplary embodiment of the present disclosure provides a method for testing the resin content, such as Figure 1 As shown, the test method includes:

[0032] S100, respectively decomposing a prepreg of a first preset weight, fibers of a second preset weight, and a resin of a third preset weight under the same preset conditions to obtain a weight loss rate of the prepreg, a weight loss rate of the fibers, and a weight loss rate of the resin; wherein the prepreg includes fibers and resin.

[0033] S200, determining the resin content in the prepreg according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin.

[0034] The decomposition of the prepreg mainly comes from the decomposition of the resin in the prepreg, and partly comes from the loss of the sizing agent on the fiber surface in the prepreg. Therefore, in the test method for the resin content provided by this exemplary embodiment, the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin are obtained by decomposing the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin under the same preset conditions, and then the resin content in the prepreg can be determined based on the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin. This test method can quickly determine the content of the resin in the prepreg without the use of solvents, reducing costs and being environmentally friendly.

[0035] It should be noted that the prepreg includes fibers and resins, that is, the fibers and resins that decompose under the same preset conditions as the prepreg should be the components of the prepreg. For example, when the resin in the prepreg is a multi-component resin, the resin that decomposes under the same preset conditions as the prepreg should be the same multi-component resin. When the fibers in the prepreg are multi-type fibers, the fibers that decompose under the same preset conditions as the prepreg should be the same multi-type fibers.

[0036] In the exemplary embodiment provided in the present disclosure, the preset conditions include: a preset temperature of 25-700° C., and during the decomposition process, the preset temperature is increased at a rate of 10-30° C. / min.

[0037] The preset condition for the decomposition of the prepreg, fiber and resin can be to heat up from 25°C at a rate of 10-30°C / min, for example, to 700°C at a rate of 10°C / min, 20°C / min or 30°C / min. When the temperature is raised to 700°C, the resin can be completely decomposed. In this way, the weight loss rate of complete decomposition of the resin in the prepreg can be measured, thereby accurately measuring the resin content in the prepreg.

[0038] In the exemplary embodiment provided by the present disclosure, the preset conditions also include a nitrogen atmosphere. During the decomposition process of the prepreg, fiber and resin, the purge gas and the protective gas are both nitrogen atmospheres, which can avoid interference from other factors during the decomposition process.

[0039] In an exemplary embodiment provided by the present disclosure, the step S200 determines the content of the resin in the prepreg according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin, including:

[0040] According to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin, the resin content in the prepreg is determined by the following calculation:

[0041]

[0042] Wherein, Rc is the content of resin in the prepreg, in %; A is the weight loss rate of the resin, in %; B is the weight loss rate of the fiber, in %; C is the weight loss rate of the prepreg, in %.

[0043] Assuming that the mass of the prepreg to be tested is m, the proportion of the resin in the prepreg to be tested is x, then the proportion of the fiber in the prepreg to be tested is 1-x, assuming that the weight loss rate of resin decomposition is A, the weight loss rate of fiber decomposition is B, and the weight loss rate of prepreg decomposition is C, then the following equation is obtained:

[0044] mC=mx·A+m(1-x)·B

[0045] After conversion, the proportion x of the resin in the prepreg to be tested can be determined:

[0046]

[0047] In this embodiment, the resin content in the prepreg can be calculated based on the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin decomposed under the same preset conditions. This testing method can quickly determine the resin content in the prepreg without the use of solvents, thereby reducing costs and being environmentally friendly.

[0048] In an exemplary embodiment provided by the present disclosure, the first preset weight is 1-5 mg, the second preset weight is 1-5 mg, and the third preset weight is 1-5 mg.

[0049] Under the same preset conditions, the first preset weight of the prepreg, the second preset weight of the fiber and the third preset weight of the resin decomposed should be relatively close. In this embodiment, the first preset weight, the second preset weight and the third preset weight are all limited to 1-5 mg, which can ensure that the amount of decomposition is sufficient to be detected and avoid prolonging the test time due to excessive decomposition.

[0050] In an exemplary embodiment provided by the present disclosure, the first preset weight is less than or equal to the second preset weight.

[0051] To avoid the situation where the fibers have been completely decomposed while the prepreg is still decomposing under the same preset conditions, the weight loss rate of the fibers cannot represent the weight loss rate of the fibers in the prepreg when the decomposition is completed, thereby affecting the test results of the resin content in the prepreg. Therefore, in this embodiment, the first preset weight is less than or equal to the second preset weight to ensure that the weight loss rate of the fibers can represent the weight loss rate of the fibers in the prepreg when the decomposition is completed.

[0052] In an exemplary embodiment provided by the present disclosure, the first preset weight is less than or equal to the third preset weight.

[0053] To avoid the situation where the resin has been completely decomposed while the prepreg is still decomposing under the same preset conditions, the weight loss rate of the resin cannot represent the weight loss rate of the resin in the prepreg when the decomposition is completed, thereby affecting the test results of the resin content in the prepreg. Therefore, in this embodiment, the first preset weight is less than or equal to the third preset weight to ensure that the weight loss rate of the resin can represent the weight loss rate of the resin in the prepreg when the decomposition is completed.

[0054] In an exemplary embodiment provided by the present disclosure, the prepreg of a first preset weight, the fiber of a second preset weight, and the resin of a third preset weight are respectively decomposed under the same preset conditions, including:

[0055] The prepreg of the first preset weight, the fiber of the second preset weight and the resin of the third preset weight are respectively placed in a thermogravimetric analyzer under the same preset conditions for decomposition to obtain a weight-temperature relationship curve of the prepreg, a weight-temperature relationship curve of the fiber and a weight-temperature relationship curve of the resin.

[0056] Thermogravimetric analyzer is an instrument that uses thermogravimetry to detect the temperature-mass change relationship of a substance. Thermogravimetry is a method of measuring the change in the mass of a substance with temperature (or time) under program temperature control. The first preset weight of prepreg, the second preset weight of fiber, and the third preset weight of resin are placed in crucibles respectively, and placed in a thermogravimetric analyzer under the same preset conditions for decomposition. After the decomposition is completed, the weight-temperature relationship curve of the prepreg, the weight-temperature relationship curve of the fiber, and the weight-temperature relationship curve of the resin can be obtained. The weight loss rate of the prepreg can be obtained from the weight-temperature relationship curve of the prepreg, the weight loss rate of the fiber can be obtained from the weight-temperature relationship curve of the fiber, and the weight loss rate of the resin can be obtained from the weight-temperature relationship curve of the resin.

[0057] Exemplarily, the crucible used for decomposition is an open crucible made of aluminum oxide without a cover.

[0058] Exemplarily, in addition to placing the prepreg, fiber and resin in a thermogravimetric analyzer for decomposition, the prepreg, fiber and resin can also be placed in another testing device for decomposition, which needs to be equipped with a temperature control element, a gas control element, a precision balance, a thermocouple component, a constant temperature water bath, a data storage component and a display component.

[0059] In the exemplary embodiments provided in the present disclosure, the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin are obtained, including:

[0060] The weight loss rate of the prepreg is determined based on the relationship curve between the weight and temperature of the prepreg.

[0061] The fiber weight loss rate is determined based on the fiber weight and temperature relationship curve.

[0062] The weight loss rate of the resin is determined based on the relationship curve between the resin weight and temperature.

[0063] By analyzing the weight-temperature relationship curve of the prepreg, the weight change of the corresponding prepreg between the starting temperature point and the end temperature point of decomposition can be extrapolated, and the weight loss rate of the prepreg during the decomposition process can be obtained. By analyzing the weight-temperature relationship curve of the fiber, the weight change of the corresponding fiber between the starting temperature point and the end temperature point of decomposition can be extrapolated, and the weight loss rate of the fiber during the decomposition process can be obtained. By analyzing the weight-temperature relationship curve of the resin, the weight change of the corresponding resin between the starting temperature point and the end temperature point of decomposition can be extrapolated, and the weight loss rate of the resin during the decomposition process can be obtained. According to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin, the content of the resin in the prepreg can be determined. This test method can quickly determine the content of the resin in the prepreg, and does not require the use of solvents, reduces costs, and is environmentally friendly.

[0064] In an exemplary embodiment provided by the present disclosure, the weight loss rate of the prepreg is determined according to a ratio between a weight reduction amount of the prepreg during the decomposition process and a first preset weight.

[0065] The prepreg will lose weight during the decomposition process, and the weight loss rate of the prepreg can be determined based on the ratio between the weight loss of the prepreg before and after decomposition and the first preset weight (i.e., the weight of the prepreg before decomposition). The weight loss rate of the prepreg can be used to subsequently determine the content of resin in the prepreg.

[0066] In an exemplary embodiment provided by the present disclosure, the weight loss rate of the fiber is determined according to a ratio between a weight reduction amount of the fiber during the decomposition process and a second preset weight.

[0067] The fiber will lose weight during the decomposition process, and the weight loss rate of the fiber can be determined based on the ratio between the weight loss of the fiber before and after decomposition and the second preset weight (i.e., the weight of the fiber before decomposition). The weight loss rate of the fiber can be used to subsequently determine the content of the resin in the prepreg.

[0068] In an exemplary embodiment provided by the present disclosure, the weight loss rate of the resin is determined according to a ratio between a weight reduction amount of the resin during the decomposition process and a third preset weight.

[0069] The resin will lose weight during the decomposition process, and the weight loss rate of the resin can be determined based on the ratio between the weight loss of the resin before and after decomposition and the third preset weight (i.e., the weight of the resin before decomposition). The weight loss rate of the resin can be used to subsequently determine the content of the resin in the prepreg.

[0070] In order to more clearly explain the technical solution of the present disclosure, a specific example of a method for testing the resin content provided by an exemplary embodiment of the present disclosure is given.

[0071] Perform baseline calibration on the thermogravimetric analyzer. Weigh 2.1 mg of prepreg, 2.6 mg of resin, and 2.3 mg of fiber and place them in three alumina crucibles respectively. Transfer the three alumina crucibles to the thermogravimetric analyzer respectively, set the heating program of the thermogravimetric analyzer to 25-700°C, the heating rate to 10°C / min, select nitrogen as the test atmosphere, run the test program and obtain the weight-temperature relationship curve of the prepreg, the weight-temperature relationship curve of the fiber, and the weight-temperature relationship curve of the resin respectively, and read the weight loss rate of the prepreg, the weight loss rate of the resin, and the weight loss rate of the fiber from each weight-temperature relationship curve. Repeat three groups of tests, Group A, Group B, and Group C, and the results of each group of tests are shown in Table 1.

[0072] Table 1

[0073] Group No. Weight loss rate of prepreg / % Weight loss rate of resin / % Fiber weight loss rate / % Group A 24.63 77.22 1.10 Group B 24.72 74.87 1.13 Group C 24.46 75.87 1.16

[0074] The weight loss rate of the prepregs, the weight loss rate of the resin and the weight loss rate of the fibers measured in groups A, B and C were respectively substituted into the following mathematical model of the relationship between the prepregs and their components to calculate the resin content in the prepregs of groups A, B and C:

[0075]

[0076] The resin contents in the prepregs of Group A, Group B and Group C measured by the resin content test method provided in this embodiment were compared with the resin contents in the prepregs obtained by the solvent washing method, as shown in Table 2.

[0077] Table 2

[0078]

[0079] It can be seen from Table 2 that the test results of the resin content in the prepreg obtained by the test method for the resin content provided in this embodiment meet the enterprise index requirements and have a small difference with the results obtained by the traditional solvent washing method.

[0080] The contents described above may be implemented individually or in combination in various ways, and these variations are all within the protection scope of the present disclosure.

[0081] Finally, it should be noted that in this article, the terms "include", "comprises" 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 other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0082] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for testing resin content, characterized in that: The test method includes: Decomposing a prepreg of a first preset weight, a fiber of a second preset weight, and a resin of a third preset weight under the same preset conditions respectively to obtain a weight loss rate of the prepreg, a weight loss rate of the fiber, and a weight loss rate of the resin; wherein the prepreg includes the fiber and the resin; The content of the resin in the prepreg is determined according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin.

2. The method for testing resin content according to claim 1, characterized in that: The step of determining the content of the resin in the prepreg according to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin comprises: According to the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin, the content of the resin in the prepreg is determined by the following calculation formula: Wherein, Rc is the content of resin in the prepreg, in %; A is the weight loss rate of the resin, in %; B is the weight loss rate of the fiber, in %; C is the weight loss rate of the prepreg, in %.

3. The method for testing the resin content according to claim 1 or 2, characterized in that: The step of respectively decomposing the prepreg of the first preset weight, the fiber of the second preset weight, and the resin of the third preset weight under the same preset conditions comprises: A prepreg of a first preset weight, a fiber of a second preset weight, and a resin of a third preset weight are respectively placed in a thermogravimetric analyzer under the same preset conditions for decomposition to obtain a weight-temperature relationship curve of the prepreg, a weight-temperature relationship curve of the fiber, and a weight-temperature relationship curve of the resin.

4. The method for testing the resin content according to claim 3, characterized in that: The method of obtaining the weight loss rate of the prepreg, the weight loss rate of the fiber and the weight loss rate of the resin comprises: Determining the weight loss rate of the prepreg according to the weight and temperature relationship curve of the prepreg; Determining the weight loss rate of the fiber according to the weight-temperature relationship curve of the fiber; The weight loss rate of the resin is determined according to the relationship curve between the weight and temperature of the resin.

5. The method for testing resin content according to claim 1, characterized in that: determining the weight loss rate of the prepreg according to the ratio between the weight reduction of the prepreg during the decomposition process and the first preset weight; and / or, determining the weight loss rate of the fiber according to the ratio between the weight reduction of the fiber during the decomposition process and the second preset weight; and / or, The weight loss rate of the resin is determined according to the ratio between the weight reduction of the resin during the decomposition process and the third preset weight.

6. The method for testing the resin content according to claim 1, characterized in that: The first preset weight is 1-5 mg; the second preset weight is 1-5 mg; and the third preset weight is 1-5 mg.

7. The method for testing the resin content according to claim 6, characterized in that: The first preset weight is less than or equal to the second preset weight.

8. The method for testing the resin content according to claim 6, characterized in that: The first preset weight is less than or equal to the third preset weight.

9. The method for testing resin content according to claim 1, characterized in that: The preset conditions include: The preset temperature is 25-700°C, and during the decomposition process, the preset temperature is increased at a rate of 10-30°C / min.

10. The method for testing resin content according to claim 9, characterized in that: The preset conditions also include a nitrogen atmosphere.

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