A method for detecting and evaluating the uniformity of a polymer-powder blend system

Abstract

The present invention discloses a method for detecting and evaluating the uniformity of a polymer-powder blend system, which relates to the field of evaluating the uniformity of a polymer-powder blend system. This method uses the polymer-powder blend system to prepare a sample to be measured with a constant phase angle element structure, and uses impedance measurement to measure the measured impedance amplitude of the sample to be measured at different sampling frequencies to obtain the measured amplitude-frequency curve of the sample to be measured; according to the amplitude-frequency model, the theoretical impedance amplitude of the sample to be measured at each sampling frequency is determined to obtain the theoretical amplitude-frequency curve, and the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the sample to be measured is calculated to obtain the detection and evaluation result. This method uses the fluctuation of the impedance amplitude with the change of frequency to characterize the uniformity state of the particle distribution in the polymer-powder blend system, which can provide a reference basis for the detection and evaluation of the uniformity of the polymer-powder blend system, and the obtained detection and evaluation result has good objectivity and accuracy.

Description

Technical Field

[0001] The present invention relates to the field of evaluating the uniformity of polymer-powder blend systems, and in particular to a method for detecting and evaluating the uniformity of polymer-powder blend systems. Background Art

[0002] Non-uniformity is a phenomenon of mass non-uniformity and instability in local areas of polymer-powder blend systems. Under the action of natural factors and external force fields, local damage will first occur in non-uniform parts and then develop into larger-area damage. Therefore, the non-uniformity phenomenon is the main reason affecting the performance of polymer-powder blend materials. Therefore, in the application of polymer-powder blend materials, the non-uniformity phenomenon should be avoided as much as possible, and ensuring mass uniformity and stability is one of the most important principles in the process of structure and material design.

[0003] The existing method mainly cures the polymer-powder blend material, and then professional personnel use an electron microscope to observe the cross-section of the cured material to detect whether there is a non-uniformity phenomenon. However, this method is greatly affected by subjectivity and the accuracy is insufficient. Summary of the Invention

[0004] In view of the above problems and technical requirements, the inventor of the present invention proposed a method for detecting and evaluating the uniformity of polymer-powder blend systems. The technical solution of the present invention is as follows:

[0005] A method for detecting and evaluating the uniformity of a polymer-powder blend system, the method comprising:

[0006] Preparing a sample to be tested, the sample to be tested comprising two conductive electrode plates and a polymer-powder blend system to be detected and evaluated for uniformity filled between the two conductive electrode plates;

[0007] Connecting the two conductive electrode plates of the sample to be tested with an impedance measuring device, and measuring the measured impedance amplitude at different sampling frequencies to obtain the measured amplitude-frequency curve of the sample to be tested;

[0008] Determining the theoretical impedance amplitude of the sample to be tested at each sampling frequency according to the amplitude-frequency model to obtain the theoretical amplitude-frequency curve;

[0009] Calculating the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the sample to be tested, and obtaining the detection and evaluation result based on the deviation parameter of the sample to be tested. The larger the deviation parameter, the worse the uniformity of the polymer-powder blend system in the sample to be tested indicated by the detection and evaluation result.

[0010] A further technical solution thereof is that calculating the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the sample to be tested includes:

[0011] Arrange the measured impedance amplitude and the theoretical impedance amplitude in a monotonically changing order according to the corresponding sampling frequencies respectively to form sequences, and determine the first-order measured difference sequence of the sequence formed by the measured impedance amplitude and the first-order theoretical difference sequence of the sequence formed by the theoretical impedance amplitude;

[0012] Calculate the sum of the variances of the first-order measured difference sequence and the first-order theoretical difference sequence as the deviation parameter between the measured amplitude frequency curve and the theoretical amplitude frequency curve.

[0013] A further technical solution thereof is that the first-order measured difference sequence and the first-order theoretical difference sequence respectively include n - 1 differential data points. The n - 1 differential data points in the first-order measured difference sequence are sequentially denoted as S 1 , S 2 , S 3 L S n-1 , and the n - 1 differential data points in the first-order theoretical difference sequence are sequentially denoted as G 1 , G 2 , G 3 L G n , then the sum of the variances of the first-order measured difference sequence and the first-order theoretical difference sequence is

[0014] A further technical solution thereof is that the frequency intervals between each sampling frequency follow the rule of an exponential distribution with a parameter of λ.

[0015] A further technical solution thereof is that measuring the measured impedance amplitude at different sampling frequencies includes:

[0016] Applying a signal intensity and a signal frequency range corresponding to the system material type of the polymer - powder blend system to the sample to be measured, and measuring the measured impedance amplitude at different sampling frequencies.

[0017] A further technical solution thereof is that the method further includes:

[0018] Preparing a reference sample, where the reference sample includes two conductive electrode plates and a polymer - powder blend system with a uniformity reaching a predetermined standard filled between the two conductive electrode plates, and measuring the deviation parameter between the measured amplitude frequency curve and the theoretical amplitude frequency curve of the reference sample;

[0019] Then, obtain the detection and evaluation result based on the deviation parameter of the sample to be measured, including: when the deviation parameter of the sample to be measured does not exceed the deviation parameter of the reference sample, obtain a detection and evaluation result indicating that the uniformity of the polymer - powder blend system in the sample to be measured reaches the predetermined standard; otherwise, obtain a detection and evaluation result indicating that the uniformity of the polymer - powder blend system in the sample to be measured does not reach the predetermined standard.

[0020] A further technical solution is that a theoretical amplitude-frequency curve of the sample to be measured at each sampling frequency is determined according to the amplitude-frequency model, including:

[0021] Construct an amplitude-frequency model with unknown parameters according to the equivalent circuit of the polymer-powder blend system;

[0022] Determine the values of the unknown parameters in the amplitude-frequency model through non-linear regression of the measured amplitude-frequency curve, and obtain an amplitude-frequency model reflecting the relationship between impedance amplitude and frequency;

[0023] Substitute each sampling frequency into the amplitude-frequency model to respectively determine the corresponding theoretical impedance amplitude, and obtain a theoretical amplitude-frequency curve.

[0024] A further technical solution is that the equivalent circuit of the polymer-powder blend system includes: a fourth resistor and a Warburg impedance form a series circuit, the series circuit is connected in parallel with a third constant phase angle element to form a third parallel circuit, a third resistor and a second constant phase angle element are connected in parallel to form a second parallel circuit, the second resistor, the third parallel circuit and the second parallel circuit are connected in series and then connected in parallel with a first constant phase angle element to form a first parallel circuit, and the first parallel circuit is connected in series with a first resistor.

[0025] A further technical solution is that the amplitude-frequency model with unknown parameters constructed according to the equivalent circuit of the polymer-powder blend system is:

[0026]

[0027] where H(f) is the impedance amplitude related to the frequency f, R 1 is the impedance of the first resistor, Y Q1 is the admittance of the first constant phase angle element, R 2 is the impedance of the second resistor, Y Q2 is the admittance of the second constant phase angle element, R 3 is the impedance of the third resistor, Y Q3 is the admittance of the third constant phase angle element, R 4 is the impedance of the fourth resistor, Z W is the impedance value of the Warburg impedance, where the impedance value of the Warburg impedance, the impedances of each resistor and the admittances of each constant phase angle element are all unknown parameters, and the impedance value of the Warburg impedance and the admittances of each constant phase angle element are related to the frequency.

[0028] A further technical solution is that the preparation of the sample to be measured includes:

[0029] The polymer-powder blend precursor is sandwiched between two conductive electrode plates and cured to obtain two conductive electrode plates and the polymer-powder blend system filled therein. The parts of the polymer-powder blend system exposed to the outside relative to the two conductive electrode plates are sealed to prepare a sample to be measured.

[0030] The beneficial technical effects of the present invention are:

[0031] The present application discloses a method for detecting and evaluating the uniformity of a polymer-powder blend system. This method uses the fluctuation of the impedance amplitude with frequency to characterize the uniformity state of the particle distribution in the polymer-powder blend system, which can provide a reference basis for the detection and evaluation of the uniformity of the polymer-powder blend system, and the obtained detection and evaluation results have good objectivity and accuracy. Moreover, through the deviation parameter, the advantages and disadvantages of the particle distribution uniformity in different polymer-powder blend systems can be intuitively compared and it can be determined whether the predetermined standard is reached. Description of the Drawings

[0032] Figure 1 is a flowchart of the method for detecting and evaluating the uniformity of the polymer-powder blend system of the present application.

[0033] Figure 2 is a circuit structure diagram of the equivalent circuit of the polymer-powder blend system. Detailed Embodiments

[0034] The following further describes the detailed embodiments of the present invention with reference to the drawings.

[0035] The present application discloses a method for detecting and evaluating the uniformity of a polymer-powder blend system. This method includes the following steps. Please refer to Figure 1 the flowchart shown:

[0036] Step 102, prepare a sample to be measured. The sample to be measured includes two conductive electrode plates and a polymer-powder blend system to be detected and evaluated for uniformity filled between the two conductive electrode plates. The sample to be measured forms a constant phase angle element structure.

[0037] Specifically, the method for preparing the sample to be measured is as follows: The polymer-powder blend precursor with certain fluidity is sandwiched between two conductive electrode plates and cured to obtain two conductive electrode plates and the polymer-powder blend system filled therein. The conductive electrode plates can be realized by conductive glass, and actually can be cured in an electrothermal blast drying oven with a certain process. The side of the obtained polymer-powder blend system is still exposed to the air, and the parts of the polymer-powder blend system exposed to the outside relative to the two conductive electrode plates are continuously sealed to prepare the sample to be measured. Vacuum silicone grease can be used for sealing during sealing.

[0038] Step 104: Connect two conductive electrodes of the sample to be measured using an impedance measurement device, and measure the measured impedance amplitude at different sampling frequencies to obtain the measured amplitude-frequency curve of the sample to be measured.

[0039] When measuring the measured impedance amplitude using an impedance measurement device, connect the positive and negative poles of the output end of the impedance measurement device to the two conductive electrodes of the sample to be measured respectively, and apply a signal intensity and signal frequency range corresponding to the system material type of the polymer-powder blend system to the sample to be measured using the impedance measurement device. Common impedance measurement devices include, for example, an electrochemical workstation. The signal intensity and signal frequency range corresponding to different system material types can be different, and the signal intensity and signal frequency range corresponding to each system material type can be determined in advance by means of experience or experimental fitting. This application does not make any limitations in this regard.

[0040] Measure the measured impedance amplitude of the sample to be measured at each different sampling frequency respectively, and thus the measured amplitude-frequency curve of the sample to be measured can be plotted.

[0041] In one embodiment, the frequency interval between each sampling frequency follows the rule of an exponential distribution with a parameter of λ. For example, the parameter λ can take a value of 100.

[0042] Step 106: Determine the theoretical impedance amplitude of the sample to be measured at each sampling frequency according to the amplitude-frequency model to obtain the theoretical amplitude-frequency curve.

[0043] Specifically, first, find an equivalent circuit of a polymer-powder blend system through impedance fitting software, and then construct an amplitude-frequency model with unknown parameters based on the equivalent circuit of the polymer-powder blend system.

[0044] In one embodiment, the equivalent circuit of the polymer-powder blend system includes: a fourth resistor R 4 and a Warburg impedance W form a series circuit. The Warburg impedance W is the impedance caused by the diffusion process. This series circuit is in parallel with a third constant phase element Q 3 to form a third parallel circuit. A third resistor R 3 and a second constant phase element Q 2 are in parallel to form a second parallel circuit. A second resistor R 2 , the third parallel circuit and the second parallel circuit are connected in series and then in parallel with a first constant phase element Q 1 to form a first parallel circuit. The first parallel circuit is connected in series with a first resistor R 1 , and the two ends of this series circuit are respectively used to connect the positive and negative poles of the output end of the impedance measurement device.

[0045] Based on Figure 2 the equivalent circuit shown, the constructed amplitude-frequency model with unknown parameters is:

[0046]

[0047] Among them, H(f) is the impedance amplitude related to the frequency f, and R 1 is the impedance of the first resistor, and Y Q1 is the admittance of the first constant phase angle element, and R 2 is the impedance of the second resistor, and Y Q2 is the admittance of the second constant phase angle element, and R 3 is the impedance of the third resistor, and Y Q3 is the admittance of the third constant phase angle element, and R 4 is the impedance of the fourth resistor, and Z W is the impedance value of the Weber impedance. Among them, the impedance value of the Weber impedance and the admittances of each resistor and each constant phase angle element are all unknown parameters, and the impedance value Z W of the Weber impedance W and each constant phase angle element Q 1 、Q 2 、Q 3 are all related to the frequency f.

[0048] Determine the values of the unknown parameters in the amplitude-frequency model through non-linear regression of the measured amplitude-frequency curve, that is, obtain the values of R 1 、R 2 、R 3 、R 4 , and obtain the variation relationships of Y Q1 、Y Q2 、Y Q3 、Z W with the frequency f. Thus, an amplitude-frequency model reflecting the relationship between the impedance amplitude H(f) and the frequency f can be obtained, and the finally obtained amplitude-frequency model only contains the unknown variable of the frequency f.

[0049] Substitute each sampling frequency into the amplitude-frequency model with known parameters to respectively determine the corresponding theoretical impedance amplitudes, and thus a theoretical amplitude-frequency curve can be fitted.

[0050] Step 108, calculate the deviation parameter between the measured amplitude-frequency curve of the sample to be tested and the theoretical amplitude-frequency curve, and obtain a detection evaluation result based on the deviation parameter of the sample to be tested. The larger the deviation parameter, the worse the uniformity of the polymer-powder blend system in the sample to be tested indicated by the detection evaluation result.

[0051] When calculating the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the sample to be measured, the measured impedance amplitude and the theoretical impedance amplitude are respectively arranged in a monotonic change order according to the corresponding sampling frequencies to form sequences. The monotonic change order can be the order of increasing sampling frequency or decreasing sampling frequency (usually the order from high frequency to low frequency). Suppose the measured amplitude-frequency curve includes the measured impedance amplitudes at n sampling frequencies, and the n measured impedance amplitudes are sequentially denoted as P 1 , P 2 , P 3 L P n . The theoretical amplitude-frequency curve includes the theoretical impedance amplitudes at the same n sampling frequencies, and the n theoretical impedance amplitudes are sequentially denoted as H 1 , H 2 , H 3 L H n .

[0052] Determine the first-order measured difference sequence of the sequence composed of the measured impedance amplitudes. The first-order measured difference sequence includes n - 1 difference data points, and the n - 1 difference data points in the first-order measured difference sequence are sequentially denoted as S 1 , S 2 , S 3 L S n-1 , where for any 1 ≤ j ≤ n - 1, S j = P j+1 - P j .

[0053] Determine the first-order theoretical difference sequence of the sequence composed of the theoretical impedance amplitudes. The first-order theoretical difference sequence includes n - 1 difference data points, and the n - 1 difference data points in the first-order theoretical difference sequence are sequentially denoted as G 1 , G 2 , G 3 L G n , where for any 1 ≤ j ≤ n - 1, G j = H j+1 - H j .

[0054] Calculate the sum of the variances of the first-order measured difference sequence and the first-order theoretical difference sequence as the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve. Specifically, the sum of the variances of the first-order measured difference sequence and the first-order theoretical difference sequence is

[0055] In practical applications, it is generally necessary to determine whether the uniformity of the polymer-powder blend system in the sample to be measured reaches a predetermined standard. If the deviation parameter of the sample to be measured does not exceed the predetermined threshold, it can be considered that the predetermined standard is reached; otherwise, the predetermined standard is not reached. The predetermined threshold can be calculated from a reference sample. Specifically, a reference sample is prepared. The reference sample includes two conductive plates and a polymer-powder blend system with uniformity reaching the predetermined standard filled between the two conductive plates. Then, the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the reference sample is measured. The specific preparation method of the reference sample and the measurement method of the deviation parameter are similar to the processing method of the above-mentioned sample to be measured, and will not be elaborated in this application.

[0056] By comparing the deviation parameter of the sample to be measured with that of the reference sample, it can be determined whether the uniformity of the polymer-powder blend system in the sample to be measured reaches the predetermined standard: when the deviation parameter of the sample to be measured does not exceed that of the reference sample, a detection and evaluation result indicating that the uniformity of the polymer-powder blend system in the sample to be measured reaches the predetermined standard is obtained; otherwise, a detection and evaluation result indicating that the uniformity of the polymer-powder blend system in the sample to be measured does not reach the predetermined standard is obtained.

[0057] The following example illustrates the process of the method of this application more clearly:

[0058] (1) A PMMA homogeneous sol was prepared by solution blending method. The specific method is as follows: First, 2.8 g of PMMA was dissolved in a mixed solvent of 10 mL of propylene carbonate and 10 mL of acetonitrile, and stirred at 60 °C for 5 hours until the PMMA solid was completely dissolved to form a uniform transparent solution. Then, 0, 0.1 g, 0.15 g, and 0.2 g of self-made oligomer powder TZPI were added to the above-prepared homogeneous sol, and mixed for another 6 hours until the solid TZPI powder in the sol was basically uniformly dispersed in the system. The sol was sealed and left standing overnight in the dark to obtain the 1st, 2nd, 3rd, and 4th polymer-powder blend precursors respectively.

[0059] (2) The 1st, 2nd, 3rd, and 4th polymer-powder blend precursors were taken and respectively sandwiched between the positive and negative electrodes composed of two pieces of conductive glass to prepare devices with a constant phase angle element structure. The devices with a constant phase angle element structure were treated at a constant temperature of 60 °C in an electrothermal blast drying oven for 2 hours.

[0060] (3) After taking out the devices with a constant phase angle element structure, the part of the polymer-powder blend system exposed to air was sealed with vacuum silicone grease to obtain the 1st, 2nd, 3rd, and 4th samples to be measured.

[0061] (4) Set the amplitude of the electrochemical impedance spectrum to 0.02 V and the frequency range to 20 - 50 kHz. For each of the samples to be tested, namely Sample No. 1, 2, 3, and 4, connect the working electrode and the counter electrode of the electrochemical workstation to the conductive electrode plates on both sides of the sample to be tested respectively.

[0062] (5) Select the frequency interval according to the rule that the frequency variable follows an exponential distribution with parameter λ, and measure the measured impedance amplitude of the sample to be tested at this sampling frequency.

[0063] (6) Based on Figure 2 the amplitude - frequency model constructed from the equivalent circuit shown, determine the theoretical impedance amplitude of the sample to be tested at each sampling frequency to obtain the theoretical amplitude - frequency curve, and calculate the deviation parameter.

[0064] The measurement data of Sample No. 1 (without powder addition) to be tested are shown in the following table, and the deviation parameter between the measured amplitude - frequency curve and the theoretical amplitude - frequency curve of Sample No. 1 is calculated.

[0065]

[0066]

[0067] The measurement data of Sample No. 2 (added with 0.1 g of oligomer powder TZPI) to be tested are shown in the following table, and the deviation parameter between the measured amplitude - frequency curve and the theoretical amplitude - frequency curve of Sample No. 2 is calculated.

[0068]

[0069]

[0070] The measurement data of Sample No. 3 (added with 0.15 g of oligomer powder TZPI) to be tested are shown in the following table, and the deviation parameter between the measured amplitude - frequency curve and the theoretical amplitude - frequency curve of Sample No. 3 is calculated.

[0071]

[0072]

[0073] The measurement data of Sample No. 4 (added with 0.2 g of oligomer powder TZPI) to be tested are shown in the following table, and the deviation parameter between the measured amplitude - frequency curve and the theoretical amplitude - frequency curve of Sample No. 4 is calculated.

[0074]

[0075]

[0076]

[0077]

[0078] In summary, the concentrations (mg / mL) of TZPI powder contained in the test samples No. 1, No. 2, No. 3, and No. 4 in the system and the corresponding calculated deviation parameters are shown in the following table:

[0079]

[0080] It can be seen that as the amount of TZPI powder added gradually increases, the calculated deviation parameter ∑Dm 2 The deviation parameter provides a certain reference for the detection and evaluation of the uniformity of the polymer-powder blend system, and has good objectivity. The deviation parameter can intuitively compare the advantages and disadvantages of the particle distribution uniformity in different polymer-powder blend systems. In this example, if the ∑Dm of the reference sample is 2 The calculated value is 3.0000, which means that the uniformity of the polymer-powder blend system in the No. 1 and No. 2 samples meets the predetermined standard, while the uniformity of the polymer-powder blend system in the No. 3 and No. 4 samples does not meet the predetermined standard.

[0081] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A method for detecting and evaluating the uniformity of a polymer-powder blend system, characterized in that, the method comprises: preparing a sample to be measured, the sample to be measured comprising two conductive electrode plates and a polymer-powder blend system to be detected and evaluated for uniformity filled between the two conductive electrode plates; connecting the two conductive electrode plates of the sample to be measured by an impedance measuring device, and measuring the measured impedance amplitude at different sampling frequencies to obtain the measured amplitude-frequency curve of the sample to be measured; determining the theoretical impedance amplitude of the sample to be measured at each sampling frequency according to the amplitude-frequency model to obtain the theoretical amplitude-frequency curve; calculating the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the sample to be measured, and obtaining the detection and evaluation result based on the deviation parameter of the sample to be measured. The larger the deviation parameter, the worse the uniformity of the polymer-powder blend system in the sample to be measured indicated by the detection and evaluation result; the determining the theoretical impedance amplitude of the sample to be measured at each sampling frequency according to the amplitude-frequency model to obtain the theoretical amplitude-frequency curve includes: constructing an amplitude-frequency model with unknown parameters according to the equivalent circuit of the polymer-powder blend system; determining the values of the unknown parameters in the amplitude-frequency model through non-linear regression of the measured amplitude-frequency curve to obtain an amplitude-frequency model reflecting the relationship between impedance amplitude and frequency; substituting each sampling frequency into the amplitude-frequency model to respectively determine the corresponding theoretical impedance amplitude to obtain the theoretical amplitude-frequency curve; the equivalent circuit of the polymer-powder blend system includes: a fourth resistor and a Warburg impedance form a series circuit, the series circuit is connected in parallel with a third constant phase angle element to form a third parallel circuit, a third resistor and a second constant phase angle element are connected in parallel to form a second parallel circuit, a second resistor, the third parallel circuit and the second parallel circuit are connected in series and then connected in parallel with a first constant phase angle element to form a first parallel circuit, and the first parallel circuit is connected in series with a first resistor; the amplitude-frequency model with unknown parameters constructed according to the equivalent circuit of the polymer-powder blend system is: where H(f) is the impedance magnitude related to the frequency f, R 1 is the impedance of the first resistor, Y Q1 is the admittance of the first constant phase angle element, R 2 is the impedance of the second resistor, Y Q2 is the admittance of the second constant phase angle element, R 3 is the impedance of the third resistor, Y Q3 is the admittance of the third constant phase angle element, R 4 is the impedance of the fourth resistor, Z W is the impedance value of the Weber impedance, where the impedance value of the Weber impedance, the impedances of each resistor, and the admittances of each constant phase angle element are all unknown parameters, and the impedance value of the Weber impedance and the admittances of each constant phase angle element are related to the frequency.

2. The method according to claim 1, characterized in that, the calculating the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the sample to be measured includes: arranging the measured impedance amplitude and the theoretical impedance amplitude in a monotonically changing order according to the corresponding sampling frequencies to form sequences, and determining the first-order measured difference sequence of the sequence formed by the measured impedance amplitude and the first-order theoretical difference sequence of the sequence formed by the theoretical impedance amplitude; calculating the sum of the variances of the first-order measured difference sequence and the first-order theoretical difference sequence as the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve.

3. The method according to claim 2, characterized in that, The first-order measured difference sequence and the first-order theoretical difference sequence each include n - 1 difference data points. The n - 1 difference data points in the first-order measured difference sequence are sequentially denoted as S 1 , S 2 , S 3 … S n-1 , and the n - 1 difference data points in the first-order theoretical difference sequence are sequentially denoted as G 1 , G 2 , G 3 … G n-1 . Then the sum of the variances of the first-order measured difference sequence and the first-order theoretical difference sequence is 4. The method according to claim 1, characterized in that, the frequency interval between each sampling frequency follows the rule of an exponential distribution with a parameter of λ.

5. The method according to claim 1, characterized in that, the measuring the measured impedance amplitude at different sampling frequencies includes: Apply a signal intensity and signal frequency range corresponding to the system material type of the polymer-powder blend system to the sample to be measured, and measure the measured impedance amplitude at different sampling frequencies.

6. The method according to claim 1, wherein, the method further includes: preparing a reference sample, the reference sample including two conductive electrode plates and a polymer-powder blend system with a uniformity reaching a predetermined standard filled between the two conductive electrode plates, and measuring the deviation parameter between the measured amplitude-frequency curve and the theoretical amplitude-frequency curve of the reference sample; then obtaining the detection evaluation result based on the deviation parameter of the sample to be measured, including: when the deviation parameter of the sample to be measured does not exceed the deviation parameter of the reference sample, obtaining a detection evaluation result indicating that the uniformity of the polymer-powder blend system in the sample to be measured reaches the predetermined standard, otherwise obtaining a detection evaluation result indicating that the uniformity of the polymer-powder blend system in the sample to be measured does not reach the predetermined standard.

7. The method according to claim 1, wherein, the preparation of the sample to be measured includes: clamping a polymer-powder blend precursor between two conductive electrode plates and curing it to obtain two conductive electrode plates and a polymer-powder blend system filled therein, and sealing the part of the polymer-powder blend system exposed to the outside relative to the two conductive electrode plates to prepare the sample to be measured.

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