Method for detecting thermal stability of 5G polymer plastic based on terahertz time-domain spectroscopy technology

Abstract

The invention relates to a terahertz time-domain spectroscopy technology-based 5G polymer plastic thermal stability detection method. The method comprises the following steps: preparing a standard sample; acquiring a reference signal; measuring a terahertz time-domain spectral signal in the heating process based on a preset measurement strategy as a target signal; based on the target signal and the reference signal, dielectric properties of the 5G polymer plastic sample material are obtained, and a plurality of average values are taken as dielectric parameters; drawing an influence curve, and determining the thermal deformation temperature and the fluctuation condition of each dielectric parameter; and evaluating the thermal stability of the 5G polymer plastic sample material. According to the method, the destructive test limitation of traditional thermogravimetric analysis and differential scanning calorimetry and the limitation of Fourier transform infrared spectroscopy are overcome, the dielectric properties of the high-molecular plastic are obtained in a non-destructive mode within the terahertz frequency range close to the 5G frequency band by means of the high penetrating power and fingerprint characteristics of terahertz waves, and the dielectric properties of the high-molecular plastic are obtained in a non-destructive mode. And the thermal stability is accurately evaluated.

Description

Technical Field

[0001] The present application relates to the technical field of terahertz detection, and in particular to a method for detecting the thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology. Background Art

[0002] 5G mobile communication technology, with its high speed, low latency, and massive connectivity, has become a hot topic over the past decade. Because 5G communications utilize electromagnetic frequency bands in the high GHz and even hundreds of GHz range, traditional metal antennas are unsuitable for such high frequencies due to severe signal interference and electromagnetic losses. Consequently, most 5G communication antennas are made of dielectric materials. Compared to metals, polymer plastics such as PEEK, PES, PI, and PPO are widely used in 5G communications due to their light weight, low dielectric constant, and low cost. 5G antennas must withstand high temperatures caused by outdoor sunlight and electromagnetic radiation during operation. High temperatures have always been a threat to polymer materials, so analyzing the thermal stability of 5G polymer plastics within the operating frequency band is crucial.

[0003] The thermal stability of polymer materials and their structural changes upon heating in other frequency bands have attracted widespread attention. Various analytical techniques, such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR), have been applied to study and analyze the thermal stability of polymer materials. However, TGA and DSC are destructive methods, while infrared spectroscopy is a spectroscopic method that measures the characteristic vibrations of atomic groups in the infrared band (>10 THz).

[0004] Terahertz radiation refers to the general term for electromagnetic radiation in the frequency band of 0.1-10 THz and the wavelength range of 0.03-3.0 mm. Terahertz (THz) spectroscopy is a new spectral detection technology with low energy, high penetration and fingerprint characteristics. The terahertz time-domain spectroscopy system (THz-TDS) can simultaneously obtain complete information on the intensity and phase of the terahertz pulse. The Fourier transform can simultaneously obtain the absorption spectrum and dielectric spectrum of the detected sample, which helps to analyze the structure, conformation and intermolecular interactions of the sample with a high signal-to-noise ratio. More importantly, terahertz waves span the 5G frequency band well. Therefore, THz-TDS technology may become a complementary technology to Fourier transform infrared spectroscopy and Raman spectroscopy, and be used to study the dielectric properties of materials in the terahertz frequency band.

[0005] Currently, there is a lack of a method to evaluate the thermal stability of 5G polymer plastics in the terahertz frequency range. Summary of the Invention

[0006] In order to solve the above-mentioned defects, the present application provides a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology.

[0007] The above-mentioned invention objective of this application is achieved through the following technical solutions:

[0008] A method for detecting the thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology, comprising the following steps:

[0009] S1. Select 5G polymer plastic sample material and prepare standard sample;

[0010] S2. Acquire a terahertz time-domain spectrum signal of the heating and insulation measurement chamber without a sample as a reference signal for terahertz spectrum measurement;

[0011] S3, pressing the standard sample into a pellet and placing it in a heating chamber, and measuring the terahertz time-domain spectroscopy signal of the corresponding temperature during the heating process as the target signal using a terahertz time-domain spectroscopy system based on a preset measurement strategy;

[0012] S4. Calculate the dielectric properties of the 5G polymer plastic sample material at the corresponding temperature based on the target signal and the reference signal, and take several average values ​​of the dielectric property results at each corresponding temperature as the dielectric parameters at each corresponding temperature, wherein the dielectric properties include refractive index, absorption intensity, dielectric constant, and dielectric loss tangent;

[0013] S5. Draw the influence curve of dielectric parameters changing with temperature at each corresponding temperature, and determine the thermal deformation temperature T of 5G polymer plastic sample material based on the influence curve. DL , and the fluctuation of each dielectric parameter during the heating process;

[0014] S6. Through the pre-set evaluation benchmark, the fluctuation of dielectric parameters during heating and the thermal deformation temperature T DL Conduct thermal stability evaluation based on 5G polymer plastic sample materials.

[0015] By adopting the above technical solution, this solution proposes a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology, which aims to solve the limitations of traditional detection technology in high frequency bands; first, select polymer plastic materials suitable for 5G communication and prepare standard samples; without placing samples, perform terahertz time-domain spectroscopy scanning on the heating and insulation measurement chamber to obtain a reference signal as the terahertz time-domain spectrum, so as to deduct the influence of environmental factors on the results in subsequent measurements; the prepared standard sample is pressed into a sheet and placed in the heating chamber, and the terahertz time-domain spectroscopy system is used according to the preset A measurement strategy was used to measure the terahertz time-domain spectral signals of the sample at different temperatures during the heating process, and these signals were used as target signals for analysis. By comparing the target signal with the reference signal, the dielectric properties of the 5G polymer plastic sample at different temperatures were calculated, including the refractive index, absorption intensity, dielectric constant, and dielectric loss tangent. To improve accuracy, the dielectric property results at each temperature were averaged over multiple measurements as the dielectric parameters at that temperature. Based on the dielectric parameters at different temperatures, the influence curves of the dielectric parameters changing with temperature were plotted, and by analyzing these curves, the thermal deformation temperature T of the sample material was determined. DL And the fluctuation of each dielectric parameter during the heating process; according to the preset evaluation benchmark, combined with the fluctuation of dielectric parameters and thermal deformation temperature T DL , and comprehensively evaluate the thermal stability of 5G polymer plastic sample materials; this application overcomes the destructive testing limitations of traditional thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), as well as the limitation that Fourier transform infrared spectroscopy (FTIR) can only measure in the infrared band. It uses the high penetration and fingerprint characteristics of terahertz waves to non-destructively obtain the dielectric properties of polymer plastics within the terahertz frequency range similar to the 5G band, and then accurately evaluate its thermal stability, which has the effect of improving the accuracy and efficiency of the test, and improving the reliability and stability of the material in 5G applications.

[0016] In a preferred example, the present application can be further configured as follows: the 5G polymer plastic sample material includes polyetheretherketone, polyetherimide, polyethersulfone, polyimide, polyphenylene ether, polyphenylene sulfide, polyphenylene sulfone, polysulfone, and polytetrafluoroethylene.

[0017] In a preferred example, the present application may be further configured as follows: the standard sample in step S1 includes a standard powder sample, a standard sheet sample, and a standard film sample;

[0018] The particle size of the standard powder sample is less than 10 μm, and the thickness of the standard sheet sample and the standard film sample are both less than 1 mm.

[0019] In a preferred example, the present application can be further configured as follows: the calculation formula of the refractive index in step S4 is:

[0020] Where n(f) is the refractive index, f is the frequency, c is the speed of light, and d is the thickness of the standard sample that the terahertz wave penetrates. are the phase information of the reference signal and the standard sample transmitted energy after Fourier transform.

[0021] In a preferred example, the present application can be further configured as follows: the calculation of the absorption intensity in step S4 requires obtaining the extinction coefficient, and the calculation formula of the extinction coefficient is:

[0022] Where κ(f) is the extinction coefficient, ρ(f) is the amplitude ratio of the reference signal and the standard sample transmission energy after Fourier transformation;

[0023] The calculation formula of the absorption intensity is:

[0024]

[0025] In a preferred example, the present application can be further configured as follows: the expression of the dielectric constant in step S4 is:

[0026] ε * (f) = ε'(f) - iε" (f), where ε'(f) is the real part of the dielectric constant, ε" (f) is the imaginary part of the dielectric constant, and i is the imaginary unit;

[0027] The calculation formula for the real part of the dielectric constant is:

[0028] ε'(f)=n 2 (f)-κ 2 (f);

[0029] The calculation formula of the imaginary part of the dielectric constant is:

[0030]

[0031] In a preferred example, the present application can be further configured as follows: the calculation formula of the dielectric loss tangent in step S4 is:

[0032]

[0033] In a preferred example, the present application can be further configured as follows: the thermal deformation temperature T DL Determination includes:

[0034] When it is identified that the change of the dielectric property with temperature in the influence curve exceeds the threshold, the temperature corresponding to the dielectric property that changes beyond the threshold is determined as the thermal deformation temperature T DL .

[0035] In summary, this application has the following beneficial technical effects:

[0036] 1. This application overcomes the destructive testing limitations of traditional thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), as well as the limitation of Fourier transform infrared spectroscopy (FTIR) that can only measure in the infrared band. By utilizing the high penetration and fingerprint characteristics of terahertz waves, the dielectric properties of polymer plastics can be non-destructively obtained within the terahertz frequency range close to the 5G band, thereby accurately evaluating their thermal stability. This has the effect of improving the accuracy and efficiency of testing, and enhancing the reliability and stability of materials in 5G applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of an embodiment of a method for detecting thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology of the present application;

[0038] Figure 2 This is a terahertz absorption spectrum of a 5G polymer plastic sample material at room temperature in an embodiment of a method for detecting thermal stability of 5G polymer plastic based on terahertz time-domain spectroscopy technology of the present application;

[0039] Figure 3 This is a graph showing the relationship between the absorption coefficient of a 5G polymer plastic sample material and temperature in an embodiment of a method for detecting thermal stability of a 5G polymer plastic based on terahertz time-domain spectroscopy technology of the present application;

[0040] Figure 4 This is a graph showing how the dielectric properties of polyetheretherketone (PEEK) vary with frequency and temperature in an embodiment of a method for detecting thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology of the present application;

[0041] Figure 5 This is a graph showing the change in dielectric loss tangent of a 5G polymer plastic sample material with temperature in an embodiment of a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology in the present application. DETAILED DESCRIPTION

[0042] The following is combined with Figure 1-5 This application is described in further detail.

[0043] In one embodiment, if Figure 1 As shown, the present application discloses a method for detecting the thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology, which specifically includes the following steps:

[0044] S1. Select 5G polymer plastic sample material and prepare standard sample;

[0045] S2. Acquire a terahertz time-domain spectrum signal of the heating and insulation measurement chamber without a sample as a reference signal for terahertz spectrum measurement;

[0046] S3, pressing the standard sample into a pellet and placing it in a heating chamber, and measuring the terahertz time-domain spectroscopy signal of the corresponding temperature during the heating process as the target signal using a terahertz time-domain spectroscopy system based on a preset measurement strategy;

[0047] S4. Calculate the dielectric properties of the 5G polymer plastic sample material at the corresponding temperature based on the target signal and the reference signal, and take several average values ​​of the dielectric property results at each corresponding temperature as the dielectric parameters at each corresponding temperature, wherein the dielectric properties include refractive index, absorption intensity, dielectric constant, and dielectric loss tangent;

[0048] S5. Draw the influence curve of dielectric parameters changing with temperature at each corresponding temperature, and determine the thermal deformation temperature T of 5G polymer plastic sample material based on the influence curve. DL , and the fluctuation of each dielectric parameter during the heating process;

[0049] S6. Through the pre-set evaluation benchmark, the fluctuation of dielectric parameters during heating and the thermal deformation temperature T DL Conduct thermal stability assessment based on 5G polymer plastic sample materials;

[0050] In this embodiment, if Figure 2 Shown is the terahertz absorption spectrum of 5G polymer plastic sample material at room temperature 25°C.

[0051] In this embodiment, the thermal deformation temperature T in step S5 is DL Determination includes:

[0052] When the change of the dielectric property with temperature in the influence curve exceeds the threshold, the temperature corresponding to the dielectric property exceeding the threshold is determined as the thermal deformation temperature T DL , among which, Figure 3 The figure shows the relationship between the standard sample absorption coefficient of 5G polymer plastic sample material and temperature, wherein the temperature shown in the figure is the thermal deformation temperature corresponding to each 5G polymer plastic sample material.

[0053] Furthermore, for polymer plastics with characteristic terahertz absorption peaks, such as PEEK, the thermal deformation temperature of the polymer can be determined more accurately by detecting the change in the area of ​​its terahertz characteristic peak with heating temperature. Figure 4 Shown is a graph showing the dielectric properties of polyetheretherketone (PEEK) as a function of frequency and temperature.

[0054] Specifically, the evaluation benchmark preset in step S6 is a standard sample whose fluctuation of dielectric parameters (ratio of standard deviation to average value) is less than 10%, that is, the 5G polymer plastic sample material is evaluated to have good thermodynamic stability.

[0055] Furthermore, the dielectric parameters in the range from room temperature to thermal deformation temperature were statistically analyzed, and the fluctuation of each dielectric parameter, that is, the ratio of the standard deviation of each dielectric parameter to the average value, was calculated. The thermal stability of the 5G polymer plastic sample material was evaluated based on the fluctuation parameters of each dielectric parameter, such as Figure 5 The figure shows the change of dielectric loss tangent of the standard sample of 5G polymer plastic sample material with temperature. Figure 5 Statistical analysis shows that except for PI and PES, whose dielectric loss tangent fluctuations are greater than 10%, the dielectric loss tangent fluctuations of other polymers are all less than 10%; based on this, it can be considered that 5G polymer plastics PEEK, PEI, PPO, PPS, PPSU, PSU, and PTFE have good thermal stability.

[0056] It should be noted that the above analysis of heat deformation temperature and thermal stability is only an example, and the evaluation can also be carried out by examining other dielectric parameters of other polymers, such as refractive index, real part or imaginary part of dielectric constant, etc.

[0057] In this embodiment, 5G polymer plastic sample materials include but are not limited to polyetheretherketone (PEEK), polyetherimide (PEI), polyethersulfone (PES), polyimide (PI), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyphenylene sulfone (PPSU), polysulfone (PSU), and polytetrafluoroethylene (PTFE);

[0058] Specifically, the measurement strategy preset in step S3 is:

[0059] The heating chamber was set to increase from room temperature (25°C) to 300°C, with a heating rate of 1°C per 0.5 minutes. The terahertz time-domain spectroscopy signal of the standard sample was measured every 2.5 minutes, with 5 frames of the standard sample's terahertz time-domain spectroscopy signal recorded each time.

[0060] In order to ensure the consistency between the actual measured temperature of the standard sample and the required heating temperature, the time interval for recording 5 terahertz time-domain spectrum signals of the standard sample is 10 seconds, that is, from the 110th second to the 150th second of each measurement interval of 2.5 minutes, a time domain signal spectrum of the terahertz time-domain spectrum signal of the standard sample is collected every 10 seconds.

[0061] Furthermore, in order to eliminate the thermal history of the 5G polymer plastic sample material, before the heating temperature reaches the thermal deformation temperature of the standard sample of the 5G polymer plastic sample material, the heating is stopped, the heating chamber is allowed to slowly cool down to room temperature, and then heated again, and the terahertz time-domain spectroscopy signal of the standard sample is measured according to the preset measurement strategy in step S3.

[0062] Specifically, in step S4, an average value of five dielectric property results at each corresponding temperature is obtained.

[0063] In this embodiment, the standard samples in step S1 include standard powder samples, standard sheet samples and standard film samples; wherein the particle size of the standard powder samples is less than 10 μm, and the thickness of the standard sheet samples and the standard film samples are both less than 1 mm to reduce scattering during terahertz spectrum detection.

[0064] In this embodiment, the calculation formula of the refractive index in step S4 is:

[0065] Where n(f) is the refractive index, f is the frequency, c is the speed of light, and d is the thickness of the standard sample that the terahertz wave penetrates. are the phase information of the reference signal and the standard sample transmitted energy after Fourier transform.

[0066] In this embodiment, the calculation of the absorption intensity in step S4 requires obtaining the extinction coefficient, and the calculation formula of the extinction coefficient is:

[0067] Where κ(f) is the extinction coefficient, ρ(f) is the amplitude ratio of the reference signal and the standard sample transmission energy after Fourier transformation;

[0068] The calculation formula for absorption intensity is:

[0069]

[0070] In this embodiment, the expression of the dielectric constant in step S4 is:

[0071] ε * (f) = ε'(f) - iε" (f), where ε'(f) is the real part of the dielectric constant, ε" (f) is the imaginary part of the dielectric constant, and i is the imaginary unit;

[0072] The formula for calculating the real part of the dielectric constant is:

[0073] ε'(f)=n 2 (f)-κ 2 (f);

[0074] The formula for calculating the imaginary part of the dielectric constant is:

[0075]

[0076] In this embodiment, the calculation formula of the dielectric loss tangent in step S4 is:

[0077]

[0078] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0079] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for detecting thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology, characterized in that: Includes steps: S1. Select 5G polymer plastic sample material and prepare standard samples; S2, obtaining a terahertz time domain spectrum signal of a heating and heat preservation measurement chamber without a sample as a reference signal for terahertz spectrum measurement; S3, pressing the standard sample into a tablet and placing it in a heating chamber, and measuring the terahertz time-domain spectroscopy signal of the corresponding temperature during the heating process by the terahertz time-domain spectroscopy system based on a preset measurement strategy as the target signal; S4. Based on the target signal and the reference signal, the dielectric properties of the 5G polymer plastic sample material at the corresponding temperature are calculated and obtained, and the dielectric property results at each corresponding temperature are averaged several times as the dielectric parameters at each corresponding temperature, wherein the dielectric properties include refractive index, absorption intensity, dielectric constant and dielectric loss tangent; S5. Draw the influence curve of dielectric parameters changing with temperature at each corresponding temperature, and determine the thermal deformation temperature T of 5G polymer plastic sample material based on the influence curve. DL , and the fluctuation of each dielectric parameter during heating; S6. Through the preset evaluation criteria, the fluctuation of dielectric parameters during heating and the thermal deformation temperature T DL Conduct thermal stability assessment based on 5G polymer plastic sample materials.

2. According to claim 1, a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology is characterized in that: The 5G polymer plastic sample materials include polyetheretherketone, polyetherimide, polyethersulfone, polyimide, polyphenylene ether, polyphenylene sulfide, polyphenylene sulfone, polysulfone, and polytetrafluoroethylene.

3. According to claim 1, a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology is characterized in that: The standard samples in step S1 include standard powder samples, standard sheet samples and standard film samples; Wherein, the particle size of the standard powder sample is less than 10 μm, and the thickness of the standard sheet sample and the standard film sample are both less than 1 mm.

4. According to claim 1, a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology is characterized in that: The calculation formula of the refractive index in step S4 is: Among them, n(f) is the refractive index, f is the frequency, c is the speed of light, and d is the thickness of the standard sample that the terahertz wave penetrates. They are the phase information of the reference signal and the standard sample transmitted energy after Fourier transform.

5. According to claim 4, a 5G polymer plastic thermal stability detection method based on terahertz time-domain spectroscopy technology is characterized in that: The calculation of the absorption intensity in step S4 requires obtaining the extinction coefficient, and the calculation formula of the extinction coefficient is: Where κ(f) is the extinction coefficient, ρ(f) is the amplitude ratio of the reference signal and the standard sample transmission energy after Fourier transformation; The calculation formula of the absorption intensity is:

6. The method for detecting thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology according to claim 5 is characterized in that: The expression of the dielectric constant in step S4 is: ε * (f) = ε'(f)-iε" (f), where ε'(f) is the real part of the dielectric constant, ε" (f) is the imaginary part of the dielectric constant, and i is the imaginary unit; The calculation formula for the real part of the dielectric constant is: e'(f)=n 2 (f)-k 2 (f); The calculation formula of the imaginary part of the dielectric constant is:

7. The method for detecting thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology according to claim 6 is characterized in that: The calculation formula of the dielectric loss tangent in step S4 is:

8. The method for detecting thermal stability of 5G polymer plastics based on terahertz time-domain spectroscopy technology according to claim 1 is characterized in that: The thermal deformation temperature T in step S5 DL Determination, including: When it is identified that the change of the dielectric property with temperature in the influence curve exceeds a threshold, the temperature corresponding to the dielectric property that changes beyond the threshold is determined as the thermal deformation temperature T DL .

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