Device and method for in-situ measurement of degradation rate of epoxy resin

Abstract

The invention discloses a device and method for in-situ measurement of the degradation rate of epoxy resin, the device comprises an interdigital electrode, a bridge, a degradation reaction kettle and a data processing terminal, the surface of the interdigital electrode is coated with epoxy resin to be degraded, the bridge is used for detecting capacitance data of the interdigital electrode changing in the degradation process of the epoxy resin, and the degradation reaction kettle is used for degrading the epoxy resin. Degradation liquid is contained in the degradation reaction kettle, the degradation liquid and the epoxy resin are subjected to degradation reaction in the degradation reaction kettle, and the data processing terminal is used for obtaining the relative dielectric constant according to the capacitance data. The interdigital electrode generates changing capacitance data in the epoxy resin degradation process, the change of epoxy resin in degradation liquid is monitored in real time by detecting the capacitance data through the bridge, a fixed time interval does not need to be waited, the method is simple and efficient, and the method can be widely popularized and applied in practical application.

Description

Technical Field

[0001] The invention belongs to the technical field of material science and chemical engineering, in particular to the technical field of epoxy resin degradation reaction, and relates to a device and method for in-situ measuring the degradation rate of epoxy resin. Background Art

[0002] Epoxy resins are widely used in wind turbine blades, electronic equipment, aerospace, floor coatings, and other fields due to their exceptional properties, including light weight, high strength, excellent electrical properties, good corrosion resistance, and good adhesion. With growing environmental awareness and the accelerated advancement of the "dual carbon" goals, the efficient and environmentally friendly recycling and reuse of epoxy resin materials is becoming increasingly urgent.

[0003] Thermosetting epoxy resin waste has an insoluble, infusible, three-dimensional cross-linked network structure, making it difficult to reprocess and degrade and recycle. This has become a hot topic for research by scholars both domestically and internationally. Traditional epoxy resin degradation research typically relies on offline experimental methods such as gravimetric methods (periodic sampling, weighing, and calculation of degradation rates) and Fourier transform infrared (FTIR) methods (periodic sampling and infrared spectroscopy). Due to the complexity of the experiments and the tedious operations, the degradation data obtained are only discrete data points in time, unable to provide real-time, continuous information on the degradation process. This leads to unclear degradation mechanisms and restricts further development of epoxy resin degradation and recycling research. Summary of the Invention

[0004] To overcome the above-mentioned problems, the present inventors conducted intensive research and developed a device and method for in-situ measurement of epoxy resin degradation rate. The device comprises: interdigital electrodes, an electrical bridge, a degradation reactor, and a data processing terminal. The interdigital electrodes are coated with the epoxy resin to be degraded. The electrical bridge is used to detect capacitance data generated by the interdigital electrodes during the degradation of the epoxy resin. A degradation solution is placed in the degradation reactor, and a degradation reaction occurs between the degradation solution and the epoxy resin in the degradation reactor. The data processing terminal is used to obtain the relative dielectric constant based on the capacitance data. The interdigital electrodes generate capacitance data that changes during the degradation of the epoxy resin. The capacitance data is detected by the electrical bridge to monitor the changes of the epoxy resin in the degradation solution in real time. This method does not require waiting for a fixed time interval. The method is simple and efficient, and can be widely promoted and applied in practical applications, thus completing the present invention.

[0005] Specifically, the purpose of the present invention is to provide the following aspects:

[0006] In a first aspect, a device for in-situ measuring epoxy resin degradation rate is provided, the device comprising:

[0007] an interdigital electrode, the surface of which is coated with epoxy resin to be degraded, the interdigital electrode being used to generate capacitance data that changes during the degradation of the epoxy resin;

[0008] A bridge is used to detect the capacitance data of the interdigital electrodes during the degradation of epoxy resin;

[0009] A degradation reactor is provided with a degradation liquid, wherein the degradation liquid and the epoxy resin undergo a degradation reaction in the degradation reactor;

[0010] and a data processing terminal for obtaining the relative dielectric constant based on the capacitance data detected by the bridge.

[0011] The interdigitated electrode includes an electrode substrate and an interdigitated structure, and the interdigitated structure is arranged in an interdigitated manner on the electrode substrate.

[0012] The interdigitated electrodes further include a working electrode and a counter electrode. One end of the interdigitated structure 12 forms the working electrode, and the other end forms the counter electrode.

[0013] The working electrode of the interdigital electrode is connected to the measuring positive electrode of the bridge through a cable, and the counter electrode is connected to the measuring negative electrode of the bridge through a cable.

[0014] Wherein, the degradation liquid is alcohol, amine or water.

[0015] Wherein, a degradation aid is also added to the degradation liquid.

[0016] Wherein, the device further includes:

[0017] A stirring bar, which is used to stir the liquid in the degradation reactor;

[0018] The temperature control unit is used to monitor and control the temperature of the degradation reactor.

[0019] In a second aspect, a method for degrading epoxy resin using the device according to the first aspect is provided, the method comprising:

[0020] Step 1: immersing an interdigital electrode coated with an epoxy resin to be degraded below the interface of a degradation solution in a degradation reactor to start a degradation reaction;

[0021] Step 2: The bridge transmits the capacitance data of the interdigital electrodes during the epoxy resin degradation process to the data processing terminal, and obtains the relative dielectric constant based on the capacitance data to determine the epoxy resin degradation rate.

[0022] Wherein, in step 1, the epoxy resin to be degraded is coated on the surface of the interdigital electrode, a curing agent is added, and the resin is cured for later use.

[0023] Wherein, in step 2, the degradation reaction temperature is 150-170°C

[0024] The beneficial effects of the present invention include:

[0025] (1) The device for in-situ measurement of epoxy resin degradation rate provided by the present invention monitors the changes of epoxy resin in the degradation liquid in real time through changing capacitance data, without waiting for a fixed time interval, making continuous observation and measurement possible.

[0026] (2) The device for in-situ measurement of epoxy resin degradation rate provided by the present invention does not require repeated treatment of epoxy resin, which not only provides an efficient and real-time monitoring method, but also provides a new way to deeply understand the degradation mechanism of epoxy resin.

[0027] (3) The method for in-situ measurement of epoxy resin degradation rate provided by the present invention is simple and efficient, and can be widely promoted and applied in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The drawings in the specification are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It is apparent that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0029] In the attached figure:

[0030] Figure 1 A schematic structural diagram of a device for in-situ measuring epoxy resin degradation rate according to a preferred embodiment of the present invention is shown;

[0031] Figure 2 A schematic diagram of an interdigitated electrode structure according to a preferred embodiment of the present invention is shown;

[0032] Figure 3 The capacitance-time variation diagram of Example 1 is shown;

[0033] Figure 4 The degradation rate-time variation diagram of Example 1 is shown;

[0034] Figure 5 The capacitance-time variation diagram of Example 2 is shown;

[0035] Figure 6 The degradation rate-time variation diagram of Example 2 is shown;

[0036] Reference numerals

[0037] 1-interdigitated electrodes;

[0038] 11-electrode substrate;

[0039] 12-interdigitated structure;

[0040] 1A-working electrode;

[0041] 1B-counter electrode;

[0042] 2-Epoxy resin;

[0043] 3-Electric bridge;

[0044] 3A-measure the positive pole;

[0045] 3B-measure the negative pole;

[0046] 4- Cable;

[0047] 5-degradation liquid;

[0048] 6-degradation reactor;

[0049] 7- stirring bar;

[0050] 8- Temperature control unit;

[0051] 9-Data processing terminal. DETAILED DESCRIPTION

[0052] The following will refer to the attached Figures 1 to 6 Specific embodiments of the present invention will now be described in greater detail. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention may be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to facilitate a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0053] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the present invention shall be as defined in the attached claims.

[0054] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front," and "rear" and the like, indicating positions or locations, are based on the operating state of the present invention and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] To facilitate understanding of the embodiments of the present invention, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0056] On the one hand, according to the present invention, a device for in-situ measuring epoxy resin degradation rate is provided, such as Figure 1 As shown, the device includes:

[0057] An interdigital electrode 1, the surface of which is coated with an epoxy resin 2 to be degraded, and the interdigital electrode 1 is used to generate capacitance data that changes during the degradation of the epoxy resin 2;

[0058] The bridge 3 is used to detect the capacitance data of the interdigital electrodes 1 during the degradation process of the epoxy resin 2;

[0059] A degradation reactor 6 is provided with a degradation liquid 5, wherein the degradation liquid 5 and the epoxy resin 2 undergo a degradation reaction in the degradation reactor 6;

[0060] and a data processing terminal 9 for obtaining the relative dielectric constant according to the capacitance data detected by the bridge 3 .

[0061] According to the present invention, the interdigital electrode 1 is an electrochemical sensor with a large surface area and good dielectric sensitivity, which reflects the real-time information of the degradation reaction by measuring the capacitance data of the interdigital electrode 1 during the degradation of the epoxy resin 2.

[0062] According to the present invention, Figure 2 As shown, the interdigitated electrode 1 includes an electrode substrate 11, an interdigitated structure 12, a working electrode 1A and a counter electrode 1B. The interdigitated structure 12 is arranged in an interdigitated manner on the electrode substrate 11, with one end of the interdigitated structure 12 forming the working electrode 1A and the other end forming the counter electrode 1B.

[0063] Furthermore, the electrode substrate 11 is any one of ceramics such as alumina ceramics, flexible materials such as PET flexible materials, and quartz glass, preferably double-sided polished quartz glass. The quartz glass has the characteristics of high thermal conductivity and high dielectric constant, acid and alkali resistance, corrosion resistance, high temperature resistance, and good electroosmosis and optical properties.

[0064] According to the present invention, the interdigitated structure 12, the working electrode 1A, and the counter electrode 1B are preferably selected from any one of titanium, chromium, and gold, preferably titanium, mainly because titanium has advantages such as excellent biocompatibility, mechanical properties, electrical stability, and ease of processing.

[0065] In the present invention, Figure 2 As shown, the interdigital electrode 1 has a line width m of 9 to 11 μm, a finger length L of 3.5 to 4 mm, and a width M of typically 11 to 13 mm; a gap distance P between adjacent fingers is 4.5 to 5.5 μm; and a thickness H of 0.4 to 0.6 mm; for example, the line width m of the interdigital electrode 1 is 10 μm, a finger length L of 3.7 mm, and a width M of typically 12 mm; a gap distance P between adjacent fingers is 5 μm; and a thickness H of 0.5 mm.

[0066] In the present invention, the line width m affects the electrode's resistance and current capacity. A smaller line width m can reduce the electrode's resistance and increase its current capacity. Depending on the electrode material and the required current capacity, selecting a line width of 9-11 μm can balance resistance and conductivity to meet the detection requirements of the present invention. Finger length L refers to the distance between two adjacent finger electrodes. The size of finger length L affects the electric field distribution and current path. By adjusting finger length L, the electric field distribution and current path can be optimized to achieve better detection performance. The electrode width M is determined based on the detection area and sensitivity. Interdigital electrodes 1 with a width M that is too large are not suitable for the detection of the present invention. Based on detection requirements such as detection sensitivity and response rate, interdigital electrodes with a width of 11-13 mm are selected to meet detection requirements. The gap distance P affects current transmission and sensor sensitivity. A gap distance P of 5 μm can meet current transmission efficiency and detection sensitivity. The thickness of the electrode also affects its resistance and conductivity. Depending on the electrode material and the required resistance value, selecting a thickness H of 0.4-0.6 mm for the interdigital electrodes 1 can balance resistance and conductivity to meet detection requirements.

[0067] According to the present invention, the interdigital electrodes 1 are not limited to any commercially available interdigital electrodes 1, such as the interdigital capacitor electrodes produced by Shenzhen Songkuihua Technology Co., Ltd.

[0068] According to the present invention, the epoxy resin 2 to be degraded is not limited to any commercially available epoxy resin and can be any one or more of alicyclic epoxy resins, glycidylamines, glycidyl esters, glycidyl ethers, nitrogen-containing epoxy resins, phenolic epoxy resins, trifunctional epoxy resins, tetrafunctional epoxy resins, or epoxidized olefins. Epoxy resin is a liquid material at room temperature and typically requires curing with a curing agent before use.

[0069] Preferably, epoxy resin 2 to be degraded is applied to the interdigital structures 12 of interdigital electrode 1, and an epoxy resin curing agent is added and cured for later use. At this point, epoxy resin 2 fills the gaps between and on the surfaces of interdigital structures 12. Working electrode 1A and counter electrode 1B are connected to positive measurement electrode 3A and negative measurement electrode 3B of bridge 3, respectively, to obtain capacitance data of interdigital structures 12 during epoxy resin 2 degradation.

[0070] Furthermore, there is no specific requirement for the epoxy resin 2 coated on the surface of the interdigital electrode 1 , and the epoxy resin 2 may be coated on the entire area of ​​the interdigital structure 12 or on a partial area of ​​the interdigital structure 12 .

[0071] According to the present invention, the curing agent can be an acid anhydride or a cationic polymerization curing agent, preferably an acid anhydride, such as methyltetrahydrophthalic anhydride, which has the characteristics of low viscosity and good weather resistance.

[0072] Furthermore, the curing temperature is 100-150°C, preferably 110-130°C, for example 120°C; the curing time is 5-24h, preferably 8-12h, for example 10h. Of course, the specific curing temperature and curing time are determined according to factors such as the type of epoxy resin, the ratio of the amount of the curing agent, and the curing heating equipment. The above parameter range fully meets the curing requirements of epoxy resin 2.

[0073] According to the present invention, the mass ratio of the epoxy resin 2 to the curing agent is 1:(0.7-0.85), preferably 1:(0.75-0.8), for example 1:0.77. Different epoxy resins are matched with different curing agents and different curing processes are used to form different cured products, which can be prepared into products that meet various performance requirements. Among them, the curing agent plays a key role in the processability and final performance of the epoxy resin cured product. The curing agent selected by the present invention is optimal within the above parameter range.

[0074] According to the present invention, the working electrode 1A of the interdigital electrode 1 is connected to the measuring positive electrode 3A of the bridge 3 via a cable 4, and the counter electrode 1B is connected to the measuring negative electrode 3B of the bridge 3 via a cable 4, thereby forming a circuit.

[0075] In a preferred embodiment, the electric bridge 3 is a WK4100 electric bridge measuring instrument.

[0076] According to the present invention, the interdigital electrode 1 is immersed below the interface of the degradation liquid 5 in the degradation reactor 6, and the epoxy resin 2 coated on the surface of the interdigital electrode 1 undergoes a degradation reaction with the degradation liquid 5 in the degradation reactor 6. During the reaction, the bridge 3 monitors the capacitance data of the interdigital electrode 1 that changes during the degradation reaction of the epoxy resin 2 in real time, and transmits the capacitance data to the data processing terminal 9.

[0077] According to the present invention, the degradation reactor 6 is provided with a feed-through filter, which is used to suppress high-frequency noise and interference and improve the purity and clarity of the signal.

[0078] According to different principles of degradation reactions, the degradation liquid 5 can be alcohol, amine or water.

[0079] When the degradation products of epoxy resin 2 are esters or ethers, the degradation liquid is an alcohol, preferably selected from any one or more of methanol, ethanol, ethylene glycol, n-butanol, isobutanol, isopropyl alcohol, tert-butyl alcohol, glycerol, n-propanol, pentanol, nonanol, hexanol, heptanol, octanol, or decyl alcohol, preferably ethylene glycol. Using ethylene glycol to degrade epoxy resin has the advantages of high reaction efficiency, low toxicity and low volatility, good polarity, and good compatibility with a variety of materials.

[0080] When the degradation products of epoxy resin 2 are amines or amides, the degradation solution is an amine, preferably selected from any one or more of ethanolamine, butylamine, hexylamine, and heptylamine, with ethanolamine being preferred. Using ethanolamine to degrade epoxy resin has the advantages of high efficiency, low toxicity, low volatility, good solubility, and stability.

[0081] When the degradation products of epoxy resin 2 are alcohol and acid, and there is no requirement for the degradation time, the degradation liquid is preferably water.

[0082] Preferably, a degradation aid may also be added to the degradation solution 5 to increase the degradation reaction rate.

[0083] When the degradation liquid is alcohol or water, the degradation aid is preferably an ester exchange catalyst, anhydride, acid, oxidant, etc.

[0084] When the degradation liquid is an amine, the degradation aid is preferably an ester exchange catalyst, an organic acid, anhydride, aluminum chloride, etc.;

[0085] Preferably, regardless of the type of degradation liquid, a transesterification catalyst can be used as a degradation aid, such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene. 1,5,7-triazabicyclo[4.4.0]dec-5-ene (bicycloguanidine; TBD) is a strong organic base. Its application in epoxy resin degradation not only serves as a degradation aid but also as a catalyst, offering the advantages of being environmentally friendly and reusable.

[0086] According to the present invention, the mass of the prodegradant in the degradation solution 5 is 3-12 wt.%, preferably 5-10 wt.%, for example 5 wt.%. Excessively high or low prodegradant concentrations can affect the degradation effect. At a concentration of 3-12 wt.%, the prodegradant can be well dissolved in the degradation solution, forming a uniform solution, which is beneficial for improving the uniformity and efficiency of the degradation reaction. Under certain temperature and pressure conditions, it can also maintain good chemical stability and catalytic activity, allowing the degradation reaction to proceed smoothly.

[0087] According to a preferred embodiment, the device for in-situ measuring the degradation rate of epoxy resin further comprises:

[0088] A stirring rod 7, which is used to stir the liquid in the degradation reactor 6;

[0089] The temperature control unit 8 is used to monitor and control the temperature of the degradation reactor 6 .

[0090] According to the present invention, the stirrer 7 is placed in the degradation reactor 6 to ensure that the epoxy resin 2 reacting with the degradation liquid 5 can be evenly exposed to the degradation conditions, thereby improving the degradation efficiency.

[0091] Furthermore, the stirrer 7 is preferably made of ceramic material, which has the advantages of good corrosion resistance, high temperature resistance, pollution-free, hardness and wear resistance, chemical stability and low cost in the degradation liquid.

[0092] During the degradation reaction, the stirring speed of the stirrer 7 is 350 to 400 rpm, preferably 400 rpm. The function of the stirrer is to fully mix the reactants and promote material transfer. The stirrer 7 can accelerate the mixing speed of the reactants in the liquid phase by stirring the degradation liquid, improve the mass transfer efficiency, and thus accelerate the reaction rate. By adjusting the stirring speed of the stirrer 7, the local concentration of each component in the reaction liquid can be controlled to make the reaction proceed more uniformly. When the stirring speed is 350 to 400 rpm, while improving the efficiency of the degradation reaction and the quality of the product, it avoids side reactions in areas with too high concentration or areas with too low concentration affecting the reaction rate.

[0093] According to the present invention, the temperature control unit 8 is arranged on the stirred degradation reactor 6, and the temperature control unit 8 includes an electric heater, a temperature sensor and a temperature feedback controller. The electric heater is used to provide heat for the degradation reactor 6, the temperature sensor is used to monitor the temperature of the degradation reactor 6, and the temperature feedback controller is used to adjust the temperature of the degradation reactor 6 according to the temperature monitored by the temperature sensor.

[0094] When degrading epoxy resin 2, the degradation reaction temperature is controlled to be between 150°C and 170°C, for example, 160°C. The degradation reaction of epoxy resin is a chemical reaction, and its rate is affected by temperature. Increasing the temperature generally accelerates the rate of the chemical reaction because the increased temperature accelerates molecular motion, thereby increasing the frequency of molecular collisions and promoting the progress of the chemical reaction. Therefore, by controlling the temperature, the rate and progress of the degradation reaction can be controlled. However, excessively high temperatures may also cause the degradation reaction of the epoxy resin to be too intense, even causing safety accidents. In addition, high temperatures may also cause certain side reactions to occur, such as thermal oxidation, which may affect the properties of the final degradation products. Degrading epoxy resin 2 at 150°C to 170°C ensures a high degradation reaction rate without causing other adverse effects.

[0095] In the present invention, one end of the data processing terminal 9 is connected to the bridge 3 , and the other end is connected to the temperature sensor in the temperature control unit 8 .

[0096] In this method, because repeated epoxy resin processing is unnecessary, data on epoxy resin degradation can be obtained more efficiently and accurately. Furthermore, microscopic bond breakage in epoxy resin may not cause mass changes, as traditional weighing methods cannot characterize such microscopic degradation. However, it can cause changes such as a decrease in crosslink density, which can be reflected in the relative dielectric constant.

[0097] Furthermore, the step of obtaining the relative dielectric constant according to the capacitance data includes:

[0098] The relationship between the relative dielectric constant ε and the measured capacitance C is expressed as follows:

[0099]

[0100] In formula (1):

[0101] C is the capacitance measured by the bridge;

[0102] C0 is the capacitance with vacuum as dielectric;

[0103]

[0104] In formula (2):

[0105] ε0 is the dielectric constant in vacuum (8.85x10 -12 F / m is farad per meter;

[0106] is the geometric factor of the interdigital electrode 1;

[0107]

[0108] In formula (3):

[0109] C′ is the capacitance of the interdigital structure 12 of the interdigital electrode 1 substrate, and has the following expression:

[0110]

[0111] In the present invention, the capacitance measured by the bridge is also expressed as follows:

[0112]

[0113] In formula (5):

[0114] K is the proportionality constant, which is 0.55; s is the initial area of ​​epoxy resin 2; t is the residual thickness of epoxy resin 2; s' is the residual area of ​​epoxy resin 2; t' is the residual thickness of epoxy resin 2; ε' is the complex dielectric constant;

[0115] ε' is the relationship between the complex dielectric constant and the relative dielectric constant as follows:

[0116] ε=ε′(1-tanδ) Formula (6)

[0117] In formula (6), tnaδ is the loss tangent value detected by bridge 3.

[0118] According to the present invention, the relationship between the residual amount of epoxy resin 2 on the interdigital electrode 1 during the degradation process and the degradation rate W of the epoxy resin 2 is shown in formula (7):

[0119]

[0120] Since the capacitance C is theoretically positively correlated with the epoxy resin material remaining on the interdigital electrodes, the residual amount of epoxy resin can be obtained by measuring the capacitance C of the interdigital electrodes, and the epoxy resin degradation rate can be obtained according to formula (7).

[0121] In the present invention, communication between the data processing terminal 9 and the bridge 3 is established via an RS232 data line, and the bridge 3 is controlled to test the capacitance of the interdigital electrode 1 at a corresponding time and frequency, such as 1 kHz. Data normalization is performed at the data processing terminal 9 according to the above formulas (1) to (7), and the relationship between the degradation rate of the epoxy resin 2 and time can be obtained.

[0122] In a second aspect, a method for degrading epoxy resin using the device of the first aspect is provided, the method comprising:

[0123] Step 1: immerse the interdigital electrode 1 coated with the epoxy resin 2 to be degraded below the interface of the degradation solution 5 in the degradation reactor 6 to start the degradation reaction;

[0124] Step 2: the bridge 3 transmits the capacitance data of the interdigital electrode 1 during the degradation of the epoxy resin (2) to the data processing terminal 9, and obtains the relative dielectric constant based on the capacitance data to determine the degradation rate of the epoxy resin.

[0125] In step 2, the degradation liquid 5 and the epoxy resin 2 undergo a degradation reaction in the degradation reactor 6. The capacitance data of the interdigital electrode 1 during the degradation of the epoxy resin 2 is transmitted to the data processing terminal 9 through the bridge 3. During degradation, the temperature of the reaction liquid in the degradation reactor 6 is adjusted to the required degradation temperature of 150-170°C, for example, 160°C, by the electric heater in the temperature control unit 8. The temperature sensor monitors the temperature of the degradation reactor 6 in real time and transmits the temperature data to the data processing terminal 9. When the monitored temperature of the reactor 6 is lower than the degradation temperature, the temperature is adjusted by the temperature feedback controller. During degradation, the stirring rate of the stirrer 7 is adjusted to 350-400 rpm, for example, 400 rpm, to improve the degradation efficiency.

[0126] In this method, the change in relative dielectric constant is obtained in real time through capacitance data, thereby reflecting the degree of epoxy resin degradation. This method not only provides an efficient and real-time monitoring method, but also provides a new approach for in-depth understanding of the epoxy resin degradation mechanism.

[0127] In the present invention, before the degradation reaction is carried out, the degradation rate is set to 99%. Since the degradation of epoxy resin is a reversible reaction, the degradation reaction cannot reach 100% completion due to the influence of factors such as reaction equilibrium, kinetic limitations, selectivity, condition control and raw material purity. The device described in the present invention is very sensitive to the degradation rate detection of epoxy resin, and the degradation rate of the epoxy resin can reach a degradation completion rate close to 100%.

[0128] Example

[0129] The present invention is further described below through specific examples. However, these examples are merely exemplary and do not constitute any limitation to the scope of protection of the present invention.

[0130] Example 1

[0131] like Figure 1 The apparatus shown is used to perform in situ measurement of epoxy resin degradation rate according to the following steps.

[0132] 15 ml of bisphenol A epoxy resin was taken as the epoxy resin 2 to be degraded. 11.5 g of methyltetrahydrophthalic anhydride was added to the epoxy resin 2 to be degraded, and the epoxy resin 2 to be degraded was evenly coated on the surface of the interdigital structure 12 of the interdigital electrode 1. The resin was cured at 120° C. for 10 hours and then dried at room temperature for later use.

[0133] The interdigitated electrode 1 used was a 5μm transparent interdigitated capacitor electrode from Shenzhen Songkuihua Technology Co., Ltd. Its electrode substrate 11 was fully transparent, double-sided polished quartz glass. The interdigitated structure 12, working electrode 1A, and counter electrode 1B were made of Ti. The operating temperature range was -150°C to 500°C. The interdigitated electrode 1 had a line width m of 10μm, a finger length L of 3.7mm, and a width M typically of 12mm. The gap P between adjacent interdigits was 5μm, and the thickness H of the interdigitated electrode 1 was 0.5mm. The bridge 3 selected was a WK4100 bridge meter. The degradation solution 5 was ethylene glycol, and the degradation aid was 1,5,7-triazabicyclo[4.4.0]dec-5-ene. The mass of 1,5,7-triazabicyclo[4.4.0]dec-5-ene in the degradation solution 5 was 5 wt.%, and the degradation rate was set at 99%.

[0134] The working electrode 1A of the interdigital electrode 1, coated with the epoxy resin 2 to be degraded, is connected to the positive electrode 3A of the bridge 3 via a cable 4. The counter electrode 1B is also connected to the negative electrode 3B of the bridge 3 via a cable 4. The interdigital electrode 1 is immersed below the interface of the degradation solution 5 in the degradation reactor 6. The temperature of the reaction solution in the degradation reactor 6 is adjusted to 160°C by the electric heater in the temperature control unit 8. The stirring rate of the stirrer 7 is adjusted to 400 rpm, and capacitance monitoring begins. During the degradation process, the degradation solution 5 and the epoxy resin 2 undergo a degradation reaction in the degradation reactor 6. The capacitance data of the interdigital electrode 1 during the degradation of the epoxy resin 2 is transmitted to the data processing terminal 9 via the bridge 3 until the set degradation rate is reached, at which point the reaction is stopped.

[0135] As time changes, the capacitance C measured by bridge 3 also changes, and the capacitance-time change is finally obtained as follows: Figure 3 As shown, the ratio of capacitance C to C0 (at ω = 1kHz, its value is 12.3pF) can be used to obtain the corresponding relative dielectric constant. Communication between the data processing terminal 9 and the bridge 3 is established via the RS232 data line. The bridge 3 is controlled to test the capacitance of the interdigital electrode 1 at the corresponding time and 1kHz frequency. The data is normalized at the data processing terminal 9 to obtain the degradation rate-time curve of the epoxy resin 2 during the epoxy resin degradation process. The degradation rate-time change is shown in FIG. Figure 4 As shown, it can be seen that as the degradation reaction time increases, the capacitance of the interdigital electrode 1 decreases and the degradation rate gradually increases until the change is insignificant.

[0136] Example 2

[0137] 15 ml of bisphenol A epoxy resin was taken as the epoxy resin 2 to be degraded. 11.5 g of methyltetrahydrophthalic anhydride was added to the epoxy resin 2 to be degraded, and the epoxy resin 2 to be degraded was evenly coated on the surface of the interdigital structure 12 of the interdigital electrode 1. The resin was cured at 120° C. for 10 hours and then dried at room temperature for later use.

[0138] The interdigitated electrode 1 used is a 5μm transparent interdigitated capacitor electrode from Shenzhen Songkuihua Technology Co., Ltd. Its electrode substrate 11 is fully transparent, double-sided polished quartz glass. The interdigitated structure 12, working electrode 1A, and counter electrode 1B are made of Ti. The operating temperature range is -150°C to 500°C. The interdigitated electrode 1 has a line width m of 10μm, a finger length L of 3.7mm, and a width M typically of 12mm. The gap distance P between adjacent interdigits is 5μm. The thickness H of the interdigitated electrode 1 is 0.5mm. The selected bridge 3 is a WK4100 bridge measuring instrument. The degradation liquid 5 is water, the degradation aid is 10wt% dodecylbenzenesulfonic acid, and the degradation rate is set to 99%.

[0139] The working electrode 1A of the interdigital electrode 1, coated with the epoxy resin 2 to be degraded, was connected to the positive electrode 3A of the bridge 3 via a cable 4. The counter electrode 1B was also connected to the negative electrode 3B of the bridge 3 via a cable 4. The interdigital electrode 1 was immersed below the interface of the degradation solution 5 in the degradation reactor 6. The temperature of the reaction solution in the degradation reactor 6 was adjusted to 180°C by the electric heater in the temperature control unit 8. The stirring rate of the stirrer 7 was adjusted to 400 rpm, and capacitance monitoring began. During the degradation process, the degradation solution 5 and the epoxy resin 2 underwent a degradation reaction in the degradation reactor 6. The capacitance data of the interdigital electrode 1 during the degradation of the epoxy resin 2 was transmitted to the data processing terminal 9 via the bridge 3. The reaction was completed after approximately 40 hours.

[0140] As time changes, the capacitance C measured by bridge 3 also changes, and the capacitance-time change is finally obtained as follows: Figure 5 As shown, the ratio of capacitance C to C0 (at ω = 1kHz, its value is 12.3pF) can be used to obtain the corresponding relative dielectric constant. Communication between the data processing terminal 9 and the bridge 3 is established via the RS232 data line. The bridge 3 is controlled to test the capacitance of the interdigital electrode 1 at the corresponding time and 1kHz frequency. The data is normalized at the data processing terminal 9 to obtain the degradation rate-time curve of the epoxy resin 2 during the epoxy resin degradation process. The degradation rate-time change is shown in FIG. Figure 6 As shown, it can be seen that as the degradation reaction time increases, the capacitance of the interdigital electrode 1 decreases and the degradation rate gradually increases until the change is insignificant.

[0141] The present invention has been described in detail above with reference to preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments are merely illustrative explanations of the present invention and do not constitute any limitation on the scope of protection of the present invention. Various improvements, equivalent substitutions, or modifications may be made to the technical content of the present invention and its embodiments without departing from the spirit and scope of protection of the present invention, and all of these fall within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the appended claims.

Claims

1. A device for in-situ measurement of epoxy resin degradation rate, characterized in that: The device comprises: An interdigitated electrode (1) having an epoxy resin (2) to be degraded coated on its surface, the interdigitated electrode (1) being used to generate capacitance data that changes during the degradation of the epoxy resin (2); An electric bridge (3) for detecting capacitance data of the interdigital electrodes (1) changing during the degradation of the epoxy resin (2); A degradation reactor (6) contains a degradation liquid (5), wherein the degradation liquid (5) and the epoxy resin (2) undergo a degradation reaction in the degradation reactor (6); and a data processing terminal (9) for obtaining the relative dielectric constant based on the capacitance data detected by the bridge (3).

2. The device according to claim 1, characterized in that Preferably, the interdigitated electrode (1) comprises an electrode substrate (11) and an interdigitated structure (12), and the interdigitated structure (12) is arranged in an interdigitated manner on the electrode substrate (11).

3. The device according to claim 2, characterized in that The interdigitated electrode (1) further comprises a working electrode (1A) and a counter electrode (1B); one end of the interdigitated structure 12 forms the working electrode (1A), and the other end forms the counter electrode (1B).

4. The device according to claim 3, characterized in that The working electrode (1A) of the interdigital electrode (1) is connected to the measuring positive electrode (3A) of the bridge (3) via a cable (4), and the counter electrode (1B) is connected to the measuring negative electrode (3B) of the bridge (3) via a cable (4).

5. The device according to claim 1, characterized in that The degradation liquid (5) is alcohol, amine or water.

6. The device according to claim 1, characterized in that A degradation aid is also added to the degradation liquid (5).

7. The device according to claim 1, characterized in that The device further comprises: a stirring bar (7) for stirring the liquid in the degradation reactor (6); A temperature control unit (8) is used to monitor and control the temperature of the degradation reactor (6).

8. A method for degrading epoxy resin according to the device according to any one of claims 1 to 7, the method comprising: Step 1: immersing an interdigital electrode (1) coated with an epoxy resin (2) to be degraded below the interface of a degradation solution (5) in a degradation reactor (6) to start a degradation reaction; Step 2: The bridge (3) transmits the capacitance data of the interdigital electrode (1) during the degradation process of the epoxy resin (2) to the data processing terminal (9), and obtains the relative dielectric constant based on the changed capacitance data to determine the degradation rate of the epoxy resin.

9. The method according to claim 1, characterized in that In step 1, the epoxy resin (2) to be degraded is coated on the surface of the interdigital electrode (1), a curing agent is added, and the epoxy resin (2) is cured for later use.

10. The method according to claim 1, characterized in that In step 2, the degradation reaction temperature is 150-170°C.

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