A method for qualitatively comparing the free volume size of different epoxy resin cured products

Abstract

The application provides a method for qualitatively comparing the free volume size of different epoxy resin cured products, and belongs to the technical field of organic luminescent materials. The method comprises the following steps: preparing a series of epoxy resin cured products with different free volumes, doping the same organic phosphor into all the epoxy resin cured products in a host-guest doping mode, and all the epoxy resin cured products being organic room-temperature phosphorescent materials; measuring the phosphorescent lifetime spectrum of all the epoxy resin cured products to obtain the organic afterglow luminescent lifetime of each epoxy resin cured product under laser excitation; and comparing the length of the organic afterglow luminescent lifetime of each epoxy resin cured product under laser excitation to qualitatively analyze the free volume size of each epoxy resin cured product. The method can qualitatively and quickly detect the free volume size of the epoxy resin cured product by using the length of the organic afterglow luminescent lifetime, is simple and convenient, and does not obviously affect the free volume of the polymer body.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic light-emitting materials, and relates to a method for qualitatively comparing the sizes of free volumes of different epoxy resin cured products. BACKGROUND

[0002] In a polymer, molecular chains are arranged in disorder and loose arrangement, have no translational symmetry and long program; there are a large number of atom-scale and size-different holes between molecular chain segments, which are referred to as free volumes. Since the free volumes can provide a space for molecular activity, the size, concentration and free volume size distribution of the free volume holes are important factors closely related to the molecular transport properties. The free volume theory proposed on this basis has successfully explained many phenomena such as viscosity, viscoelasticity, glass transition and the like of the polymer material.

[0003] At present, the commonly used methods for testing free volumes, such as positron annihilation, photochromatography and fluorescence spectrum, small-angle X-ray diffraction, neutron scattering analysis and the like have certain limitations. For example, although the positron annihilation can accurately measure the free volume, the experimental conditions are harsh, and many laboratories are difficult to support; the photochromatography and fluorescence spectrum need to inject tracer atoms into the polymer material, so that the original free volume characteristics are changed, and the experimental results are affected; the small-angle X-ray diffraction cannot detect the free volume with a hole diameter less than 1 nm; the neutron scattering analysis method is helpless for the hole with a diameter less than 1*10 -9 m 3 Therefore, the commonly used methods for testing free volumes have certain inconvenience for the measurement of the free volume,

[0004] Therefore, in order to more simply judge the size difference of the polymer free volume, a convenient and practical method is urgently needed. SUMMARY

[0005] Therefore, the application provides a method for qualitatively comparing the sizes of free volumes of different epoxy resin cured products, a series of epoxy resin cured products with different free volumes are prepared, the same organic phosphor is doped into all the epoxy resin cured products in a host-guest doping manner, all the epoxy resin cured products are organic room-temperature phosphorescent materials, the size of the free volume of the epoxy resin cured product is qualitatively detected by using the long and short organic afterglow light-emitting life, which is simple and convenient, and does not obviously affect the free volume of the polymer body.

[0006] To achieve the above object, the application provides a method for qualitatively comparing the sizes of free volumes of different epoxy resin cured products, comprising the following steps:

[0007] A series of epoxy resin cured products with different free volumes are prepared, the same organic phosphor is doped into all the epoxy resin cured products in a host-guest doping manner, and all the epoxy resin cured products are organic room-temperature phosphorescent materials.

[0008] measuring the phosphorescence lifetime spectrum of all the epoxy resin cured products to obtain the organic afterglow light lifetime of each epoxy resin cured product under laser excitation;

[0009] comparing the length of the organic afterglow light lifetime of each epoxy resin cured product under laser excitation to qualitatively analyze the free volume size of each epoxy resin cured product, wherein the shorter the organic afterglow light lifetime, the larger the free volume of the corresponding epoxy resin cured product.

[0010] Preferably, the organic phosphor is any one of 3,6-diphenyl carbazole, tetramethyl benzidine, 7H-dibenzo carbazole and 1-pyrene boronic acid.

[0011] Preferably, the preparation method of the epoxy resin cured product is as follows:

[0012] First, a stoichiometric ratio of diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and organic phosphor is poured into a thick aluminum pan and heated and mixed, after being cooled to room temperature, a certain amount of 5-methyl hexahydrophthalic anhydride is added and heated and mixed, then pre-polymerized for a period of time, and then cured at high temperature and high pressure;

[0013] The molar ratio of the 1,5,7-triazabicyclo[4.4.0]dec-5-ene and the organic phosphor is 5:1; the molar ratio of the diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and 5-methyl hexahydrophthalic anhydride is 1:0.01:0.85.

[0014] Preferably, the diglycidyl ether includes bisphenol Z diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether and bisphenol Ap diglycidyl ether.

[0015] Preferably, a stoichiometric ratio of diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and phosphor is first poured into a thick aluminum pan and heated and mixed, specifically heated to 130℃ for 4-6min to melt and mix the raw materials.

[0016] Preferably, after being cooled to room temperature, a certain amount of 5-methyl hexahydrophthalic anhydride is added and heated and mixed, specifically heated to 80℃ for 3min and mixed.

[0017] Preferably, the pre-polymerization for a period of time is specifically gradually heating to 120℃ for 3min while stirring uniformly.

[0018] Preferably, the high temperature and high pressure curing is specifically hot pressing for 2 hours under the action of 150℃ and a pressure of 5MPa.

[0019] Preferably, a method for qualitatively comparing the free volume size of different epoxy resin cured products comprises the following steps:

[0020] A bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product, a bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product, a bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product, a bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product and a bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product are respectively prepared, wherein 3,6-diphenylcarbazole is doped in all the above epoxy resin cured products in a host-guest doping manner;

[0021] The phosphorescence lifetime spectra of all the above epoxy resin cured products are measured, and the organic afterglow light lifetime of each epoxy resin cured product at 487 nm after irradiation by 340 nm excitation light is 1897 ms, 1648 ms, 1539 ms, 1474 ms and 1345 ms, respectively;

[0022] The length of the organic afterglow light lifetime of each epoxy resin cured product under laser excitation is compared, and the free volume size of each epoxy resin cured product is qualitatively analyzed, that is, bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product.

[0023] The technical scheme of the present application has the following advantages:

[0024] The method for qualitatively comparing the free volume size of different epoxy resin cured products of the present application prepares a series of epoxy resin cured products with different free volumes, all of which doped with the same organic phosphor in a host-guest doping manner, are organic room-temperature phosphorescent materials, and the different free volumes of the epoxy resin cured products have different binding effects on the vibration and rotation of the same organic phosphor, resulting in different organic afterglow light lifetimes of the epoxy resin cured products with different free volumes. The length of the organic afterglow light lifetime can be used to qualitatively and quickly detect the size of the free volume of the epoxy resin cured product, which is simple and convenient, and does not have a significant impact on the free volume of the polymer body, thereby providing a new method for comparing the free volume size of different epoxy resin cured products. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only need to be some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0026] Figure 1 The normalized comprehensive spectrum of phosphor spectrum of the bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application;

[0027] Figure 2 The lifetime graph of the bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application at 487 nm;

[0028] Figure 3 The normalized comprehensive spectrum of phosphor spectrum of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application;

[0029] Figure 4 The lifetime graph of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application at 487 nm;

[0030] Figure 5 The normalized comprehensive spectrum of phosphor spectrum of the bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application;

[0031] Figure 6 The lifetime graph of the bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application at 487 nm;

[0032] Figure 7 The normalized comprehensive spectrum of phosphor spectrum of the bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application;

[0033] Figure 8 The lifetime graph of the bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application at 487 nm;

[0034] Figure 9 The normalized comprehensive spectrum of phosphor spectrum of the bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application;

[0035] Figure 10 The lifetime graph of the bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product in Example 1 of the present application at 487 nm;

[0036] Figure 11 Columnar chart of free volume fraction and phosphorescence lifetime of the epoxy resin cured product prepared in ①-⑤ in the embodiment of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0038] Long lifetime organic room temperature phosphorescence refers to a characteristic that the material has a luminescence lifetime longer than 0.1 s after external excitation. The luminescence lifetime of organic room temperature phosphorescence is often very close to the environment of the luminescence center. For example, a rigid environment can effectively inhibit the non-radiative transition path, thereby prolonging the luminescence lifetime, while a relatively flexible environment makes the luminescence lifetime shorter. In a polymer network, there is a certain free volume space. If a small amount of long lifetime room temperature phosphorescence material is added to the polymer network, it can be imagined that the luminescence material must interact with the network of the polymer. For the fixed luminescence material, in a large free volume polymer, the interaction between the luminescent body and the polymer is weakened, thereby increasing the vibration of the excited state of the luminescent body, causing additional non-radiative transition, and making the luminescence lifetime decrease. In the epoxy resin, the free volume obtained by polymerization of different monomers is different, and this difference also affects the performance of the cured product. Therefore, the free volume size in the polymer can be monitored by adding phosphor to the epoxy resin, so as to judge the polymer material at the microscale.

[0039] Based on the above theory, the present application provides a method for qualitatively comparing the free volume sizes of different epoxy resin cured products, comprising the following steps:

[0040] A series of epoxy resin cured products with different free volumes are prepared, and the same organic phosphor is doped into all the epoxy resin cured products in a host-guest doping manner. All the epoxy resin cured products are organic room temperature phosphorescence materials.

[0041] The phosphorescence lifetime spectrum of all the epoxy resin cured products is measured to obtain the organic afterglow luminescence lifetime of each epoxy resin cured product under laser excitation.

[0042] The lengths of the organic afterglow luminescence lifetime of each epoxy resin cured product under laser excitation are compared, and the free volume sizes of the epoxy resin cured products are qualitatively analyzed. The shorter the organic afterglow luminescence lifetime, the larger the free volume of the corresponding epoxy resin cured product.

[0043] In some preferred embodiments, the organic phosphor is selected as any one of 3,6-diphenylcarbazole, tetramethyl benzidine, 7H-dibenzo carbazole and 1-pyrene boronic acid, etc.

[0044] In some preferred embodiments, the preparation method of the epoxy resin cured product is as follows:

[0045] First, a stoichiometric ratio of diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and organic phosphor is poured into a thick aluminum pan and heated and mixed, after being cooled to room temperature, a certain amount of 5-methyl hexahydrophthalic anhydride is added and heated and mixed, then after a period of prepolymerization, high temperature and high pressure curing is carried out;

[0046] The molar ratio of 1,5,7-triazabicyclo[4.4.0]dec-5-ene and organic phosphor is 5:1; the molar ratio of diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and 5-methyl hexahydrophthalic anhydride is 1:0.01:0.85.

[0047] Among them, the diglycidyl ether includes bisphenol Z diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether and bisphenol Ap diglycidyl ether, etc.

[0048] Among them, first, a stoichiometric ratio of diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and phosphor is poured into a thick aluminum pan and heated and mixed, specifically heated to 130℃ for 4-6min to melt and mix the raw materials. After being cooled to room temperature, a certain amount of 5-methyl hexahydrophthalic anhydride is added and heated and mixed, specifically heated to 80℃ for 3min and mixed. Prepolymerization for a period of time, specifically gradually heated to 120℃ for 3min while stirring uniformly. High temperature and high pressure curing, specifically hot pressing for 2 hours under the action of 150℃, 5MPa pressure.

[0049] The present application provides an embodiment, a method for qualitatively comparing the free volume size of different epoxy resin cured products, comprising the following steps:

[0050] Bisphenol Z diglycidyl ether-5-methyl hexahydrophthalic anhydride epoxy resin cured product, bisphenol A diglycidyl ether-5-methyl hexahydrophthalic anhydride epoxy resin cured product, bisphenol F diglycidyl ether-5-methyl hexahydrophthalic anhydride epoxy resin cured product, bisphenol B diglycidyl ether-5-methyl hexahydrophthalic anhydride epoxy resin cured product and bisphenol Ap diglycidyl ether-5-methyl hexahydrophthalic anhydride epoxy resin cured product are prepared respectively, wherein 3,6-diphenylcarbazole is doped in all the above epoxy resin cured products in a host-guest doping manner;

[0051] The phosphorescence lifetime spectra of all the above epoxy resin cured products were measured, and the organic afterglow luminescence lifetimes of each epoxy resin cured product at 487nm after being irradiated with 340nm excitation light were 1897ms, 1648ms, 1539ms, 1474ms, and 1345ms, respectively.

[0052] By comparing the organic afterglow luminescence lifetime of various epoxy resin cured products under laser excitation, the free volume of each epoxy resin cured product was qualitatively analyzed, namely: bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product.

[0053] Example 1

[0054] A method for qualitatively comparing the free volume of cured epoxy resins includes the following steps:

[0055] (1) A series of epoxy resin cured products with different free volumes were prepared, and the process is as follows:

[0056] ① The preparation process of bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product is as follows:

[0057] Bisphenol Z diglycidyl ether (1 mmol, 0.38 g), TBD (0.01 mmol, 0.014 g), and 3,6-diphenylcarbazole molecules were poured into a thickened aluminum pan and then heated on a hot plate at 130°C for 4-6 minutes to completely melt and mix the raw materials. The molar ratio of TBD to 3,6-diphenylcarbazole was 5:1. After cooling to room temperature, 5-methylhexahydrophthalic anhydride (0.85 mmol, 0.29 g) was added, and the temperature was raised to 80°C and mixed. The temperature was gradually increased to 120°C for a period of prepolymerization. A layer of polytetrafluoroethylene film was placed under a hot press, and a suitable mold was placed on top as the reaction vessel for the polymerization reaction. The mixture was stirred evenly as the prepolymerization reaction temperature rose until slight stringing occurred. The reactants were immediately transferred to the reaction mold. The reaction was hot-pressed at 150°C and 5 MPa for 2 hours to complete the polymerization reaction. After cooling to room temperature, the mixture was demolded.

[0058] ② The preparation process of bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product is as follows:

[0059] Bisphenol A diglycidyl ether (1 mmol, 0.34 g), TBD (0.01 mmol, 0.014 g), and 3,6-diphenylcarbazole molecules were poured into a thickened aluminum pan and then heated on a hot plate at 130°C for 4-6 minutes to completely melt and mix the raw materials. The molar ratio of TBD to 3,6-diphenylcarbazole was 5:1. After cooling to room temperature, 5-methylhexahydrophthalic anhydride (0.85 mmol, 0.29 g) was added, and the temperature was raised to 80°C and mixed. The temperature was gradually increased to 120°C for a period of prepolymerization. A layer of polytetrafluoroethylene film was placed under a hot press, and a suitable mold was placed on top as the reaction vessel for the polymerization reaction. The mixture was stirred evenly as the prepolymerization reaction temperature rose until slight stringing occurred. The reactants were immediately transferred to the reaction mold. The reaction was hot-pressed at 150°C and 5 MPa for 2 hours to complete the polymerization reaction. After cooling to room temperature, the mixture was demolded.

[0060] ③ The preparation process of bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product is as follows:

[0061] Bisphenol F diglycidyl ether (1 mmol, 0.31 g), TBD (0.01 mmol, 0.014 g), and 3,6-diphenylcarbazole molecules were poured into a thickened aluminum pan and then heated on a hot plate at 130°C for 4-6 minutes to completely melt and mix the raw materials. The molar ratio of TBD to 3,6-diphenylcarbazole was 5:1. After cooling to room temperature, 5-methylhexahydrophthalic anhydride (0.85 mmol, 0.29 g) was added, and the temperature was raised to 80°C and mixed. The temperature was gradually increased to 120°C for a period of prepolymerization. A layer of polytetrafluoroethylene film was placed under a hot press, and a suitable mold was placed on top as the reaction vessel for the polymerization reaction. The mixture was stirred evenly as the prepolymerization reaction temperature rose until slight stringing occurred. The reactants were immediately transferred to the reaction mold. The reaction was hot-pressed at 150°C and 5 MPa for 2 hours to complete the polymerization reaction. After cooling to room temperature, the mixture was demolded.

[0062] ④ The preparation process of bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product is as follows:

[0063] Bisphenol B diglycidyl ether (1 mmol, 0.35 g), TBD (0.01 mmol, 0.014 g), and 3,6-diphenylcarbazole molecules were poured into a thickened aluminum pan and then heated on a hot plate at 130°C for 4-6 minutes to completely melt and mix the raw materials. The molar ratio of TBD to 3,6-diphenylcarbazole was 5:1. After cooling to room temperature, 5-methylhexahydrophthalic anhydride (0.85 mmol, 0.29 g) was added, and the temperature was raised to 80°C and mixed. The temperature was gradually increased to 120°C for a period of prepolymerization. A layer of polytetrafluoroethylene film was placed under a hot press, and a suitable mold was placed on top as the reaction vessel for the polymerization reaction. The mixture was stirred evenly as the prepolymerization reaction temperature rose until slight stringing occurred. The reactants were immediately transferred to the reaction mold. The reaction was hot-pressed at 150°C and 5 MPa for 2 hours to complete the polymerization reaction. After cooling to room temperature, the mixture was demolded.

[0064] ⑤ The preparation process of bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product is as follows:

[0065] Bisphenol A diglycidyl ether (1 mmol, 0.40 g), TBD (0.01 mmol, 0.014 g), and 3,6-diphenylcarbazole molecules were poured into a thickened aluminum pan and then heated on a hot plate at 130°C for 4-6 minutes to completely melt and mix the raw materials. The molar ratio of TBD to 3,6-diphenylcarbazole was 5:1. After cooling to room temperature, 5-methylhexahydrophthalic anhydride (0.85 mmol, 0.29 g) was added, and the temperature was raised to 80°C and mixed. The temperature was gradually increased to 120°C for a period of prepolymerization. A layer of polytetrafluoroethylene film was placed under a hot press, and a suitable mold was placed on top as the reaction vessel for the polymerization reaction. The mixture was stirred evenly as the prepolymerization reaction temperature rose until slight stringing occurred. The reactants were immediately transferred to the reaction mold. The reaction was hot-pressed at 150°C and 5 MPa for 2 hours to complete the polymerization reaction. After cooling to room temperature, the mixture was demolded.

[0066] (2) The phosphorescence lifetime spectrum of the samples prepared in ①-⑤ above was measured using a Horiba JY FL-3 spectrometer and the phosphorescence spectrum was measured using an Ocean Optics QE65 Pro with an excitation laser wavelength of 340 nm.

[0067] like Figure 1The image shows the normalized composite phosphorus spectrum of the cured bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin. The phosphorescence spectrum of the cured bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin was obtained by exciting the cured bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin with a light source at an excitation wavelength of 340 nm. A very obvious emission peak can be seen in the phosphorescence spectrum, which is around 487 nm. This indicates that phosphorescence is present in the light emitted by the cured bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin after being excited by a light source at room temperature.

[0068] like Figure 2 The figure shows the lifetime of the bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product at 487 nm. As can be seen from the figure, the phosphorescence lifetime of the bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system can reach 1897 ms.

[0069] like Figure 3 The figure shows the normalized composite phosphorus spectrum of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system. The phosphorescence spectrum of the cured bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin was obtained by exciting the cured bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin with a light source of 340 nm. A very obvious emission peak can be seen from the phosphorescence spectrum, which is around 487 nm. This indicates that phosphorescence is present in the light emitted by the cured bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin after being excited by a light source at room temperature.

[0070] like Figure 4 The figure shows the lifetime of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product at 487 nm. As can be seen from the figure, the phosphorescence lifetime of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system can reach 1648 ms.

[0071] like Figure 5 The figure shows the normalized composite phosphorus spectrum of the bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system. The phosphorescence spectrum of the cured bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin was obtained by exciting the cured bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin with a light source of 340 nm. A very obvious emission peak can be seen from the phosphorescence spectrum, which is around 487 nm, indicating that phosphorescence is present in the light emitted by the cured bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin after being excited by a light source at room temperature.

[0072] like Figure 6 The figure shows the lifetime of the bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product at 487 nm. As can be seen from the figure, the phosphorescence lifetime of the bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system can reach 1539 ms.

[0073] like Figure 7 The image shows the normalized composite phosphorus spectrum of the bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system. The phosphorescence spectrum of the cured bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin was obtained by exciting the cured bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin with a light source of 340 nm. A very obvious emission peak can be seen in the phosphorescence spectrum, which is around 487 nm. This indicates that phosphorescence is present in the light emitted by the cured bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin after being excited by a light source at room temperature.

[0074] like Figure 8 The figure shows the lifetime of the bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product at 487 nm. As can be seen from the figure, the phosphorescence lifetime of the bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system can reach 1474 ms.

[0075] like Figure 9 The image shows the normalized composite phosphorus spectrum of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system. The phosphorescence spectrum of the cured bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin was obtained by exciting the cured bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin with a light source of 340 nm. A very obvious emission peak can be seen from the phosphorescence spectrum, which is around 487 nm. This indicates that phosphorescence is present in the light emitted by the cured bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin after being excited by a light source at room temperature.

[0076] like Figure 10 The figure shows the lifetime of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product at 487 nm. As can be seen from the figure, the phosphorescence lifetime of the bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured system can reach 1345 ms.

[0077] (3) The organic afterglow luminescence lifetimes of each epoxy resin cured product under laser excitation were compared to qualitatively analyze the free volume of each epoxy resin cured product. After irradiation with 340nm excitation light, the organic afterglow luminescence lifetimes of the samples prepared in ①-⑤ at 487nm were 1897ms, 1648ms, 1539ms, 1474ms, and 1345ms, respectively; therefore, the free volume sizes were: bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product.

[0078] The free volume fraction of samples prepared in steps ①-⑤ was measured using an EG&G Ortec fast-fast spectrometer with a positron annihilation valve, achieving a time resolution of 220 ps. A 22Na positron source (~10 μCi) placed between two identical samples was deposited within a 7.5 μm thick DuPont Kapton film cladding. At least two spectra were acquired for each sample, with a cumulative count of 1 million for each spectrum to verify instrument stability. The measurement results show that the free volume fractions of the bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured systems, bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured systems, bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured systems, bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured systems, and bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured systems are 2.915%, 3.042%, 3.137%, 3.256%, and 3.305%, respectively.

[0079] like Figure 11 The figure shows a bar chart of the free volume fraction and phosphorescence lifetime of the epoxy resin cured products prepared in ①-⑤ above. It can be seen from the figure that as the free volume fraction of the epoxy resin cured product increases, its phosphorescence lifetime gradually decreases. This also indicates that as the free volume of the epoxy resin cured product increases, its binding effect on the vibration and rotation of the phosphor decreases, and the organic afterglow emission lifetime is shorter. That is, the method of detecting the free volume of epoxy resin cured products by organic afterglow emission lifetime is feasible.

[0080] The advantages of the above technical solution adopted in this invention are:

[0081] This invention provides a method for qualitatively comparing the free volume of different epoxy resin cured products. A series of epoxy resin cured products with different free volumes are prepared. All epoxy resin cured products are incorporated into the same organic phosphor using a host-guest doping method. These are all organic room-temperature phosphorescent materials. The different free volumes of the epoxy resin cured products exert different binding effects on the vibration and rotation of the same organic phosphor, resulting in different organic afterglow luminescence lifetimes. The length of the organic afterglow luminescence lifetime can be used to qualitatively and quickly detect the free volume of the epoxy resin cured products. This method is simple and convenient, and does not significantly affect the free volume of the polymer matrix, providing a new method for comparing the free volume of different epoxy resin cured products.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for qualitatively comparing the free volume of cured epoxy resins, characterized in that, Includes the following steps: A series of epoxy resin cured products with different free volumes were prepared. All epoxy resin cured products were doped with the same organic phosphor by host-guest doping. All epoxy resin cured products were organic room temperature phosphorescent materials. The phosphorescence lifetime spectrum of all epoxy resin cured products was measured to obtain the organic afterglow luminescence lifetime of each epoxy resin cured product under laser excitation. By comparing the organic afterglow luminescence lifetime of various epoxy resin cured products under laser excitation, the free volume of each epoxy resin cured product can be qualitatively analyzed. The shorter the organic afterglow luminescence lifetime, the larger the free volume of the corresponding epoxy resin cured product. The organophosphorus is 3,6-diphenylcarbazole; The preparation method of epoxy resin cured product is as follows: First, diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and organophosphors in a certain stoichiometric ratio are poured into a thickened aluminum pan and heated and mixed. After cooling to room temperature, a certain amount of 5-methylhexahydrophthalic anhydride is added and heated and mixed. Then, the mixture is prepolymerized for a period of time and then cured under high temperature and high pressure. The molar ratio of 1,5,7-triazabicyclo[4.4.0]dec-5-ene to the organophosphorus is 5:1; the molar ratio of diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene to 5-methylhexahydrophthalic anhydride is 1:0.01:0.

85. The diglycidyl ethers include bisphenol Z diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether, and bisphenol Ap diglycidyl ether.

2. The method for qualitatively comparing the free volume of different epoxy resin cured products according to claim 1, characterized in that, First, diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene and phosphor in a certain stoichiometric ratio are poured into a thickened aluminum pan and heated and mixed. Specifically, the mixture is heated to 130°C and held for 4-6 minutes to melt and mix the raw materials.

3. The method for qualitatively comparing the free volume of different epoxy resin cured products according to claim 1, characterized in that, After cooling to room temperature, add a certain amount of 5-methylhexahydrophthalic anhydride and heat to mix. Specifically, heat to 80°C and hold for 3 minutes while mixing.

4. The method for qualitatively comparing the free volume of different epoxy resin cured products according to claim 1, characterized in that, The prepolymerization period specifically involves gradually increasing the temperature to 120°C and holding it at that temperature for 3 minutes while stirring evenly.

5. The method for qualitatively comparing the free volume of different epoxy resin cured products according to claim 1, characterized in that, High temperature and high pressure curing specifically involves hot pressing at 150℃ and 5MPa for 2 hours.

6. The method for qualitatively comparing the free volume of different epoxy resin cured products according to claim 1, characterized in that, Includes the following steps: Bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured products, bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured products, bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured products, bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured products, and bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured products were prepared respectively. Among them, 3,6-diphenylcarbazole was incorporated into all the above epoxy resin cured products in a host-guest doping manner. The phosphorescence lifetime spectra of all the above epoxy resin cured products were measured, and the organic afterglow luminescence lifetimes of each epoxy resin cured product at 487nm after being irradiated with 340nm excitation light were 1897ms, 1648ms, 1539ms, 1474ms, and 1345ms, respectively. By comparing the organic afterglow luminescence lifetime of various epoxy resin cured products under laser excitation, the free volume of each epoxy resin cured product was qualitatively analyzed, namely: bisphenol Z diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol A diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol F diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol B diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product < bisphenol Ap diglycidyl ether-5-methylhexahydrophthalic anhydride epoxy resin cured product.

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