A modified polysilane-polysiloxane body-type crosslinking copolymer scintillator and a method for preparing the same

Abstract

The application discloses a modified polysilane-polysiloxane body type crosslinking copolymer scintillator and a preparation method thereof. The crosslinking copolymer scintillator is a body type crosslinking structure formed by crosslinking of modified polymethylhydrosilane and polymethylphenylsiloxane. In the application, a scintillation group with 2-3 aromatic rings is introduced into a Si-Si main chain through a Grignard reaction, so that an original sigma conjugated system is expanded into a sigma-pi and sigma-pi conjugated system. Correspondingly, introduced pi electrons and lone pair electrons (n electrons) are converted into pi to sigma transition and pi to n to sigma transition, so that the energy gap width is changed, and the fluorescence emission spectrum of the polysilane becomes adjustable. After modification, the conjugated system is expanded, and the intermolecular electron transfer is improved, so that the fluorescence intensity and the quantum yield of the polysilane are improved. The fluorescence intensity of the modified scintillation group is 20-40 times higher than that of the unmodified polysilane-polysiloxane crosslinking copolymer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-molecular light-emitting materials, and particularly relates to a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator and a preparation method thereof. BACKGROUND

[0002] Polymer fluorescent materials have the advantages of low cost, unrestricted shape and volume, strong environmental tolerance, etc., and have become the focus of attention in recent years. At present, in the fields of civil and military, as supporting materials in the fields of information display, lighting source, optoelectronic devices, etc., small volume, light weight, large area, foldable fluorescent materials have been widely valued. In addition, many inorganic and organic fluorescent materials can emit fluorescent pulses after absorbing high-energy particles or rays, so they are also called scintillators, which are the core materials of radiation detection. The light pulse is converted into an electric signal and amplified by a photomultiplier tube, and then the radiation intensity is obtained after counting, storing and processing by a main module.

[0003] The existing plastic scintillator has the following three deficiencies: first, the light-emitting efficiency is low. Since polystyrene itself has no fluorescent properties, and the solute and wavelength shifter molecules with fluorescent properties are dispersed in the solvent, the light quantum yield is low. Second, it is very sensitive to high temperature and oxygen. Since the solute and wavelength shifter both contain a large number of unsaturated double bonds, they are easy to oxidize, and long-term storage will cause yellowing, aging cracking, reduction of light quantum yield, and prolongation of fluorescent relaxation time, etc., thereby affecting the radiation detection accuracy. Third, it is highly toxic and not environmentally friendly. The existing scintillation solute and wavelength shifter are mostly benzene homologues and fused ring aromatic hydrocarbons, which are highly toxic and carcinogenic, seriously threatening the life of living beings and the natural environment.

[0004] In summary, the current fusion reactor radiation detection has not developed a dedicated scintillator, and still uses the general liquid scintillator, which has low light-emitting efficiency and can only be used for static or intermittent sampling detection. SUMMARY

[0005] To solve the above technical problems, the present application provides a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator. The body-type crosslinking copolymer scintillator can improve the neutron and gamma ray detection sensitivity and realize real-time and online detection.

[0006] The technical problem to be solved by the present application is to provide a preparation method of the modified polysilane-polysiloxane body-type crosslinking copolymer scintillator.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0008] A modified polysilane-polysiloxane body-type crosslinking copolymer scintillator, the crosslinking copolymer scintillator is a body-type crosslinking structure formed by crosslinking of modified polymethylhydrosilane and polymethylphenylsiloxane; and the molecular structure formula is:

[0009] ;

[0010] wherein, A-PMS is modified polymethylhydrosilane, and PSO is polymethylphenylsiloxane.

[0011] wherein, the modified polymethylhydrosilane is obtained by substituting H in Si-H bond of polymethylhydrosilane with a scintillation group; and the structure of the modified polymethylhydrosilane is as follows:

[0012] ;

[0013] wherein, R is , , , , , one or more of the following.

[0014] wherein, the polymethylhydrosilane is a linear polymer, and the number average polymerization degree is about 18-25, and the number average molecular weight is about 792-1100.

[0015] wherein, the crosslinking agent is a hydroxyl-terminated polymethylphenylsiloxane, and the molecular structure of the crosslinking agent is as follows:

[0016] ;

[0017] wherein, n = 18-25.

[0018] wherein, the number average molecular weight of the hydroxyl-terminated polymethylphenylsiloxane is 2500-3400.

[0019] The preparation method of the modified polysilane-polysiloxane body type crosslinking copolymer scintillator described above comprises the following steps:

[0020] S1: slowly mix Grignard reagent and polymethylhydrosilane solution, and react at constant temperature for 4-6 h; wherein the Grignard reagent is obtained by reacting a scintillation group carrier with magnesium powder in anhydrous tetrahydrofuran solvent, and the polymethylhydrosilane solution is obtained by dissolving polymethylhydrosilane in CCl4; the constant temperature is the reflux temperature of tetrahydrofuran;

[0021] S2: purify the product obtained in step S1 to obtain modified polymethylhydrosilane;

[0022] S3: mix the modified polymethylhydrosilane and polymethylphenylsiloxane to make them undergo crosslinking reaction, wherein the molar ratio of the modified polymethylhydrosilane to the polymethylphenylsiloxane is 1:2-1:1.

[0023] The mass / volume concentration of the polymethylhydrosilane and CCl4 in step S1 is 11-44 g / 100 mL.

[0024] The polymethylhydrosilane solution is obtained by dissolving polymethylhydrosilane in CCl4 under anhydrous and oxygen-free conditions, and then removing residual CCl4 under vacuum after 1-4 hours of reaction at room temperature.

[0025] The slow mixing of the Grignard reagent and the polymethylhydrosilane solution is adding the Grignard reagent dropwise into the polymethylhydrosilane solution under an inert gas atmosphere.

[0026] The slow mixing of the Grignard reagent and the polymethylhydrosilane solution is adding the Grignard reagent dropwise into the polymethylhydrosilane solution under an inert gas atmosphere.

[0027] The scintillation group carrier is a bromide or iodide of a biphenyl group, a phenyloxazolyl group, a phenyloxadiazolyl group, a pyridylthiadiazolyl group, or a chlorothienyl group.

[0028] The modified polysilane-polysiloxane bulk crosslinking copolymer scintillator of the present application has the following advantages:

[0029] (1) The scintillation group with 2-3 aromatic rings is introduced into the Si-Si main chain through Grignard reaction in the present application, so that the original σ conjugated system is expanded into σ-π and σ-p-π conjugated systems. Correspondingly, the introduced π electrons and lone pair electrons (n electrons) are converted into π→σ transition and π→n→σ transition, thereby changing the energy gap width and making the fluorescence emission spectrum of the polysilane adjustable. After modification, the conjugated system is expanded, and the intermolecular electron transfer is improved, thereby increasing the fluorescence intensity and quantum yield of the polysilane. The fluorescence intensity of the scintillation group after modification is significantly improved by 20-40 times compared with that of the unmodified polysilane-polysiloxane crosslinking copolymer.

[0030] (2) The mechanical properties of the copolymerized elastic scintillator of the present application are obtained from the polymethylphenylsiloxane crosslinking agent. The high elasticity, thermal stability, and weather resistance of the polysiloxane can form a three-dimensional spatial network structure after crosslinking and curing with the scintillation group modified polymethylhydrosilane, thereby obtaining higher elasticity and chemical stability than ordinary thermoplastic elastic scintillators. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The chemical structure diagram of the modified polysilane-polysiloxane bulk crosslinking copolymer scintillator of the present application is shown in the figure.

[0032] Figure 2The elastic modulus and hysteresis loss curves of the modified polysilane-polysiloxane bulk crosslinking copolymer scintillator under the action of alternating stress at different frequencies;

[0033] Figure 3 The fluorescence emission curve of the modified polysilane-polysiloxane bulk crosslinking copolymer scintillator;

[0034] Figure 4 The neutron-gamma ray discrimination curve of the modified polysilane-polysiloxane bulk crosslinking copolymer scintillator under the action of Am-Be neutron source. 241 Am-Be neutron source. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0036] The test materials and reagents used in the following examples, etc., can be obtained from commercial channels unless otherwise specified.

[0037] A modified polysilane-polysiloxane bulk crosslinking copolymer scintillator, the crosslinking copolymer scintillator is a bulk crosslinking structure formed by crosslinking modified polymethylhydrosilane (A-PMS) and polymethylphenylsiloxane (PSO); the molecular structure formula is:

[0038] .

[0039] In addition, the molecular structure formula of the modified polysilane-polysiloxane bulk crosslinking copolymer scintillator of the present application can also be further referred to Figure 1 As shown in Figure 1 , the modified polysilane-polysiloxane bulk crosslinking copolymer scintillator of the present application is to replace the H in Si-H on PMS with a scintillation group with 2-3 aromatic rings, thereby introducing the scintillation group into the Si-Si main chain of PMS, and expanding the original σ conjugate system into σ-π and σ-p-π conjugate system. Correspondingly, the introduced π electrons and lone pair electrons (n electrons) are converted into π→σ transition and π→n→σ The transition changes the energy gap width, so that the fluorescence emission spectrum of polysilane becomes adjustable. After modification, the conjugated system is expanded, and the intermolecular electron transfer is improved, so that the fluorescence intensity and quantum yield of polysilane are improved. The fluorescence intensity of the modified polysilane-polysiloxane crosslinking copolymer is 20-40 times higher than that of the unmodified polysilane-polysiloxane crosslinking copolymer. Linear polymethylphenylsiloxane is selected as the crosslinking agent, and the terminal hydroxyl group is dehydrogenated and coupled with the residual Si-H on the modified polymethylphenylsilane to realize the three-dimensional network structure of the body crosslinking copolymer structure. The use of polymethylphenylsiloxane as a crosslinking agent can form a body structure and increase the solubility of PMS and improve the fluorescence efficiency.

[0040] Preferably, the modified polymethylhydrogen silane is obtained by replacing H in the Si-H bond of polymethylhydrogen silane with a scintillation group; the structure of the modified polymethylhydrogen silane is:

[0041] ;

[0042] wherein R is one or more of , , , , , .

[0043] More preferably, the polymethylhydrogen silane is a linear polymer with a number average polymerization degree of about 18-25 and a number average molecular weight of about 792-1100.

[0044] Preferably, the crosslinking agent is a hydroxyl-terminated polymethylphenylsiloxane, and the molecular structure of the crosslinking agent is:

[0045] ;

[0046] wherein n is 18-25.

[0047] More preferably, the number average molecular weight of the hydroxyl-terminated polymethylphenylsiloxane is about 2500-3400.

[0048] The preparation method of the modified polysilane-polysiloxane body crosslinking copolymer scintillator described above comprises the following steps:

[0049] S1: slowly mix the Grignard reagent (R-Mg-Br) and polymethylhydrosilane solution, and react at constant temperature for 4-6 h; wherein the Grignard reagent is obtained by reacting a scintillation group carrier with magnesium powder in anhydrous tetrahydrofuran solvent, and the polymethylhydrosilane solution is obtained by dissolving polymethylhydrosilane in CCl4; the constant temperature is the refluxing temperature of tetrahydrofuran; in this step, the Grignard reagent and Si-Cl of the product of step S1 undergo nucleophilic substitution reaction, and the Si-H substitution rate is about 4%-10%. Preferably, the Grignard reagent (R-Mg-Br) and polymethylhydrosilane solution are mixed at a molar ratio of Grignard reagent to Si-H bond of 0.1-1:1.

[0050] The reaction formula of step S1 is as follows:

[0051] ;

[0052] S2: purify the product obtained in step S1 to obtain modified polymethylhydrosilane; purification can be performed by steps such as filtration, extraction, and rotary evaporation to remove solvents; wherein the synthesis solvent tetrahydrofuran is dried by sodium refluxing method; other solvents are dried by 4Å molecular sieves, and the residual water content is <10 ppm.

[0053] After the scintillation group in this step is connected to the Si-Si main chain through Grignard reaction, a scintillation group modified polysilane luminescent functional polymer can be obtained, which improves the fluorescence intensity and quantum yield of polysilane.

[0054] S3: mix the modified polymethylhydrosilane and polymethylphenylsiloxane to make them undergo crosslinking reaction, wherein the molar ratio of the modified polymethylhydrosilane to the polymethylphenylsiloxane is 1:2-1:1.

[0055] In step S3, linear polymethylphenylsiloxane (number average molecular weight about 2500-3400) is selected as a crosslinking agent, which undergoes dehydrogenation coupling reaction with the residual Si-H on the modified polymethylhydrosilane synthesized in S3, to realize three-dimensional network body crosslinking copolymerization structure, and obtain a body crosslinking copolymerization scintillator.

[0056] The reaction formula of step S3 is as follows:

[0057] ;

[0058] In the above preparation method, steps S1-S3 synthesize modified polymethylhydrosilane (A-PMS), and step S4 is to crosslink A-PMS and PSO to form the final product modified polysilane-polysiloxane body crosslinking copolymerization scintillator.

[0059] The high polymer matrix polymethylhydrosilane can be purchased or synthesized on site; preferably, it is synthesized on site. The high polymer matrix polymethylhydrosilane (PMS) is obtained by a sodium coupling reaction (Wurtz reaction) in a xylene (benzene or toluene) solvent with dichloromethylsilane as a raw material. The polysilane used in the application is a polymethylhydrosilane (PMS) linear polymer, and the number average polymerization degree is about 18-25, and the number average molecular weight is about 792-1100.

[0060] The Grignard reagent is obtained by reacting a scintillation group carrier (usually a bromide or iodide of a biphenyl, phenyloxazolyl, phenyloxadiazolyl phenyl, pyridylthiadiazolyl, chlorothiophenyl) with magnesium powder in anhydrous tetrahydrofuran solvent; and the reaction formula is as follows:

[0061] .

[0062] The preparation process of the polymethylhydrosilane solution is as follows: the polymethylhydrosilane is dissolved in CCl4, and after 1-4 hours of reaction at room temperature, the residual CCl4 is removed under vacuum; in this step, the PMS and CCl4 undergo Cl substitution reaction; and the reaction formula is as follows:

[0063] .

[0064] Preferably, the mass / volume ratio of the polymethylhydrosilane and CCl4 in step S1 is 11-44 g / 100 mL.

[0065] Preferably, the step S1 is carried out under anhydrous and anaerobic conditions.

[0066] Preferably, the slow mixing of the Grignard reagent and the polymethylhydrosilane solution is to add the Grignard reagent dropwise into the polymethylhydrosilane solution under an inert gas atmosphere;

[0067] Or the slow mixing of the Grignard reagent and the polymethylhydrosilane solution is to add the polymethylhydrosilane solution dropwise into the Grignard reagent.

[0068] The synthesis of the modified polysilane-polysiloxane body type crosslinked copolymer scintillator of the application uses a scintillation group carrier, polymethylhydrosilane (PMS) and polymethylphenylsiloxane as raw materials, grafts the scintillation group carrier onto the PMS molecular chain through Grignard reaction under anhydrous and anaerobic conditions, and then uses polymethylphenylsiloxane as a crosslinking agent to prepare a polysilane-polysiloxane crosslinked copolymer. By introducing a scintillation group on the Si-Si main chain, the fluorescence intensity and quantum yield of the polysilane are improved; and by crosslinking copolymerization of the polysiloxane, the elasticity and chemical stability of the scintillator are enhanced.

[0069] Example 1

[0070] A preparation method of a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator, comprising the following steps:

[0071] (1) Synthesis of a high molecular matrix polymethylhydrosilane;

[0072] The high molecular matrix polymethylhydrosilane (PMS) is obtained by a sodium coupling reaction (Wurtz reaction) in a xylene solvent with dichloromethylsilane as a raw material, and the polysilane main body is a polymethylhydrosilane (PMS) linear polymer with a number average polymerization degree of about 21 and a number average molecular weight of about 920;

[0073] (2) Polymethylhydrosilane solution: dissolve the polymethylhydrosilane in CCl4, and the mass / volume ratio of the polymethylhydrosilane and CCl4 is 22 g / 100 mL. After reacting at room temperature for 1-4 h, remove the residual CCl4 under vacuum;

[0074] (3) Preparation of a Grignard reagent.

[0075] The specific preparation process of the modified polysilane-polysiloxane body-type crosslinking copolymer scintillator PP-PMS-PSO is as follows:

[0076] S1: Under an argon atmosphere, slowly add the Grignard reagent drop by drop to the polymethylhydrosilane solution, and react for 6 h at a constant temperature; wherein the Grignard reagent is obtained by reacting the scintillation group carrier 1-bromo-4-phenylbenzene with magnesium powder in anhydrous tetrahydrofuran solvent at a molar ratio of 1:1; the constant temperature is the refluxing temperature of tetrahydrofuran;

[0077] S2: Purify the product obtained in step S1 to obtain modified polymethylhydrosilane. The Si-H substitution rate of the modified polymethylhydrosilane in this embodiment is about 8%;

[0078] S3: Mix the modified polymethylhydrosilane and polymethylphenylsiloxane to make them crosslink to obtain a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator, wherein the molar ratio of the modified polymethylhydrosilane to the polymethylphenylsiloxane is 1:1.

[0079] The commercial linear polymethylphenylsiloxane used in this embodiment has a molecular weight of 2500-3400.

[0080] Performance test (the same performance test method is used in the following embodiments):

[0081] (1) Elastic modulus, viscoelastic hysteresis.

[0082] Polymer scintillators may be subjected to repeated deformation, stretching, and other destructive forces during use. Therefore, dynamic mechanical analysis (DMA) was used to study the mechanical properties of the modified polysilane-polysiloxane bulk crosslinked copolymer scintillators. This analysis yielded the changes in the elastic modulus of the bulk crosslinked copolymer scintillators with frequency and their viscoelastic hysteresis, as shown in the attached figure. Figure 2 As shown. The elastic modulus E of a material reflects the ease or difficulty of elastic deformation, determined by... Figure 2 As can be seen, in the low-frequency region (<2Hz), the E value is approximately 2000 kPa, exhibiting obvious elastic deformation characteristics; as the frequency increases, the E value gradually increases to 3500 kPa, exhibiting hardening characteristics under alternating stress. The stress loss tangent tanδ is the ratio of the polymer's dissipation modulus to its elastic modulus, used to measure the viscosity and elasticity characteristics of the polymer under alternating stress. Figure 2 The value of tanδ in the middle shows a trend of first increasing rapidly and then gradually decreasing with the increase of frequency. The peak value is located at 56~79Hz, indicating that in this frequency range, more mechanical energy of the modified polysilane-polysiloxane cross-linked copolymer scintillator will be converted into the internal energy of the polymer and dissipated, causing the temperature of the scintillator material itself to rise, which is prone to damage. Long-term operation under stress at this frequency should be avoided.

[0083] (2) Fluorescence performance test.

[0084] The fluorescence properties of the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator were analyzed using a combined UV absorption-fluorescence excitation-fluorescence emission spectroscopy approach. First, the maximum absorption wavelength of the polysilane-polysiloxane bulk crosslinked copolymer scintillator was determined using UV absorption spectroscopy. Then, steady-state fluorescence emission spectra were obtained using the maximum UV absorption wavelength as the fluorescence excitation wavelength. Next, the fluorescence excitation spectrum was tested again while maintaining the maximum fluorescence emission wavelength. Finally, the steady-state fluorescence emission spectrum and transient fluorescence decay spectrum were obtained using the corrected fluorescence excitation wavelength, as shown in the attached figure. Figure 3 As shown, PP-PMS-PSO exhibits a peak at a wavelength of 362~380nm, which is about 60nm red-shifted compared to the unmodified PMS-PSO crosslinked copolymer. This corresponds to the fluorescence emission peak of the Si-Si backbone affected by biphenyl, and the peak intensity is also significantly increased by about 21 times compared to the unmodified scintillation group.

[0085] (3) Scintillation counting performance test

[0086] The scintillation counting performance of the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator was measured using a photomultiplier tube coupled to an electronic circuit. The scintillation count rate of the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator under gamma rays was measured. The prepared bulk crosslinked copolymer scintillator was installed in a probe housing and coupled with a photomultiplier tube. With the corresponding electronic circuit, scintillation pulses were collected by computer under a natural gamma-ray background, and the scintillation count rate was calculated to be 16.4 times / minute.

[0087] (4) Neutron / gamma-ray discrimination performance test

[0088] The neutron / gamma-ray discrimination performance of the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator was tested by recoil proton method. The prepared bulk crosslinked copolymer scintillator was loaded into a probe shell and coupled with a photomultiplier tube, and was matched with corresponding electronic circuit. Under the Am-Be neutron source, the neutron / gamma-ray was measured by recoil proton method and the pulse shape discrimination (PSD) analysis was performed, as shown in FIG. 3. The horizontal axis of the PSD scatter plot represents the channel number, which represents different particle energies, and the vertical coordinate represents the PSD value and the particle number. It can be seen from FIG. 3 that the PSD plot can clearly distinguish the neutron and gamma-ray receiving events, indicating that the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator has good PSD effect. 241 Am-Be neutron source, the neutron / gamma-ray was measured by recoil proton method and the pulse shape discrimination (PSD) analysis was performed, as shown in FIG. 3. The horizontal axis of the PSD scatter plot represents the channel number, which represents different particle energies, and the vertical coordinate represents the PSD value and the particle number. It can be seen from FIG. 3 that the PSD plot can clearly distinguish the neutron and gamma-ray receiving events, indicating that the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator has good PSD effect. Figure 4 Figure 4 It can be seen from FIG. 3 that the PSD plot can clearly distinguish the neutron and gamma-ray receiving events, indicating that the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator has good PSD effect.

[0089] Example 2

[0090] A preparation method of a modified polysilane-polysiloxane bulk crosslinked copolymer scintillator, comprising the following steps: (the preparation process of Grignard reagent and polymethylhydrosilane solution is the same as that in Example 1)

[0091] S1: under a helium atmosphere, the Grignard reagent was slowly added dropwise into the polymethylhydrosilane solution, and the reaction was carried out at a constant temperature for 4 h; wherein the Grignard reagent was obtained by reacting the scintillation group carrier 2-(4-bromophenyl)-5-phenyl-1,3,4-oxadiazole with magnesium powder in anhydrous tetrahydrofuran solvent at a molar ratio of 1:1, and the mass / volume ratio of polymethylhydrosilane and CCl4 was 11 g / 100 mL; the constant temperature was the refluxing temperature of tetrahydrofuran;

[0092] S2: the product obtained in step S1 was purified to obtain modified polymethylhydrosilane. The Si-H substitution rate of the modified polymethylhydrosilane in this embodiment was about 4%;

[0093] S3: the modified polymethylhydrosilane and polymethylphenylsiloxane were mixed to undergo crosslinking reaction to obtain a modified polysilane-polysiloxane bulk crosslinked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrosilane to the polymethylphenylsiloxane was 1:1.

[0094] The molecular weight of the commercial linear polymethylphenylsiloxane used in this embodiment was 2500-3400.

[0095] The scintillation counting rate of the modified polysilane-polysiloxane bulk crosslinked copolymer scintillator in this embodiment was 18.2 times / min.

[0096] Example 3 ​

[0097] A method for preparing a modified polysilane-polysiloxane body-type crosslinked copolymer scintillator, comprising the following steps: (the preparation process of Grignard reagent and polymethylhydrosilane solution is the same as that in Example 1)

[0098] S1: slowly add the polymethylhydrosilane solution drop by drop into the Grignard reagent, and react at a constant temperature for 6h; wherein the Grignard reagent is obtained by reacting a scintillation group carrier 2-(4-bromophenyl)-5-phenyl-1,3,4-oxadiazole with magnesium powder in a molar ratio of 1:1 in anhydrous tetrahydrofuran solvent, and the mass / volume ratio of polymethylhydrosilane and CCl4 is 11g / 100mL; the constant temperature is the refluxing temperature of tetrahydrofuran;

[0099] S2: purify the product obtained in step S1 to obtain a modified polymethylhydrosilane. The Si-H substitution rate of the modified polymethylhydrosilane in this embodiment is about 4%;

[0100] S3: mix the modified polymethylhydrosilane and polymethylphenylsiloxane to make them crosslink to obtain a modified polysilane-polysiloxane body-type crosslinked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrosilane and the polymethylphenylsiloxane is 1:2.

[0101] The molecular weight of the commercial linear polymethylphenylsiloxane used in this embodiment is 2500-3400.

[0102] The modified polysilane-polysiloxane body-type crosslinked copolymer scintillator of this embodiment has a scintillation count rate of 16.8 times per minute.

[0103] Example 4

[0104] A method for preparing a modified polysilane-polysiloxane body-type crosslinked copolymer scintillator, comprising the following steps:

[0105] (the preparation process of Grignard reagent and polymethylhydrosilane solution is the same as that in Example 1)

[0106] S1: under an argon atmosphere, slowly add the Grignard reagent drop by drop into the polymethylhydrosilane solution, and react at a constant temperature for 6h; wherein the Grignard reagent is obtained by reacting a scintillation group carrier 2-bromo-5-(4-pyridyl)-1,3,4-thiadiazole with magnesium powder in a molar ratio of 1:1 in anhydrous tetrahydrofuran solvent, and the mass / volume ratio of polymethylhydrosilane and CCl4 is 35g / 100mL; the constant temperature is the refluxing temperature of tetrahydrofuran; the polymethylhydrosilane in this step is also self-made, and the number average degree of polymerization is about 20, and the number average molecular weight is about 880;

[0107] S2: purifying the product obtained in step S1 to obtain modified polymethylhydrosilane. The Si-H substitution rate of the modified polymethylhydrosilane in this embodiment is about 4%;

[0108] S3: mixing the modified polymethylhydrosilane and polymethylphenylsiloxane to make them crosslink to obtain a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator, wherein the molar ratio of the modified polymethylhydrosilane to the polymethylphenylsiloxane is 1:1.

[0109] The molecular weight of the commercial linear polymethylphenylsiloxane used in this embodiment is 2500-3400.

[0110] The modified polysilane-polysiloxane body-type crosslinking copolymer scintillator in this embodiment has a scintillation count rate of 13.8 times per minute.

[0111] Example 5

[0112] A method for preparing a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator, comprising the following steps:

[0113] (The preparation process of Grignard reagent and polymethylhydrosilane solution is the same as that in Example 1)

[0114] S1: under a helium atmosphere, slowly dropwise add Grignard reagent to a polymethylhydrosilane solution, and react at a constant temperature for 6 hours; wherein the Grignard reagent is obtained by reacting a scintillation group carrier 2-chloro-5-bromothiophene with magnesium powder in anhydrous tetrahydrofuran solvent at a molar ratio of 1:1, the mass / volume ratio of polymethylhydrosilane to CCl4 is 44 g / 100 mL; the constant temperature is the refluxing temperature of tetrahydrofuran; the polymethylhydrosilane in this step is also self-made, and the number average degree of polymerization is about 25, and the number average molecular weight is about 1100;

[0115] S2: purify the product obtained in step S1 to obtain modified polymethylhydrosilane. The Si-H substitution rate of the modified polymethylhydrosilane in this embodiment is about 10%;

[0116] S3: mixing the modified polymethylhydrosilane and polymethylphenylsiloxane to make them crosslink to obtain a modified polysilane-polysiloxane body-type crosslinking copolymer scintillator, wherein the molar ratio of the modified polymethylhydrosilane to the polymethylphenylsiloxane is 1:1.

[0117] The molecular weight of the commercial linear polymethylphenylsiloxane used in this embodiment is 2500-3400.

[0118] The modified polysilane-polysiloxane body-type crosslinking copolymer scintillator in this embodiment has a scintillation count rate of 12.4 times per minute.

[0119] The portions of the present application specification not described in detail are provided for the purpose of illustration and not limitation. The scope of the present application is defined by the appended claims. Various equivalents substitutions and modifications, not described above, are encompassed by the scope of the present application.

Claims

1. A modified polysilane-polysiloxane block crosslinking copolymer scintillator characterized by, The crosslinked copolymer scintillator is a three-dimensional spatial network body crosslinked structure formed by modified polymethyl hydrogen silane and polymethyl phenyl siloxane; The molecular structure formula is: ； Wherein, A-PMS is modified polymethyl hydrogen silane, and PSO is polymethyl phenyl siloxane. The modified polymethyl hydrogen silane is obtained by replacing H in Si-H bond of polymethyl hydrogen silane with a scintillation group; wherein the Si-H replacement rate is 4%~10%.

2. The modified polysilane-polysiloxane topological crosslinked copolymeric scintillator of claim 1, wherein, The structure of the modified polymethyl hydrogen silane is: ； wherein R is , , , , , one or more of the following:

3. The modified polysilane-polysiloxane topological crosslinked copolymeric scintillator of claim 2, wherein, The polymethyl hydrogen silane is a linear polymer, and the number average polymerization degree is 18~25, and the number average molecular weight is 792~1100.

4. The modified polysilane-polysiloxane topological crosslinked copolymeric scintillator of claim 1, wherein, The polymethyl phenyl siloxane is a hydroxyl-terminated polymethyl phenyl siloxane, and the molecular structure of the hydroxyl-terminated polymethyl phenyl siloxane is: ； Wherein, n=18~25.

5. The modified polysilane-polysiloxane topological crosslinked copolymeric scintillator of claim 4, wherein, The number average molecular weight of the hydroxyl-terminated polymethyl phenyl siloxane is 2500~3400.

6. A method of producing the modified polysilane-polysiloxane body-type crosslinking copolymer scintillator according to any one of claims 1 to 5, characterized by, Comprising the following steps: S1: slowly mix Grignard reagent and polymethyl hydrogen silane solution, and react for 4~6 h at constant temperature; wherein the Grignard reagent is obtained by reacting a scintillation group carrier with magnesium powder in anhydrous tetrahydrofuran solvent, and the polymethyl hydrogen silane solution is obtained by dissolving polymethyl hydrogen silane in CCl4; the constant temperature is the reflux temperature of tetrahydrofuran; the Grignard reagent and the polymethyl hydrogen silane solution are mixed according to a molar ratio of Grignard reagent to Si-H bond in polymethyl hydrogen silane solution of 0.1~1:1; S2: purify the product obtained in step S1 to obtain modified polymethyl hydrogen silane; S3: mix the modified polymethyl hydrogen silane and polymethyl phenyl siloxane to make them crosslink, wherein the molar ratio of the modified polymethyl hydrogen silane to the polymethyl phenyl siloxane is 1:2~1:

1.

7. The production method according to claim 6, wherein The mass / volume concentration of the polymethyl hydrogen silane and CCl4 in step S1 is 11~44 g / 100 mL.

8. The preparation method according to claim 6, characterized in that, The polymethyl hydrogen silane solution is obtained by dissolving polymethyl hydrogen silane in CCl4 under anhydrous and anaerobic conditions, reacting for 1~4 h at room temperature, and then removing the residual CCl4 under vacuum.

9. The preparation method according to claim 6, characterized in that, The slow mixing of the Grignard reagent and the polymethyl hydrogen silane solution is to add the Grignard reagent dropwise into the polymethyl hydrogen silane solution under inert gas atmosphere; Or the slow mixing of the Grignard reagent and the polymethyl hydrogen silane solution is to add the polymethyl hydrogen silane solution dropwise into the Grignard reagent.

10. The method of claim 6, wherein, The scintillation group carrier is a bromide or iodide of biphenyl, phenyloxazolyl, phenyloxadiazolylphenyl, pyridylthiadiazolyl, or chlorothiophenyl.

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