Modified polysilane-polysiloxane body type cross-linked copolymerization scintillator and preparation method thereof

Abstract

The invention discloses a modified polysilane-polysiloxane body type cross-linked copolymerization scintillator and a preparation method thereof. The cross-linked copolymerization scintillator is of a body type cross-linked structure formed by cross-linking modified polymethylhydrosilane and polymethylphenylsiloxane. 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 conjugated system and a sigma-p-pi conjugated system. Correspondingly, introduced pi electrons and lone pair electrons (n electrons) are converted into pi-to-sigma # imgabs 0 # transition and pi-to-n-to-sigma # imgabs 1 # transition, so that the energy gap width is changed, and the fluorescence emission spectrum of the polysilane becomes adjustable. After modification, a conjugated system is expanded, the fluorescence intensity and the quantum yield of polysilane are improved due to intermolecular electron transfer, and the fluorescence intensity of a scintillation group after modification is remarkably improved by 20-40 times compared with that of an unmodified polysilane-polysiloxane cross-linked copolymer.

Description

Technical Field

[0001] The invention relates to the technical field of polymer luminescent materials, and in particular to a modified polysilane-polysiloxane type cross-linked copolymer scintillator and a preparation method thereof. Background Art

[0002] Polymer fluorescent materials have the advantages of low cost, unlimited shape and volume, and strong environmental tolerance, and have become the focus of attention in recent years. At present, in the civil and military fields, as supporting materials for information display, lighting sources, optoelectronic devices, etc., small-volume, light-weight, large-area, and foldable fluorescent materials have received widespread attention. 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 for radiation detection. The light pulses are converted into electrical signals and amplified by the photomultiplier tube, and then the radiation intensity is obtained after counting, storage, and processing by the main module.

[0003] Existing plastic scintillators have the following three deficiencies: First, the luminous efficiency is low. Since polystyrene itself has no fluorescent properties, and the fluorescent solutes and wavelength shifter molecules are dispersed in the solvent, the photon yield is low. Second, it is very sensitive to high temperature and oxygen. Since both the solutes and wavelength shifters contain a large number of unsaturated double bonds and are easily oxidized, long-term storage will lead to yellowing, aging and cracking, reduced photon yield, prolonged fluorescence relaxation time and other problems, which will affect the accuracy of radiation detection. Third, it is highly toxic and not environmentally friendly. Existing scintillation solutes and wavelength shifters are mostly benzene homologues and polycyclic aromatic hydrocarbons, which are highly toxic and carcinogenic, and seriously threaten life and the natural environment.

[0004] In summary, currently, dedicated scintillators have not been developed for fusion reactor radiation detection. Common liquid scintillators are still used, which have low luminous efficiency and can only be used for static or intermittent sampling and detection. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a modified polysilane-polysiloxane bulk cross-linked copolymer scintillator. The bulk cross-linked copolymer scintillator can improve the sensitivity of neutron and gamma ray detection and realize real-time and online detection.

[0006] A further technical problem to be solved by the present invention is to provide a method for preparing a modified polysilane-polysiloxane type cross-linked copolymer scintillator.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme:

[0008] A modified polysilane-polysiloxane bulk cross-linked copolymer scintillator, wherein the cross-linked copolymer scintillator is a bulk cross-linked structure formed by cross-linking modified polymethylhydrogensilane and polymethylphenylsiloxane; the molecular structure is:

[0009] ;

[0010] Among them, A-PMS is modified polymethylhydrogensilane, and PSO is polymethylphenylsiloxane.

[0011] Wherein, the modified polymethylhydrogensilane is obtained by replacing the H in the Si-H bond of polymethylhydrogensilane with a scintillating group; the structure of the modified polymethylhydrogensilane is:

[0012] ;

[0013] Among them, R is , , , , , One or more of .

[0014] The polymethylhydrogensilane is a linear polymer with a number average degree of polymerization of about 18 to 25 and a number average molecular weight of about 792 to 1100.

[0015] Wherein, the crosslinking agent is hydroxyl-terminated polymethylphenylsiloxane, and the molecular structure of the crosslinking agent is:

[0016] ;

[0017] Among them, 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 cross-linked copolymer scintillator comprises the following steps:

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

[0021] S2: purifying the product obtained in step S1 to obtain modified polymethylhydrogensilane;

[0022] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to allow them to undergo a cross-linking reaction, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:2 to 1:1.

[0023] Wherein, the mass / volume concentration of the polymethylhydrogensilane and CCl4 in step S1 is 11~44g / 100mL.

[0024] The polymethylhydrogensilane solution is obtained by dissolving polymethylhydrogensilane in CCl4 under anhydrous and oxygen-free conditions, reacting at room temperature for 1 to 4 hours, and then removing residual CCl4 in vacuo.

[0025] Wherein, the slowly mixing of the Grignard reagent and the polymethylhydrogensilane solution is to add the Grignard reagent dropwise into the polymethylhydrogensilane solution under an inert gas atmosphere;

[0026] Alternatively, the slowly mixing of the Grignard reagent and the polymethylhydrogensilane solution is adding the polymethylhydrogensilane solution dropwise into the Grignard reagent.

[0027] Wherein, the scintillating group carrier is a bromide or iodide of biphenyl, phenyloxazolyl, phenyloxadiazolylphenyl, pyridylthiadiazolyl, or chlorothienyl.

[0028] The beneficial effects of the modified polysilane-polysiloxane cross-linked copolymer scintillator of the present invention are as follows:

[0029] (1) The present invention introduces a scintillating group with 2 to 3 aromatic rings into the Si-Si main chain through the Grignard reaction, so that the original σ conjugated system is expanded to σ-π and σ-p-π conjugated systems. Correspondingly, the introduced π electrons and lone pair electrons (n ​​electrons) transform it into π→σ Transition and π→n→σ The transition changes the energy gap width, making the fluorescence emission spectrum of polysilane adjustable. After modification, the conjugated system is expanded, and the intermolecular electron transfer increases the fluorescence intensity and quantum yield of polysilane. The fluorescence intensity of the modified scintillating group is significantly increased by 20 to 40 times compared with the unmodified polysilane-polysiloxane cross-linked copolymer.

[0030] (2) The mechanical properties of the copolymer elastic scintillator of the present invention are obtained by a polymethylphenylsiloxane crosslinker. By utilizing the high elasticity, thermal stability and weather resistance of polysiloxane, it can form a three-dimensional network structure after crosslinking and curing with scintillating group-modified polymethylhydrogensilane, thereby obtaining elasticity and chemical stability higher than that of ordinary thermoplastic elastic scintillators. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The chemical structure diagram of the modified polysilane-polysiloxane cross-linked copolymer scintillator of the present invention;

[0032] Figure 2The elastic modulus and hysteresis loss curves of modified polysilane-polysiloxane cross-linked copolymer scintillator under alternating stress of different frequencies;

[0033] Figure 3 is the fluorescence emission curve of the modified polysilane-polysiloxane cross-linked copolymer scintillator;

[0034] Figure 4 To modify the polysilane-polysiloxane cross-linked copolymer scintillator 241 Neutron-gamma ray discrimination curve under Am-Be neutron source. DETAILED DESCRIPTION

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

[0036] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0037] A modified polysilane-polysiloxane bulk cross-linked copolymer scintillator, wherein the cross-linked copolymer scintillator is a bulk cross-linked structure formed by cross-linking modified polymethylhydrogensilane (A-PMS) and polymethylphenylsiloxane (PSO); its molecular structure is:

[0038] .

[0039] In addition, the molecular structure of the modified polysilane-polysiloxane cross-linked copolymer scintillator of the present invention can also be further referred to Figure 1 .like Figure 1 As shown in the figure, the modified polysilane-polysiloxane cross-linked copolymer scintillator of the present invention replaces the H in Si-H on PMS with a scintillating group with 2 to 3 aromatic rings, thereby introducing the scintillating group into the Si-Si main chain of PMS, so that the original σ conjugated system is expanded to σ-π and σ-p-π conjugated systems. Correspondingly, the introduced π electrons and lone pair electrons (n ​​electrons) transform it into π→σ Transition and π→n→σ Transition, thereby changing the energy gap width, making the fluorescence emission spectrum of polysilane adjustable. After modification, the conjugated system is expanded, and the intermolecular electron transfer improves the fluorescence intensity and quantum yield of polysilane. The fluorescence intensity of the modified scintillating group is significantly increased by 20 to 40 times compared with the unmodified polysilane-polysiloxane cross-linked copolymer. Linear polymethylphenylsiloxane is selected as a cross-linking agent, and a three-dimensional network-shaped cross-linked copolymer structure is achieved through a dehydrogenation coupling reaction between the terminal hydroxyl group and the residual Si-H on the modified polymethylphenylsilane. Using polymethylphenylsiloxane as a cross-linking agent can form a three-dimensional structure on the one hand, and on the other hand, it can increase the solubility of PMS and improve the fluorescence efficiency.

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

[0041] ;

[0042] Among them, R is , , , , , One or more of .

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

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

[0045] ;

[0046] Among them, 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 cross-linked copolymer scintillator comprises the following steps:

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

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

[0051] ;

[0052] S2: The product obtained in step S1 is purified to obtain modified polymethylhydrosilane; the purification can be carried out by filtering, extracting, removing the solvent by rotary evaporation, etc.; the synthetic solvent tetrahydrofuran is dried by sodium reflux method; other solvents are dried by 4Å molecular sieve, 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 the Grignard reaction, a scintillation group-modified polysilane luminescent functional polymer can be obtained, thereby improving the fluorescence intensity and quantum yield of the polysilane.

[0054] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to allow them to undergo a cross-linking reaction, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:2 to 1:1.

[0055] In step S3, linear polymethylphenylsiloxane (number average molecular weight is about 2500-3400) is selected as a cross-linking agent, and a dehydrogenation coupling reaction occurs between the terminal hydroxyl group and the residual Si-H on the modified polymethylhydrosilane synthesized in S3 to achieve a three-dimensional network of bulk cross-linked copolymer structure, thereby obtaining a bulk cross-linked copolymer scintillator.

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

[0057] ;

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

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

[0060] The preparation of the Grignard reagent is to react a scintillating group carrier (usually a bromide or iodide of biphenyl, phenyloxazolyl, phenyloxadiazolylphenyl, pyridylthiadiazolyl, chlorothienyl) with magnesium powder in anhydrous tetrahydrofuran solvent; the reaction formula is:

[0061] .

[0062] The preparation process of the polymethylhydrogensilane solution is as follows: dissolve polymethylhydrogensilane in CCl4, react at room temperature for 1 to 4 hours, and then remove the residual CCl4 in vacuo; in this step, PMS and CCl4 undergo Cl substitution reaction; the reaction formula is as follows:

[0063] .

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

[0065] Preferably, step S1 is performed under anhydrous and oxygen-free conditions.

[0066] Preferably, the slowly mixing of the Grignard reagent and the polymethylhydrogensilane solution is performed by adding the Grignard reagent dropwise into the polymethylhydrogensilane solution under an inert gas atmosphere;

[0067] Alternatively, the slowly mixing of the Grignard reagent and the polymethylhydrogensilane solution is adding the polymethylhydrogensilane solution dropwise into the Grignard reagent.

[0068] The synthesis of the modified polysilane-polysiloxane cross-linked copolymer scintillator of the present invention uses a scintillating group carrier, polymethylhydrogensilane (PMS) and polymethylphenylsiloxane as raw materials. Under anhydrous and oxygen-free conditions, the scintillating group carrier is grafted onto the PMS molecular chain through a Grignard reaction, and polymethylphenylsiloxane is used as a cross-linking agent to prepare a polysilane-polysiloxane cross-linked copolymer polymer. The fluorescence intensity and quantum yield of the polysilane are improved by introducing the scintillating group on the Si-Si main chain; the elasticity and chemical stability of the scintillator are enhanced by cross-linking copolymerization of the polysiloxane.

[0069] Example 1

[0070] A method for preparing a modified polysilane-polysiloxane cross-linked copolymer scintillator comprises the following steps:

[0071] (1) Synthesis of polymer matrix polymethylhydrogensilane;

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

[0073] (2) Polymethylhydrogensilane solution: Dissolve polymethylhydrogensilane in CCl4 with a mass / volume ratio of polymethylhydrogensilane to CCl4 of 22 g / 100 mL. After reacting at room temperature for 1 to 4 h, remove the residual CCl4 in vacuo.

[0074] (3) Preparation of Grignard reagent.

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

[0076] S1: In an argon atmosphere, a Grignard reagent is slowly added dropwise to a polymethylhydrosilane solution, and the reaction is carried out at a constant temperature for 6 hours; wherein the Grignard reagent is obtained by reacting a scintillating group carrier 1-bromo-4-phenylbenzene with magnesium powder in an anhydrous tetrahydrofuran solvent in a molar ratio of 1:1; the constant temperature is the reflux temperature of tetrahydrofuran;

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

[0078] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to undergo a cross-linking reaction to obtain a modified polysilane-polysiloxane body-type cross-linked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:1.

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

[0080] Performance test (the following examples all use the same performance test method):

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

[0082] Polymer scintillators may be subjected to repeated deformation, stretching and other destructive effects during use. Therefore, dynamic mechanical analysis (DMA) was used to analyze the mechanical properties of the modified polysilane-polysiloxane bulk cross-linked copolymer scintillator to obtain the change of elastic modulus with frequency and viscoelastic hysteresis of the bulk cross-linked copolymer scintillator. Figure 2 The elastic modulus E of a material reflects the ease of elastic deformation and is given by Figure 2 It can be seen that in the low frequency region (<2Hz), the E value is about 2000kPa, showing obvious elastic deformation characteristics; as the frequency increases, the E value gradually increases to 3500kPa, showing the hardening characteristics under alternating stress. The stress loss tangent tanδ is the ratio of the polymer dissipation modulus to the elastic modulus, which is used to measure the viscosity and elastic characteristics of the polymer under alternating stress. Figure 2 The value of tanδ increases rapidly at first and then decreases gradually with the increase of frequency, and 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 easy to cause damage. Long-term operation under the stress of this frequency should be avoided.

[0083] (2) Fluorescence performance test.

[0084] The fluorescence properties of the modified polysilane-polysiloxane cross-linked copolymer scintillator were analyzed by ultraviolet absorption-fluorescence excitation-fluorescence emission spectrum. The maximum absorption wavelength of the polysilane-polysiloxane cross-linked copolymer scintillator was first determined by ultraviolet absorption spectrum; then the steady-state fluorescence emission spectrum was obtained by taking the maximum ultraviolet absorption wavelength as the fluorescence excitation wavelength; the fluorescence excitation spectrum was tested by fixing the maximum fluorescence emission wavelength again; finally, the steady-state fluorescence emission spectrum and transient fluorescence decay spectrum were obtained by obtaining the corrected fluorescence excitation wavelength, as shown in the attached figure. Figure 3 PP-PMS-PSO has a peak at a wavelength of 362-380nm, which is about 60nm red-shifted compared with the PMS-PSO cross-linked copolymer before modification, corresponding to the fluorescence emission peak of the Si-Si main chain affected by the biphenyl group, and the peak intensity is also significantly increased by about 21 times compared with before the scintillating group modification.

[0085] (3) Scintillation counting performance test

[0086] The scintillation counting performance of modified polysilane-polysiloxane bulk cross-linked copolymer scintillator was measured by photomultiplier tube coupling electronic circuit under γ-ray. The prepared bulk cross-linked copolymer scintillator was placed in the probe housing, coupled with the photomultiplier tube, matched with the corresponding electronic circuit, and the scintillation pulses were collected by computer under the natural background of γ-ray and the scintillation counting 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 modified polysilane-polysiloxane bulk cross-linked copolymer scintillator was studied by recoil proton method. The prepared bulk cross-linked copolymer scintillator was loaded into the probe housing, coupled with a photomultiplier tube, and matched with the corresponding electronic circuit. 241 Under the Am-Be neutron source, the recoil proton method is used to measure neutrons / γ rays and perform pulse shape discrimination (PSD) analysis, as shown in the attached Figure 4 As shown. In the PSD scatter plot, the horizontal axis is the channel number, representing different particle energies, and the vertical axis represents the PSD value and the number of particles. Figure 4 It can be seen that the PSD diagram can clearly distinguish neutron and gamma-ray reception events, indicating that the modified polysilane-polysiloxane cross-linked copolymer scintillator has a good PSD effect.

[0089] Example 2

[0090] A method for preparing a modified polysilane-polysiloxane cross-linked copolymer scintillator comprises the following steps: (the preparation process of the Grignard reagent and the polymethylhydrogensilane solution is the same as that in Example 1)

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

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

[0093] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to undergo a cross-linking reaction to obtain a modified polysilane-polysiloxane body-type cross-linked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:1.

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

[0095] The scintillation counting rate of the modified polysilane-polysiloxane cross-linked copolymer scintillator of this embodiment is 18.2 times / minute.

[0096] Example 3

[0097] A method for preparing a modified polysilane-polysiloxane cross-linked copolymer scintillator comprises the following steps: (the preparation process of the Grignard reagent and the polymethylhydrogensilane solution is the same as that in Example 1)

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

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

[0100] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to undergo a cross-linking reaction to obtain a modified polysilane-polysiloxane body-type cross-linked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:2.

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

[0102] The scintillation counting rate of the modified polysilane-polysiloxane cross-linked copolymer scintillator of this embodiment is 16.8 times / minute.

[0103] Example 4

[0104] A method for preparing a modified polysilane-polysiloxane cross-linked copolymer scintillator comprises the following steps:

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

[0106] S1: Under an argon atmosphere, the Grignard reagent is slowly added dropwise to the polymethylhydrogensilane solution, and the reaction is carried out at a constant temperature for 6 hours; wherein the Grignard reagent is obtained by reacting the scintillating group carrier 2-bromo-5-(4-pyridyl)-1,3,4-thiadiazole with magnesium powder in anhydrous tetrahydrofuran solvent in a molar ratio of 1:1, and the mass / volume ratio of polymethylhydrogensilane and CCl4 is 35g / 100mL; the constant temperature is the reflux temperature of tetrahydrofuran; the polymethylhydrogensilane in this step is also homemade, with a number average degree of polymerization of about 20 and a number average molecular weight of about 880;

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

[0108] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to undergo a cross-linking reaction to obtain a modified polysilane-polysiloxane body-type cross-linked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:1.

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

[0110] The scintillation counting rate of the modified polysilane-polysiloxane cross-linked copolymer scintillator of this embodiment is 13.8 times / minute.

[0111] Example 5

[0112] A method for preparing a modified polysilane-polysiloxane cross-linked copolymer scintillator comprises the following steps:

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

[0114] S1: In a helium atmosphere, the Grignard reagent is slowly added dropwise to the polymethylhydrogensilane solution, and the reaction is carried out at a constant temperature for 6 hours; wherein the Grignard reagent is obtained by reacting the scintillating group carrier 2-chloro-5-bromothiophene with magnesium powder in anhydrous tetrahydrofuran solvent in a molar ratio of 1:1, and the mass / volume ratio of polymethylhydrogensilane and CCl4 is 44g / 100mL; the constant temperature is the reflux temperature of tetrahydrofuran; the polymethylhydrogensilane in this step is also homemade, with a number average degree of polymerization of about 25 and a number average molecular weight of about 1100;

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

[0116] S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to undergo a cross-linking reaction to obtain a modified polysilane-polysiloxane body-type cross-linked copolymer scintillator, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:1.

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

[0118] The scintillation counting rate of the modified polysilane-polysiloxane cross-linked copolymer scintillator of this embodiment is 12.4 times / minute.

[0119] The parts not elaborated in detail in the description of the present invention belong to the known technology in the art. The above embodiments are provided only for the purpose of describing the present invention, and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A modified polysilane-polysiloxane cross-linked copolymer scintillator, characterized in that: The cross-linked copolymer scintillator is a body-type cross-linked structure formed by cross-linking modified polymethylhydrogensilane and polymethylphenylsiloxane; Its molecular structure is: ； Among them, A-PMS is modified polymethylhydrogensilane, and PSO is polymethylphenylsiloxane.

2. The modified polysilane-polysiloxane cross-linked copolymer scintillator according to claim 1, characterized in that: The modified polymethylhydrogensilane is obtained by replacing the H in the Si-H bond of polymethylhydrogensilane with a scintillating group; the structure of the modified polymethylhydrogensilane is: ； Among them, R is , , , , , One or more of .

3. The modified polysilane-polysiloxane cross-linked copolymer scintillator according to claim 2, characterized in that: The polymethylhydrogensilane is a linear polymer with a number average degree of polymerization of about 18 to 25 and a number average molecular weight of about 792 to 1100.

4. The modified polysilane-polysiloxane cross-linked copolymer scintillator according to claim 1, characterized in that: The crosslinking agent is hydroxyl-terminated polymethylphenylsiloxane, and the molecular structure of the crosslinking agent is: ； Among them, n=18~25.

5. The modified polysilane-polysiloxane cross-linked copolymer scintillator according to claim 4, characterized in that: The number average molecular weight of the hydroxyl-terminated polymethylphenylsiloxane is 2500-3400.

6. The method for preparing the modified polysilane-polysiloxane cross-linked copolymer scintillator according to any one of claims 1 to 5, characterized in that: The steps include: S1: slowly mix the Grignard reagent and the polymethylhydrogensilane solution, and react at a constant temperature for 4 to 6 hours; wherein the Grignard reagent is obtained by reacting the scintillating group carrier with magnesium powder in anhydrous tetrahydrofuran solvent, and the polymethylhydrogensilane solution is obtained by dissolving polymethylhydrogensilane in CCl4; the constant temperature is the reflux temperature of tetrahydrofuran; S2: purifying the product obtained in step S1 to obtain modified polymethylhydrogensilane; S3: mixing the modified polymethylhydrogensilane and polymethylphenylsiloxane to allow them to undergo a cross-linking reaction, wherein the molar ratio of the modified polymethylhydrogensilane to the polymethylphenylsiloxane is 1:2 to 1:

1.

7. The preparation method according to claim 6, characterized in that: The mass / volume concentration of the polymethylhydrogensilane and CCl4 in step S1 is 11-44 g / 100 mL.

8. The preparation method according to claim 6, characterized in that: The polymethylhydrogensilane solution is obtained by dissolving polymethylhydrogensilane in CCl4 under anhydrous and oxygen-free conditions, reacting at room temperature for 1 to 4 hours, and then removing residual CCl4 in vacuo.

9. The preparation method according to claim 6, characterized in that: The slowly mixing of the Grignard reagent and the polymethylhydrogensilane solution is performed by adding the Grignard reagent dropwise into the polymethylhydrogensilane solution under an inert gas atmosphere; Alternatively, the slowly mixing of the Grignard reagent and the polymethylhydrogensilane solution is adding the polymethylhydrogensilane solution dropwise into the Grignard reagent.

10. The preparation method according to claim 6, characterized in that: The scintillating group carrier is a bromide or iodide of biphenyl, phenyloxazolyl, phenyloxadiazolylphenyl, pyridylthiadiazolyl, or chlorothienyl.

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