Gamma ray shielding composite material and preparation method thereof

Abstract

The invention discloses a gamma ray shielding composite material and a preparation method thereof, and belongs to the technical field of shielding materials. The invention aims to solve the problems that the existing radiation shielding material cannot have high shielding property, flexibility, high shape follow-up property, quick and convenient constructability and the like. The composite material is composed of a metal surface layer, a flexible polymer-based composite material shielding layer and a reinforced fiber layer. The metal surface layer is composed of an ultrathin lead film and / or a tantalum film. The flexible polymer-based composite material shielding layer is composed of a flexible polymer material and a shielding filler. The reinforced fiber layer is composed of one or more of a nylon fiber net, a polyethylene fiber net and a polypropylene fiber net. The gamma radiation shielding fabric has the advantages of being good in gamma radiation shielding performance and shape follow-up performance; the flexible polymer matrix composite material shielding layer has the characteristic of good gamma ray shielding performance; the reinforced fiber layer provides excellent mechanical properties, including tensile property and tear resistance, for the novel heterogeneous multilayer radiation shielding composite material.

Description

Technical Field

[0001] The invention belongs to the technical field of shielding materials and relates to a gamma ray shielding composite material and a preparation method thereof. Background Art

[0002] Radiation protection is mainly aimed at the protection of gamma rays. Gamma rays have extremely strong penetrating power and strong interactions with matter. Once leaked, they will cause great harm to the human body, environment and equipment. Therefore, shielding of gamma rays is very important. There are two types of traditional radiation shielding materials. One is hard protective materials mainly based on pure metal materials, metal-based composite materials and concrete. Although these materials have good shielding performance, their large mass and difficulty in forming limit their application. The other is flexible radiation shielding materials mainly for human protection. This material mainly protects low-energy rays and has insufficient protection against high-energy rays. Therefore, it has broad application prospects to develop a radiation shielding material that has good high-energy ray shielding performance, good flexibility, high conformability and fast and convenient construction. Summary of the invention

[0003] The purpose of the present invention is to solve the problems that existing radiation shielding materials cannot have high shielding performance, flexibility, high conformability and fast and convenient construction, and to provide a gamma-ray shielding composite material and a preparation method thereof. The composite material has excellent high-energy ray shielding performance, good construction performance and versatility, a simple preparation process, low cost, easy operation and good performance.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A gamma ray shielding composite material consists of a metal surface layer, a flexible polymer-based composite material shielding layer and a reinforced fiber layer.

[0006] Furthermore, the metal surface layer is composed of an ultra-thin lead film and / or a tantalum film.

[0007] Furthermore, the flexible polymer-based composite material shielding layer is composed of a flexible polymer material and a shielding filler.

[0008] Furthermore, the flexible polymer material is composed of one or more of nitrile rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS), polyethylene and silica gel.

[0009] Furthermore, the shielding filler is composed of one or more of tungsten powder, lead powder and tantalum powder.

[0010] Furthermore, the mass fraction of the shielding filler in the shielding layer component of the flexible polymer-based composite material is 50%-90%.

[0011] Furthermore, the reinforcing fiber layer is composed of one or more of a nylon fiber mesh, a polyethylene fiber mesh, and a polypropylene fiber mesh.

[0012] A method for preparing the above-mentioned gamma-ray shielding composite material, the method comprising:

[0013] Step 1: Mix the shielding filler and the flexible polymer material evenly for 10 minutes;

[0014] Step 2: preparing the flexible polymer-based composite material into a film;

[0015] Step 3: The metal surface layer is used as the uppermost layer and the lowermost layer, one or more layers of flexible polymer-based composite film are added between the two metal surface layers, and one or more of the reinforcing fiber layers are added between the metal surface layer and the flexible polymer-based composite film and between the flexible polymer-based composite films to prepare a multilayer structure of the gamma-ray shielding composite material;

[0016] Step 4: heating the hot press to a target temperature, placing the multilayer structure of the gamma-ray shielding composite material into the heated hot press, and applying pressure for hot pressing;

[0017] Step 5: Release the pressure of the hot press, take out the multilayer structure of the gamma-ray shielding composite material, and cool it at room temperature to obtain the gamma-ray shielding composite material.

[0018] Furthermore, in step 2, the thickness of the flexible polymer-based composite material is 20 μm-3 mm.

[0019] Furthermore, in step 4, the target temperature is 50-250° C.; the hot pressing pressure is 16-20 kPa, and the duration is 1-10 min.

[0020] The beneficial effects of the present invention over the prior art are as follows: the composite material of the present invention is composed of a metal surface layer, a flexible polymer-based composite shielding layer and a reinforcing fiber layer. The metal surface layer is composed of one or two of an ultra-thin lead film and a tantalum film, and has good gamma radiation shielding performance and conformability; the flexible polymer-based composite shielding layer is composed of a flexible polymer material and a shielding filler, wherein the flexible polymer material is composed of one or more of nitrile rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS), polyethylene and silica gel, and the shielding filler is composed of one or more of tungsten powder, lead powder and tantalum powder, and the flexible polymer-based composite shielding layer has good gamma ray shielding performance; the reinforcing fiber layer is composed of one or more of a nylon fiber mesh, a polyethylene fiber mesh and a polypropylene fiber mesh, and the reinforcing fiber layer provides excellent mechanical properties for the new heterogeneous multilayer radiation shielding composite material, including tensile properties and tear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of preparation of gamma-ray shielding composite material;

[0022] Figure 2 is a diagram of HVL gamma-ray shielding parameters of the shielding material of Example 1;

[0023] Figure 3 is a TVL gamma-ray shielding parameter diagram of the shielding material of Example 1;

[0024] Figure 4 is a graph of the RPE gamma ray shielding parameters of the shielding material of Example 1;

[0025] Figure 5 This is a tensile strength parameter diagram of the shielding material of Example 1;

[0026] Figure 6 is a diagram of HVL gamma-ray shielding parameters of the shielding material of Example 2;

[0027] Figure 7 is a TVL gamma-ray shielding parameter diagram of the shielding material of Example 2;

[0028] Figure 8 is a graph of the RPE gamma ray shielding parameters of the shielding material of Example 2;

[0029] Fig. 9 This is a tensile strength parameter diagram of the shielding material of Example 2. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the protection scope of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0031] Embodiment 1:

[0032] The functional layer of the novel gamma-ray shielding composite material is divided into five layers, the first metal surface layer is a metal lead film, the second layer is a nitrile rubber / lead powder composite shielding layer, the third layer is a nitrile rubber / tantalum powder composite shielding layer, the fourth layer is a nitrile rubber / tungsten powder composite shielding layer, and the fifth layer is a metal lead film. The thickness of the metal surface layer is 20μm.

[0033] The nitrile rubber and metal lead powder were heated and mixed in a mixer at 80°C for 1 h and 100°C for 0.5 h. After mixing, the mixture was cooled to room temperature to prepare a nitrile rubber / lead powder composite shielding layer with a thickness of 0.5 mm.

[0034] The nitrile rubber and metal tantalum powder were heated and mixed in a mixer at 80°C for 1 h and 100°C for 0.5 h. After mixing, the mixture was cooled to room temperature to prepare a nitrile rubber / tantalum powder composite shielding layer with a thickness of 0.5 mm.

[0035] The nitrile rubber and metal tungsten powder were heated and mixed in a mixer at 80°C for 1 h and 100°C for 0.5 h. After mixing, the mixture was cooled to room temperature to prepare a nitrile rubber / tungsten powder composite shielding layer with a thickness of 0.5 mm.

[0036] The heat press was heated to a target temperature of 200°C, and a nylon fiber layer was added between every two layers of the five functional layers, and the layers were put into the heated heat press, and a pressure of 16-20 kPa was applied, and the heat press was performed for 10-15 minutes to prepare a gamma ray shielding composite material. The thickness of a single nylon fiber layer was 10 μm.

[0037] The important parameters of gamma ray shielding are half value layer (HVL), tenth value layer (TVL) and mean free path (MFP). HVL (cm) is the parameter of the material thickness required to reduce the initial radiation intensity to half the value, TVL (cm) is the parameter of the material thickness required to reduce the initial radiation intensity to one tenth the value, and MFP (%) is the radiation shielding efficiency. In order to verify the performance of the shielding material for gamma ray shielding, the present invention experimentally obtained some gamma ray shielding parameters of the shielding material and the shielding parameters of the comparison group of the same thickness (lead, tantalum and tungsten). It can be observed from the accompanying drawings of Example 1 that whether it is HVL or TVL data, the shielding material is the lowest, indicating that the thickness of the shielding material required to reduce the initial radiation intensity to a specific value is the smallest. In addition, the RPE value of the shielding material is also the highest, indicating that its radiation shielding efficiency is the best. All of the above illustrate the advantages of the shielding performance of the shielding material.

[0038] In order to verify the advantages of the mechanical properties of the shielding material, the present invention also conducted tensile strength tests on the shielding material and lead, tantalum and tungsten of the same thickness. Figure 5 It can be clearly observed that the tensile strength parameters of the shielding material are significantly higher than those of other materials, which indicates that the shielding material has good mechanical properties.

[0039] Embodiment 2:

[0040] The functional layer of the novel gamma-ray shielding composite material is divided into five layers, the first layer is a metal lead film, the second layer is a nitrile rubber / lead powder composite shielding layer, the third layer is a nitrile rubber / tungsten powder composite shielding layer, the fourth layer is a nitrile rubber / tungsten carbide powder composite shielding layer, and the fifth layer is a metal lead film. The thickness of the metal surface layer is 20μm.

[0041] The nitrile rubber and metal lead powder were heated and mixed in a mixer at 80°C for 1 h and 100°C for 0.5 h. After mixing, the mixture was cooled to room temperature to prepare a nitrile rubber / lead powder composite shielding layer with a thickness of 0.5 mm.

[0042] The nitrile rubber and tungsten powder were heated and mixed in a mixer at 80°C for 1 h and 100°C for 0.5 h. After mixing, the mixture was cooled to room temperature to prepare a nitrile rubber / tungsten powder composite shielding layer with a thickness of 0.5 mm.

[0043] The nitrile rubber and tungsten carbide powder were heated and mixed in a mixer at 80°C for 1 h and 100°C for 0.5 h. After mixing, the mixture was cooled to room temperature to prepare a nitrile rubber / tungsten carbide powder composite shielding layer with a thickness of 0.5 mm.

[0044] The heat press was heated to the target temperature of 200°C, and a nylon fiber layer was added between every two layers of the five functional layers, and the layers were put into the heated heat press, and a pressure of 16-20 kPa was applied, and the heat press was performed for 10-15 minutes to prepare a new heterogeneous multilayer radiation shielding composite material. The thickness of a single nylon fiber layer was 10 μm.

[0045] The important parameters of gamma ray shielding are half value layer (HVL), tenth value layer (TVL) and mean free path (MFP). HVL (cm) is the parameter of the material thickness required to reduce the initial radiation intensity to half the value, TVL (cm) is the parameter of the material thickness required to reduce the initial radiation intensity to one tenth the value, and MFP (%) is the radiation shielding efficiency. In order to verify the performance of the shielding material for gamma ray shielding, the present invention experimentally obtained some gamma ray shielding parameters of the shielding material and the shielding parameters of the comparison group of the same thickness (lead and tungsten). It can be observed from the accompanying drawings of Example 1 that whether it is HVL or TVL data, the shielding material is the lowest, indicating that the thickness of the shielding material required to reduce the initial radiation intensity to a specific value is the smallest. In addition, the RPE value of the shielding material is also the highest, indicating that its radiation shielding efficiency is the best. All of the above illustrate the advantages of the shielding performance of the shielding material.

[0046] In order to verify the advantages of the mechanical properties of the shielding material, the present invention conducted a tensile strength test on the shielding material and lead and tungsten of the same thickness. Fig. 9It can be clearly observed that the tensile strength parameters of the shielding material are significantly higher than those of other materials, which indicates that the shielding material has good mechanical properties.

Claims

1. A gamma-ray shielding composite material, characterized in that: The composite material consists of a metal surface layer, a flexible polymer-based composite material shielding layer and a reinforcing fiber layer.

2. A gamma-ray shielding composite material according to claim 1, characterized in that: The metal surface layer is composed of an ultra-thin lead film and / or a tantalum film.

3. The gamma-ray shielding composite material according to claim 1, characterized in that: The flexible polymer-based composite material shielding layer consists of flexible polymer material and shielding filler.

4. A gamma-ray shielding composite material according to claim 3, characterized in that: The flexible polymer material is composed of one or more of nitrile rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS), polyethylene and silica gel.

5. The gamma-ray shielding composite material according to claim 3, characterized in that: The shielding filler is composed of one or more of tungsten powder, lead powder and tantalum powder.

6. The gamma-ray shielding composite material according to claim 3, characterized in that: The mass fraction of the shielding filler in the shielding layer component of the flexible polymer-based composite material is 50%-90%.

7. The gamma-ray shielding composite material according to claim 1, characterized in that: The reinforcing fiber layer is composed of one or more of a nylon fiber mesh, a polyethylene fiber mesh, and a polypropylene fiber mesh.

8. A method for preparing the gamma-ray shielding composite material according to any one of claims 1 to 7, characterized in that: The method is: Step 1: Mix the shielding filler and the flexible polymer material evenly; Step 2: preparing the flexible polymer-based composite material into a film; Step 3: The metal surface layer is used as the uppermost layer and the lowermost layer, one or more layers of flexible polymer-based composite film are added between the two metal surface layers, and one or more of the reinforcing fiber layers are added between the metal surface layer and the flexible polymer-based composite film and between the flexible polymer-based composite films to prepare a multilayer structure of the gamma-ray shielding composite material; Step 4: heating the hot press to a target temperature, placing the multilayer structure of the gamma-ray shielding composite material into the heated hot press, and applying pressure for hot pressing; Step 5: Release the pressure of the hot press, take out the multilayer structure of the gamma-ray shielding composite material, and cool it at room temperature to obtain the gamma-ray shielding composite material.

9. The method for preparing a gamma-ray shielding composite material according to claim 8, characterized in that: In step 2, the thickness of the flexible polymer-based composite material is 20 μm-3 mm.

10. The method for preparing a gamma-ray shielding composite material according to claim 8, characterized in that: In step 4, the target temperature is 50-250°C; the hot pressing pressure is 16-20 kPa, and the duration is 1-10 min.

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