一种防中子辐射的高强氧化石墨烯复合纤维及其制备方法

正本发明涉及一种防中子辐射的高强氧化石墨烯复合纤维及其制备方法,将芳纶纳米纤维、经表面处理的B4C和Zn B以及氧化石墨烯溶解并制得纺丝液,再通过湿法纺丝而得。相较于传统的辐射防护材料,本发明的氧化石墨烯复合纤维不仅具有良好的力学性能、防中子辐射性能及阻燃性能,其还可以依据自身的形状特点应用于各种防辐射设备。专利申请号:2019106680035     

防辐射纤维及材料的研究进展

本文主要概述了防护X、γ射线和中子射线用纤维及材料的发展状况,介绍了它们的防护效果、组成结构及其力学等性能.并对这些射线的性质和危害作了简述.     

防辐射纤维及其织物的研究进展

介绍了电磁波辐射的危害、防护原理,以及防辐射纤维及织物的研究进展。详述了X射线、γ射线的防护及其织物的研究状况;简述了防辐射纤维及织物的发展趋势。指出应用纳米技术制成的具有屏蔽电磁辐射功能的纤维具有广阔的前景,频段更宽的电磁波的防护纤维及材料的研制和开发将成为发展趋势     

辐射防护材料的研究进展

简述了核辐射中各种高能粒子的特点,提出了核辐射防护的主要目标。详述了X射线、γ射线及中子屏蔽材料的屏蔽机制、材料设计方法及研究进展。最后,指出了核辐射防护材料的发展方向:屏蔽性能与其他各性能之间的结合,重、轻元素的配合以及模拟方法的应用。     

铕掺杂Gd2Zr2O7透明陶瓷的制备及闪烁性能

与传统闪烁陶瓷相比,基于立方相Gd₂Zr₂O₇具有高密度、高光学透过率和良好的闪烁性能等特征,本工作采用真空烧结法,成功制备出系列Eu³⁺掺杂Gd₂Zr₂O₇透明陶瓷,研究了掺杂离子及掺杂量对其晶体结构、光学透过率、荧光性能及闪烁性能的影响。结果表明,所制备的透明陶瓷样品具有良好的光透过能力;光谱表征发现,20%Eu³⁺掺杂Gd₂Zr₂O₇具有最佳的光致荧光和辐照发光强度,其最强发射峰位于630 nm。X射线成像实验表明,Gd_1.8Eu_0.2Zr₂O₇透明陶瓷的X射线成像分辨率可达11 lp·mm^–1,具备对不同材质物体的成像应用潜力。在医学成像、工业探伤、高能物理等领域具有潜在的应用价值。     

防辐射玻璃的改进

在Ｋ２Ｏ（Ｎａ２Ｏ）－ＰｂＯ（ＴｉＯ２）－ＳｉＯ２（Ａｌ２Ｏ３）系统中，对高能辐射的防护能力可以用Ｃｏ＾６０－γ源检测。玻璃的化学稳定性，折射率，密度，硬度及线膨胀系数的测试研究结果表明：玻璃的防辐射能力不但取决于玻璃的密度及组分的质量吸收系数，而且与玻璃的结果特征有关。根据实验结果，提出了组成和结构玻璃辐射能力的综合效应观点。     

防辐射含钐有机玻璃的制备与性能

采用重结晶法制备了甲基丙烯酸钐盐[Sm(MAA)3],然后以偶氮二异丁腈为引发剂,将Sm(MAA)3与甲基丙烯酸甲酯通过本体聚合反应,制成具有防X射线和防紫外线辐射的透明有机玻璃。研究中,考察了在甲基丙烯酸甲酯本体聚合中加入Sm(MAA)3对有机玻璃的透光率、耐溶剂性、防辐射性能的影响。结果显示,新型的有机稀土盐玻璃不仅具有良好的X射线屏蔽性能,同时具有优异的透光率,并兼具较佳的紫外线吸收特性。     

钕掺杂钡铝硅透明玻璃陶瓷的制备和表征

采用熔融-晶化技术制备了含纳米微晶的Nd3+:BaO-Al2O3-SiO2透明玻璃陶瓷,用差热分析仪、X射线衍射分析仪、扫描电子显微镜和紫外-可见-近红外分光光度计和Fourier变换荧光光谱仪对样品的成核-晶化温度、晶相组成、微观形貌、光透过率和光谱性能进行了测试和表征.结果表明,钕掺杂钡铝硅系透明玻璃陶瓷的最佳成核温度为690℃,最佳成核时间为4 h,观测到钕掺杂钡铝硅玻璃陶瓷在808 nm激发下于1068nm处存在较强发射峰.     

透明零膨胀LAS系微晶玻璃的制备和研究

以TiO2和ZrO2作为晶核剂,采用"两步法"热处理工艺,制备了透明、零膨胀的Li2O-Al2O3-SiO2(LAS)系微晶玻璃.利用X射线衍射分析和扫描电子显微镜对该微晶玻璃的物相和微观结构进行分析,结果表明:微晶玻璃中析出大量β-锂辉石晶粒,其晶粒半径仅为50～100nm.LAS系微晶玻璃热膨胀系数在20～400℃范围内趋向于零,而在400～750℃范围内热膨胀系数不断升高,趋向于8×10-7/K.该LAS系微晶玻璃具有良好的透光性能,于可见光范围内透过率为70%.     

透明氟铝酸盐微晶玻璃研究

为改善氟化物玻璃的物理化学性能,对氟铝酸盐玻璃进行了晶化实验,制备了透明氟铝酸盐微晶玻璃.对微晶玻璃进行了X射线衍射(XRD)、透射光谱研究和扫描电镜(SEM)观察.结果表明:热处理温度不同,玻璃中析出的晶相会有差异.微晶玻璃中有一些异常的大尺寸晶体,这些晶体的存在影响玻璃中晶体的均匀性,降低微晶玻璃的红外透过能力.     

磁铁矿防辐射超高性能混凝土制备及性能研究

核技术在造福人类的同时,也产生了无处不在的核辐射,而当前的普通防辐射混凝土并不能完全满足安全防护的需要。本文基于最紧密堆积理论,采用不同比例的磁铁矿替换河砂,制备了防辐射超高性能混凝土(UHPC),并对其工作性能、力学性能、微观结构、孔结构,以及γ射线屏蔽性能进行了研究。结果表明,磁铁矿的加入使得UHPC的流动性以及抗压强度略有降低,但降幅较小。随着磁铁矿替换比例的增加,UHPC对γ射线的屏蔽性能明显提高。当磁铁矿替换率为100%(体积分数)时,UHPC的线性衰减系数增大了31.3%,而半值层及十值层均下降了23.8%。与此同时,磁铁矿的加入并未改变水化产物的类型,但可改善UHPC的孔结构,有效降低其孔隙率。     

Physical,thermal, optical,structural and nuclear radiation shielding properties of Sm2O3 reinforced borotellurite glasses

To observe direct effect of samarium (III) oxide reinforcement on physical, thermal, optical, structural and nuclear radiation attenuation properties, a broad-range experimental and numerical investigations were performed with a group of novel borotellurite glasses. FTIR spectra of powdered samples were taken at 250-4000 cm^-1. The transmittance and absorption characteristics, optical band gaps, and Urbach energies were measured. The glass transition temperatures, crystallization temperatures and melting temperature values of the samples were determined. Nuclear radiation shielding properties have been determined for gamma-ray, neutrons and heavy charged particles. The lowest transmittance and highest absorbance were reported for the TBVS1.5 sample with highest Sm₂O₃ additive. In addition, obtained results from the nuclear radiation shielding calculations have showed that TBVS1.5 sample has superior nuclear radiation shielding properties against gamma-ray, neutron and heavy charged particles. The increasing Sm2O3 additive has visibly improved the nuclear radiation attenuation properties by keeping other material properties within usable limits.     

High loading boron nitride chemically bonded with silicone rubber to enhance thermal neutron shielding and flexibility of polymer nanocomposites

Flexible materials with excellent radiation shielding and flexibility are essential to the personal protective equipments (PPEs) for protecting workers from nuclear radiations. However, it is an enormous challenge to obtain the desired materials since high loading filler in polymer nanocomposites usually promotes radiation shielding while restrains its flexibility. Here, a facile “thiol-ene click” means is applied to chemically bond high loading boron nitride (BN) nanoparticles with silicone rubber (SR) in SR/BN nanocomposites for thermal neutron shielding. Uniform dispersion of BN nanoparticles and good compatibility of interfaces in the nanocomposites with high loading filler lead to increased flexibility instead of decrease. In particular, the nanocomposite with 40 wt% BN displays 911% of elongation at break that is about 50% enhancement to that of neat SR. Furthermore, higher loading BN in the nanocomposites means better thermal neutron shielding. Namely, enhanced thermal neutron shielding and flexibility is achieved at SR/BN nanocomposite with 40 wt% BN. The present work provides a facile strategy towards superior integrated performance of flexible materials for radiation shielding, such as wearable devices.     

Poly(vinyl alcohol)–bismuth oxide composites for X-ray and γ-ray shielding applications

Polymer composites, which are light in weight, cost effective, and less toxic, have potential applications in X-ray and γ-ray shielding and protection. In this work, we have explored the efficacy of poly(vinyl alcohol)–bismuth oxide composites as radiation shielding materials. Poly(vinyl alcohol) composites with different wt % (0–50) of bismuth were prepared by a simple solution casting technique. Structural and thermal characterization of these samples was carried out using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). TGA revealed the enhanced thermal stability of these composites. AC conductivity measurements and optical spectroscopy were used to analyze their electrical behavior. The composites showed low conductivity, and the energy gap obtained also showed their tendency to be insulators. The radiation attenuation properties were investigated using X-ray (5.895 and 6.490 keV) and γ-ray (59.54 and 662 keV) transmission measurements. The shielding efficiency of the composites increased with filler wt %. The 40 wt % composites exhibited mass attenuation coefficients of 122.68 and 93.02 cm²/g at photon energies of 5.895 and 6.490 keV, respectively, while the 50 wt % composites showed 1.57 and 0.092 cm²/g at photon energies of 59.54 and 662 keV, respectively. The effective atomic number quantifies the probability of interaction of radiation with matter. The effective atomic number of the composites calculated by the direct method was in good agreement with the theoretical value obtained from Auto-Zeff software. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47949.     

Thermal,mechanical and γ-ray shielding properties of micro- and nano-Ta2O5 loaded DGEBA epoxy resin composites

In this work, we have investigated the synergistic effect of micro- and nano-Ta₂O₅ fillers in the epoxy matrix on the thermal, mechanical, and radioprotective properties of the composites. Morphological analysis revealed uniform dispersion of fillers in the matrix. Both the thermal stability and tensile properties of matrices have enhanced in the presence of fillers. Although the nanocomposites showed significantly higher tensile strength and Youngs modulus compared to micro-composites, the enhancement in these properties was predominant at low loadings. Dynamic mechanical analysis indicated good interfacial adhesion and positive reinforcing effect on the matrix even at higher loading (30 wt%) of nano-Ta₂O₅. γ-Ray attenuation studies performed in the energy range of 0.356–1.332 MeV revealed better γ-ray shielding ability of nanocomposites compared to microcomposites at same weight fraction of fillers. In particular, γ-ray attenuation at 0.356 MeV for 30 wt% nano-Ta₂O₅ loaded epoxy composite was enhanced by around 13% compared to the microcomposite at the same loading. Increased surface-to-volume ratio of nanofillers and consequent increase in matrix-filler adhesion and radiation-matter interaction have manifested in an overall enhancement in the thermal, mechanical, dynamic mechanical, and radiation shielding characteristics of nano-Ta₂O₅/epoxy composites, proving them as promising γ-ray shields.     

Developing a radiation shield and investigating the mechanical properties of polyethylene-polyester/CdO bilayer composite

Radiation attenuation and mechanical properties are two key parameters for shielding in space. This study explored the attenuation parameters of cadmium as a popular filler for the shielding of thermal neutrons in the unsaturated polyester (UPS) polymer matrix. The polyester matrix was used for the first time. The composite behavior against gamma radiation (by applying Cs-137 radioisotope, E gamma = 0.662 MeV) was evaluated using the gamma spectrometer. Also, the sample was exposed to neutron radiation by utilizing a²³⁹Pu–Be neutron source. The effect of the composite sample produced with the cadmium filler was also examined when exposed to gamma radiation. Further, the attenuation parameters of the gamma rays were studied. The observations indicated the suitable shielding of this composite for thermal neutrons, such that the half-value layer (HVL) decreased from 7.8 cm in the polyester sample to 0.22 cm in the polyester/10 wt% CdO composite sample. The linear attenuation coefficient of the thermal neutron increased from 0.0888 (cm^-1) in the polyester sample to 3.15 (cm^-1) in the 10 wt% CdO composite sample, thus indicating more than 35-fold improvement in the neutron attenuation. Composite samples were exposed to gamma radiation; contrary to the expectations, the results showed an almost twofold improvement in the attenuation of gamma radiation, as compared to the polyester sample. This composite specimen was coupled to a 2 mm thick linear low-density polyethylene (LLDPE) layer for the better shielding of thermal neutrons. Finally, the composite sample was mechanically reinforced with a silica glass fiber, which enhanced the ultimate tensile strength (UTS) from 39 to 298 MPa. Also, the elongation rate (% E) was raised from 6% in the polyester sample to 10.5% in the polyester/10 wt% CdO- silica glass fiber sample. Thus, the results indicated the production of a strong composite capable of attenuating neutron and gamma radiation. Accordingly, this composite could be considered a reliable option for use as a shield in space missions.     

高填料、超厚防辐射屏蔽材料的研制

以富氢聚乙烯为基材,通过加入高填充量的中子吸收剂--硼化合物来制备高填料、超厚防辐射屏蔽材料。研究了聚乙烯熔体流动速率、碳化硼及氧化钆含量对防辐射屏蔽材料力学性能和屏蔽性能的影响,并探讨不同成型工艺对材料性表观性能的影响。结果表明,选用高熔体流动速率的高压低密度聚乙烯粉料及同等粒径的硼化合物作为填料,通过工艺条件设置和模具改进,能够制备出力学性能优异、内外观质量俱佳的高填料、超厚防辐射屏蔽材料,其中子屏蔽（削弱）系数大于6,伽玛屏蔽（削弱）系数大于8。     

Microstructure and properties of WB/Al nuclear shielding composites prepared by spark plasma sintering

In this paper, a novel nuclear shielding material capable of shielding neutrons and gamma rays, WB-reinforced Al (WB/Al) composites, was prepared by spark plasma sintering (SPS) process. The microstructure of the composites was characterized, and the effects of WB content, heat treatment and matrix type on the properties of the composites were discussed. The results demonstrate that the WB particles are uniformly dispersed in the aluminum matrix and formed a good binding interface with the matrix. WAl₁₂ as an interfacial reaction product is identified, and segregation of Si and Mg elements at the reinforcement/matrix interface occurs. The mechanical properties of the WB/Al composites are sensitive to the WB content. The hardness, elastic modulus and bending strength of the composites increase monotonously as the WB volume fraction increasing, up to 234%, 107% and 91.6% higher respectively than those of the monolithic 6061Al. However, the tensile strength reaches a peak point when the volume fraction is 20%. The effects of T6 treatment and matrix type are not pronounced, especially for the composites with high WB content. The thermal neutron and gamma ray shielding properties of the composites both increase with the increase of material thickness and WB content. The WB/Al composites developed in this work show good application prospects in the field of nuclear radiation protection, due to their good mechanical properties and well neutron and gamma-ray shielding performance.     

Mechanical and radiation shielding properties of tellurite glasses doped with ZnO and NiO

This study examines the basic mechanical parameters and radiation shielding properties of (100−x)TeO₂+xZnO+4NiO glasses (where x = 9.6, 19.2, 28.8, and 38.4 mol%) glass system. The mechanical study included basic parameters such as hardness, packing density, elastic moduli, and Poisson's ratio. Shielding ability of the glasses was tested against gamma and neutron radiations as well as against charged particles such as electron, proton, and alpha. Geant4 simulations and theoretical calculations by using Phy-X computer program were carried out to estimate mass attenuation coefficient (μ/ρ), neutron removal cross section (RCS), transmission factors namely; half value layer (HVL) and mean free path (MFP), and effective atomic number for total interaction of gamma (Z_eff-G), electron (Z_eff-E), proton (Z_eff-P), and alpha (Z_eff-A) radiations. The results showed that ZnO concentration had a significant influence on the mechanical properties and the shielding capability for glasses involved. The values effective atomic number were in the range of 30.2–46.1 for Z_eff-G, 21.2–26.5 for Z_eff-E, 16.9–19.7 for Z_eff-P, and 15.3–18.6 for Z_eff-A, respectively. The current glasses can act as superior shielding material as compared with those of Pb-free glasses, commercial glasses, and traditional concrete.