Preparation And Properties Of Anti-radiation Composite Fiber

With the development of X-ray technology,the research of radiation protection materials has attracted much attention.Lead containing protective materials do not meet the requirements of environmental protection and safety,so in recent years,the research in this field focused on the development of lead-free materials.Due to the special 4f electron layer structure and abundant electron energy levels,rare earth is a very good radiation protection material.At present,a variety of rare earth/polymer radiation protection materials have been developed,such as rare earth/rubber composites,rare earth/resin composites and so on.There are few researches on rare earth/polymer fiber materials.In the early work of the research group,a series of rare earth/polymer composite fiber materials were prepared by melt spinning and melt blown spinning.The preparation process,the structure and properties of the composite materials were studied in detail.It was found that although these two processes could produce composite fiber materials in large quantities,the interface effect between rare earth and polymer in the composite materials was not good enough,When the amount of rare earth is large,the polymer acts as a binder.In order to better study the binding mechanism of rare earth and polymer in fiber materials,we used electrospinning process to prepare rare earth/polymer fiber membrane.The effects of rare earth modifier,spinning conditions,rare earth content and thermal crosslinking on the structure and properties of the obtained fiber membrane were investigated,and the radiation protection properties of the obtained fiber membrane were discussed.1.In this study,lanthanum oxide and gadolinium oxide were selected as rare earth materials,and unsaturated carboxylic acid was used to modify them.In order to select the most suitable rare earth salt for electrospinning,the methacrylate was characterized by SEM,FT-IR,TGA and particle size.The results show that the single preparation of lanthanum methacrylate and gadolinium methacrylate is better than the mixed preparation in terms of particle size and appearance,which is more suitable for the preparation of electrospun fiber membrane as a functional filler.The purity and thermal stability of gadolinium methacrylate are better than that of lanthanum methacrylate.2.The effects of the optimum addition of gadolinium methacrylate,spinning temperature and conductivity on the structure and properties of the electrospun films were investigated.The spinning solution and fiber film were tested by rheological viscometer,SEM,fluorescence microscope and tensile test.The results show that gadolinium methacrylate is dispersed in the fiber through the spinning process,and the structure and properties of the electrospun film are better when the maximum amount of Gd(MAA)₃ is 15%and the spinning temperature is 30?.3.The influence of DCP on the electrospun membrane was studied.The fiber membranes with different proportions of DCP were heat crosslinked.The structure and properties of the fiber membranes before and after heat treatment were compared by means of SEM,TGA,IR and swelling method.The results showed that when 15%DCP was added,the structure of crosslinked fiber membrane was uniform and the tensile strength was the best.It can be seen from the infrared spectrum that in the process of TPU crosslinking,the rare earth salt also polymerizes.In addition,the dissolution method showed that the residual amount of fiber changed little when the DCP content exceeded 15%,so the optimal DCP content in electrospinning solution was 15%.4.The fiber membranes containing different proportion of La(MAA)₃ were prepared with DCP as the quantitative component.The effects of different content of La(MAA)₃ on the structure and properties of electrospun membranes before and after crosslinking were investigated.The results show that the microstructure of the fiber membrane containing 10%La(MAA)₃ is better than that of the crosslinked fiber.But from the tensile properties,when the salt content of fiber membrane is 15%,it is the best.5.The hygroscopicity and X-ray shielding properties of the electrospun films with different Gd(MAA)₃ content were investigated.The results showed that the hygroscopicity of the uncrosslinked electrospun films increased with the increase of rare earth content,and the hygroscopicity of the crosslinked electrospun films decreased significantly.X-ray shielding test shows that with the increase of rare earth salt content,lead equivalent increases gradually,and the maximum is only 0.041 mm Pb.6.The application of electrospun fiber film in radiation protection materials is discussed.The multi-layer superposition can effectively shield the radiation damage of low energy rays to human body.Based on the previous work of the research group,the advantages of the composite non-woven fabric,such as high rare earth content and good radiation protection performance,and the characteristics of the electrospun membrane,such as fine moisture absorption and uniform dispersion of rare earth,are fully utilized.The combination of the electrospun membrane and the non-woven fabric is considered to form a layered material,which is expected to achieve more excellent personal protection materials.