Preparation And Properties Of Gadolinium Oxide/Poly (Ether Ether Ketone) Composites

Within the advent of polymer materials, poly（ether ether ketone）（PEEK） resinmaterial by virtue of its excellent overall performance has been widely used inaerospace, automotive and transportation, electrical and electronic, petrochemical andother fields. Compared to polyethylene, a traditional radiation shielding material, theradiation resistance of PEEK began to cut a figure in the field of radiation shielding inrecent years. With the development of science and technology, the rays are applied invarious fields. While people enjoy the benefits of rays, they have to suffer its sideeffect. Therefore, there is a large number of scientists paying attention to the researchof shielding materials. Because traditional shielding material has its owndisadvantages in the wide range of application fields, people began to try to adddifferent ray absorbing material filler to polymer material in order to product polymermaterial composites with excellent performance. There are rich rare earth resourceswith complete range of articles and high grade resources in China, and rare earthelements have special electronic shell structure and good absorption capacity, so it isan ideal carrier for preparing a ray shielding materials filler and it can remedy the“weak absorption area” of lead elements. However, the dispersion in the polymermatrix is the important factor of the radiation shielding composites. This thesis isdesigned from the point of PEEK resin and Gd₂O₃with their own characteristics.Market demand PEEK resin was used as matrix material and the Gd₂O₃as filleraround the preparation to abtain a lightweight, inexpensive, non-toxic, stableperformance and good ray shielding composite material.We take into account the special molecular chain structure of PEEK and the specialrequirements for the thermal stability of modifier as well as the physical and chemical properties of the Gd₂O₃. We design and synthesis the filler surface treatment agent ofSPEEK with high temperature resistant by controlling the sulfonation conditions,which has the sulfonic acid group in the main chain of the PEEK, and then prepare aratio of modifier by the modified the Gd₂O₃with different amount of SPEEK in a wetway. The XRD confirmed that the compositing or modifying process did not disturbthe crystalline structure of the PEEK component.We use the pure Gd₂O₃, modifiedGd₂O₃,and pure PEEK to prepare a series of shielding materials with different contentof Gd₂O₃by melt extrusion. And we analyze the mechanical properties, temperatureresistance, ray shielding performance, and the crystallization behavior of this series ofcomposite materials.Firstly, we analyzed and compared the properties of the composites with differentcontents of modified and unmodified gadolinium oxide filler, and investigated whichimpact was caused by introducing SPEEK into the materials. The analysis resultsshow that the Gd₂O₃improves the modulus and tensile strength of the material andreduces the breaking elongation of the material, which is general pattern wheninorganic filler is added to polymers. But the SPEEK improves the tensile strength,modulus and elongation at break compared to the unmodified composite materials,and the dispersion diameter of Gd₂O₃particles in the matrix becomes better byenhancing the adhesiveness with PEEK matrix, to reduce the phenomenon of Gd₂O₃fall off from PEEK and SPEEK as the modifier will not affect the thermal stability ofthe composite materials. This is due to the interface layer in Gd₂O₃and PEEK resinwhich can pass the stress and block the stress rupture in effectively.Then we discuss the impact of different content modifier to the composites by thefixing10wt%Gd₂O₃content with different SPEEK content in composites. We find thecomposites with4wt%SPEEK show better mechanical properties than other content.We select the optimum ratio to design the composites to evaluate and analyzeray-shielding performance, and composites have a good shielding effect under the40keV and80keV, and the transmittance of45%S4GPEEK was zero at10mm, butthey have a poor shielding effect under140keV and164keV. This is because theincrease of the content of the absorbing material, increasing the probability of theray-absorbing material to the photoelectric effect occurs, which is beyond theabsorption edge of the absorbing material to weaken the absorption effect. Finally, research and analysis are made on the crystallization kinetics ofPEEK/Gd₂O₃composites. Analysis results indicate that the Gd₂O₃particles did notchange the crystal structure of the PEEK, but it hinders the nucleation andcrystallization rate. Because the SPEEK was introduced to the composites, it increasesthe nucleation rate of the PEEK compared to the unmodified Gd₂O₃filler incomposite materials.In summary, through the introduction of modifier SPEEK with better stability intothe composites, it effectively improves the dispersion of Gd₂O₃particles in the matrixresin and enhances the adhesion between the particle and the matrix. It also makes agreat contribution to the mechanical properties and shielding performance. We alsoanalyze the thermal properties, mechanical properties, and ray shielding performanceof composites. PEEK/Gd₂O₃can be considered as a good radiation shielding materialswith excellent mechanical properties, good thermal stability, and light weight, lowcost, non-toxic.