Effect Of SiO₂ On The Fluorescence Properties And Reinforce Ability Of CaCO₃:Eu³⁺

As the range of application of rare earth phosphors becomes wider and wider,the versatility of phosphors is becoming higher and higher.In this study,calcium oxide was used as raw material to prepare CaCO₃ phosphor by carbonization method,and then sodium silicate and tetraethyl orthosilicate were used as raw materials to prepare amorphous precipitate by using external acid?hydrochloric acid?and sodium silicate.SiO₂ was prepared by sol-gel method to prepare spherical SiO₂.The CaCO₃ phosphor was coated to prepare composite phosphor CaCO₃:Eu³⁺@SiO₂.The particle size,morphology,structure,hydrophilicity and fluorescence properties of the phosphors were measured by particle size analyzer,scanning electron microscope,X-ray diffractometer,contact angle tester,fluorescence spectrometer and tensile tester.Comparative analysis,analysis of the fluorescent properties,section morphology and mechanical properties of filled rubber and plastic,the main conclusions are as follows:?1?CaCO₃:Eu³⁺phosphor powder was successfully prepared by carbonization method,and Eu³⁺ions were present in CaCO₃ crystals in a lattice substitution manner.Two kinds of CaCO₃:Eu³⁺@SiO₂ composite particles were successfully prepared by sol-gel method and precipitation method.SiO₂ was chemically coated on the surface of CaCO₃:Eu³⁺by using silicon hydroxy groups on the surface.The obtained precipitation method CaCO₃:Eu³⁺@SiO₂ has the strongest hydrophobicity,the sol-gel method CaCO₃:Eu³⁺@SiO₂ has the hydrophobicity,and the CaCO₃:Eu³⁺filler has the worst hydrophobicity.The three kinds of phosphors emit red light under the excitation of ultraviolet light,and the composite of SiO₂makes the fluorescence intensity increase obviously.At the same time,the CaCO₃:Eu³⁺@SiO₂ composite particles show the best fluorescence effect.?2?The three phosphor powder-filled rubbers were kept in an environment of 50?,100?,and 150? for 24 hours,and the fluorescence properties were not changed,which satisfied the conventional processing and use environment.Scanning electron microscopy and AFM images of the filled rubber section show that after coating the surface with SiO₂,the two CaCO₃:Eu³⁺@SiO₂ composite particles are in close contact with the rubber,and no obvious pores appear,indicating that the addition of SiO₂ increases the compatibility of the filler with the rubber matrix..At the same time,the sol-gel method CaCO₃:Eu³⁺@SiO₂formed more agglomerates in the rubber and the size was larger.The CaCO₃:Eu³⁺@SiO₂filling rubber had the smallest particle size and the best surface flatness.?3?The binding rubber content of the three kinds of phosphor powder filled rubber was3.35%,4.69%and 4.78%,respectively.The SiO₂ composite enhanced the interaction force between CaCO₃:Eu³⁺and rubber.Precipitation method CaCO₃:Eu³⁺@SiO₂ has the best reinforcing performance for rubber.The relative tensile strength is up to 3.61,and the effective range of filler reinforcement is the widest?30-60 wt%?.For the sol-gel method,CaCO₃:Eu³⁺@SiO₂ has the second reinforcing effect,the relative tensile strength is up to2.98,and the effective range of filler reinforcement is narrow?30-50 wt%?.For CaCO₃:Eu³⁺has the worst reinforcing effect,the relative tensile strength is up to 2.63,and the effective range of filler reinforcement is the narrowest?40-50 wt%?.?4?From the impact,tensile and bending properties of the two kinds of composite phosphor reinforced polypropylene materials,the mechanical properties of polypropylene materials are improved within a certain range of addition,and excessive addition will lead to a decrease in mechanical properties.For impact strength,two CaCO₃:Eu³⁺@SiO₂phosphor composite polypropylene materials reached a maximum at a loading of 50 wt%,respectively4.10 KJ/m³,4.59 KJ/m³;for tensile strength,sol-gel Method CaCO₃:Eu³⁺@SiO₂phosphor composite polypropylene material has a filling capacity of 40 wt%to a maximum of 59.35Mpa,and a precipitation method of CaCO₃:Eu³⁺@SiO₂ at a filling amount of 50 wt%to a maximum of 64.52 Mpa;for bending strength,sol-Gel method CaCO₃:Eu³⁺@SiO₂phosphor composite polypropylene material reached a maximum value of 33.27 Mpa at a filling amount of 40 wt%,and CaCO₃:Eu³⁺@SiO₂ at a filling amount of 30 wt%reached a maximum value of 29.62 Mpa.Combining the three mechanical properties,the optimum addition amount of the two composite phosphors should be 30-40 wt%.