| As a multifunction material,borates had been applied in many fileds,such as non-liner optical material,phosphor,flame retardant,Li-ion battery.Among the most borates,zinc borate is a kind of halogen-free,non-toxic,smoke suppression,and inexpensive addition of flame retardant.But its application is limited by its poor compatibility with polymer.In addition,there are many studies on zinc borate as a phosphor matrix material,which has the advantages of self-emission,matrix sensitization,stable physical and chemical properties,low synthesis temperature and high luminous efficiency.However,the preparation methods are few and mainly focus on high temperature solid method;so,the obtained products are almost anhydrous zinc borate.Moreover,the research on the structure and property of hydrated-zinc borate-based luminescent materials is also rare.In otder to broaden the research system of borate luminescent materials,we will study the relationship of preparation method and prepartion conditions on the product morphology,particle size and luminous properties,which will help us to discover new borate matrix luminescent materials.Therefore,the simultaneous investigations of series of hydrated zinc borate matrix luminescent materials and hydrated zinc borate flame retardant materials are of important significance and application value.In this work,we have prepared several hydrated zinc borates with different composition and differnent structure as matrix of phosphor and one kind of zinc borate composite with carbon microsphere material by different preparation methods.The obtained products have been characterized by EDS,XRD,IR,SEM,TEM and TG-DTA,and their luminescent properties and flame retardancy have also been studied.The specific research contents are as follows:(1)A novel monodisperse microsphere with a hole for Zng[(BO3)3O2(OH)3](ZBH):Eu3+phosphor has been successfully prepared via a simple hydrothermal treatment,and the crystal growth mechanism was also proposed.The effects of reaction time,reaction temperature and the concentration of Eu3+ on the morphology and luminescence properties of the obtained products were investigated.The optimum preparation conditions were obtained.It was found that the R/O ratio was different when the samples were excitated under two different wavelengths.In addition,according to the influences of Eu3+ doped concentration and reaction time on the luminescence properties,it was found that Eu3+replaces the two different symmetries of Zn2+(Zn(1)and Zn(2))in ZBH.This ZBH:Eu3+microsphere with a hole product exhibits both higher intensity and the highest R/O ratio under the 245 nm excitation,so it can be used as a potential red luminescent material.(2)Eu3+,Tb3+,Dy3+ single-doped or co-doped samples of ZBH:Tb3+,ZBH:Dy3+,ZBH:Eu3+/Tb3+,ZBH:Tb3+/Dy3+ have been successfully prepared via a simple hydrothermal treatment.XRD and SEM results indicated that the doped rare earth ions can change the crystal structure and morphology of ZBH.PL spectra show that ZBH:Tb3+ and ZBH:Dy3+were green and blue,respectively.The emission colors of ZBH:Eu3+/Tb3+ and ZBH:Tb3+/Dy3+ can be controlled by changing the excitation wavelength and relative doping concentration.Moreover,the change of relative doping concentration and excitation wavelength of the two kinds of rare earth ions in ZBH:Eu3/Tb3+ phosphor can produce white light,and realize single phase white light.In the ZBH:Eu3+/Tb3+ and ZBH:Tb3+/Dy3+phosphor,the energy transfers between Tb3+?Eu3+,Dy3+?Tb3+,and Tb3+?Dy3+ are occurred under the appropriate excitation wavelength.The energy transfer efficiency was calculated by measuring the fluorescence lifetime.And the mechanism of Tb3+?Eu3+,matrix?Dy3+??Tb3+ is decuded.(3)Three kinds of structure of zinc borates:Zn(H2O)B2O4·0.12H2O,Zn2(OH)BO3,and H[Zn6O2(BO3)3]have been successfully prepared only by changing the reaction temperature.Only by changing the pH value of reaction system,three kind of morphologies of Zn(H2O)B2O4 O.12H2O can be obtained.The reasons why the reaction temperature drives the structural change and the effect of pH on the morphology are discussed.The growth mechanism of Zn(H2O)B2O4·0.12H2O was proposed.The effect of doping concentration on the fluorescence properties was investigated.The fluorescence spectra showed that Zn(H2O)B2O4 0.12H2O:Tb3+ had the highest fluorescence intensity at 7%doping concentration.The fluorescence spectra of Zn(H2O)B2O4 0.12H2O:Tb3+ with the changing temperature were measured and found to be thermally stable in the range of 50?250 ?.The fluorescence spectra of different morphologies for Zn(H2O)B2O4·0.12H2O:Tb3+ were investigated.The results show that the fluorescence intensity of hexahedron sample is the highest,and the reason of different morphology on fluorescence spectra is discussed.Finally,the fluorescence properties of Zn(H2O)B2O4·0.1H2O:Tb3+,Zn2(OH)BO3:Tb3+,and H[Zn6O2(BO3)3]:Tb3+ were investigated.The results show that the fluorescence intensity of Zn(H2O)B2O4·0.12H2O:Tb3+is the highest,and the reason for different fluorescence spectra is discussed.(4)Three kinds of phosphors of Zn4B6O13,Zn4B6O13:Eu3+,and Zn4B6O13:Tb3+ were successfully prepared by high temperature solid-state method.The results of XRD and SEM show that the doping concentrations of rare earth ions have little effect on the crystal structure of Zn4B6O13,but have a great influence on the morphology.PL spectra show that Zn4B6O13,Zn4B6O13:Eu3+ and Zn4B6O13:Tb3+ are blue,orange-red and light green,respectively,under UV irradiation.The change of CTB position and the refinement diffraction data of Zn4B6P13:Eu3+ powder show that the concentration of rare earth ions can affect the bond length of Ln-O.(5)The nano-fiber morphology of Zn2(BO3)(OH)0.75F0.25 have been prepared by hydrothermal method.The structures were characterized by XRD,SEM,EDS and TG.The Ce3+,Tb3+ saingle-doped and co-doped of Zn2(BO3)(OH)0.75F0.25:Ce3+,Zn2(BO3)(OH)0.75F0.25:Tb3+ and Zn2(BO3)(OH)0.75F0.25:Tb3+/Ce3+ have also been prepared.In the Zn2(BO3)(OH)0.75F0.25:Tb3+/Ce3+phosphor,the emission intensity of Tb3+ increases first and then decreases with the increases concentration of Ce3+.It is deduced that the energy transfer from Ce3+ to Tb3+?but concentration quenching was occurred in a large doping Ce3+concentration.The CIE diagram indicates that the color of Zn2(BO3)(OH)0.25F0.25 and Zn2(BO3)(OH)0.75F0.25:Ce3+ are blue,and the color of Zn2(BO3)(OH)0.75F0.25:Tb3+ is green.(6)The flame retardant for monodispersed C@Zn4B6O13 was prepared by hydrothermal method.We mixed 4ZnO-B6O3·H20,ZnO·B2O3·1 · 12H2O,commercially available 3Zn0 3B2O3·3.5H2O,commercially available Mg(OH)2 and prepared C@Zn4B6O13 these into PP,respectively,and their flame retardancy was measured by thermogravimetry(TG)and limit oxygen index(LOI).The results showed that the flame retardancies of 4ZnO·B2O3.H2O and C@Zn4B6O13 were higher than those of the commercially available 3Zn0·3B2O3-3.5H2O and Mg(OH)2.The flame retardant mechanism of PP with 4ZnO B2O3·H2O rod added was discussed.The tensile strength(TS)and elongation at break(EAB)were measured by universal testing machine.The results also showed that 4ZnO.B2O3.H2O and C@Zn4B6O13 had little effect on the TS of PP,but enhanced the EAB.In addition,the surface modification of 4ZnO B2O3-H2O was carried out by using AMEO and OA respectively,and the effects of different surface modifiers on the flame retardancy and mechanical properties of PP mixed with different modified 4ZnO B2O3·H2O were compared. |
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