Studies On The Preparation Of Strontium Aluminates: Europium Dysprosium Phosphors Powder And Applicates In Waterborne Polyurethane Paint

Luminescence is a process during which the absorbed energy in some way is converted to optical radiation. The research status for luminescent material of the rare earth ions doped the alkali earth aluminate was summarized in this thesis. The synthesis for the ultra-fine powder of Eu²⁺, Dy³⁺ co-doped the strontium aluminate persistent luminescent material, the improvement of its surface encapsulation and its application in the paints were studied respectively.A Long afterglow luminescent powder of SrAl₂O₄:Eu²⁺,Dy³⁺ with loose texture and strong luminescent intensity was prepared by the method of improved high temperature solid-state. The Long afterglow luminescent properties of SrAl₂O₄:Eu²⁺,Dy³⁺ were analyzed with the emission spectra, the excitation spectra, the afterglow decay curves and the scan electricity mirror (SEM). The appropriate compound ratio of the raw material and the appropriate condition of the process were confirmed. The compound ratio of the raw material was that the content of the activated carbon was 18%, the ratio of the Al/Sr was 0.4, the concentration of the Eu²⁺ was 2% and the content of the H₃BO₃ was 8%. The synthesizing condition of the process was that the raw material were mixed equally after skiving, and dispersed with the absolute ethyl alcohol to pulpiness, and dried in vacuum. Then the surfaces of the mixed raw material were covered with powdery activated carbon. And then the mixed raw material were calcinated at 1300℃with 3 hours, finally cooled with the temperature of the stove after the reaction was finished. And the effects of the usage method of the activated carbon(a reducer) on the luminescent properties of the SrAl₂O₄:Eu²⁺,Dy³⁺ luminescent powder were studied.The waterborne polyurethane latex (WPL) with stable properties was synthesized with the prepolymerization decentralization method. By analyzing the effects of the size, the viscosity, the water absorption, the stability, the reaction temperature, the reaction time and the dehydration of raw material on the properties of the WPL, the compound ratio of the raw material and the condition of the process were confirmed. The compound ratio of the raw material was that the ratio of the -NCO/-OH was 1.6 and the amount of the catalyst was 0.05%. The synthesized condition of the process was that the temperature of the polymerization was around 80℃, the temperature of the emulsification was about 35～40℃, the temperature of the neutralisations was about 40℃and the raw material must be dehydration before reaction. Besides, the effects of the water content on the WPL properties were studied.The SrAl₂O₄:Eu²⁺,Dy³⁺ luminescent powder were encapsulated with Al₂O₃ to improve the water-resistance property. The water-resistance property of the sample, the structure and the luminescent properties of the luminescent powder were investigated by measuring the pH of the water in which the samples were dispersed. The experiment results showed that the encapsulation film of the Al₂O₃ was covered completely, and the water-resistance property was good. The original samples hydrolyzed completely in the deionizer water within 105 minutes, but the encapsulated ones had a small quantity hydrolyzed in the deionizer water within 45 minutes and didn't hydrolyzed after 45 minutes and the luminescent properties of the samples nearly weren't affected. The intensity of the emission spectrum only dropped by about 5.2% and the intensity of the excitation spectrum only dropped by about 7.6%.The waterborne polyurethane luminescent paint was prepared by using the encapsulated phosphors powder as the pigments and the waterborne polyurethane as the binder. The effects of the factor that different ratio of the luminescent powder and the Polyurethane, different thickness of the coating film and different time of the illumination on the luminescent properties of the coating film were studied.