The preparation of ThFS-doped luminous fibers includes StAl,O.: EU²+, Dy²+ luminous powder, and three
Three aspects: aryl sulfonium hexafluoroantimonate and luminous fibers. Among them, the preparation of triarylsulfonium hexafluoroantimonate has been elaborated in detail in the previous section, SrAl,O. The preparation of Eu²+ and Dy+ luminous powder was carried out by microwave calcination. The preparation process parameters were referred to relevant research, such as raw material ratio, calcination temperature and microwave time, etc. Meanwhile, in combination with the characteristic requirements of microwave calcination, the process parameters were moderately adjusted. The preparation method of THFS-doped luminous fibers also refers to relevant studies and is prepared by melt blending. However, due to the direct blending of triarylsulonium hexafluoroantimonate with SrAl,O, :Eu²+, Dy°+ luminescent powder and polypropylene substrate during spinning, the luminescent particles are prone to agglomeration and clogging the twin-screw extruder, causing feeding difficulties and subsequently affecting the uniformity of luminescent fiber filaments. Therefore, the rare earth strontium aluminate luminous powder is pre-treated with a coupling agent before blending, with the aim of improving the dispersion of the luminous powder in the fiber matrix and fully exerting its excellent fluorescence performance.
This chapter uses KH550 silane coupling agent (3-aminopropyltriethoxysilane) as the coupling agent
Gon SrAl2O4: Eu2+Dy3+ Surface modifier for luminous powder. Silane coupling agent KH550 is a type of low-molecular-weight organosilicon compound with a special structure, and its general formula is RSiX. R represents the active functional group that has affinity or reactivity with polymer molecules, and X represents the alkoxy group that can be hydrolyzed. Due to the fact that the surface of SrAl2O4: Eu2+Dy3+ luminescent powder is highly prone to adsorb a water film, when the surface of the luminescent powder is modified, the X-group water in the silane coupling agent KH550 forms silanol, which then reacts with the hydrophilic hydroxyl groups on the surface of the luminescent powder particles to form hydrogen bonds and condense into SiO-M covalent bonds (M represents the surface of the luminescent powder particles). Meanwhile, the silanols of each molecule of silane are interlinked and aggregated to form a reticular film covering the surface of the luminous particles, making the surface of the SrAl2O4: Eu2+Dy3+ powder organic.
The preparation process route of THFS-doped luminous fibers roughly includes three steps. Firstly, SrAl2O4: Eu2+Dy3+ luminous powder is prepared by microwave calcination. The raw materials are SrCO3, Al2O3, Eu2O3, and Dy2O3. Mix it evenly with H3BO3 in a mortar in a certain proportion, add an appropriate amount of anhydrous ethanol and grind for 30 minutes to make the mixture more uniform. After drying at 80℃, place it in an alumina ark and then put it into a microwave calcination furnace to be fully calcined for 2 hours with carbon powder as the reducing agent. After natural cooling, take out the sample. The calcined finished product is ground again and ready for use. Rare earth strontium aluminate luminous powder was screened and prepared. Then, KH550 modified luminous powder was used, and a certain amount of strontium rare earth aluminate luminous powder was added to anhydrous ethanol (the mass ratio of strontium rare earth aluminate luminous powder to anhydrous ethanol was 1 After ultrasonic dispersion for 30 minutes, an appropriate amount of KH550 silane coupling agent was added, and the mixture was stirred in a constant temperature water bath at 60℃ for 4 hours. Then, 2mol/L acetic acid was added drop by drop to adjust the pH to approximately 3. Finally, the sample was filtered and washed three times with anhydrous ethanol, and dried in an oven at 90℃ for 24 hours to obtain the reserve sample. The last step is the melt spinning process of the fibers. After drying the polymer PP chips, they are combined with the previously prepared modified SrAl2O4: Eu2+Dy3+ luminous powder and the prepared triarylsulfonium hexafluoroantimonate are mixed in a certain proportion in a melt spinning machine. Then, they are extruded by a twin-screw extruder at a melting temperature of around 220 to 250℃, and finally, luminous fiber samples are drawn and wound.