CRITERIA FOR SELECTING INORGANIC PHOSPHORS WHEN DEVELOPING TECHNOLOGY FOR THE PRODUCTION OF FUNCTIONAL HYDROGELS
Abstract and keywords
Abstract:
Currently, hydrogel compositions with organic and inorganic fillers are widely used in various industries worldwide. The requirements for a polyacrylamide hydrogel matrix with a phosphor are analyzed: hydrolytic and thermal stability of inorganic phosphors; particle size distribution; luminescence efficiency of micron-sized particles; morphological and structural characteristics of protective compositions "phosphor-polyacrylamide hydrogel". The hydrolytic stability of the inorganic phosphor was determined by impregnation followed by decanting. The thermal stability of the phosphors was determined using thermal heating, and anti-Stokes luminescence was determined using IR radiation. Particle size distribution for the phosphors and finished protective compositions was determined using laser diffraction. UV luminescence of the test objects was assessed under a UV radiation source with an emission maximum of 365 nm. Anti-Stokes luminescence of objects with the Y2O2S:Yb,Er phosphor and flash luminescence of the SrS:Eu,Sm phosphor were assessed under a laser source of IR radiation with a wavelength of 980 nm. It was found that samples of inorganic phosphors based on strontium aluminate (SrAl2O4:Eu,Dy) degraded in a polyacrylamide hydrogel medium, resulting in a loss of luminescent properties. The optimal characteristics of a complex matrix with a hydrogel based on the SrAl2O4:Eu,Dy phosphor were determined. The research enabled the development of a technology for producing polyacrylamide hydrogel with phosphors using combined processes and the scaling of the process on a complex setup for producing composite hydrogel material particles. The design of the setup's homogenizer, which allows for controlling the degree of grinding of the phosphor-polyacrylamide hydrogel matrix, is separately described. It is shown that an important factor in the technology of producing high-quality security documents in sheet form is the technology of introducing a hydrogel matrix and inorganic phosphors into an aqueous suspension of cellulose fibers in paper pulp.

Keywords:
HYDROGEL CARRIER, POLYACRYLAMIDE, LUMINESCENT MATERIAL, INORGANIC LUMINOPHORE, POLYMERIZATION, MORPHOLOGY, STRUCTURE, SUSPENSION, INSTALLATION, PAPER
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