Ethyl vinyl acetate copolymer—SrAl₂O₄:Eu,Dy and Sr₄Al₁₄O₂₅:Eu,Dy phosphor‐based composites: Preparation and material properties

Abstract

New photoactive composite based on ethyl vinyl acetate (EVA) and SrAl 2 O 4 :Eu,Dy or Sr 4 Al 14 O 25 :Eu,Dy were prepared by melt mixing or extrusion methodologies. The phosphorescent behavior and material properties of the polymer-phosphor composites were studied. The morphology of the polymer and the composites were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The SEM shows that the physical and chemical behavior of the matrix and the extrusion conditions were primarily responsible for the surface morphology. TEM and EDS show that the phosphor particles were uniformly dispersed in the EVA matrix. A broad band of ultraviolet (UV)-excited phosphorescence of SrAl 2 O 4 :Eu,Dy and Sr 4 Al 14 O 25 :Eu,Dy phosphors and the respective composites were observed at wavelengths of 516 nm and 490 nm, respectively. The photoluminescence (PL) spectra showed less intense phosphorescence but no shift in the wavelength of the emission peak for all the composites. The Hamburg wheel test was done on all the composites and the PL measurements before and after the test showed almost no change in the intensity of the emission. Thermal studies showed that the presence of the phosphors in the matrix slightly increased the crystallinity of EVA, which leads to higher melting enthalpies. Tensile testing shows very little change in the tensile strength and flexibility of the ethylene vinyl acetate copolymer.

Developments in Eu+2‐Doped Strontium Aluminate and Polymer/Strontium Aluminate Composite

“…These encapsulation procedures are complex, require elaborate equipment, and adversely affect the luminescence output. 53 (Fig. This procedure allowed the phosphor composites to be transparent, to exhibit good physical and chemical stability, and to be easily processed.…”

“…The EVA matrix has been chosen because of its desirable properties such as UV stability, good clarity and gloss, resistance to crack, toughness, and heat‐sealing properties. The water intake and thermal and mechanical stability of the composites was studied, and the resulting luminescence spectra of the phosphor and the composites were compared . When compared the SrAl 2 O 4 :Eu,Dy and Sr 4 Al 14 O 25 :Eu,Dy phosphor, the highest intensity of luminescence emission was shown by the Sr 4 Al 14 O 25 :Eu,Dy phosphor (Figs.…”

“…Photoluminescence emission spectra of the EVA‐SrAl 2 O 4 :Eu,Dy and EVA‐Sr 4 Al 14 O 25 :Eu,Dy . Reproduced with permission from John Wiley and Sons.…”

The effect of the surface coating of a strontium mono-aluminate europium dysprosium-based (SrAl2O4:Eu2+,Dy3+) phosphor by polyethylene (PE), polystyrene (PS) and their dual system on the photoluminescence properties of the pigment

“…17 The encapsulation (coating) of SrAl 2 O 4 :Eu 2+ ,Dy 3+ with an organic material, i.e., a polymer or polymer blend improves the dispersion state of the pigment in the organic paint because of chemical structure similarity. Mishra et al 18 coated the surface of SrAl 2 O 4 :Eu 2+ ,Dy 3+ with ethyl vinyl acetate (EVA). They found that the EVA-coated pigment particles achieved a uniform dispersion.…”

Mechanical, morphological, and luminescent properties of strontium phosphorescent filler-filled NR/PP/PEC blends as affected by processing design

“…2 Photoluminescent polymers are gaining interest in many applications, such as advertisement cards, playtoys, safety indicators, and luminous paints, due to the quality of emitted light and the ease of production. [3][4][5] Photoluminescent materials use photons as the energy source and can be separated into two subclasses: fluorescence and phosphorescence. Phosphorescence, focused in the present study, is a term of light emission of specific de-excitation process.…”