Comparative study of the persistent luminescence in strontium-aluminate based polymer composites

In this study, Polypropylene (PP), PP with a compatibilizer (maleic anhydride grafted PP compatibilizer; PRIEX), HDPE, and LDPE matrices are melt-mixed with strontium aluminate-based phosphorescent fillers [SrAl2O4:Eu2+/Dy3+ (S1) Sr4Al14O25: Eu+2, Dy+3 (S2)]. The composite’s auto-glowing properties, thermal, mechanical, and rheological properties were studied and compared. After the UV excitation at 320 nm, the S1 composites showed a green emission at ∼520 nm and for the S2 composites, a blue emission was observed at ∼490 nm. For the S1 composites, the phosphorescence intensity was in the order of HDPE/S1 ˃ LDPE/S1 ˃ PP/S1 and PP/PRIEX/S1. In S2 composites, no change in the intensity of phosphorescence emission was observed. The DSC studies show that both the S1 and S2 fillers decrease the overall crystallinity of the composite and the HDPE composite has the highest crystallinity among the matrices studied. The rheological studies show that the storage modulus of the composites is in the order of HDPE/10S ˃ LDPE/10S ˃ PP/10S ˃ PP/PRIEX/10S.