Study on characteristics and afterglow properties of luminous polypropylene/ rare earth strontium aluminate fiber

Luminous polypropylene (PP) fibers were produced through melt spinning using different amounts of phosphor strontium aluminate (SrAl₂O₄: Eu⁺², Dy⁺³) (SAOED) particles as a luminescent agent. Melt rheology, morphology, crystalline structure, orientation, tensile and photoluminescence properties of the fibers were investigated by melt flow index, SEM, WAXD and DSC, birefringence, tensile tester and photoluminescence spectroscopy, respectively. Incorporating SAOED particles (10 wt%) into the PP matrix decreased the melt flow index of polymer. SEM images showed that the particles were uniformly distributed over the PP matrix albeit with some agglomerations. WAXD results confirmed that the presence of SAOED particles in the fibers structure and the crystal size did not change significantly. Moreover, addition of SAOED particles did not change the crystallinity of virgin PP fiber. The luminous PP/SAOED fibers had lower orientation as compared to virgin PP fiber and this parameter has the main role in determining tensile properties of the prepared fibers. The afterglow intensity of yarn were investigated under two light sources and different activation times and found that the speed of decrease in afterglow intensity was higher for initial 30 min.