Crosslinked Reprocessable Phosphor/Polyurethane Hybrid Networks with Thermal Induced Self-Healing Capacity and Ultraviolet Conducted Fluorescence Effect

Abstract In recent years, self-healing materials have attracted extensive attentions, however, the low elasticity and self-healing efficiency have limited their applications. Herein covalently crosslinked polyurethane (PU) composite networks were developed with ultraviolet (UV) initiated fluorescence effect and thermal induced self-healing capability. These smart PU networks were synthesized by polytetrahydrofuran glycol (PTMG) as soft segment, hexamethylene diisocyanate (HDI) as hard segment, incorporating with blue phosphate (BP) of SrAl2O4 doped with Eu2+, Dy3+. The physio chemical properties and self-healing process of polyurethane were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), atomic force microscope (AFM), optical microscope (OM), dynamic mechanical analysis (DMA) and tensile test. The results show that the network materials were successfully developed with high elastic tensile properties. After healing at 60°C for one hour, the PU network demonstrated a high healing efficiency of 80.9% and elongation at break of 970%. Moreover, the obtained hybrid networks emitted an intense blue light under UV with high fluorescent intensity. Additionally, the synergistic effect of transesterification of dynamic hydrogen bond provided the composite networks reproducibility for recycling use. This self-healing polyester material shows promising applications in the fields of diagnostic healing, anticounterfeiting, and optoelectronic components.