High-performance thermoplastic polyurethane elastomer/carbon dots bulk nanocomposites with strong luminescence

In this work, high-performance thermoplastic polyurethane elastomer/carbon dots (TPU/CDs) bulk nanocomposites with strong luminescence were fabricated via in situ polymerization. The CDs were synthesized from citric acid and 2-aminothiophenol. Transmission electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and systematic characterization indicated the formation of the CDs and the covalent conjugation of the CDs with TPU. The optical properties of the TPU/CDs nanocomposites were characterized by ultraviolet–visible and fluorescence spectroscopy. Compared to the initial solid-state CDs (the absolute photoluminescence quantum yields (QY): 20%), all the composites exhibited stronger luminescence behavior. When the CDs content was 0.5 wt%, the QY was as high as 68%. Furthermore, the rheological, mechanical, and thermal properties of the nanocomposites were investigated. The rheological properties established the structure–property relationships of the composites. The incorporation of the CDs enhanced the elastic response in viscoelasticity of the nanocomposites. The tensile strength of 1.0 wt% CDs loaded TPU increased from 18.2 MPa to 28.6 MPa, nearly 57% higher than that of the neat TPU. Given the excellent Ag+ detection performance of the CDs, the high QY and the processability of the nanocomposites, Ag+ detection experiments for the composite film were performed. The study will facilitate the applications of luminescent nanocomposites in potential fields.