Polyurethane-based thin-film composites with carbon micro- to nanoscale fillers and their microwave properties

Polyurethane-based thin-film composites (PUR-based TFCs) with different carbon fillers, namely, carbon flocs formed by carbon dots (CDs) containing O, N, and F heteroatoms and carbon nanotubes (CNTs), were prepared by hot pressing. The morphology and composition of the carbon fillers were investigated by SEM/EDX. Temperature-programmed desorption mass spectrometry and thermogravimetric analysis revealed that the CNTs have the highest thermostability among the fillers. Microwave studies in the X-band showed that the PUR-based TFCs with the CNTs were characterized by higher reflection losses and lower transmission losses than the PUR-based TFCs with the flocs formed by the studied CDs.